Determination of amounts of polyamines excreted in urine: demonstration of N1,N8-diacetylspermidine and N1,N12-diacetylspermine as components commonly occurring in normal human urine

An analytical system developed for fractionating free and monoacetylated polyamines [Hiramatsu, K. et al. (1994) J. Biochem. 115, 584-589] was proved useful also in detecting diacetylpolyamines, namely N1,N8-diacetylspermidine (diAcSpd) and N1,N12-diacetylspermine (diAcSpm). Detection limits were 0.9 and 0.6 pmol (S/N = 5) for diAcSpd and diAcSpm, respectively. Analytical recovery and within-run variation were also satisfactory. Human urine samples were found to contain diAcSpd and diAcSpm. These polyamines were identified on the basis of the following observations: (i) their retention times were coincident with those of authentic samples; (ii) they were deacetylated to N8-acetylspermidine and monoacetyl- and free spermine, respectively, by acetylpolyamine amidohydrolase; and (iii) they were practically inert to direct oxidation by bacterial polyamine oxidase as were authentic samples. The amounts of eleven polyamine species including diAcSpd and diAcSpm in urine samples from 52 healthy persons were determined. Mean values for the major polyamine components were consistent with those reported by others. Although the amounts of diAcSpd and diAcSpm were very small, comprising only 1.4 and 0.46% of total polyamines, respectively, these two compounds were found to be always present in healthy human urine as regular constituents. Moreover, variation in their content among individuals was small, suggesting that excretion of these components in urine is strictly regulated.

[Calvarial metastasis of cervical carcinoma showing the dural tail sign on magnetic resonance imaging]

A 42-year-old female was admitted to our department on 3 August, 1993 with a 3-month history of steadily enlarging subgaleal mass (3.2 x 3.0 cm) in the parietal region. She had been doing well following radiotherapy for cervical carcinoma of the uterus one year previously. Neurological examination on admission was negative. Axial T1-weighted MR images showed a low-intensity mass with marked homogeneous enhancement in the area of bone destruction, and a dural tail adjacent to the tumor (flare sign) after Gd-DTPA administration. The tumor was totally resected, and was pathologically diagnosed as a calvarial metastasis of the cervical carcinoma. However, 5 months later the tumor recurred anterior to the site of the resection. Since the dura mater adjacent to the tumor exhibited collagen fiber proliferation, the dural tail sign was appeared to represent a reaction to the tumor. Other calvarial metastatic lesions appeared adjacent to the initial lesion 5 months after the initial lesion was resected, however, suggesting that tumor cell nests were present in the dura mater which exhibited the dural tail sign. Extensive pathological examination of the dura mater appears necessary whenever a dural tail sign is detected by magnetic resonance imaging.

Pulsed-field gel electrophoresis of chromosomal DNA of methicillin-resistant Staphylococcus aureus associated with nosocomial infections

Methicillin-resistant Staphylococcus aureus (MRSA) infection has been endemic in the University Hospital, Kuala Lumpur since the late 1970s. Fifty isolates of MRSA obtained from clinical specimens of patients with nosocomial infections associated with this organism have been studied by pulsed-field gel electrophoresis (PFGE) of its chromosomal DNA fragments to discrimate between strains and to identify the predominant strain. Twenty-one chromosomal patterns were observed which could be further grouped into nine types. The predominant strain was Type 9-b (40% of isolates) found mainly in the Orthopaedic and Surgical Units. Outbreak strains found in the Special Care Nursery were of Type 1, entirely different from those of the surgical ward S2, which were of Type 9-b. Type 8 strains were found mainly at one end of the hospital building where the maternity, paediatric and orthopaedic units were situated. Genomic DNA fingerprinting by PFGE is recommended as a useful and effective tool for the purpose of epidemiological studies of MSRA infections, particularly for nosocomial infections.

Colocalization of NADPH-diaphorase with neuropeptides in the intrapancreatic neurons of the chicken

Colocalization of nitric oxide with neuropeptides was investigated in the chicken pancreas by use of double staining combined with the indirect immunofluorescence technique and histochemistry for NADPH-diaphorase, a specific marker for neural nitric oxide synthase. NADPH-diaphorase positive ganglia were easily detected in the interlobular connective tissue. Many NADPH-diaphorase positive ganglion cells also showed immunoreactivity for VIP (80.9%) or galanin (76.2%). Some ganglion cells showed enzyme activity only (about 20%). Very few neurons were NADPH-diaphorase negative, but immunopositive for VIP (2.0%) or galanin (3.7%). The present study provides evidence that nitric oxide colocates with VIP and galanin in the chicken pancreas.

