Local changes in oxygen tension and blood flow in the brain under hyperthermia induced by intracerebroventricular NMDA in rats

Intracerebroventricular administration of N-methyl-D-aspartate (NMDA; 100 nmol) to rats increased oxygen tension and blood flow of the caudate putamen and the ventral hippocampus. The regional differences in the increase in oxygen tension could not be explained in terms of those in the blood flow. NMDA also increased the temperature of the two brain regions to a similar extent, and these increases preceded that in the rectum. These findings suggest that NMDA receptor stimulation leads to exposure of the brain to a higher oxygen level and higher temperature, which might be involved in NMDA neurotoxicity.

A case of Crush syndrome with giant negative T waves and reversible left ventricular dysfunction

A 54-year-old male experienced the Hanshin earthquake at 5:46 am on Jan. 17, 1995. He was rescued after being buried under his house for 20 h. After being treated at two hospitals, he was admitted to our hospital with acute renal failure caused by crush syndrome. The maximal serum creatinine kinase level was 35,000 IU/L (CK-MM: 100%), and the maximal myoglobin level was 12,600 ng/ml. An electrocardiogram showed inverted T waves in V5,6 which later became giant negative T waves, and a QS pattern in a VL and V1-6. Two-dimensional echocardiography showed a hypokinetic left ventricle. He was treated with hemodialysis 13 times. Cardiac contraction gradually improved to the normal level. Coronary angiography revealed normal coronary arteries and acetylcholine did not induce coronary spasm. Biopsy specimens from the right ventricular septum showed slight degeneration. 201Tl imaging showed hypoperfusion except in the anterior wall and 123I-MIBG imaging showed a perfusion defect except in the anterior wall. After about 1 month, only 201Tl imaging showed improvement. We believe that myocardial ischemia, cardiac sympathetic nerve damage and/or cardiac contusion caused giant negative T waves and left ventricular dysfunction. This is a rare case which showed significant myocardial damage with crush syndrome.

Truncation at the C-terminus of the DAX-1 protein impairs its biological actions in patients with X-linked adrenal hypoplasia congenita

The DAX-1 [DSS (dosage-sensitive sex)-AHC critical region in the X, gene 1] gene has been reported to be responsible for X-linked adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism. However, the function and structure of the DAX-1 protein have not been characterized. In this study, molecular analysis of the DAX-1 gene from 6 patients with AHC, including 2 siblings, identified 5 novel mutations with 3 nonsense mutations and 2 frameshift mutations. Case 1 had a nonsense mutation at position 395 (Q395X). Cases 2 and 3, who were siblings, had a nonsense mutation at position 91 (Y91X). Case 4 had a 2-base deletion (AT) at nucleotides 1610 and 1611 and a 1-base insertion (G) resulting in a premature stop codon at position 462 (1610-1611 del AT ins G). Case 5 had a nonsense mutation at position 271 (Y271X). Case 6 had a 1-base deletion (C) at nucleotide 1169, which induced a frame shift and a premature stop codon at position 371 (1169 del C). All mutated DAX-1 proteins had truncated C-terminal domains. In addition, reverse transcription-PCR and direct sequencing characterized the mutant messenger ribonucleic acid in testis from case 1. Our results suggest that these 5 novel mutations are responsible for X-linked AHC and that the C-terminus of the DAX-1 protein, especially the terminal 11 amino acids, is necessary for normal adrenal cortical embryogenesis.

An imprinted gene p57KIP2 is mutated in Beckwith-Wiedemann syndrome

p57KIP2 is a potent tight-binding inhibitor of several G1 cyclin/Cdk complexes, and is a negative regulator of cell proliferation. The gene encoding p57KIP2 is located at 11p15.5 (ref. 2), a region implicated in both sporadic cancers and Beckwith-Wiedemann syndrome, a cancer-predisposing syndrome, making it a tumour-suppressor candidate. Several types of childhood tumours including Wilms' tumour, adrenocortical carcinoma and rhabdomyosarcoma exhibit a specific loss of maternal 11p15 alleles, suggesting that genomic imprinting is involved. Genetic analysis of the Beckwith-Wiedemann syndrome indicated maternal carriers, as well as suggesting a role of genomic imprinting. Previously, we and others demonstrated that p57KIP2 is imprinted and that only the maternal allele is expressed in both mice and humans. Here we describe p57KIP2 mutations in patients with Beckwith-Wiedemann syndrome. Among nine patients we examined, two were heterozygous for different mutations in this gene-a missense mutation in the Cdk inhibitory domain resulting in loss of most of the protein, and a frameshift resulting in disruption of the QT domain. The missense mutation was transmitted from the patient's carrier mother, indicating that the expressed maternal allele was mutant and that the repressed paternal allele was normal. Consequently, little or no active p57KIP2 should exist and this probably causes the overgrowth in this BWS patient.

