Indomethacin reduces ischemia-induced alteration of blood-brain barrier transport in piglets

Cerebral ischemia-reperfusion (Isc-Rep) alters blood-brain barrier (BBB) transport properties in piglets. Pretreatment with superoxide dismutase and catalase partially attenuates these effects. Activated O2 species produced with Isc-Rep in piglets are generated via prostaglandin (PG) H synthase. This experiment determines if products of PGH synthase alter BBB transport of sodium and albumin. Piglets anesthetized with nitrous oxide and halothane were divided into four groups: 1) control, 2) indomethacin (5 mg/kg iv) with no Isc-Rep, 3) Isc-Rep alone, and 4) Isc-Rep after pretreatment with indomethacin (Indo). Regional transfer coefficients (Kin) and regional cerebral blood flow (microspheres) were measured at 2 h reperfusion after 20 min total global cerebral ischemia. Kin values are represented as absolute values and also relative to blood flow to account for any changes in perfusion caused by ischemia and/or Indo. Indo alone did not alter sodium or albumin transfer compared with control animals. Isc-Rep alone caused a significant increase in sodium and albumin transport compared with all other groups (control cerebral sodium Kin was 18.2 +/- 2.7 cm3.g-1.s-1.10(6) vs. 32.9 +/- 3.1 for Isc-Rep, P < 0.05). In contrast, there was no significant difference in sodium or albumin transfer with Isc-Rep after Indo pretreatment (e.g., cerebral sodium Kin was 22.0 +/- 2.0 for Isc-Rep after Indo) compared with the control or Indo alone groups. Indo pretreatment effectively attenuates increased BBB transport of both sodium and albumin following cerebral ischemia. We conclude that products of PGH synthase are involved in BBB alterations of protein and cation transport that follow the early stages of cerebral reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of sympathectomy on the cutaneous temperature abnormalities in rats with chronic constriction injury of the sciatic nerve

Effects of surgical sympathectomy on the cutaneous temperature abnormalities of plantar surface evoked by the chronic constriction injury (CCI) of the sciatic nerve were investigated in the rat. In normal animals, there were very small temperature differences between both plantar surfaces. There were also very small temperature differences in plantar surfaces following the sympathectomy prior to CCI. In rats with CCI, the cutaneous temperature of the nerve-injured plantar surface was significantly higher (warmer) than that of the contralateral plantar surface during the first week following CCI, and then became lower (cooler). Surgical sympathectomy prior to and just after CCI significant suppressed the temperature abnormalities during the first week, but no effect was observed after 2 weeks following CCI. These observations indicate that sympathetic vasoconstriction may contribute to the cutaneous temperature abnormalities evoked by CCI during the early stage, but does not affect the abnormalities at later stages.

CO2 and cerebral circulation in newborn pigs: cyclic nucleotides and prostanoids in vascular regulation

The role of cyclic nucleotides and prostanoids in cerebrovascular reactivity to increased carbon dioxide was investigated in anesthetized and artificially ventilated newborn pigs equipped with closed cranial windows. Pial arteriolar diameter was measured, and cortical periarachnoid cerebrospinal fluid (CSF) was collected from beneath the cranial window for determination of adenosine 3',5'-cyclic monophosphate (cAMP), guanosine 3',5'-cyclic monophosphate (cGMP), and prostanoids. Progressively increasing arterial PCO2 (PaCO2) from normocapnia (33 +/- 1 mmHg) to hypercapnia (final PaCO2, 83 +/- 2 mmHg) resulted in dose-dependent pial arteriolar dilation and concomitant increases in cAMP, cGMP, and 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) in cortical CSF. N omega-methyl-L-arginine, N omega-nitro-L-arginine, N omega-nitro-L-arginine methyl ester, methylene blue, and LY 83583 did not inhibit cerebral vasodilation or the increases in cortical cAMP/cGMP induced by hypercapnia. Indomethacin abolished the vasodilatory response to hypercapnia and attenuated the hypercapnia-induced increases in cAMP and cGMP. Prostacyclin analogues increased both cAMP and cGMP levels in cortical CSF and induced pial arteriolar dilation (iloprost > carbaprostacyclin). The present data suggest that in newborn pigs cyclic nucleotides are involved in cerebral vasodilation in response to hypercapnia via a prostanoid-dependent mechanism.

