A clinical evaluation of sulbactam/ampicillin in the treatment of pediatric infections

We have treated 42 episodes of pediatric infections with sulbactam/ampicillin since 1987. Included were 9 cellulitis, 9 urinary tract infections, 5 cervical lymphadenitis, 4 meningitis, 2 thoracic empyema, 2 osteomyelitis, 2 sepsis, 1 furuncle, 1 perianal abscess, 1 dental abscess, 1 peritonsillitis, 1 salmonellosis, 1 shigellosis, 1 peritonitis, 1 suppurative thyroiditis, 1 infective endocarditis. Responsible pathogens were Escherichia coli in 8, Staphylococcus aureus in 6, Hemophilus influenzae in 2, Streptococcus pneumoniae in 3, Streptococcus viridans in 2, Staphylococcus epidermidis in 1, Bacteroides fragilis in 1, Salmonella D1 in 1, Shigella sonnei in 1, Klebsiella pneumoniae in 1, Enterobacter agglomerans in 1, Acinetobacter calcoaceticus in 1, Enterobacter cloacae in 1, group A beta-hemolytic streptococcus in 1, and polymicrobial infection in 4 cases. Thirty-nine out of 41 (95%) clinically evaluable patients cured and all (34/34) bacteriologically evaluable patients eradicated their pathogens after treatment with sulbactam/ampicillin. Side reactions were seen in five patients; one maculopapular skin rash, one hemolytic anemia, two diarrhea, and one liver function impairment plus leukopenia. All these reactions were transient and did not require interruption of therapy. These results indicate that sulbactam/ampicillin is safe and effective in the treatment of common pediatric infections beyond the neonatal period.

Oxidative and mitochondrial toxic effects of cephalosporin antibiotics in the kidney. A comparative study of cephaloridine and cephaloglycin

Cephaloridine and cephaloglycin are the two most nephrotoxic cephalosporins released for human use. Cephaloridine has been shown to produce both oxidative and mitochondrial respiratory injury in renal cortex in patterns of dose (or concentration) and time that are consistent with pathogenicity. Cephaloglycin also produces respiratory toxicity, and recent studies have provided evidence that this injury results from an inactivation of mitochondrial anionic substrate transporters. The abilities of cephaloglycin to produce oxidative changes and cephaloridine to block mitochondrial substrate uptake have not been examined yet. We therefore compared these two cephalosporins with one another and with cephalexin, which is not nephrotoxic, in the production of the following: (1) several components of oxidative stress or damage [depletion of reduced glutathione (GSH) and production of oxidized glutathione (GSSG) in renal cortex, inhibition of glutathione reductase in vitro, and production of the lipid peroxidation products malondialdehyde (MDA) and conjugated dienes (CDs) in renal cortex]; and (2) renal cortical mitochondrial toxicity [to both respiration with, and the transport of, succinate]. Cephaloridine depleted GSH and elevated GSSG in renal cortex, inhibited glutathione reductase, and increased both MDA in whole cortex and CDs in cortical microsomes and mitochondria. While cephaloglycin depleted GSH at least as much as did cephaloridine, it produced one-fifth as much GSSG and had little or no effect on glutathione reductase activity or on cortical MDA or microsomal CDs; cephaloglycin caused a transient small increase of mitochondrial CDs. Cephalexin produced no oxidative changes except for a slight increase of mitochondrial CDs comparable to that produced by cephaloglycin. Both cephaloridine and cephaloglycin, but not cephalexin, decreased the unidirectional uptake of, and respiration with, succinate in cortical mitochondria. We conclude that cephaloridine and cephaloglycin are both toxic to mitochondrial substrate uptake and respiration, but differ significantly in their generation of products of oxidation.

Polyethylene glycol-conjugated superoxide dismutase and catalase reduce ischemic brain injury

Superoxide dismutase and catalase enzymatically scavenge superoxide and hydrogen peroxide, respectively. Conjugation of polyethylene glycol to superoxide dismutase (PEG-SOD) or catalase (PEG-CAT) prolongs the circulatory half-life of the native enzymes and enhances their intracellular access. We studied the protective effect of these free radical scavengers on ischemic brain injury using a rat model of focal cerebral ischemia, which is suitable for therapeutic trials. Intravenous administration of PEG-SOD (10,000 U/kg) and PEG-CAT (10,000 U/kg) before ischemia reduced the infarct volume (treatment, 139 +/- 9 mm3, means +/- SE, N = 38; placebo, 182 +/- 8 mm3, n = 37, P less than 0.002). This finding supports the concept that superoxide and hydrogen peroxide contribute to brain injury following focal cerebral ischemia.

Conserved and unique sequences in the 3'-untranslated region of rat smooth-muscle alpha-actin mRNA

We have isolated a cDNA clone corresponding to rat smooth-muscle alpha-actin mRNA [Hsu and Frankel, J. Biol. Chem. 262 (1987) 9594-9600]. We present here the sequence of the 3'-untranslated region (3'-UTR) of the cDNA. By comparison with the reported sequence of the chicken gene, this 3'-UTR region contains a conserved 36-bp sequence and a unique 48-bp G + C-rich sequence. An RNA probe containing only the 3'-UTR of the cDNA was synthesized and shown to be specific for smooth-muscle alpha-actin message.

