The investigation of post-thaw chilled storage and the applicability of large-scale cryopreservation in chub (Squalius cephalus) sperm.

Chub (reophillic cyprinids) is one of the most sensitive bioindicator fish of environmental changes following anthropogenic activities. The improvement of different biotechnological procedures could help support its conservation and strengthen the natural populations. The aim of this study was to compare the effects of two different hormonal agents (carp pituitary extract and Ovopel™) on various motility parameters (pMOT-%, DAP-µm, VCL µm s-1, VSL-µm s-1, LIN-%, ALH-µm, BCF-Hz) of fresh and cryopreserved/thawed sperm (stored at 4 °C for 6 h). Additionally, we sought to develop a novel, large-scale cryopreservation method for chub sperm, assessing freezing methods (Styrofoam box and a controlled-rate freezer) and different containers (0.5, 5 mL straw and 4 mL cryotube) for sperm cryopreservation. The results of this study indicated no difference between the carp pituitary extract and Ovopel treated groups in either the fresh or frozen/thawed sperm (at 0, 3, 6, hour post thawing, P = 0.4351). In contrast, the quality of the thawed chub sperm was negatively affected after 3 h chilled storage in both hormonal treatments (P = 0.0036, P < 0.0001). When assessing the motility parameters of the sperm between the 5 mL straw and 4 mL cryotube groups cryopreserved in a Styrofoam Box, no difference was observed (P = 0.103). Additionally, sperm loaded in 4 mL cryotubes showed no difference in motility when cryopreserved with either the Styrofoam box or controlled-rate freezer methods (P = 0.109). A similar hatching rate was observed in sperm preserved using the Styrofoam box (35 ± 7 %) and controlled rate freezer (25 ± 9 %) methods (P = 0.300). In a second fertilization trial, hatching rate was similar between control (72 ± 19 %) and cryopreserved (4 mL cryotube and Styrofoam box, 61 ± 5 %) groups. (P = 0.257). Based on our findings and its standard features (less species specific, precise dose calculation), Ovopel can be a good candidate for the stimulation of spermiation in chub sperm prior to cryopreservation. Furthermore, our study presents a novel and applicable method for the large-scale cryopreservation of chub sperm.

The systematic development and optimization of large-scale sperm cryopreservation in northern pike (Esox lucius).

In our study, a systematic development of a new large-scale sperm cryopreservation protocol was carried out in northern pike (Esox lucius). The effect of 2 sugar based (glucose and trehalose) extenders, 3 dilution ratios (1:3, 1:9 and 1:19) 2 vol straws (0.5 and 5 mL) and a 10 mL cryotube, 2 different cryopreservation methods (Polystyrene box-P. box and Controlled Rate Freezer-CRF), as well as 3 different thawing periods (3, 3.5 and 4 min) were investigated on the motility of thawed sperm. The glucose based extender showed significantly higher pMOT (1:3-18 ± 16%, 1:9-20 ± 13%, 1:19-16 ± 12%) at all dilution ratios than in the trehalose based extender (1:3-0.3 ± 1%, 1:9-1±1%, 1:19-4±2%). A similar tendency was recorded in VCL and STR at a ratio 1:3 and 1:9. No significant difference was measured in sperm movement between the P. box and CRF using the 0.5 mL straw. Similarly no significant difference was observed in all motility parameters with 10 mL cryotube frozen in CRF at a ratio 1:3-1:19. An effective and short thawing period (3 min) was experimentally specified for the 10 mL cryotube cryopreserved in the CRF. In all large-scale cryopreservation methods, high pMOT (straw CRF: 57 ± 10%, straw P. box: 50 ± 9%, cryotube CRF: 41 ± 10%), and STR were measured, and no significant difference was recorded in all motility parameters. Our results demonstrate the effectiveness of our newly developed extender and the applicability of 3 different large-scale cryopreservation methods in pike sperm. Our protocols could be new prospective candidates for future exploitation in hatchery practice.

The effects of different preservation methods on ide (Leuciscus idus) sperm and the longevity of sperm movement.