Changes in the basal ganglia and thalamus following reperfusion after complete cerebral ischaemia

We report specific changes bilaterally in the basal ganglia and thalamus following reperfusion after complete cerebral ischaemia. A 69-year-old man, resuscitated after cardiac arrest, showed symmetrical low-density lesions in the head of the caudate nucleus and lentiform nucleus on CT. MRI revealed methaemoglobin derived from minor haemorrhage in the basal ganglia and thalamus, not evident on CT. We suggest that this haemorrhage results from diapedesis of red blood cells through the damaged capillary endothelium following reperfusion.

Specific changes in human brain following reperfusion after cardiac arrest

BACKGROUND AND PURPOSE

Very few reports are available on serial changes in human brain after cardiac arrest. The primary objective of this study is to investigate sequential neuroradiological changes in patients remaining in a persistent vegetative state following resuscitation after cardiac arrest.

METHODS

We repeatedly studied eight vegetative patients resuscitated from unexpected out-of-hospital cardiac arrest using computed tomographic (CT) scanning and high-field magnetic resonance (MR) imaging at 1.5 T.

RESULTS

In seven of the eight patients, CT scans obtained between days 2 and 6 features symmetrical low-density lesions in the bilateral caudate, lenticular, and/or thalamic nuclei. These ischemic lesions were persistently of low density on serial CT scans. In these seven patients, MR images demonstrated what were thought to be hemoglobin degradation products derived from minor hemorrhages localized in the bilateral basal ganglia, thalami, and/or substantia nigra. Diffuse brain edema in the acute stage and diffuse brain atrophy in the chronic stage were consistent neuroradiological findings. No abnormal enhanced lesions were demonstrated by CT scans.

CONCLUSIONS

The most characteristic findings on high-field MR images were symmetrical lesions in the bilateral basal ganglia, thalami, and/or substantia nigra with specific changes suggestive of minor hemorrhages that were not evident on CT scans. We speculate that these minor hemorrhages result from diapedesis of red blood cells in these regions during the reperfusion period through the endothelium disrupted by ischemia-reperfusion insult.

[Ultrastructural morphological changes of cortical microvessels following transient cerebral ischemia--a transmission electron microscopic study]

Post-ischemic hypoperfusion may play a significant role in reperfusion injury. Since there is no established treatment for hypoperfusion, however we decided to explore the morphological cause of post-ischemic hypoperfusion. In this study we used transmission electron microscopy to investigate the capillaries in ischemic/reperfused neocortex induced by 2 hours of middle cerebral artery occlusion followed by either 3 or 24 hours of reperfusion in 14 cats. Post-ischemic hypoperfusion was confirmed by measuring regional blood flow through a cranial window just above the left ectosylvian gyrus, which has poor anastomosis. A greater number of endothelial microvilli and capillary endothelial cell swelling were detected in the ischemic/reperfused neocortex, when compared with contralateral control neocortex. Especially after 24-hour reperfusion, collapse of some capillaries was observed with severe perivascular glial swelling and adhesion of PMN leukocytes to the endothelium. These findings yielded the following statistically significant results. 1) The number of endothelial microvilli in the ischemic/reperfused neocortex (mean +/- SD/1 blood vessel = 6.58 +/- 4.32) was significantly greater than in the control neocortex (3.13 +/- 2.68, p = 0.0001). 2) The ratio of capillary inner diameter (ID) to outer diameter (OD) in the ischemic/reperfused neocortex (ID/OD%, mean +/- SD = 75.4 +/- 16.7) was significantly smaller than in the control neocortex (89.2 +/- 10.8, p = 0.0001), indicating endothelial cell swelling. We concluded that these ultrastructural changes might be the cause of the multifactorial development of post-ischemic hypoperfusion, and that especially the number of endothelial microvilli and the endothelial cell swelling ratio might serve as morphological indicators of therapeutic efficacy for reperfusion injury in experimental studies.