Oleic acid-induced pulmonary injury in rats: potential role of sulfidopeptide leukotrienes

Lung injury following intravenous oleic acid is characterized by pulmonary edema, leukopenia and hypoxemia. Because leukotrienes can increase permeability and cause leukocyte adherence, we evaluated their potential role in oleic acid-induced lung injury in the anesthetized rat using a selective LTD4/E4 antagonist, LY171883. 99mTc-albumin and 99mTc-red blood cells (99mTc-RBC) were used to measure changes in the pulmonary permeability index and intravascular space by non-invasive scintigraphy. Intravenous oleic acid (0.06 ml/kg) increased the pulmonary permeability index 11 (P less than 0.01) and 5.8 fold (P less than 0.01) at 5 and 50 min after its injection compared to baseline, but had no effect on mean pulmonary arterial pressure or pulmonary distribution of 99mTc-RBC. Oleic acid also induced arterial hypoxemia, and increased bronchoalveolar lavage-fluid levels of immunoreactive (i) leukotriene LTC4 from 0.40 +/- 0.14 ng/ml to 2.27 +/- 0.55 ng/ml (mean +/- S.E.M., n = 4, P less than 0.05) and iLTB4 (from 0.42 +/- 0.05 ng/ml to 1.91 +/- 0.63 ng/ml, n = 5-7, P less than 0.01). LY171883 attenuated the elevated permeability by 24% and 68% at 5 (P less than 0.05) and 50 min (P less than 0.01), but did not alter the hypoxemia. These results support the hypothesis that oleic acid elevates leukotriene levels which may increase pulmonary vascular permeability. Furthermore, they suggest that the prevention of elevated pulmonary vascular permeability and edema may be necessary, but are clearly not sufficient to prevent arterial hypoxemia following oleic acid injury in the rat.

Pentoxifylline in acute nonhemorrhagic stroke. A randomized, placebo-controlled double-blind trial

The efficacy and safety of pentoxifylline were assessed in 297 adult patients with ischemic stroke in a multicenter, double-blind, randomized and placebo-controlled trial. Treatment was started within 12 hours after the stroke onset. Study medication was administered intravenously continuously (16 mg/kg/day, maximum 1,200 mg/day) for 3 days and per os (400 mg t.i.d.) for the remainder of 28 days. Demographic data were comparable, and functional impairment and mortality (pentoxifylline 12%, placebo 10%) were not different between the two groups. Neurologic deficit scores improved from baseline admission scores during the 4-week study in both groups but did not differ between groups at admission or throughout the study except during the first few days when the consciousness level (Days 1 and 2), motor function (Days 1 and 2), cranial nerve function (Days 1-4), and total neurologic deficit scores (Days 1 and 2) were better in the pentoxifylline group than in the placebo group, especially in a subset of patients with severe deficits at admission. Laboratory values and side effects were also comparable between groups. Our study indicates that pentoxifylline can be given safely in patients with acute ischemic stroke. Although pharmacologic effects were present during the first few days, the clinical benefits were small and not sustained.

Regulation of alpha 2(I), alpha 1(III), and alpha 2(V) collagen mRNAs by estradiol in the immature rat uterus

We show that mRNAs for alpha 2(I), alpha 1(III), and alpha 2(V) collagens are regulated by estradiol in the immature rat uterus. Clones for alpha 2(I) and alpha 1(III) collagen were induced in a cDNA library prepared from estradiol-stimulated rat uterine mRNA. Alpha 2(I) collagen cDNA was identified by its characteristic hybridization pattern on Northern blots and hybridization to known probes. The sequence of alpha 1(III) collagen cDNA showed 91% amino acid sequence homology with the corresponding 525-nucleotide segment of human alpha 1(III) procollagen cDNA. Type I and type III collagen mRNAs were coordinately regulated, and showed peaks of induction at 4 and 24 hr. Three injections of estradiol, 24 hr apart, produced induction maxima 24 hr apart. The third induction, however, was suppressed relative to the first, suggesting that estrogen-stimulated factors may act to negatively regulate the uterine response to estrogen.

The mitochondrial respiratory toxicity of cephalosporin antibiotics. An inhibitory effect on substrate uptake

Cephalosporin antibiotics can produce renal cortical mitochondrial respiratory toxicity after either in vitro or in vivo exposure. In vitro toxicity is immediate, nonselective among toxic and nontoxic cephalosporins and reversed by substrate excess. In vivo toxicity is delayed, specific to the nephrotoxic cephalosporins and not reversible. Both routes of exposure affect respiration with succinate (S) more than with glutamate plus malate as substrates. Because glutamate and malate gain access to the intramitochondrial electron transport chain proximal to S, this pattern suggests that the cephalosporins affect a mitochondrial function outside the respiratory chain. A model of respiratory toxicity incorporating all of these features proposes that all cephalosporins can fit the affected transporters for mitochondrial substrate uptake, but, in the intact kidney, this causes limited or transient respiratory inhibition with nontoxic cephalosporins; in vivo toxicity, which is seen after later isolation and washing of mitochondria exposed in situ, develops with the more sequestered and reactive (nephrotoxic) cephalosporins that acylate these transporters. As a test of this hypothesis, studies were done, using the method of sieve filtration, to evaluate the effects of in vivo and in vitro exposure to cephaloglycin (toxic) and cephalexin (nontoxic) on the uptake of S and ADP by rabbit renal cortical mitochondria. In vivo and in vitro exposure to cephaloglycin reduced the net uptake of S by 70% and had a considerably smaller and less consistent effect on ADP uptake; cephalexin inhibited S uptake only with in vitro exposure. The rate of S washout from cephaloglycin-intoxicated mitochondria was no greater than from controls, ruling out increased efflux as a cause of decreased net uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Estrogen suppression of preincubated tadpole ovaries in vitro by cyanoketone