Modification of striatal arginine and citrulline metabolism by nitric oxide synthase inhibitors

The effects of NG-substituted L-arginine (ARG) analogues on striatal ARG and citrulline (CIT) levels were investigated using in vivo microdialysis technique. A microdialysis probe was implanted into the striatum of anaesthesized Sprague-Dawley rats. Direct intrastriatal perfusion with 1 mM NG-nitro-L-arginine methyl ester (n = 8) increased striatal ARG release and decreased CIT release, suggesting suppressed NO synthase activity in the tissue. On the other hand, 1 mM NG-monomethyl-L-arginine (L-NMMA) (n = 6) evoked a persistent increase in both ARG and CIT. Considering that 4-320 microM L-ARG (n = 8) failed to increase CIT formation, CIT seems to be synthesized in the striatal tissue from L-NMMA by the enzyme that has been demonstrated in the kidney and aortic endothelium (NG,NG-dimethylarginine dimethyl-aminohydrolase).

Sustained release of phenytoin following the oral administration of phenytoin sodium/ethylcellulose microcapsules in human subjects and rabbits

Phenytoin sodium was microencapsulated with ethylcellulose (EC) by a coacervation-phase separation method from ethyl acetate solution to develop a prolonged release dosage form of phenytoin. Release of phenytoin from the microcapsules (phenytoin sodium/EC) was evaluated by the JP dissolution test in JP disintegration media No. 1 and No. 2. The release rates of phenytoin from phenytoin sodium powders were extremely rapid in both media, however, the release rates from the microcapsules were much more retarded. Following the oral administration of microcapsules to rabbits, prolonged plasma concentrations of phenytoin were obtained, while microcapsules orally administered to human subjects showed prolonged urinary excretion of phenytoin metabolites.

Evaluation of pulmonary arterial pressure in acute pulmonary embolism

Twenty-six patients with acute pulmonary embolism underwent hemodynamic examination. Twenty-three of the patients were free of prior cardiopulmonary diseases. The other 3 patients had prior history of cardiac disease. In the 23 patients, the mean pulmonary arterial pressure (PAm) ranged from normal range to 35 mmHg at the time of the embolic event and generally declined within ten days after the embolic event. However, in the 3 patients with a history of disease, reelevation of PAm was observed during the pressure monitoring. PAm was positively correlated with the extent of pulmonary vascular obstruction (r = 0.863, p < 0.01) and also with mean right atrial pressure (RAm, r = 0.830, p < 0.01). In the presence of prior cardiac disease, PAm in patients with normal preembolic PAm increased proportionally to the extent of obstruction. Continuous hemodynamic monitoring is valuable for estimating the degree of embolic obstruction and the speed of embolus resolution and for detecting new embolic episodes in some cases.

[Experimental study of peripheral nerve expansion with a tissue expander]

If a peripheral nerve could be elongated by a tissue expander (TE) without apparent damage, the length gained could be used to overcome a nerve gap without recourse to nerve graft. An experimental study was made to investigate whether this method for repairing a nerve gap is feasible. The tissue expander was designed by the authors and the median nerve of rabbits were stretched with TE at the rate of about 1 mm/day. The results showed that when the elongation rate was 18.4%, the motor nerve conduction velocity (MCV) was 67.8% and the myelinated nerve fibres (MNF) was 82.9% of the control nerves. In a further study nerve grafting and nerve expansion for repairing segmental nerve loss were compared with 10 mm defects. 4 months later the MCV, MNF, isometric contraction force (ICF) and muscle wet weight (MWW) were not significantly different between the 2 techniques. But with the 15 mm defects, elongated nerve were inferior to the nerve grafting method.