The present study investigated the effects of chilled storage and cryopreservation on ide sperm motility and fertilizing capacity alongside the longevity of sperm movement. The parameters of motility (progressive motility-pMOT, curvilinear velocity-VCL and straightness-STR) have been recorded during 48 h of chilled storage (4 °C) at 24-h intervals. The longevity of sperm movement was measured following activation for up to 120 s (in a range at 10-120 s) in freshly stripped and thawed sperm. A formerly established cryopreservation method was tested on ide sperm where motility parameters, hatching rate and larval malformation (according to 7 category groups) were investigated. Significant decrement of pMOT has already been observed after 24 h (6 ±â€¯5%) compared to the freshly stripped sperm (49 ±â€¯22%). pMOT and STR showed no significant changes for up to 120 s following activation in fresh sperm, whereas VCL showed significant difference between 10 (51 ±â€¯11 µm/s), 90 (33 ±â€¯3 µm/s) and 120 (31 ±â€¯4 µm/s) seconds as well as between 20 (48 ±â€¯12 µm/s), and 120 s. No negative effect of cryopreservation was recorded on pMOT (fresh: 49 ±â€¯19%, cryopreserved: 22 ±â€¯22%), VCL (fresh: 45 ±â€¯9 µm/s and cryopreserved: 57 ±â€¯5 µm/s), STR (fresh: 81 ±â€¯3% and cryopreserved: 92 ±â€¯1%) hatching rate (fresh: 22 ±â€¯15%, cryopreserved: 33 ±â€¯18%) or larval malformation (fresh: 12 ±â€¯4%, cryopreserved: 12 ±â€¯4%). No significant correlation was found between the three motility parameters and hatching rate. Cryopreservation had no effect on hatching and the prevalence of larval deformity. Furthermore craniofacial and eye deformities were characteristic in the group originating from fertilization with cryopreserved sperm, while edemas (pericardial, yolk) occurred more frequently in the control. The formerly developed cryopreservation protocol (method for cyprinids) was applicable to ide sperm.

Chilled and post-thaw storage of sperm in different goldfish types.

The effective storage time of sperm after stripping (for 48 hr in 6-hr intervals) and after thawing (for 6 hr in 2-hr intervals) in Black moor, Oranda and Calico goldfish types was investigated. Variations in sperm density were also measured in all lines. The efficiency of a sperm cryopreservation method formerly developed for common carp was recorded in all three goldfish lines. Motility parameters ((pMOT, %), curvilinear velocity (VCL, µm/s) and straightness (STR, %)) of Black moor sperm did not decrease significantly during 48 hr of storage. A significant reduction in the Oranda type compared to the fresh control was observed in pMOT after 42 (23 ± 2%) and VCL after 36 (94 ± 12 µm/s) hours (pMOT 84 ± 5%, VCL 150 ± 11 µm/s). In the Calico type, pMOT decreased significantly already after 18 (42 ± 26%) and VCL after 6 (105 ± 8 µm/s) hours (fresh: pMOT 92 ± 5%, VCL 151 ± 6 µm/s). A high pMOT immediately following thawing was measured in Oranda (46 ± 12%) and Calico (55 ± 15%) types, whereas a reduced pMOT was recorded in Black moor (24 ± 19%). In Calico, pMOT showed a significant reduction after 6 hr (19 ± 11%) in comparison with the initial value, with no changes observed in VCL and STR. None of the parameters changed in the Black moor and Oranda types. Evidence was found that different goldfish lines have different sperm quality and characteristics. Further studies can investigate the possible effects of chilled and post-thaw storage on the fertilizing capacity of sperm in the Black moor, Oranda and Calico goldfish types.

Commercial-scale out-of-season cryopreservation of Eurasian perch (Perca fluviatilis) sperm and its application for fertilization.