In a previous RIA study we found that cyanoketone (CK) inhibited ovarian E2 secretion of tadpoles in vitro and that this inhibition effect was through inactivation of delta 5-3 beta-HSD activity. A complete 100% inhibition was expected at a CK dosage of 0.1 microgram/ml of the medium, but, instead, it was 85%. The discrepancy might be due to the fact that the previous experiments did not preincubate the ovaries with CK in order to get rid of the residual E2. To this end, the present study was designed. Tadpole ovaries of Rana catesbeiana were preincubated with CK of a dosage of 0, 0.001, 0.01, 0.1, 1, or 10 micrograms/ml of the KRbb medium for 30 min. The media were discarded. Fresh media with the same series of CK doses were added to the ovaries and were incubated again for 6 hr. The media were collected for RIA of estrogen. The results showed the same tendency of estrogen inhibition as the previous study. However, a maximal inhibition effect of 95% was obtained at the dose of 0.1 microgram/ml. Therefore, the difference between non-preincubation of the previous experiments and preincubation of the present study does exist as we predicted.

Mechanisms of the bacterial endotoxin-cephaloridine toxic synergy and the protective effects of saline infusion in the rabbit kidney

To examine the mechanisms of the nephrotoxic synergy of bacterial cell wall lipopolysaccharide (LPS) (or endotoxin) and the cephalosporin antibiotics, we have studied: 1) the effects on mean arterial blood pressure and the clearances of inulin, p-aminohippurate and cephaloridine (Cld) of a 12%-lethal dose of Escherichia coli 0111-B4 LPS (0.05 mg/kg b.wt.i.v.), with both low and high rates of saline infusion (0.1 ml/min vs. a 7.5-ml/kg load followed by 0.4 ml/min, respectively, in approximately 2-kg rabbits); 2) the separate and combined effects of LPS and saline infusion on the concentrations of Cld in renal cortex and serum; and 3) the separate and combined effects of LPS and saline infusion on the nephrotoxicity of Cld, quantified by acute tubular necrosis scoring and serum creatinine concentrations 48 hr after treatment with 90 mg/kg of Cld i.v. and by mitochondrial respiratory toxicity, depletion of reduced glutathione and production of lipid peroxidation products in renal cortex 1 hr after treatment with 90 to 360 mg/kg of Cld i.v. The following was found: 1) the increased saline infusion (saline) largely prevented an LPS-induced fall of inulin clearance and partially prevented a fall of blood pressure and p-aminohippurate and Cld clearance; 2) as a result, saline prevented slightly elevated late serum and cortical Cld concentrations in LPS-treated animals; 3) the tubular necrosis and elevation of serum creatinine caused by Cld alone was reduced slightly and that produced by the combination of LPS plus Cld was reduced greatly by saline; 4) the comparable mitochondrial respiratory toxicity found after Cld and LPS-plus-Cld was prevented by saline infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Cloning of estrogen-regulated messenger ribonucleic acids from rat uterus

A cDNA library prepared from the mRNA of uteri of estrogen-stimulated immature female rats was constructed in lambda gt10. Differential screening of the hybrid phages was performed using control and stimulated cDNAs as probes. Selected clones were then characterized by Northern and Southern blot hybridizations. In all, eight unique clones corresponding to estrogen-stimulated messages in rat uterus were identified. These clones hybridized to uterine mRNAs varying in size from 1.4-8.4 kilobases. Three of the clones were characterized as coding for three different types of collagen, and one as coding for smooth muscle actin. These are described in more detail elsewhere. The kinetics of increase in estrogen-regulated messages was examined. After a single injection of estradiol, five clones, including the three collagen mRNAs, showed two peaks of accumulation, at 4 and 24 h. Messages of two other clones were maximal at 12 h. The actin clone hybridized to mRNAs with peaks at 4 h for cytoskeletal actins and 8-12 h for smooth muscle actins. Sequential 24-h injections of the hormone produced multiple peaks of mRNA accumulation with a timing consistent with the kinetics found after a single injection of hormone. The multiple injections, however, did not result in enhanced mRNA accumulation for any of these clones. In fact, several messages showed suppressed accumulation with continued estradiol administration. Accumulated inhibitory factors in uterine cells may be responsible for this refractory condition. Except for the actin mRNA, the estradiol-stimulated mRNAs were expressed mainly in uterus and ovary. These clones may be useful in studies on the mechanism of action of estrogenic hormones and their tissue-specific regulation of gene expression.