[Blood pressure change and syncope during leg phlebography]

Although syncope attacks such as black-out, faint consciousness, and cold sweat are sometimes experienced during leg phlebography, no study of their incidence and mechanism has been reported. We measured blood pressure noninvasively by using a Finapress with ECG monitor during overall examinations (21 cases, 33 limbs; male 8, female 13) following anamnesis. Age, sex, and past history of drug, syncope, leg phlebography, and other diseases were determined. All examinations were done in the upright position. Three cases (14.3%) and four limbs (12.1%) showed syncope attacks during leg phlebography. Syncope occurred after steps taken for the evaluation of venous return in two limbs, during infusion of contrast medium in one, and after infusion in the other. In all cases, the systolic blood pressure measurement during syncope was below 80 mmHg, and the sudden decrease of both systolic blood pressure (-83.0 +/- 22.0 mmHg) and heart rate (-29.5 +/- 5.0/min) suggested vasovagal reaction as a mechanism of syncope. Other causes of syncope including anaphylaxy, hyperventilation syndrome, seizure, and arrhythmia (except for bradycardia) were not found. There were also significant changes in blood pressure and heart rate in the nonsyncope group during leg phlebography that seemed to trigger vasovagal excitation. Premedication, contrast media, and position might be important factors and should be discussed further.

[Malignant parasagittal meningioma appearing as a large subcutaneous mass]

We present a rare case of malignant meningioma appearing as an extracranial soft-tissue mass. A 34-year-old male was admitted with left parietal subcutaneous soft-tissue mass. Neurological examination on admission revealed right leg monoparesis and papilledema. Skull X rays showed hyperostosis of the left parietal bone. There was no evidence of bony destruction. CT and MRI showed a tumor with a large intracranial component, which was homogeneously enhanced. The tumor was totally removed by left ostoplastic craniotomy. The light-microscopic examination showed a meningothelial meningioma accompanied by malignant components with necrotic foci and mitotic figures. Tumor cells had invaded all the layers of the skull via the Haversian canals. We propose that hyperostosis with tumor invasion through all three layers of the skull should be considered as a malignant feature.

[A case of rheumatoid arthritis associated with agranulocytosis during bucillamine treatment]

Bucillamine has been reported to have beneficial effects in rheumatoid arthritis. This report concerns a case of RA in which agranulocytosis developed while on a course of bucillamine. A 52-year-old female with RA developed a rapid fall in white blood cell count after 4 weeks of bucillamine treatment at daily dose of 50 mg. Agranulocytosis was diagnosed (WBC 1300/mm3, granulocytes 5%). The administration of bucillamine was halted and she was treated with only prophylactic antibiotic regime. The peripheral granulocyte count result rapidly reversed within 3 days after discontinuation of the bucilamine treatment. Anti-leukocyte antibody was detected by the leukocyte lysis phenomenon method during the period of agranulocytosis. And high intrinsic G-CSF activities were detected in the patient serum before the recovery period of agranulocytosis. Agranulocytosis is a rare side effect of bucillamine but it is potentially more harmful than other side effects. In treatment with bucillamine, therefore, the drug should be carefully administered and regular blood examinations carried out to prevent the occurrence of this side effect.

Identification of a novel sugar, 4-amino-4,6-dideoxy-2-O-methylmannose in the lipopolysaccharide of Vibrio cholerae O1 serotype Ogawa

A novel sugar in the lipopolysaccharide of Vibrio cholerae O1 serotype Ogawa has been identified. The sugar was liberated from the lipopolysaccharide when hydrolyzed in 10 M HCl at 90 degrees C for 15 min. The sugar was purified and identified as 4-amino-4,6-dideoxy-2-O-methylmannose (2-O-methylperosamine). Since it was found only in the lipopolysaccharide of Vibrio cholerae O1 serotype Ogawa, it seems that the sugar is one of the specific constituents determining Ogawa serotype specificity.

Current status of angiography and interventional radiology in Japan: survey results

PURPOSE

Because the practice of interventional radiology in Japan seems very different from that in western countries, a survey was conducted to define practice patterns and the current position of radiologists in the field of vascular and interventional radiology in Japan.

MATERIALS AND METHODS

During the spring of 1992, a questionnaire was mailed to all institutions to which members of the Japanese Society of Angiography and Interventional Radiology belong.