The quality and fertilizing capacity of perch (Perca fluviatilis) sperm collected outside of the spawning season (off-season) and cryopreserved at a commercial scale, were tested. Basic parameters (equilibration time, dilution ratio, sperm concentration, post-thaw motility duration) which can have a significant effect on cryopreservation success were systematically investigated for effects on sperm quality using computer assisted sperm analysis (CASA). No significant decrease in progressive motility (pMOT) and straightness (STR) of fresh-diluted sperm was recorded among groups equilibrated for 0, 30 or 60min in an extender with cryoprotectants. Curvilinear velocity (VCL) was reduced significantly after 30min (30min: 146±15µm/s, 60min: 124±18µm/s) of equilibration compared to the control (174±9µm/s). After thawing, no decrease in pMOT or VCL was observed at different equilibration times in any of the analyzed groups. No correlation was observed among progressive motility, dilution ratios (p=0.7) and cell concentrations (p=0.1). The use of different activating solutions resulted in similar pMOT and VCL in the first 120s post-thaw. Nevertheless, post-thaw sperm motility was reduced after 30s using all activators. Motility parameters with low variation were recorded after thawing of 57 straws (pMOT: 37±7%, VCL: 92±10µm/s, STR: 89±3%). Ten randomly selected straws from commercial-scale cryopreservation resulted in a high fertilization rate (cryopreserved sperm: 72±14%, fresh control: 94±2%). An optimized commercial-scale cryopreservation protocol was successfully developed for Eurasian perch. The applicability of the off-season collected perch sperm for cryopreservation and fertilization was demonstrated.

Comparison of two different methods in the cryopreservation of Eurasian perch (Perca fluviatilis) sperm.

Two different cryopreservation methods were compared and an optimal dilution ratio for the use of controlled-rate freezer (CRF) was established for Eurasian perch (Perca fluviatilis) sperm. Progressive motility (72 ± 15%) and curvilinear velocity (VCL, 146 ± 11 µm/s) of sperm cryopreserved with CRF did not reduce significantly compared to fresh sperm [progressive motility (90 ± 4%), VCL (173 ± 24 µm/s)]. On the other hand, progressive motility (62 ± 15%) and VCL (120 ± 21 µm/s) of sperm cryopreserved with the conventional floating frame technique were significantly lower when compared to the fresh control. Sperm in both cryopreserved groups showed significantly higher straightness [STR, CRF (84 ± 4%), frame (84 ± 2%)] than in the fresh control group (68 ± 4%). Perch sperm cryopreserved with CRF at a dilution ratio of 1:20 showed significantly higher progressive motility (49 ± 6%) than at a ratio of 1:5 (39 ± 6%) and showed significantly higher VCL (129 ± 11 µm/s) than at dilution ratios of 1:10 (112 ± 17 µm/s) and 1:5 (115 ± 9 µm/s).

Basic forms of supramolecular self-assembly organized by parallel and antiparallel hydrogen bonds in the racemic crystal structures of six disubstituted and trisubstituted cyclopentane derivatives.

A selection of stereoisomeric 2-hydroxy-1-cyclopentanecarboxamides, a 4-tert-butyl derivative and three tert-butyl derivatives of the respective carboxylic acid were subjected to X-ray crystallography. The optically active molecules (I)--(VI) form racemic crystals. Each racemic structure is basically determined by two intermolecular hydrogen bonds of O--H...O==C--XH and O==C--X--H...OH types (X = O, NH). The partially similar patterns of close packing observed reflect five basic forms of supramolecular self-assembly. In the racemic crystals of chiral molecules, there are homo- and heterochiral chains of molecules formed by the principal (O--H...O==C) hydrogen bonds. These chains assemble either in a parallel or antiparallel mode. The parallel homochiral chains (hop) observed in structure (II), (1R*,2R*)-2-hydroxy-1-cyclopentanecarboxamide, demand the polar space group Pca2(1), while the parallel heterochiral chains (hep) are organized in antiparallel layers with space group P2(1)/n in structure (VI), (1R*,2S*,5R*-5-tert-butyl-2-hydroxy-1-cyclopentanecarboxylic acid). Heterochiral chains in an antiparallel array (hea) are found in (I), (1R*,2S*)-2-hydroxy-1-cyclopentanecarboxamide, and (V) [(1R*,2S*4S*)-4-tert-butyl-2-hydroxy-1-cyclopentanecarboxylic acid, space group P2(1)/c]. Structures (IV), (1R*,2S*,4R*)-4-tert-butyl-2-hydroxy-1-cyclopentanecarboxylic acid, and (III), (1R*,2R*,4S*)-4-tert-butyl-2-hydroxy-1-cyclopentanecarboxamide, reveal that homochiral chains in an antiparallel array (hoa; cross-linked by heterochiral dimers held together by the second hydrogen bonds) can be formed by either translation (space group P1) or a screw axis (space group P2(1)/c). These alternatives are denoted hoa1 and hoa2. Similarly, within each pattern (hea, hep and hop) two slightly different alternatives can be expected. The partial similarities in the identified five patterns of hydrogen bonding are described by graph-set notations. Structures (I), (IV) and (V) can be characterized by a common supramolecular synthon, while the highest degree of similarity is shown by the isostructurality of (I) and (V).