Selective cortical infarction reduces [3H]sulpiride binding in rat caudate-putamen: autoradiographic evidence for presynaptic D2 receptors on corticostriate terminals

Although the existence of presynaptic D2 dopamine receptors on corticostriate terminals has been supported by numerous receptor-binding studies, recent autoradiographic data has failed to demonstrate loss of striatal D2 receptors following cortical lesions. In the present study, Long-Evans rats were subjected to unilateral middle cerebral artery (MCA) infarction in order to produce reproducible lesions of the neocortex without damaging subcortical structures. Animals were sacrificed 2 and 4 wk following lesion and brains were prepared for receptor autoradiography. D2 receptors were studied using the selective ligand [3H]sulpiride, while D1 dopamine receptors were examined using [3H]SCH 23390. Sodium-dependent, high-affinity choline uptake sites were labeled with [3H]hemicholinium-3, thereby providing a quantitative measure of cholinergic neuronal integrity. Unilateral cortical infarction resulted in approximately a 20% reduction in [3H]sulpiride binding in several discrete regions of the ipsilateral caudate-putamen (CPu), but not in the nucleus accumbens. D2 receptor binding was also reduced significantly in some areas of the contralateral CPu when compared with [3H]sulpiride binding in sham-operated, control animals. In contrast, D1 receptors (as identified by [3H]SCH 23390 and high-affinity choline uptake sites (labeled with [3H]-HC-3) were not affected by the cortical lesion. The results provide autoradiographic confirmation of the existence of presynaptic D2 receptors on corticostriate terminals.

Moyamoya disease in Taiwan

Moyamoya disease occurring in Chinese has been inadequately described. Here we report 13 cases of this disease identified by review of 3,200 cerebral angiograms performed between August 1979 and March 1986. Nine were males and four were females; there were 12 adults (aged 34-51 years) and one child (aged 11 years). All had hemorrhagic strokes with one exception, a patient with an occipital infarction. Intraventricular hemorrhage was noted by computed tomography in 10; five of these emanated from the caudate nucleus. A localized hematoma without intraventricular hemorrhage was found in two. All 13 angiograms had smokelike basal anastomoses with various degrees of stenosis or occlusion of the anterior portion of the circle of Willis; the involvement was bilateral in 12 and unilateral in one. Aneurysms were found in two patients, one in the anterior communicating artery and the other in the left anterior choroidal artery. Eleven patients recovered from the initial stroke, but two died with recurrent hemorrhage. This series differs from the series reported in Japan by the predominance of adult males. The high incidence of intraventricular hemorrhage and intracerebral hematoma is not in keeping with the previous Chinese series, in which subarachnoid hemorrhage was suspected to be the major clinical manifestation.

Temporal profile of thromboxane-prostacyclin imbalance in experimental spinal cord injury

Thromboxane-prostacyclin imbalance may be an important determinant of platelet-vessel wall interactions that are vital in circulatory homeostasis. In experimental spinal cord injury, the vascular damage contributes substantially to the process of progressive secondary injury culminating in post-traumatic myelopathy. In this study, we found a time-dependent alteration of thromboxane-prostacyclin balance in the injured spinal cord with thromboxane dominance during the first 2 h: a time when maximal vascular injury is reflected by extravasation of 125I-labelled serum albumin. The thromboxane-prostacyclin imbalance reverted to favor prostacyclin by 18 h post-injury. This time-dependent alteration of thromboxane-prostacyclin balance should be considered in the planning of therapeutic attempts to prevent secondary injury by pharmacological modulation of platelet-vessel wall interaction.

In vitro inhibition of estradiol secretion of tadpole ovaries by cyanoketone

We have demonstrated the presence of delta 5-3 beta-hydroxysteroid dehydrogenase (HSD) activity in tadpole ovaries of Rana catesbeiana. In the present study, we wish to determine whether estradiol (E2) secretion of tadpole ovaries could be influenced by cyanoketone (CK), a specific inhibitor of delta 5-3 beta-HSD. R catesbeina tadpoles at the premetamorphic climax were used, and pooled ovaries were incubated, 30 mg/tube, with CK at dosages of 0, 0.001, 0.01, 0.1, 1, and 10 micrograms/ml of Krebs-Ringer bicarbonate buffer for 6 hr. Media were collected for assay of E2 by radioimmunoassay (RIA). Results showed an inhibition of E2 secretion by CK that was positively correlated with CK dosage, but plateaued at doses of 0.1 microgram/ml and higher. This finding was comparable to that of G.F. Young, H. Kagawa, and Y. Nagahama (1982, Gen. Comp. Endocrinol. 47, 357-360) on adult fish ovaries. However, adult vertebrates depend on gonadotropins to regulate secretion of E2 while tadpoles, being immature, might secrete E2 independently of pituitaries. When the histochemical test for delta 5-3 beta-HSD activity was performed on in vitro CK-treated ovaries, there was a decrease of enzyme activity by CK. The RIA and histochemical findings may contribute to the concept of sex transformation in which a disturbance of steroidogenesis may induce sex reversal from females to males, at least in tadpoles.