[Parametric images of central-type benzodiazepine receptor binding and ligand transport by two SPECT scans of 123I-iomazenil: relative quantification without blood data]

Parametric images of intrasubject distribution of the central-type benzodiazepine receptor binding and ligand transport were determined from two SPECT images after an intravenous bolus injection of 123I-iomazenil in six healthy volunteers and five patients by using a table look-up procedure based on a 3-compartment, 2-parameter kinetic model. Individual arterial input functions were estimated by calibrating a standardized input function with the injected dose to avoid blood sampling. The parametric images without blood data provided the same information as those determined by using measured arterial input function. A simulation study suggested that this method gave relatively small error as long as true receptor binding and ligand transport did not differ from each other in a large extent. The present method may be practical in clinical settings.

Rapid and large-scale isolation of microsomal fraction of mouse liver by lyophilization and low speed centrifugation

We could prepare the microsomal fraction of mouse liver, without using an ultracentrifuge but with a low speed centrifuge. The procedure includes 1) lyophilization of post-mitochondrial fraction (9,000 x g supernatant) of mouse liver, 2) powdering of the lyophilized sample, 3) the addition of 1.15 per cent potassium chloride solution or distilled water, which afforded microsomal aggregates, 4) sedimentation of microsomal fraction by low-speed centrifugation (20,000 x g, 20 min). The sedimented microsomal fraction showed normal contents of cytochrome P-450 and cytochrome b5, and gave a normal pattern on SDS polyacrylamide gel electrophoresis and normal electron microscopic feature. This method should be convenient for rapid and large-scale preparation of microsomes, especially for the preparation of cytochrome b5 and cytochrome P-450.

Frequency stabilization of a semiconductor laser by external phase-conjugate feedback

We report the stabilization of a laser diode by external phase-conjugate feedback from a broad-area laser diode. The linewidth of the stabilized laser diode was reduced from 5 MHz to 25 kHz, approaching the limit set by the fluctuations of the pump beam for the phase conjugator. Clear evidence of phase conjugation was the observation of paired half-axial side modes spaced at frequencies of c/4L with respect to the main mode.

Direct observation of soliton and normal pulse propagation by spectral domain reflectometry

We report what are to our knowledge the first continuous observations of optical fiber solitons and nonsoliton pulses in the spectral domain. Using a novel optical time-resolved spectral ref lectometer that measures the backscattered light spectrum, we directly observed (with 200-m spatial resolution) the propagation of ~8.5-ps solitons and nonsolitons traveling down 5-km fibers. Spectral breathing and the recovery of the original spectral widths are clearly seen for higher-order solitons. Possible applications include in situ measurements of soliton parameters, fiber dispersions, and nonlinearities, experimental verifications of pulse propagation theories, and optical sensing.

Measurement of regional cerebral blood flow with copper-62-PTSM and a three-compartment model

We evaluated quantitatively 62Cu-labeled pyruvaldehyde bis(N4-methylthiosemicarbazone) copper II (62Cu-PTSM) as a brain perfusion tracer for positron emission tomography (PET). For quantitative measurement, the octanol extraction method is needed to correct for arterial radioactivity in estimating the lipophilic input function, but the procedure is not practical for clinical studies. To measure regional cerebral blood flow (rCBF) by 62Cu-PTSM with simple arterial blood sampling, a standard curve of the octanol extraction ratio and a three-compartment model were applied.

METHODS

We performed both 15O-labeled water PET and 62 Cu-PTSM PET with dynamic data acquisition and arterial sampling in six subjects. Data obtained in 10 subjects studied previously were used for the standard octanol extraction curve. Arterial activity was measured and corrected to obtain the true input function using the standard curve.