[Preparation and steric structure elucidation of saturated or partially saturated isoindolo[2,1-a][3,1]benzoxazinones, -[1,2-b][2,4]benzoxazepinones, cyclopentane- and -cyclohexane[b]pyrrolo[2,1-a][3,1]-benzoxazines]. / Telített és részlegesen telített izoindolo[2,1-a] [3,1]benzoxazinok, -[1,2-b][2,4]benzoxazepinonok, ciklopentán- és -hexán[b]pirrolo[2,1-a][3,1]benzoxazin izomerek szintézise.

The reactions of 2-carboxybenzaldehyde (1) with 1,3- or 1,4-aminoalcohols (2a-i, 3a,b) were used to prepare partially or fully saturated tetra- and pentacyclic compounds containing a condensed 1,3-oxazino- or oxazepinoisoindolone moiety and one terminal saturated carbocycle. Isoindolo[2,1-a][3,1]benzoxazinones (4a-d, 6, 7), stereoisomeric isoindolo[1,2-b][2,4]benzoxazepinones (5a-c) hexahydrocyclopentane[b]pyrrolo[1,2-a][3,1]-benzoxazinone (10a,b), octahydroindolo[1,2-b]- and decahydroindolo[1,2-a]benzoxazinone (11a,b and 12a,b) and related pentacyclic derivatives (4e-g) were prepared. The diastereomers 5a-c differ in the ring annelation or in the position of the NCHO hydrogens and annelational hydrogens. The stereostructures of these compounds were elucidated by means of 1H and 13C NMR spectroscopy, including DNOE, DEPT, 2D-HSC measurements and X-ray analysis.

[Saturated heterocyclic compounds. 216 (1). Synthesis, structure and ring opening of trans-perhydro-1,4-benzoxazepin-3-one derivatives]. / Telített heterociklusok, 216 [1]. Transz-Perhidro-1, 4-benzoxazepin-3-on származékok szintézise és gyürüfelnyílása.

trans-Perhydro-1,4-benzoxazepin-3-ones 2a-e were synthesized and transformed to condensed-skeleton perhydro-trans-1,4-benzoxazepines 3a,b, the thiones 4a,b, the urea derivatives 5a,b, and N-acylated compounds 6a-e. Compounds 6b,d were ring-opened by hydrochloride acid in ethanol to yield trans-2 (1-carbethoxyethoxy)-1-(acylaminomethyl)-cyclohexane derivatives 7b,d. The 1H- and 13C-nmr investigation and X-ray analysis of 5b and 6c,d proved that the expected N-acylated derivatives were formed and that both rings of the annolated compounds have a chair conformation.

[Synthesis of quinazolino-1,3-benzothiazine derivatives]. / Kinazolino-1,3-benztiazinszármazékok szintézise.

The ring-closure reactions of N-(3,4-dimethoxyphenylthio-methyl)-2-nitrobenzamide derivatives 5a,b with phosphoryl chloride gave 4-(2'-nitrophenyl)-2H-1,3-benzothiazine derivatives 7a,b, which on reduction yielded 4-(2'-aminophenyl)-3,4-dihydro-2H-1,3-benzothiazines 8a,b. Reaction of these compounds with phosgene led to the derivatives 9a,b of a new heterocyclic ring system, 6H,8H-quinazolino[3,4-c] [1,3]benzothiazine. The structures of the title compounds were proved by their ir and nmr (1H, 13C) spectra.

[Synthesis of tert-butylcyclopentane-fused 1,3-oxazines and 1,3-thiazines]. / terc-Butil-ciklopentánnal kondenzált 1,3-oxazinok és 1,3-tiazinok szintézise.