Contrasting effects of ACTH and cyanoketone on delta 5-3 beta-hydroxysteroid dehydrogenase activity in interrenal glands of tadpoles of Rana catesbeiana in vitro

The present communication describes an investigation of stimulation and inhibition of delta 5-3 beta-hydroxysteroid dehydrogenase in interrenal glands of tadpoles of Rana catesbeiana. Frozen sections of interrenal glands, together with kidneys, were prepared histochemically for assay of delta 5-3 beta-HSD activity. Concentrations of 0.01, 0.1, 1, and 10 IU/ml of ACTH or of 0.01, 0.1, 1, and 10 micrograms/ml of cyanoketone were added to the incubation media. The reaction products of the histochemically prepared slides, in terms of absorbance, were scanned at a defined area with a computerized microscope spectrophotometer. The results indicate that ACTH causes a significant dose-response stimulation of delta 5-3 beta-HSD activity in tadpole interrenals; cyanoketone, on the other hand, causes significant dose-dependent inhibition.

The multimolecular cascade of spinal cord injury. Studies on prostanoids, calcium, and proteinases

Experimental spinal cord injury in animals induced by weight drop produces neurological deficit and paralysis. Correlation of the progressive morphological changes in the lesion by both light and electron microscopy with the biochemical alterations revealed ischemia, edema, hemorrhage, tissue necrosis, granular changes in axons, vesicular degeneration of myelin and axonal calcification. The biochemical pathology was that of degradation of axonal (neurofilaments) and myelin proteins (MBP and PLP) with increased activities of proteolytic enzymes and particularly the neutral proteinase. The level of total calcium increased progressively in the lesion to a peak at 8 hrs. and subsequently remained constant thereafter. The capacity of calcium for activating proteinases and lipases and fostering the degradation of axon and myelin proteins as well as the liberation of arachidonic acid required for the synthesis of prostanoids must be relevant. An increased production of prostanoids is indicated by elevation of thromboxane (TxB2), a stable metabolite of TXA2 at 1 hour after injury. The 6-keto-PG1(1)a was also increased but to a lesser extent. We suspect that the activation of arachidonic acid metabolism contributes to post-traumatic vascular injury and the progressive ischemia. These putative roles for calcium in proteolysis and lipolysis, inducing degradation of macromolecules and production of prostanoids which initiate edema, lysolecithin a myelinolytic factor and mitochondrial dysfunction in spinal cord injury are discussed.

Effect of estrogen on the expression of mRNAs of different actin isoforms in immature rat uterus. Cloning of alpha-smooth muscle actin message

Cytoplasmic beta- and gamma-actin mRNAs as well as smooth muscle actin mRNAs have been shown to be transiently increased in rat uterus after treatment with the steroid hormone estradiol. A clone isolated as an estradiol-induced message from a lambda-gt10 cDNA library prepared from the mRNA of estrogen-stimulated immature rat uterus was identified as alpha-smooth muscle actin. A single-stranded RNA probe composed mainly of the 3'-untranslated region of this clone, as well as DNA probes derived from the 3'-untranslated regions of other actin genes, were used to study the induction kinetics of different actin isoforms in rat uterus after being stimulated by estradiol. The beta- and gamma-cytoskeletal actins showed an induction peak at 4 h after estradiol administration with 1.4- and 1.8-fold increases, respectively. The smooth muscle actin was maximally increased 2.1-fold at 8-12 h. Messages of alpha-skeletal and alpha-cardiac actins were neither expressed nor induced by estradiol in this tissue. The different induction kinetics of the cytoplasmic and smooth muscle actins suggest that they are regulated by different mechanisms and possibly in different cell types of the uterus.

Brain calcium content in ischemic infarction

Three degrees of focal ischemic infarction in the rat were created in the cerebral cortex supplied by the right middle cerebral artery, by ligation of the right middle cerebral artery and the right common carotid artery and temporary clip compression of the left common carotid artery, in succession. The postischemic accumulation of calcium in cerebral cortex of the right middle cerebral artery territory, determined by atomic absorption spectrometry, correlated with the infarct volume. The results are consistent with the hypothesis that calcium has role as a mediator in the pathogenesis of cerebral infarction.

Intravenous prostacyclin in acute nonhemorrhagic stroke: a placebo-controlled double-blind trial

The therapeutic efficacy of prostacyclin in nonhemorrhagic cerebral infarction was assessed in a placebo-controlled double-blind trial. A total of 80 patients with stroke onset within 24 hours were randomized into placebo (37 patients) and prostacyclin (43 patients) groups. Demographic data and risk factors were comparable. Patients in the prostacyclin group received a continuous i.v. infusion of prostacyclin at an average rate of 8.5 ng/kg/min for an average of 64 hours. The placebo group received vehicle only in a similar fashion. During treatment hemodynamic changes were more prominent in the patients receiving prostacyclin and included reduction of systolic and diastolic blood pressure and increase in pulse rate. In contrast there was only a slight (but significant) reduction of diastolic blood pressure in the placebo group. Neurologic deficit scores were determined on admission, at Day 3, and at Weeks 1, 2, and 4. Mean neurologic deficit scores upon entry were comparable in the placebo and prostacyclin groups, and a significant improvement in the score for neurologic deficit was noted in both. The placebo group tended to fare better throughout the study, with a significant difference in neurologic deficit score favoring the placebo group at Week 2 (p = 0.0048). Two patients in the placebo and one in the prostacyclin group died. The only difference in adverse reactions was flushing (6 patients in prostacyclin vs. 0 in placebo group, p less than 0.05). The results of this study suggest a lack of therapeutic efficacy of prostacyclin in a defined population of patients with nonhemorrhagic cerebral infarction.