RESULTS

For abdominal, thoracic, and peripheral angiography, more than 50% of procedures were controlled by radiologists. The majority of abdominal embolotherapy (87%) and peripheral angioplasty (70%) procedures were performed by interventional radiologists. On the other hand, 64.3% of neurointerventions, 74% of abscess drainage, and 98% of coronary angioplasty procedures were performed by other specialists. In most institutions, embolotherapy for liver neoplasms was commonly performed by radiologists (97%). Peripheral and renal angioplasty and thrombolysis were performed by 74% of respondents, although less than 10 cases per year were encountered at 81% of institutions. Abscess drainage and biopsy were performed by radiologists in more than 50% of institutions. In other nonvascular interventional procedures, especially lithotripsy, the practice by and experiences of radiologists were very limited. Fifty-seven percent of radiology departments have beds allocated and radiologists serve as attending physicians for interventional purposes.

CONCLUSION

The practice pattern of interventional radiology in Japan is quite different from that in other countries because of differences in patients' diseases, historical backgrounds, number of interventional radiologists, and department organization.

Acquired amegakaryocytic thrombocytopenic purpura with humoral inhibitory factor for megakaryocyte colony formation

A 67-year-old man with thrombocytopenia, and amegakaryocytic but otherwise normal bone marrow, was evaluated. Antibody against thrombocytes was negative and the half-life of thrombocytes was normal. In vitro clonal culture of the patient's bone marrow cells yielded no megakaryocyte colony with normal granulocyte-macrophage and erythroid colony formation. Megakaryocyte colony formation of the control bone marrow cells was significantly suppressed by the addition of the patient's serum to the culture, suggesting the existence of humoral inhibitory factor(s) for megakaryocyte colony formation. Therapeutic trials with plasma exchange, cyclosporine, prednisolone, and cyclosporine plus prednisolone were all unsuccessful, but serious bleeding has been absent.

An improved method of determining free and acetylated polyamines by HPLC involving an enzyme reactor and an electrochemical detector

We developed an improved system for the simultaneous measurement of free and acetylated polyamines, which comprised a HPLC pump, a separation column, an enzyme reactor, and an electrochemical detector, connected in series. Polyamines were separated with an isocratic elution system, and the separated polyamines were introduced into the enzyme reactor, in which they were deacetylated and oxidized to generate hydrogen peroxide. The amount of hydrogen peroxide generated was then determined with the electrochemical detector. Analysis of a mixture of nine standard polyamines including both free forms and acetylated derivatives with this method revealed that the analytical variables were satisfactory. For the analysis of polyamines in urine, pretreatment of samples with a weakly acidic ion exchange resin was necessary to reduce the interfering substances present in the urine. On successive determinations of polyamines in a urine sample, the coefficients of variation obtained were below 5.4%, except that for spermine (27.6%), and the analytical recovery rates were above 90%, except that for acetylputrescine (78.5%). The correlation coefficient between the total polyamine content in urine estimated by our method and that obtained by means of a commercially available enzymatic assay system was calculated to be 0.98, and the regression equation was expressed as y = 0.81 x + 0.89.

Strategies to improve the outcome of carotid endarterectomy

The outcomes of carotid endarterectomy (CEA) including long-term results in 121 patients (126 procedures) were retrospectively analyzed to identify the causes of operative morbidity. The angiographic internal carotid artery (ICA) stenosis was severe (> 70%) in 62 patients and moderate (50-70%) with ulceration in 64. The arterial wall was sutured primarily in 91 patients and with patch graft in 35. The outcomes 3 months after operation were good recovery in 86 patients, moderately disabled in 20, severely disabled in 11, and death in four. Three patients suffered operative morbidity (2.5%). During follow-up, three patients (2.6%) suffered transient ischemic attack on the operative side due to middle cerebral artery stenosis (50%) or ICA occlusion at the origin, and recurrent stenosis (40%) of the common carotid artery and ICA (1 each). In the latter two cases, the artery was primarily sutured. Improved therapeutic results require use of patch vein graft for the arterial wall suture, checking of the CEA patency, and prevention of intracranial ischemic events and hemorrhage due to associated lesions.