Chlorosulphonyl isocyanate (CSI) addition to 4-tert-butylcyclopentene furnished the azetidinone (3) in a stereospecific reaction. Azetidinone 3 was transformed by ring opening esterification and lithium aluminium hydride (LAH) reduction to the 2-hydroxy-methyl-4-tert-butyl-1-cyclopentylamine (6). The N-methyl-aminoalcohol (8) was prepared from amino esters (5) with ethyl chloroformate and subsequent LAH reduction. By different ring-closure methods, a number of tert-butyl-cyclopentante-fused 1,3-oxazines and 1,3-thiazines were synthesized. A comparative study of the prepared compounds was performed by IR, 1H- and 13C-NMR, DEPT and DNOE measurements.

[Preparation and steric structure of condensed-skeleton saturated diphenyl-substituted isoindolones]. / Kondenzáltvázas telített difenilszubsztituált izoindolonok elöállítása és szerkezete.

The Friedel-Crafts reaction of benzene with cis-4-cyclohexene-1,2-dicarboxylic anhydride (1) yields trans-5-phenyl-cis-2-benzoylcyclohexanecarboxylic acid (2), which gave cyclohexane-condensed pyridazinone (3) with hydrazine, and cis-4,5-tetramethylene-1,2-oxazin-8-one (4) with hydroxylamine. From 2 with ethylenediamine, the saturated imidazol[2,3-a]iso-indolone (5) was prepared, while the reaction of 2 with 1,3-diaminopropane furnished a mixture of two isomeric pyrimido[2,3-a]isoindolones (6a,b) in the relative positions of the benzene ring and cyclohexane annelation hydrogens. From the reaction of 2 with 3-aminopropanol, the oxazino[2,3-a]isoindolone (7) was obtained. The reaction of 2 with cis-2-hydroxymethylcyclohexylamine gave the tetracyclic (8), while 2 and diendo-3-hydroxymethylbicyclo[2.2.1]hept-5-enyl-2-amine yielded the isomers (9a,b), which differ in the mutual positions of the phenyl group on the quaternary carbon and cyclohexane annelation hydrogens. 1H and 13C-nmr spectra and DNOE and 2D-HSC measurements proved that the 5-phenyl group is cis-equatorial to the two annelated hydrogens of the cyclohexane ring.

Effects of N-substitution on the fragmentations of some cyclohexene-fused 2-N-phenyliminoperhydro-3,1-oxazines and related thiazines.

Six cyclohexene-fused 2-N-phenyliminoperhydro-3,1-oxazines and four related thiazines were prepared and their mass spectrometric behavior was studied by means of metastable ion analysis and exact mass measurement. In most of the fragmentations, extensive rearrangements took place. The decompositions through the retro-Diels-Alder reaction initiated by the double bond dominated in the case of the unsubstituted compounds. The effect of the double bond, however, was greatly outweighed by the effect of the substituent on the ring nitrogen atom. In comparison with the unsubstituted compounds, both electron-releasing (methyl) and electron-withdrawing (benzyl) substituents increased the contribution of the ring cleavage reactions in the heterocyclic part of the molecule; in the case of the benzyl group the loss of the substituent also became important. For isomeric compounds, the relative peak intensities were so different that such compounds were easy to differentiate.

Increasing atrial pressure during cardiac tamponade does not elevate plasma levels of the peptide ANP in conscious dogs.

1. Factors influencing the release of atrial natriuretic peptide (ANP) are not well understood. We chose a conscious euvolaemic canine model of cardiac tamponade to investigate the roles played by atrial blood pressure, transmural atrial pressure, atrial size, and arginine vasopressin (AVP) on ANP release since during cardiac tamponade the atrial transmural pressure and size decrease as atrial pressure increases. The haemodynamic response to acute cardiac tamponade in conscious dogs differs from that in anaesthetized or convalescent animals. 2. Eighteen mongrel dogs were prepared for the chronic measurement of: ascending aortic blood flow (electromagnetic flowmeter); intrapericardial, right atrial and aortic blood pressures, and the evaluation of right atrial size (two-dimensional echocardiography). After the animals had recovered from surgery, data were collected during progressive cardiac tamponade induced by intrapericardial infusion of warmed saline (20 ml/min) to the point of haemodynamic decompensation. Decompensated cardiac tamponade (DCT) was defined as a decline in mean aortic blood pressure to 70% of the level present when the pericardial space was drained of fluid (baseline) and was produced in all animals within 25 min. Plasma ANP and AVP levels were measured at selected intervals. 3. Cardiac output decreased progressively as intrapericardial pressure, right atrial blood pressure and heart rate increased. Mean aortic blood pressure was well maintained until late in tamponade when it declined rapidly, while atrial transmural pressure and atrial size decreased continuously. These haemodynamic changes were associated with stable ANP plasma levels. There was no significant change in AVP plasma levels from the baseline level of 2.5 +/- 0.4 pg/ml until the point of DCT when they abruptly increased to 117 +/- 36.4 pg/ml. 4. The ability to increase ANP plasma levels was confirmed in a subgroup of animals by noting the response to AVP injection. Although the animals were able to increase plasma ANP levels in response to AVP injection (when intrapericardial pressure was normal) and the plasma AVP level was markedly increased late in tamponade, the time course of plasma AVP elevation could not explain why plasma ANP levels did not decrease as atrial transmural pressure and atrial size declined. 5. Thus, although atrial distention and not simply atrial blood pressure must play a dominant role in stimulating ANP release from the atria, decreased atrial size does not result in lowering of plasma ANP levels below baseline levels in this conscious euvolaemic canine model.