Therapeutic model for experimental spinal cord injury in the rat: I. Mortality and motor deficit

In the course of establishing a therapeutic model for experimental spinal cord injury in the rat, we determined the effects of trauma dose (20, 30, 40, 50, and 60 g-cm) on the mortality and motor deficit in the 4 weeks following injury. Mortality was dependent upon the trauma dose: 20 g-cm, 11%; 30 g-cm, 14%; 40 g-cm, 27%; 50 g-cm, 32%; 60 g-cm, 41%. Statistical analysis by linear regression is highly significant for increasing mortality with increasing trauma dose. The motor deficit determined by a modified Tarlov scale also was dependent upon trauma dose. A trauma dose-response curve based on this study indicates that a drug which reduces the motor deficit from that found at 40 g-cm to that at 30 g-cm may be detected at a significant level of 0.05 with a power of 0.8 if 30 rats are included in each of placebo and treated groups. The same sample size would detect a significant reduction of mortality from that of 40 g-cm to 30 g-cm.

A model of focal ischemic stroke in the rat: reproducible extensive cortical infarction

In the search for a more reproducible focal ischemic stroke model in the rat, we systematically interrupted blood flow to the right middle cerebral artery territory by ligating the right middle cerebral artery, and the right and left common carotid arteries in succession. Using a laser-Doppler flowmeter, we found that the relative surface blood flow in cerebral cortex supplied by the right middle cerebral artery decreased to 62, 48, and 18% of baseline respectively after successive ligation of the right middle cerebral artery, and the right and left common carotid arteries. A focal infarct in the cerebral cortex supplied by the right middle cerebral artery was consistently noted after ligation of the right middle cerebral and the right common carotid arteries and temporary clip occlusion of the left common carotid artery for 60 min. The surface areas of infarction measured 100 +/- 6 mm2 and the maximal cross-sectional area of infarction was 10.4 +/- 1.1 mm2 (N = 10). The mortality rate was 7% (N = 70). The characteristic changes of ischemic necrosis were limited to the cortex with sparing of subcortical structures. No motor deficits occurred. Occlusion of the right middle cerebral artery alone or together with the right common carotid artery did not consistently cause gross infarction and the maximal cross-sectional area of infarction was smaller (the right middle cerebral artery, 1.7 +/- 0.8 mm2, N = 10; the right middle cerebral artery plus the right common carotid artery, 4.8 +/- 1.9 mm2, N = 10). Permanent ligation of the right middle cerebral artery and both common carotid arteries had a high mortality (60% in 3 days, N = 10).(ABSTRACT TRUNCATED AT 250 WORDS)

Increased thromboxane level in experimental spinal cord injury

An increased accumulation of tissue thromboxane A2 occurred shortly after spinal cord injury. Prostacyclin formation was not affected. The magnitude of the increase in thromboxane and the extent of post-traumatic vascular damage as determined by extravasation of 125I-labeled human serum albumin were both dependent on the degree of injury. These findings raise the possibility that activation of arachidonic acid metabolism with a preponderance in thromboxane formation may contribute to microvascular injury in experimental spinal cord contusion.

Thromboxane, prostacyclin, and leukotrienes in cerebral ischemia

Our understanding of the biochemistry and biologic actions of AA metabolites has been greatly expanded in recent years. The discoveries of TXA2, PGI2, and LTs have fostered new concepts of the pathophysiology of cerebral ischemia. New approaches to treatment of ischemia include seeking an optimal dose of aspirin, developing drugs that selectively inhibit or antagonize TXA2 or LTs, and administering PGI2 or its analogues. Altering the dietary content of essential fatty acids for prophylaxis is also being studied. Though the results of this thrust are still preliminary, the exploration of these therapeutic strategies in cerebrovascular disorders based on further understanding of the pathophysiologic roles of TXA2, PGI2, LTs and probably other AA metabolites is anticipated with some optimism.

Spondylotic high cervical spinal cord compression presenting with hand complaints

Three patients with spondylotic compression of the upper cervical spinal cord presented with complaints of sensory dysfunction in their hands. Sensory dysfunction in the hands may signal a lesion in the upper cervical spinal cord if other common neurological causes can be excluded. Somatosensory evoked potentials may be useful in providing objective information to supplement subjective complaints in the hands caused by a high cervical lesion.

Vascular permeability in experimental spinal cord injury

Following spinal cord injury in rats there was a time-dependent change of vascular permeability as reflected by extravasation of 125I-labelled serum albumin. The change of vascular permeability correlated with tissue calcium and water accumulation suggesting that cord exposure to plasma calcium as a consequence of vascular injury may contribute to the progressive post-traumatic cord necrosis.