Clinicopathological study of proliferating cell nuclear antigen (PCNA) of hepatocytes in primary biliary cirrhosis

The DNA synthesis activities of hepatocytes in primary biliary cirrhosis (PBC) and other chronic liver diseases and control subjects were examined by staining proliferating cell nuclear antigen (PCNA) with anti-PCNA monoclonal antibody. The number of PCNA-positive cells (PCNA value) was significantly higher in PBC (375 +/- 281 parts per thousand; ppt) than in other chronic liver diseases, i.e., chronic hepatitis (95 +/- 83 ppt), liver cirrhosis (72 +/- 71 ppt), and alcoholic liver disease (73 +/- 56 ppt), and in control subjects (11 +/- 14 ppt). The PCNA value of PBC in stages I-III of Scheuer's classification was remarkably high, while in stage IV it was low. Even in identical, Scheuer's stages, the PCNA value of PBC was higher in patients who were not given ursodeoxycholic acid (UDCA) than in those who received UDCA. In identical patients, the PCNA value was lowered significantly after UDCA treatment. It was concluded that the DNA synthesis activity of PBC in stages I-III was accelerated and that UDCA can alleviate the abnormality in DNA synthesis activity.

Detection of human cytomegalovirus DNA in dried newborn blood filter paper

To detect human cytomegalovirus (HCMV) DNA, filter paper spotted with peripheral blood from newborns 4 to 7 days after birth was dried and subjected to the polymerase chain reaction (PCR) followed by Southern blot hybridization with a nonradioactive oligonucleotide probe. The detection rates were 25.1% in healthy individuals and 33.0% in low body weight neonates weighing not more than 2500 g at birth, most of whom appeared to have been infected transplacentally or by other means within the uterus. HCMV was detected after only heating the dried blood on the filter paper, and may be applied as a screening method for the early diagnosis of HCMV.

Light/dye microvascular injury selectively eliminates hypercapnia-induced pial arteriolar dilation in newborn pigs

Cerebral vasodilation in response to hypercapnia involves prostanoids in newborn pigs. This study examines the hypothesis that endothelial injury in vivo inhibits cerebral vasodilation and prostacyclin synthesis in response to hypercapnia, thus suggesting prostacyclin is a primary endothelium-derived vasodilating factor in newborn pig cerebral circulation. Anesthetized piglets with closed cranial windows were studied before and after injury caused by light/dye or before and after dye-only sham control. Light/dye injury was produced by injecting sodium fluorescein intravenously and passing filtered light from a mercury arc lamp through the cranial window. Ultrastructural changes to endothelium of pial vessels were produced that were characterized by surface pits, vacuolar cytoplasmic inclusions, and mitochondrial injury. After the light/dye injury, dilation to hypercapnia was absent while dilations to iloprost, isoproterenol, and sodium nitroprusside and constrictions to norepinephrine and acetylcholine were retained. Before light/dye treatment, hypercapnia increased cortical periarachnoid 6-keto prostaglandin F1 alpha concentration approximately threefold. However, after treatment, 6-keto-prostaglandin F1 alpha was not increased significantly in response to hypercapnia. These findings are consistent with the hypothesis that endothelial prostacyclin synthesis induced by hypercapnia participates in dilation of adjacent smooth muscle.

[Myocardial infarction in infective endocarditis]

Two patients with chronic valvular heart disease and myocardial infarction were assisted at our hospital. Both of them were febrile and only one had petechiae associated with signs of valvular involvement led to suspicion of infective endocarditis. Although blood cultures were negative, echocardiographic, surgical and anatomopathologic findings were compatible with infective endocarditis. They required cardiac surgery during the acute phase of the infection because they presented progressive hemodynamic deterioration and no satisfactory response to antimicrobial regimen too. One patient died at late follow-up (two weeks after the hospital discharge) and the other survived, but with signs of cardiac failure (class II of NYHA) one year after the procedure.

Gastrointestinal physiology-regulated dogs: utilization of a bioavailability study of a new thieno[3,2-f][1,2,4]triazolo[4,3-a][1,4]-diazepine, an antagonist of platelet-activating factor, and its preparations

The gastrointestinal (GI) physiology of beagle dogs was effectively regulated with a combined treatment using intramuscular pentagastrin (10 micrograms/kg x 2) and intravenous atropine sulfate (0.02 mg/kg x 1). The superiority of the GI physiology regulated-dogs over the intact dogs was confirmed by comparative bioavailability studies using two classes of preparations of poorly water-soluble 4-(2-chlorophenyl)-2-[2-(4-isobutylphenyl)ethyl]-6,9-dimethyl-6H- thieno[3,2-f][1,2,4]triazolo[4,3-a][1,4]diazepine (Y-24180). Both the fine granules and the tablets of Y-24180 exhibited similar absorption profiles in the intact dogs, whereas the latter preparations revealed a delayed plasma curve of the drug in the regulated-dogs. The absorption profiles of the two classes of Y-24180 preparations in the regulated-dogs simulated those in healthy volunteers. The combined-treatment of beagle dogs with pentagastrin and atropine sulfate was suggested to supply a useful animal model for predicting the absorption characteristics of poorly water-soluble drugs and their preparations in humans.