Coronary artery hemodynamics in conscious dog during cardiac tamponade.

We tested the hypothesis that coronary artery blood flow is sufficient to meet myocardial requirements throughout cardiac tamponade in a conscious euvolemic canine model recovered from surgery. Seven mongrel dogs were chronically instrumented to measure ascending aortic blood flow (electromagnetic flowmeter); intrapericardial, right atrial, and aortic blood pressures; regional myocardial blood flow (radionuclide labelled microspheres); and myocardial consumption of lactate, pyruvate, and oxygen. Data were collected during progressive cardiac tamponade induced by intrapericardial saline infusion to the point of hemodynamic decompensation. Decompensated cardiac tamponade (DCT) was defined as a decline in mean aortic blood pressure to 70% of the level present when the pericardial space was drained of fluid (baseline) and was produced in all animals within 25 minutes. Cardiac tamponade caused a continuous decline in coronary artery blood flow from 1.26 +/- 0.35 (baseline, mean +/- SD) to 0.53 +/- 0.15 ml/min/g (DCT, p less than 0.01), which was associated with a decrease in myocardial oxygen consumption from 1.26 +/- 0.35 (baseline) to 0.74 +/- 0.27 ml/min/g (DCT, p less than 0.05) and a slight increase in myocardial oxygen extraction from 71 +/- 3 (baseline) to 81 +/- 4% (DCT, p less than 0.05). This change in oxygen extraction occurred because of both an increase in arterial and a decrease in coronary venous oxygen content. At all degrees of cardiac tamponade, the lactate-pyruvate ratio did not change significantly from baseline (7.56 +/- 2.31), there was no evidence of lactate production, and the normal endocardial to epicardial blood flow ratio present at baseline (1.41 +/- 0.23) was preserved.(ABSTRACT TRUNCATED AT 250 WORDS)

Regional distribution of blood flow at the onset of right ventricular diastolic collapse during cardiac tamponade.

The onset of right ventricular diastolic collapse has been shown to be a very sensitive and specific sign of cardiac tamponade in both clinical and conscious canine studies, and is associated with a decline in cardiac output of about 20%. To determine if blood flow to critical regions was affected at the time of onset of right ventricular diastolic collapse, seven unanesthetized, chronically instrumented dogs were studied during cardiac tamponade induced by the intrapericardial infusion of warm saline solution. Aortic blood pressure, heart rate, and cardiac output (electromagnetic flowprobe) were recorded at baseline (drained pericardial space) and at the onset of right ventricular diastolic collapse as seen on two-dimensional echocardiography. Regional blood flow was measured with radionuclide-labeled microspheres. Despite the expected decline in cardiac output, there was no significant change in cardiac, renal, or cerebral cortical blood flow at the onset of right ventricular diastolic collapse. Therefore, this noninvasive marker of early cardiac tamponade begins before vital organ perfusion is compromised, thus strengthening its clinical value.

Influences on the distribution of blood flow during cardiac tamponade in the conscious dog.