Augmentation of antibiotic nephrotoxicity by endotoxemia in the rabbit

The acute renal failure complicating bacterial septicemia has multiple potential causes, prominent among which are endotoxemic and antibiotic nephrotoxic injury. Because the toxic interactions of endotoxin and antibiotics cannot be manipulated for study in human disease, we have developed a model of this interaction in the rabbit. Toxicity was assessed by quantification of tubular necrosis and serum creatinine concentrations 48 hr after single-dose i.v. endotoxin and/or antibiotic administration. A minimally nephrotoxic quantity of endotoxin (Escherichia coli lipopolysaccharide 0111:B4, 0.5 mg/kg b.w.) significantly increased the nephrotoxicity of the cephalosporins cephaloglycin (60 mg/kg) and cephaloridine (90 mg/kg) and the aminoglycoside neomycin (60 mg/kg), each of which was mildly-to-minimally damaging by itself. In studies of the acute functional effects of endotoxemia, the lipopolysaccharide had different effects on the renal handling of the two cephalosporins. Endotoxin increased the uptake of cephaloglycin, but decreased uptake of cephaloridine, in renal cortex in the first 0.5 hr after antibiotic administration. However, a prolonged elevation of serum levels of cephaloridine allowed later uptake of toxic amounts of this cephalosporin. Although these findings suggest a role of altered transport in the endotoxin-cephalosporin toxic synergy, the synergy was not reduced when cephaloglycin was given 1.5 hr before the endotoxin, a time which allows substantial elimination of antibiotic before the endotoxemic insult. Studies in another laboratory have demonstrated an endotoxin-induced increase of cortical concentrations of aminoglycosides, which could be a mechanism of the augmented toxicity seen in the present study. It is concluded that endotoxemia causes significant augmentation of the nephrotoxicity of cephalosporin and aminoglycoside antibiotics.(ABSTRACT TRUNCATED AT 250 WORDS)

Alteration of thromboxane and prostacyclin levels in experimental spinal cord injury

We measured levels of thromboxane B2 and 6-keto-PGF1 alpha in rabbit spinal cord and cat CSF after impact injury to spinal cord. Rabbit tissue thromboxane B2 levels increased more than 6-keto-PGF1 alpha. In cat, CSF thromboxane B2 was higher the first hour postinjury; CSF 6-keto-PGF1 alpha also increased, but less so. These results imply activation of arachidonic acid metabolism. The relatively greater increase of thromboxane B2 suggests that thromboxane-prostacyclin imbalance may contribute to post-traumatic ischemia.

In vitro estradiol synthesis and secretion by tadpole ovaries of different developmental stages

The tadpole ovaries at TK stage XIX can synthesize and secrete estradiol (E2), yet it is unknown when this ovarian function starts and how it develops. To this end, the present work has been carried out. The ovaries of different developmental stages of tadpoles and young frogs of Rana catesbeiana were taken, cut into small pieces, and incubated for 6 hr at 20 degrees in Krebs-Ringer bicarbonate buffer. The media were then analyzed for E2 by radioimmunoassay. The results indicate that the tadpoles synthesize and release E2 as early as stage X, that E2 increases slowly and gradually through stage XXV, and that E2 increases rapidly in juvenile frogs. This trend of growth of the ovarian function in estradiol secretion in vitro is in accordance with that reported for female chick embryos. There exists the possibility that the growth of E2 secretion could be biphasic, one with slow increment of autonomous E2 secretion at early stages and the other with quick increase due to pituitary stimulation at the stage of metamorphic climax.

The development of ACTH-like substance during tadpole metamorphosis

The interrenals of tadpoles of Rana catesbeiana at various developmental TK stages were frozen, sectioned, and prepared histochemically for assessment of delta 5-3 beta-hydroxysteroid dehydrogenase (delta 5-3 beta-HSD) activity. The interrenals of hypophysectomized (HX) tadpoles from the same batch of eggs as control tadpoles were prepared similarly for delta 5-3 beta-HSD activity following a series of intraperitoneal injections of different concentrations of mammalian ACTH. The histochemically stained sections of control and HX tadpoles were scanned with a computerized microscope spectrophotometer for diformazan absorbance. Two regression equations were obtained: Y = 0.1460 + 0.0015X and Y' = 0.1494 + 0.0893X', where Y or Y' = delta 5-3 beta-HSD activity absorbance (for the control and HX tadpoles, respectively), X = developmental stages of control, and X' = exogenous ACTH dosage administered to the HX tadpoles. Taking absorbance of delta 5-3 beta-HSD activity as the common factor, a curve of concentrations of ACTH-like substance against TK stages was made. The developing concentration of ACTH-like substance was very low at first and then rose during metamorphic climax. The trend of the development of ACTH-like substance was discussed from the view point of thyroid and delta 5-3 beta-HSD activities.

Orthostatic hypotension with brainstem tumors

Three patients with brainstem tumors had orthostatic hypotension as the major presenting manifestation. Two patients had primary tumors that involved the dorsal medulla, pons, and rostral spinal cord; one was a malignant astrocytoma and the other a hemangioblastoma. The third patient had an oat cell carcinoma of the lung with subependymal spread to the medulla, pons, hypothalamus, and thalamus. Evaluation of baroreceptor function in the patient with the malignant astrocytoma showed a defect in the efferent sympathetic limb of the baroreceptor reflex arc.

Progressive Multifocal Leukoencephalopathy Occurring With the Acquired Immune Deficiency Syndrome

A 33-year-old homosexual man with symptoms and signs of a focal brain process was subsequently found to have an acquired immune deficiency syndrome (AIDS) with biopsy-proven progressive multifocal leukoencephalopathy. This report reemphasizes the association of progressive multifocal leukoencephalopathy with AIDS and probably is best viewed as another example of an opportunistic CNS infection complicating deficient cell-mediated immunity.