Effects of two dual-function compounds, U92798 and U92032, on transient focal ischemia in rats

Two newly-developed compounds (U92798 and U92032), which inhibit lipid peroxidation and block calcium entry, were studied for their effects on neocortical damage after transient focal ischemia. Ischemia was induced in Sprague-Dawley rats by simultaneous occlusion of the left middle cerebral artery and both common carotid arteries for a period of 3 hours. Compounds (1 mg/kg) were administered intravenously 30 minutes before occlusion and again 2.5 hours after the cessation of blood flow. After a 72-hour period of reperfusion, the animals were killed and examined for cerebral infarction and edema. Treatment with U92798 or U92032 significantly reduced the volume of cortical infarction. Edema was also reduced in these groups; however, this effect did not achieve statistical significance. These results suggest that dual function compounds, which both inhibit lipid peroxidation and block calcium entry, are promising therapeutic agents for the amelioration of ischemic cerebral damage.

[Mechanisms of antimicrobial resistance]

Most fundamental differences in the bacterial structure between the gram positive and negative bacteria are whether the organism has the outer membrane. The most essential mechanism of antimicrobial resistance in the gram negative bacteria are the alteration of membrane permeability to antibiotics. The outer membrane can perform as the barrier to prevent the cells from being exposed to antibiotics. On the other hand, the gram positive bacteria need to alternate the antimicrobial targets for reducing their binding affinity with antibiotics, because of defect of the outer membrane. On the basis of the structural difference between gram positive and negative bacteria, the mechanisms of bacterial resistance to beta-lactams, amino glycosides, macrolides, newer quinolones and vancomycin are discussed.

Swallowing dysfunction and aspiration in neonates and infants

In children, swallowing dysfunction and aspiration are common causes of recurrent pneumonia and can be fatal. The underlying mechanism is still unknown. In this study, we evaluated the swallowing function in 72 neonates and infants by fluoroscopy and followed the course of 39 patients for more than one year. The results of all the examinations were recorded on videotape or a digital imaging system. All 10 patients with neurologic disorder presented cricopharyngeal dysfunction. Of the 12 patients with near miss sudden infant death syndrome, 10 showed nasopharyngeal reflux, and 5 demonstrated cricopharyngeal dysfunction. In the 50 patients without neurologic disorder, 29 revealed cricopharyngeal dysfunction. Laryngeal elevation was not seen in 75%. Three of these 29 patients had no other abnormality. All patients without neurologic disorder recovered well. Seven patients demonstrated prolonged aspiration. Four of them had neurologic disorder, and the rest had near miss sudden infant death syndrome. Fluoroscopic examination showed two types of aspiration: one was caused not only by pharyngeal but also by lingual muscles. It was not associated with any neurologic disorders and the symptoms were transient. The other was caused by cricopharyngeal dysfunction and most of these patients had neurologic diseases and prolonged symptoms.

Revaluation of endoscopic laser therapy for treatment of early cancer in the stomach

The efficacy and safety of the endoscopic laser therapy for eradication of early cancer in the stomach was revaluated in fourty-eight patients. In 37 of the 42 patients (88%) treated with the laser therapy alone, the procedure was effective and the complete eradication was confirmed at the end of the follow-up period. In seven of fourteen patients with the incomplete treatment, residual cancer cells were successfully removed by repeated laser therapy. The endoscopic mucosal resection was effective in 21 of the 30 patients (70%) with the early gastric cancer. Interestingly, six of the eleven cases with incomplete treatment with the endoscopic mucosal resection underwent the laser therapy and the complete eradication was achieved in all patients. Although the endoscopic mucosal resection is now the main method for the endoscopic treatment of the early gastric cancer, these data favor offering the endoscopic laser therapy as the combined method with the mucosal resection therapy.

Ultrastructural study of post-hatching development in the pineal gland of the Japanese quail

The pineal gland of the Japanese quail (Coturnix coturnix japonica) retained numerous follicular structures, each of which was composed mostly of pinealocytes and supporting cells radially arranged around the follicular lumen during the first 6 weeks of age. In the pinealocytes, paraboloids and regular stacks of lamellar disks, which were demonstrated at 1 day of age in a previous study [14], rapidly decreased in number after 1 week of age. From 1 to 6 weeks of age, the pinealocytes had more developed lamellar whorls in the follicular lumen with the increased numbers of mitochondria in their apical protrusions and synaptic ribbons in their basal processes. In addition to these photosensory elements, pigment-containing cells occasionally accumulated in the basal side of the follicular structure. Their pigment granules, which were considered as melanin, gradually became larger and more roundish in shape after 1 week of age. The histological elements associated with the secretory function of the quail pineal were dense-cored vesicles and lysosomes in the pinealocytes and dense bodies in the supporting cells. The synaptic ribbons and the dense-cored vesicles in the pinealocytes rapidly increased in number at 1 week of age, scarcely exhibiting distinct changes thereafter. Thus, it is clarified that the foregoing photosensory and secretory elements change during the post-hatching development. Furthermore, it is suggested that, in respect of these elements, the pineal gland of the quail assumes more active appearances than that of the chicken.

