Comparison of ischemic vulnerability and responsiveness to cardioplegic protection in crystalloid-perfused versus blood-perfused hearts

The possibility of differences between crystalloid-perfused and blood-perfused hearts in their vulnerability to ischemia and responsiveness to protective interventions has been investigated in isolated rabbit hearts perfused with bicarbonate buffer or arterial blood. In preliminary studies with 165 minutes of aerobic perfusion at constant perfusion pressure (55 +/- 3 mm Hg), the stability of left ventricular developed pressure was significantly better in blood-perfused hearts. In subsequent studies, hearts were subjected to 20 minutes of aerobic perfusion (coronary flow, 2.0 +/- 0.3 ml/min/gm wet weight in blood-perfused hearts versus 11.3 +/- 3.0 ml/min/gm wet weight in crystalloid-perfused hearts; left ventricular developed pressure, 90 +/- 4 and 91 +/- 2 mm Hg, respectively) followed by 30, 45, 60, 75, 90, or 105 minutes of normothermic global ischemia and 40 minutes of reperfusion (n = 4 per group). In the buffer-perfused groups the postischemic recoveries of left ventricular developed pressure were 74% +/- 6%, 45% +/- 7%, 39% +/- 6% 32%, +/- 5%, 27% +/- 4%, and 12% +/- 3% of preischemic control, respectively. In blood-perfused groups they were consistently greater (91% +/- 3%, 55% +/- 5%, 46% +/- 5%, 45% +/- 1%, 33% +/- 2%, and 19% +/- 3%, respectively). In further studies, hearts (n = 5 per group) were perfused with buffer (groups 1 and 2) or blood (groups 3 and 4), and each was subjected to 60 minutes of normothermic global ischemia, with (groups 2 and 4) or without (groups 1 and 3) a 3-minute preischemic infusion of St. Thomas' Hospital cardioplegic solution. After 60 minutes of reperfusion, the postischemic recoveries of left ventricular developed pressure in groups 1, 2, 3, and 4 were 32% +/- 3%, 44% +/- 4%, 43% +/- 7%, and 72% +/- 6%, respectively, with coronary flow recovering to 64% +/- 7%, 82% +/- 4%, 82% +/- 4%, and 110% +/- 5%, respectively. Left ventricular end-diastolic pressures were 20 +/- 5, 24 +/- 7, 15 +/- 4, and 4 +/- 3 mm Hg, and tissue water contents were 4.76 +/- 0.11, 4.87 +/- 0.55, 3.93 +/- 0.05, and 3.68 +/- 0.02 ml/gm dry weight, respectively. In conclusion, compared with crystalloid perfusion, the blood-perfused rabbit heart has a greater resistance to ischemia, a superior response to cardioplegic protection, and a lower tissue water content.

Nucleocytoplasmic transport: the influenza virus NS1 protein regulates the transport of spliced NS2 mRNA and its precursor NS1 mRNA

Influenza virus unspliced NS1 mRNA, like retroviral pre-mRNAs, is efficiently exported from the nucleus and translated in the cytoplasm of infected cells. With human immunodeficiency virus (HIV), the transport of viral pre-mRNAs is facilitated by the viral Rev protein. We tested the possibility that the influenza virus NS1 protein, a nuclear protein that is encoded by unspliced NS1 mRNA, has the same function as the HIV Rev protein. Surprisingly, using transient transfection assays, we found that rather than facilitating the nucleocytoplasmic transport of unspliced NS1 mRNA, the NS1 protein inhibited the transport of NS2 mRNA, the spliced mRNA generated from NS1 mRNA. The efficient transport of NS2 mRNA from the nucleus to the cytoplasm occurred only when the synthesis of the NS1 protein was abrogated by amber mutations. The NS1 protein down-regulated the export of NS2 mRNA whether or not it was generated by splicing, indicating that the NS1 protein acted directly on transport. Actinomycin D chase experiments verified that the NS1 protein acted on the transport and not on the differential stability of NS2 mRNA in the nucleus as compared to the cytoplasm. In addition, the NS1 protein inhibited the transport of NS1 mRNA itself, which contains all of the sequences in NS2 mRNA, particularly when NS1 mRNA was released from the splicing machinery by mutating its 3'-splice site. Our results indicate that the NS1 protein-mediated inhibition of transport requires sequences in NS2 mRNA. The transport of the viral PB1 protein, nucleocapsid protein, hemagglutinin, membrane protein, and M2 mRNAs was not affected by the NS1 protein. When the NS2 mRNA sequence was covalently attached to the PB1 mRNA, the transport of the chimeric mRNA was inhibited by the NS1 protein. Our results identify a novel function of the influenza virus NS1 protein and demonstrate that post-transcriptional control of gene expression can also occur at the level of the nucleocytoplasmic transport of a mature, spliced mRNA.