A cytochemical study of acid phosphatase, thiamine pyrophosphatase and horseradish peroxidase in the Golgi-GERL complex of hepatoma ascites cells

Data from studies of ascitic cells of Chang hepatoma have shown that acid phosphatase (ACPase) can be localized simultaneously within the trans portion of the Golgi apparatus and in tubules of the Golgi-endoplasmic reticulum-lysosome (GERL) system. Reaction products of thiamine pyrophosphatase (TPPase) were also present consistently within trans elements of the Golgi apparatus and within GERL tubules. These new findings indicate that a close physiological association may exist between the Golgi apparatus and GERL, a concept that is consistent with previous observations of fibroblasts. When horseradish peroxidase (PO) is injected intraperitoneally into ascites-bearing rats and the ascitic cells withdrawn at different time intervals, PO could be localized within vesicles and tubules in the GERL region but could not be detected within the Golgi apparatus. Bulk-phase endocytosis requires a long time and a high concentration of PO to occur. The presence of PO within GERL indicates that this organelle may play a role in transporting or processing of certain exogenous proteins.

Effects of piperonyl butoxide on cephalosporin nephrotoxicity in the rabbit. An effect on cephaloridine transport

To evaluate the hypothesis that cytochrome P-450 mixed-function oxidase (MFO) activity may have a causal role in the production of cephalosporin nephrotoxicity, the effects of the MFO inhibitors cobaltous chloride and piperonyl butoxide on the nephrotoxicity of cephaloridine in the rabbit were examined. Although cobaltous chloride had no effect on cephaloridine nephrotoxicity, piperonyl butoxide had a significant protective effect. However, in correlated studies of the effects on the renal cortical uptake and disappearance of cephaloridine, it was found that piperonyl butoxide significantly reduces (by 50%) the cortical concentrations of the cephalosporin, both decreasing its uptake by and increasing its disappearance from tubular cells. Finally, we evaluated the effect of piperonyl butoxide on the nephrotoxicity of cephaloglycin, a more toxic cephalosporin that lacks the thiophene side-ring proposed as the target of MFO activation in earlier studies with cephaloridine. No protection against cephaloglycin was found. It is concluded that these inhibitors of MFO activity do not reduce cephalosporin nephrotoxicity in general, and that the reduction of cephaloridine toxicity by piperonyl butoxide can be explained by an effect on the intracellular concentrations of that particular cephalosporin.

Interaction of ischemic and antibiotic-induced injury in the rabbit kidney

The tubular necrosis produced by transient unilateral ischemia, three toxic cephalosporins, and the aminoglycoside neomycin were studied separately and in different combinations in the rabbit kidney. It was found that (1) mildly damaging transient ischemia (25 min) and a minimally toxic dose of the rapidly secreted cephalosporin cephaloglycin (60 mg/kg of body weight) are synergistically damaging; (2) there is no synergy between ischemia and the nonsecreted cephalosporin cephaloridine (90 mg/kg); and (3) ischemia and neomycin (100 mg/kg per day for three days) are not additively damaging, but the aminoglycoside has an additive effect with the combined insults of ischemia and cefazolin (500 mg/kg). Studies of transport showed that ischemia potentiates cephalosporin toxicity probably because it increases postischemic antibiotic concentrations in proximal tubular cells and that this increased uptake is the result of transiently augmented tubular secretion. Although this ischemic protocol reduced inulin clearance by 40%, it increased cephaloglycin secretion by an amount more than sufficient to overcome the decrease in filtration.

RNA polymerase: linear competitive inhibition by bis-(3' to 5')-cyclic dinucleotides,NpNp

We have investigated the possible role of the bis-(3' to 5')-cyclic dinucleotides UpUp and ApUp as kinetic inhibitors of the DNA dependent RNA polymerase enzyme of E. coli, using T7 delta D111 deletion mutant DNA and several synthetic DNA polymers as templates. We have established that UpUp is a linear competitive inhibitor of the initiation phase of the polymerization (Ki = 28 microM using T7 delta D111 DNA as a template), but that it has no effect when added during the elongation phase. The compound ApUp is an inhibitor of the reaction only when poly(dA-T).poly(dA-T) is used as a template, and UpUp is an inhibitor of the reaction when poly(dA).poly(dT) was employed as the DNA template.

RNA polymerase: correlation between transcript length, abortive product synthesis, and formation of a stable ternary complex

In order to investigate the relationship between the stability of the ternary complex RNA polymerase-T7 D111 DNA-RNA product and the length of the bound RNA product, we have developed a protocol for the production of stable ternary complexes of known length and composition. The assembly of the ternary complex is achieved by utilizing a dinucleotide tetraphosphate (pppApU) as a selective primer, which is augmented by one or more appropriate nucleotides. The labeled products were characterized by autoradiography of gel electrophoresis patterns, which were then quantified. The criterion for stability is the protection from perturbations (a salt-jump or a rifampicin challenge), which effectively inhibit initiation. The formation of a bound ribotetranucleotide ternary complex confers stability and terminates abortive product synthesis.