Inhibition of nitric oxide synthesis suppresses sleep in rabbits

The effects of N omega-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthesis, on spontaneous and interleukin-1 (IL-1)-induced sleep were examined in rabbits. Animals were injected intracerebroventricularly or intravenously during the light phase with vehicle, L-NAME, IL-1, or the combination of L-NAME and IL-1. Injection of L-NAME (5 mg icv and 100 mg/kg iv) suppressed both non-rapid eye movement sleep (NREMS) and rapid eye movement sleep (REMS) for 4-6 h. The sleep-suppressive effects are unlikely due to pressor responses to L-NAME because administration of L-NAME (5 mg icv) produced only a transient (3-4 min) slight increase in systemic blood pressure. Injection of IL-1 (20 ng icv) elicited fever, suppressed REMS, and increased NREMS for 6 h. NREMS was suppressed for 3 h after the combined intracerebroventricular injections of 5 mg L-NAME and 20 ng IL-1 and was elevated during postinjection hours 4-6. Administration of IL-1 (30 ng/kg iv) increased NREMS and brain temperature for 2 h. After the combined injection of IL-1 and L-NAME (100 mg/kg), NREMS was significantly suppressed during postinjection hours 1-5. It is not known whether the interactions between the sleep-suppressive effects of L-NAME and the NREMS-promoting effects of IL-1 are specific, being mediated via a common mechanism, or whether they are additive, being mediated via independent mechanisms. The pyrogenic and REMS-suppressive actions of either intracerebroventricularly or intravenously injected IL-1 were not affected by L-NAME.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinomycin D blocks interleukin-1 alpha-induced pial arteriolar dilation and increased prostanoid production in newborn pigs

Effects of protein synthesis and cyclooxygenase inhibitors on interleukin-1 alpha (IL-1 alpha)- and histamine-induced pial arteriolar dilation and cerebrospinal fluid (CSF) prostanoid increases were examined in anesthetized piglets using closed cranial windows. Topical IL-1 alpha (10.8 micrograms) increased pial arteriolar diameter from 15 to 30 min after its infusion, and enhanced CSF prostanoids. Topical protein synthesis inhibitor, actinomycin D, at a concentration of 10(-8) M attenuated and 10(-6) M completely blocked both IL-1 alpha-induced vasodilation and CSF prostanoid increase. Inhibition of prostaglandin H synthases with indomethacin blocked both vasodilation and CSF prostanoid increase by IL-1 alpha. Topical histamine (10(-6) M) also increased pial arteriolar diameter and CSF prostanoids but without the delay seen between IL-1 alpha infusion and responses. These histamine effects were not modified by coinfusion of actinomycin D but blocked by indomethacin. These results suggest that, although IL-1 alpha and histamine do share the same mechanism insofar as activation of prostaglandin synthesis is concerned, an additional step appears to be involved for IL-1 alpha, likely involving de novo protein synthesis.

Applicability of PM3 to transphosphorylation reaction path: toward designing a minimal ribozyme

A growing body of evidence shows that RNA can catalyze many of the reactions necessary both for replication of genetic material and the possible transition into the modern protein-based world. However, contemporary ribozymes are too large to have self-assembled from a prebiotic oligonucleotide pool. Still, it is likely that the major features of the earliest ribozymes have been preserved as molecular fossils in the catalytic RNA of today. Therefore, the search for a minimal ribozyme has been aimed at finding the necessary structural features of a modern ribozyme (Beaudry and Joyce, 1990). Both a three-dimensional model and quantum chemical calculations are required to quantitatively determine the effects of structural features of the ribozyme on the reaction it catalyzes. Using this model, quantum chemical calculations must be performed to determine quantitatively the effects of structural features on catalysis. Previous studies of the reaction path have been conducted at the ab initio level, but these methods are limited to small models due to enormous computational requirements. Semiempirical methods have been applied to large systems in the past; however, the accuracy of these methods depends largely on the system under investigation. In the present study we assess the validity of the MNDO/PM3 method on a simple model of the ribozyme-catalyzed reaction, or hydrolysis of phosphoric acid. We find that the results are qualitatively similar to ab initio results using large basis sets. Therefore, PM3 is suitable for studying the reaction path of the ribozyme-catalyzed reaction.