Cardiac tamponade is a spectrum ranging from pericardial effusions with minimal hemodynamic impairment to effusions causing circulatory collapse. In this study, we examined the roles played by the sympathetic nervous system and the renin-angiotensin system in controlling the distribution of blood flow in chronically instrumented conscious dogs during progressive cardiac tamponade. Fifty-one episodes of acute cardiac tamponade were induced to decompensation (decline in mean aortic blood pressure to 70% of the level present when the pericardium was free of fluid) in 6 dogs by intrapericardial infusion of warmed saline solution. Cardiac output (electromagnetic flow probe), intrapericardial pressure, aortic and right atrial blood pressures, and renal, coronary, and mesenteric artery blood flows (Doppler flow probes) were recorded during tamponade in the absence of blockade (control), during alpha-adrenergic blockade (phenoxybenzamine), beta-adrenergic blockade (propranolol), or angiotensin-converting enzyme blockade (captopril). Aortic and mesenteric artery blood flow decreased progressively during cardiac tamponade regardless of the presence or absence of blockade. Coronary artery blood flow did not significantly change during alpha-adrenergic blockade, suggesting that the continuous decline observed during cardiac tamponade in the absence of blockade was at least in part mediated by alpha-adrenergic mechanisms. Renal artery blood flow, in contrast, was well maintained in all situations, confirming the importance of autoregulation in this vascular bed during cardiac tamponade.

Total peripheral resistance during cardiac tamponade: adrenergic and angiotensin roles.

During progressive cardiac tamponade in conscious dogs, cardiac output falls continuously while arterial blood pressure is maintained until cardiovascular decompensation by increases in total peripheral resistance (TPR). Plasma renin activity (PRA) is known to increase at decompensation. We hypothesized that the increase in TPR during cardiac tamponade was mediated by alpha-adrenergic and renin-angiotensin mechanisms. Twelve adult dogs were instrumented to measure cardiac output (electromagnetic flow probe), aortic and right atrial blood pressures, and intrapericardial pressure (IPP). TPR was calculated as the conscious euvolemic animals underwent cardiac tamponade induced by intrapericardial saline infusion at 20 ml/min. Six dogs underwent cardiac tamponade in the control condition (no medications) and during independent alpha- and beta-adrenergic and angiotensin-converting enzyme (ACE) inhibition. PRA and angiotensin II (ANG II) were measured during control tamponade. We found that TPR increased continuously to levels of greater than 200% of base line as IPP rose during cardiac tamponade (P less than 0.01). This increase in TPR was unaffected by beta-adrenergic or ACE blockade but was blunted by alpha-adrenergic blockade. PRA and ANG II increased only at decompensated tamponade (P less than 0.05) when arterial blood pressure had fallen by 30%. These changes in PRA and ANG II during tamponade were not altered by beta-blockade in six separate animals. We conclude that cardiac tamponade stimulates renin release and ANG II generation by a non-beta-receptor-mediated mechanism. The increase in TPR during cardiac tamponade is primarily dependent on alpha-adrenergic mechanisms, with a limited late contribution from the renin-angiotensin system.

The shift in the relationship between intrapericardial fluid pressure and volume induced by acute left ventricular pressure overload during cardiac tamponade.

We hypothesized that a process leading to an acute increase in cardiac size would change the relationship between intrapericardial pressure and fluid volume during cardiac tamponade, resulting in a change in the time of onset of right ventricular diastolic collapse (RVDC) as seen on the two-dimensional echocardiogram. Five spontaneously breathing dogs were instrumented to measure ascending aortic and right atrial blood pressures and intrapericardial pressure (IPP). A hydraulic occluder was placed around the proximal descending thoracic aorta. Each animal underwent six consecutive episodes of cardiac tamponade, three in the presence alternating with three in the absence of aortic constriction. The onset of RVDC was recorded and the volume infused into the pericardial space was measured. In the presence of aortic constriction, the relationship between pericardial pressure and incremental pericardial fluid volume was shifted so that IPP was an average of 3.4 mm Hg higher at any given intrapericardial fluid volume (p less than .001). At the onset of RVDC, the mean IPP was higher and the intrapericardial fluid volume was lower during aortic constriction than under control conditions (p less than .001 for both comparisons). Thus, a rapid increase in left ventricular volume in the presence of an otherwise unimportant pericardial effusion may increase intrapericardial fluid pressure sufficiently to cause RVDC.