RESULTS

Graphical analysis (Gjedde-Patlak plot) with the data for each subject fitted by a straight regression line suggested that 62Cu-PTSM can be analyzed by the three-compartment model with negligible K4. Using this model, K1-K3 were estimated from curve fitting of the cerebral time-activity curve and the corrected input function. The fractional uptake of 62Cu-PTSM was corrected to rCBF with the individual extraction at steady state calculated from K1-K3. The influx rates (Ki) obtained from three-compartment model and graphical analyses were compared for the validation of the model. A comparison of rCBF values obtained from 62Cu-PTSM and 150-water studies demonstrated excellent correlation.

CONCLUSION

The results suggest the potential feasibility of quantitation of cerebral perfusion with 62Cu-PTSM accompanied by dynamic PET and simple arterial sampling.

Chromosomal assignment and imprinting tests for the mouse delta subunit of the cytosolic chaperonin containing TCP-1 (Cct4) gene to proximal chromosome 11

The CCT (chaperonin containing TCP-1) complex functions as a molecular chaperone in the eukaryotic cytosol. This complex consists of several species of related polypeptides. The chromosomal localization of the mouse Cct4 gene encoding the delta subunit of CCT was assigned in this study to proximal chromosome 11 by genetic mapping. Restriction mapping analysis using YAC and pulse-field gel electrophoresis showed that Cct4 is located within a region about 300 kb from the imprinted gene U2af1-rs1. Expression of Cct4 was biallelic, and therefore Cct4 is not imprinted in neonatal mice. The localization of the human homologue of Cct4 on chromosome 2 corresponds well with the fact that homologues of other genes in the proximal region of mouse chromosome 11 also map to the region of conserved synteny in human chromosome 2.

Genomic imprinting of human p57KIP2 and its reduced expression in Wilms' tumors

p57KIP2 is a potent tight-binding inhibitor of several G1 cyclin complexes, and is a negative regulator of cell proliferation. The gene encoding human p57KIP2 is located on chromosome 11p15.5, a region implicated in both sporadic cancers and Beckwith-Wiedemann syndrome (BWS), a cancer syndrome, making it a tumor suppressor candidate. Several types of childhood tumors including Wilms' tumor, adrenocortical carcinoma and rhabdomyosarcoma display a specific loss of maternal 11p15 alleles, suggesting that genomic imprinting plays an important part. Genetic analysis of the familial BWS has indicated maternal carriers and suggested a role in genomic imprinting. Previously, we demonstrated that p57KIP2 is imprinted in the mouse. Here we describe the genomic imprinting of human p57KIP2 and the reduction of its expression in Wilms' tumors. High resolution mapping locates p57KIP2 in the region responsible for both tumor suppressivity and BWS.

Salivacin 140, a novel bacteriocin from Lactobacillus salivarius subsp. salicinius T140 active against pathogenic bacteria

Fifteen of 353 environmental isolates of lactic acid bacteria consistently showed activity against Listeria monocytogenes, Streptococcus mutans, Actinomyces viscosus, and/or Propionibacterium acnes. Strain T140, isolated from the surface of Japanese pampas grass leaves and identified as Lactobacillus salivarius subsp. salicinius, also had activity against several Lactobacillus species, Staphylococcus aureus and Yersinia enterocolitica. Since the antagonistic factor(s) produced by T140 was sensitive to a proteolytic enzyme, it was concluded that a bacteriocin (named salivacin 140) was involved in the inhibition activity. Strain T140 required a high initial pH (7.5-8.5) in agar plates for bacteriocin production.

Depletion of dietary sulphamonomethoxine and sulphadimethoxine from various tissues of laying hens

Sulphamonomethoxine (SMM) or sulphadimethoxine (SDM) was fed to laying hens at 400 mg/kg diet for 5 successive days. After withdrawal of the drugs, contents (mg/kg) of SMM and SDM in the blood, kidney, liver, ovary, muscle and adipose tissue were determined by HPLC. 2. The disappearance of dietary SMM and SDM from the tissues of laying hens was rapid and, except for the liver, was very similar in all tissues. 3. A common biological half-life (t1/2) of SMM in the above 6 tissues was estimated to be 5.2 h. The t1/2 of SDM in the liver was 6.9 h, significantly longer than that of 4.4 h in the other 5 tissues. The values were much shorter than 51/2 (reported elsewhere) for other drugs. 4. Comparing the data found in this study with those obtained from previous papers, the depletion velocities of SMM and SDM from the hen's body were much faster than those from albumen in egg. The reason for this is probably related to the longer time period over which albumen formation occurs.