Cyclic nucleotides and cerebrovascular tone in newborn pigs

Relationships between cyclic nucleotides and cerebrovascular tone were investigated using closed cranial windows in anesthetized newborn pigs. Pial arteriolar diameter was monitored and cerebrospinal fluid (CSF) was collected from beneath the cranial window. Adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (cGMP) concentrations in CSF were 1,690 +/- 200 and 730 +/- 40 fmol/ml, respectively. Topically applied isozyme-selective and nonselective inhibitors [3-isobutyl-1-methylxanthine (IBMX), theophylline, Ro 201724, dipyridamole, zaprinast, calmidazolium, and W-7] of cyclic nucleotide phosphodiesterases dilated pial arterioles with concomitant increases in cAMP and/or cGMP levels in CSF. Topical application of dibutyryl-cAMP and dibutyryl-cGMP also resulted in pial arteriolar dilation. Ten-minute hypercapnia, which results in pial arteriolar dilation, increased cAMP to 5,240 +/- 900 and cGMP to 1,350 +/- 200 fmol/ml. IBMX and zaprinast potentiated the increases in cAMP and cGMP as well as the cerebrovascular dilation in response to hypercapnia. These data suggest that cyclic nucleotides contribute to regulation of cerebral vascular tone during control conditions. Furthermore, cAMP and/or cGMP appears to be involved in arterial vasodilation in response to hypercapnia in newborn pigs.

T-cell receptor V alpha region usage in the cerebrospinal fluid of patients with mumps meningitis

To investigate clonality of local T cells in viral infections of the central nervous system, the T-cell receptor (TCR) repertoire was evaluated in T cells from the cerebrospinal fluid (CSF) of nine patients with mumps meningitis, using the polymerase chain reaction (PCR) assay. The usage of the variable region of TCR alpha chain gene (V alpha gene) in the CSF was widespread, and an average of 13 out of the 18 V alpha families were expressed. Quantitative PCR analyses showed that the V alpha gene expression was biased toward three or less V alpha families in the CSF of each patient. When compared with peripheral blood T cells, the average percentages of V alpha 11 and V alpha 12 gene expression were significantly higher in the CSF than in the peripheral blood. These results suggested that mumps-specific T lymphocytes with a restricted TCR repertoire are selectively recruited to the central nervous system in mumps meningitis, although polyclonal, probably nonspecific, T-cell populations are present in the CSF.

Cerebral blood flow decreased by adrenergic stimulation of cerebral vessels in anesthetized newborn pigs with traumatic brain injury

Changes in cerebral blood flow (CBF), pial arteriolar diameter, and arterial blood pressure, gases, and pH were examined before and for 3 hours after fluid-percussion brain injury in alpha-chloralose-anesthetized piglets. The brain injury was induced by a percussion of 2.28 +/- 0.06 atm applied for 23.7 +/- 0.5 msec to the right parietal cortex. Regional CBF was measured with radiolabeled microspheres, and changes in pial arteriolar diameter were monitored in the left parietal cortex using closed cranial windows. Immediately following brain injury, mean blood pressure transiently (for approximately 10 minutes) either increased or decreased and then exhibited a prolonged decrease in all of the animals. The brains showed changes consistent with traumatic brain injury such as subarachnoid hemorrhage, contusions, or reactive axonal swelling; none showed histological evidence of a global alternative pathogenetic mechanism such as hypoxic ischemic damage. While CBF of uninjured control animals did not change over a 3-hour observation period, after brain injury blood flow decreased 30% +/- 1% below the baseline level within 10 minutes and remained there for 2 to 3 hours posttrauma. After adrenergic blockade, CBF did not decrease at any time during the 3-hour period in either the uninjured control or the injured animals. Concomitant with the decreased blood flow after brain injury, pial arteriolar diameter decreased 14% below the preinjury level. However, in piglets treated with adrenoceptor antagonists, uninjured control and brain-injured animals did not show a decrease in pial arteriolar diameter. The present results support the hypothesis that increased sympathetic outflow to the cephalic vasculature following the fluid-percussion brain injury causes cerebral vasoconstriction decreasing pial arteriolar diameter and regional CBF.