Sequential acquisition of norfloxacin and ofloxacin resistance by methicillin-resistant and -susceptible Staphylococcus aureus

The acquisition of ofloxacin resistance by a susceptible clinical Staphylococcus aureus strain was found to be achieved in two sequential steps: the first step was accompanied by 4-fold increases in the ofloxacin MIC and 8- to 16-fold increases in the norfloxacin MIC. The second step was accompanied by further increases in both the ofloxacin and the norfloxacin MICs. A mutation of the gyrA gene resulting in an amino acid substitution was found in the second-step but not in the first-step resistant subclone. On the other hand, there was no difference in the accumulation of norfloxacin in the parent strain and the resistant subclones of each step. The rates of mutation to resistance in the steps were (1.58 to 6.81) x 10(-9) and (0.71 to 2.59) x 10(-9), respectively, and did not depend on whether the parent strain was resistant to methicillin. Some implications of these observations for clinical as well as mechanistic aspects of the prevalence of methicillin- and ofloxacin-resistant S. aureus are discussed.

[A case of cytomegalovirus pneumonia and Pneumocystis carinii pneumonia with lung cancer--diagnosis by the polymerase chain reaction]

A 64-year-old male was admitted to Oita Medical University Hospital because of primary lung cancer. After the anticancer chemotherapy, the patient developed a high fever. His chest X-ray showed diffuse reticular shadows bilaterally, which were considered to be a drug induced pneumonia, then pulse therapy with corticosteroid was performed. With this treatment, the diffuse reticular shadows disappeared. One month later, however, a severe interstitial pneumonia developed, and the patient died of respiratory failure. Autopsy findings demonstrated cytomegalovirus (CMV) and Pneumocystis carinni pneumonia. The polymerase chain reaction (PCR) for CMV in mononuclear cells in the blood was positive through out his hospitalization. In the sera, however, it was negative at the time of admission, then became positive 10 days before the onset of pneumonia. In addition, the PCR for P. carinni on the swab became positive as well. These results imply that PCR can be used for diagnosis of CMV and P. carinii infections from sera or swabs.

Potent in vitro bactericidal activity of polymyxin B against methicillin-resistant Staphylococcus aureus (MRSA)

Eradication of methicillin-resistant Staphylococcus aureus (MRSA) carried by inpatients or healthy hospital personnel by topical use of antibiotics is an important step for preventing outbreak of MRSA nosocomial infection. In the screening of the antibiotic best suited for this purpose, we have found that polymyxin B, a commonly used antibiotic for gram-negative infection, had an unexpected strong cytokilling activity towards MRSA clinical strains, which was more potent than that of vancomycin or gentamicin. The data suggested that polymyxin B could be an antibiotic of choice in the treatment of topical carriage of or infection caused by MRSA.

Improved posthypoxic recovery of synaptic transmission in gerbil neocortical slices treated with a calpain inhibitor

BACKGROUND AND PURPOSE

Among the various calcium-induced biologic events occurring in hypoxic neurons, activation of the calcium-activated neutral proteinase (calpain) is a likely mediator of neuronal degeneration. In this study, we assessed the protective effects of a calpain inhibitor (Cbz-Val-Phe-H) against hypoxic damage to the neocortex.

METHODS

An in vitro neocortical slice model from gerbils was used to study the delay to hypoxic depolarization during hypoxia and the recovery of synaptic responses after hypoxia. These responses were examined in control slices and slices treated with Cbz-Val-Phe-H.

RESULTS

The delay to hypoxic depolarization did not differ between treated and control groups. In contrast, synaptic recovery after a fixed period of hypoxia (15 minutes) was significantly improved in the Cbz-Val-Phe-H-treated slices (P < .01). Concentrations of Cbz-Val-Phe-H of 50 mumol/L or greater were significantly more protective than a concentration of 20 mumol/L (P < .01).

CONCLUSIONS

The data indicate that calcium-activated proteolysis plays a critical role in hypoxic damage to the neocortex and that calpain inhibitors may be useful therapeutic agents.