Vasectomy and spermatic granuloma in hamsters

Fifty-eight hamsters were bilaterally vasectomized either 1, 2, 3 or 6 months before experimentation. Fifty-five sham-vasectomized hamsters served as control. Cauda epididymal fluid was obtained by micropuncture. The effect of vasectomy on the incidence of spermatic granuloma was studied. The data were analyzed according to the presence or absence of granuloma after vasectomy and were compared with the data of their respective control. The incidence of granuloma increased with the duration of vasectomy and reached 92.8% at the end of 6 months after operation. Distension of the epididymis increased to a maximum at 1 month, but recovered to nearly normal irrespective of the existence of granuloma. The weight of the testis, spermatocrit and sperm density significantly decreased, and the percentage of abnormal sperm in the cauda and caput increased markedly in the absence of granuloma compared with their respective tract with granuloma or control. The testes in both the group with and without granuloma showed marked atrophy 6 months after vasectomy. The concentration of carnitine in the cauda epididymal plasma was significantly reduced from 2-6 months. The possible protective effect of a granuloma formation is discussed.

Morphometric study of cervical anterior horn cells and pyramidal tracts in medulla oblongata and the spinal cord in patients with cerebrovascular diseases

To clarify the effect of damage to the upper motor neurons on lower motor neurons, quantitative studies were made regarding the cross-sectional area and the number of the individual anterior horn cells in the lateral nuclear cell groups of the 5th segment of the cervical spinal cord (C5), and regarding the cross-sectional areas of the pyramidal tract in the medulla, and in the spinal cord at the C5 and L2 levels. The subjects included 45 patients with cerebrovascular disease (CVD), and 50 age-matched controls without neurological disease. The medullary pyramid (MP) and the ventral funiculus (VF), ipsilateral to the hemispheric lesion, were compared with the MP and VF of the other, unaffected, side. The ventro-lateral funiculus (VLF), anterior horn (AH) and C5 anterior horn cell (AHC), contralateral to the lesion, were also compared with the VLF, AH, and AHC of the other, unaffected, side. The AHC area (mean cross-sectional area of anterior horn cells) and the MP area, VF area, VLF area, AH area (mean cross-sectional areas of MP, VF, VLF and AH) associated with the hemispheric lesional side were significantly decreased, compared with those of the unaffected sides and the controls. However, there was no significant difference in AHC number between the affected and unaffected sides in patients with CVD, nor between the affected side and the controls. In order to examine the relationship between a decrease in AHC area and degree of paralysis, CVD patients were divided into two groups according to degree of muscle strength: the severe and mild paralysis groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Double exposure hologram of hyperbolic fringes and its use in the measurement of optical coherence

A hologram of hyperbolic fringes generated by double exposure is presented in this paper. The principle and experimental results of using it to measure optical coherence are given as well.

The influence of N-acetylcysteine on cardiac function and rhythm disorders during ischemia and reperfusion

To assess the ability of N-acetylcysteine to reduce the vulnerability of the heart to arrhythmias and improve its mechanical function during ischemia and reperfusion, groups of Langendorff-perfused rat hearts (15 per group) were subjected to 20 minutes of aerobic perfusion, 10 minutes of regional ischemia and 10 minutes of reperfusion. The hearts were perfused with N-acetylcysteine throughout the study. The incidences of ventricular premature beats and ventricular tachycardia induced by ischemia fell from 93% and 67%, in the N-acetylcysteine-free control group, to 40% and 27% with 8 microM N-acetylcysteine, to 33% and 27% with 80 microM N-acetylcysteine, and to 40% and 13% with 2000 microM N-acetylcysteine. The incidence of ventricular fibrillation induced by reperfusion was reduced from 93% to 60%, 67% and 47%, respectively. N-acetylcysteine had no significant effect upon the coronary flow and heart rate. When the ischemic period was prolonged to 30 minutes, N-acetylcysteine (8 microM) was shown to delay the time of onset of arrhythmias during ischemia and reperfusion. Thus, the incidences of ventricular premature beats and ventricular tachycardia were greatest after 15 minutes of ischemia in controls but were maximal after 18 minutes in hearts treated with N-acetylcysteine. N-acetylcysteine (8 microM) also improved the recovery of mechanical function after ischemia both in Langendorff preparations and in working preparations. In the working heart the post-ischemic recovery of aortic flow, coronary flow, cardiac output and aortic developed pressure after ischemia was improved from their control values of 30 +/- 5%, 82 +/- 2%, 43 +/- 2% and 63 +/- 4% to 59 +/- 7%, 98 +/- 5%, 71 +/- 3% and 80 +/- 6% respectively. Our results support the concept that agents which can alter redox state may exert protective effects against myocardial injury during both ischemia and reperfusion.