Subarachnoid blood causes pial arteriolar constriction in newborn pigs

BACKGROUND AND PURPOSE

The present study was designed to determine in newborn animals the delayed effect of subarachnoid blood on pial arteriolar diameter and eicosanoid concentrations in cortical periarachnoid fluid.

METHODS

Forty-eight to 96 hours after subarachnoid blood installation, closed cranial windows were implanted over the cerebral area exposed to blood in anesthetized, artificially ventilated newborn piglets. All pial arterioles greater than 60 microns in diameter were measured, and cortical periarachnoid fluid was collected for the determination of eicosanoids.

RESULTS

Subarachnoid blood resulted in a 20% to 30% decrease in the average diameter of pial arterioles exposed to blood for 48 to 96 hours, a decreased number of large pial arterioles (greater than 200 microns), and an increased number of small arterioles (60 to 100 microns). No changes in dilator prostanoids (prostacyclin [as 6-keto-prostaglandin F1 alpha] and prostaglandin E2) were detected. Concentrations of vasoconstrictor prostanoids in cortical cerebrospinal fluid increased. Thromboxane B2 increased to 430 +/- 70 pg/mL, and prostaglandin F2 alpha increased to 1370 +/- 180 pg/mL compared with 250 +/- 20 and 860 +/- 70 pg/mL, respectively, in the control group. The concentration of peptidoleukotrienes increased to 400 to 600 pg/mL 72 to 96 hours after blood installation, while the level in the control group was less than 80 pg/mL.

CONCLUSIONS

The altered balance between vasodilator and vasoconstrictor eicosanoids could contribute to cerebral vasoconstriction after subarachnoid blood installation in newborn pigs.

Phosphorylation of a 62 kd porcine alpha-internexin, a newly identified intermediate filament protein

A 62 kd protein was purified from the Triton-insoluble fraction of porcine brain white matter. This protein formed 10nm filaments, in vitro. The phosphorylation of the 62 kd protein by cAMP-dependent protein kinase caused electrophoretic mobility to shift to 66 kd on SDS-PAGE and a complete loss of the filament forming ability ensued. Amino acid sequences of four peptide fragments obtained from the 62 kd protein by lysylendopeptidase were identical with that of a 66 kd rat brain alpha-internexin. Amino acid analyses of the phosphopeptide fragment derived from phosphorylated porcine alpha-internexin revealed that the phosphorylation sites by cAMP-dependent protein kinase located in the amino-terminal head domain of this protein. These results strongly suggest that alpha-internexin polymerizes into 10nm filaments in vitro and that phosphorylation of the amino-terminal domain of alpha-internexin controls its polymerizability.

Quantitative analysis of herpes simplex virus DNA in cerebrospinal fluid of children with herpes simplex encephalitis

Herpes simplex virus (HSV) DNA in the cerebrospinal fluid (CSF) of children with herpes simplex encephalitis (HSE) was quantified and typed using the polymerase chain reaction (PCR) assay. During the acute phase, HSV-DNA was detected in the CSF of 13 patients with HSE, including 5 neonates. A restriction profile of the PCR products cleaved with the restriction enzymes XhoI and BglII showed that 2 neonatal samples were HSV-2, and the remainder were HSV-1. The amount of HSV-DNA in the initial CSF ranged from 10(2)-10(5) copies/ml. A significantly greater number of HSV-DNA copies was detected in neonates than in older children (mean 3.9 vs. 2.5, log 10 copies/ml p < .05). Except for one patient, the amount of HSV-DNA decreased gradually with acyclovir therapy. These results show that a quantitative PCR assay is applicable not only to the diagnosis of HSE but also for monitoring the response to antiviral drugs.