Mexican-American and Anglo-American children's responsiveness to a theory-centered AIDS education program

Third, fifth, and seventh graders, most of them Mexican-American, were exposed to an empirically based and culturally sensitive AIDS curriculum designed to replace their intuitive theories with a coherent, scientific account of the causal processes that lead from risk behavior to AIDS symptomatology. Compared to students in control classes, experimental students knew more about AIDS risk factors and AIDS generally, displayed more conceptual understanding of the causes of AIDS and flu, and were more willing to interact with people who have AIDS (although not less worried about AIDS) at posttest and typically at follow-up 10-11 months later. The findings point to the potential value of adopting an intuitive theories approach in assessing and modifying children's concepts of health and illness and suggest, contrary to Piagetian formulations, that even relatively young children can, with appropriate instruction, grasp scientific theories of disease.

Distinct effects of N omega-nitro-L-arginine on seizures induced by several drugs in mice

A potent nitric oxide (NO) synthase inhibitor, N omega-nitro-L-arginine (L-NA), suppressed tonic seizure elicited by pentylenetetrazol (PTZ; 100 mg/kg, SC) in a dose-related manner (25 to 100 mg/kg, IP), but had no effect on clonic seizure. The effect was most potent at 1 h after the administration of L-NA. L-NA (100 mg/kg, IP) suppressed clonic seizure as well as tonic seizure in bicuculline-treated (3.0 or 4.5 mg/kg, SC) mice. However, it did not affect seizures elicited by picrotoxin (2.0 to 6.0 mg/kg, SC). On the other hand, N-methyl-DL-aspartate (NMDLA; 300 mg/kg or 350 mg/kg, IP) induced clonic seizure, but tonic seizure was not always noted. All mice with clonic and tonic seizures died, and some mice with clonic seizure died without accompanying tonic seizure. L-NA did not influence NMDLA-induced seizures, but it appeared to enhance NMDLA lethality, though without statistical significance. These findings suggest distinct roles of NO in seizures induced by different drugs in mice.

Noninvasive quantification of iodine-123-iomazenil SPECT

The feasibility of a noninvasive method for quantification of [123I]iomazenil binding using a standardized arterial input function and a single venous blood sample was assessed in normal volunteers.

METHODS

Serial SPECT images and blood data from six healthy male volunteers after intravenous injection of [123I]iomazenil were used. The standardized input function was derived by averaging the six subjects' arterial curves. Individual input functions were estimated by calibrating the standardized input function with one-point venous blood radioactivity concentration. Ligand transport (K1) and receptor binding were computed from the estimated input functions and two separate SPECT scans using a table look-up procedure based on a three-compartment, two-parameter model. Reference values for K1 and receptor binding were determined from the serial SPECT data and individual arterial curves using a three-compartment, three-parameter model and curve fitting.

RESULTS

Analyses of the error caused by the calibration in relation to the time postinjection revealed that the optimal calibration time was 30 min postinjection. Receptor binding obtained by this simplified method correlated well with the reference values (r = 0.941) and was estimated within an error of 10% in the cerebral cortical regions. Although the estimated K1 showed relatively poor correlation (r = 0.699) with the reference value, it was an excellent relative measure in each subject.

CONCLUSION

Our method provided an absolute measure of the benzodiazepine receptor binding and a relative measure of ligand transport from two SPECT scans and a venous blood sample. This method would be useful for quantitative assessment of benzodiazepine receptors in clinical settings.

Stability of a metabolizable ester bond in radioimmunoconjugates

Ester bonds have been used as metabolizable linkages to reduce radioactivity levels in non-target tissues following the administration of antibodies labeled with metallic radionuclides. In this radiochemical design of antibodies, while the ester bonds should be cleaved rapidly in non-target tissues, high stability of the ester bonds in plasma is also required to preserve target radioactivity levels. To assess the structural requirements to stabilize the ester bond, a new benzyl-EDTA-derived bifunctional chelating agent with an ester bond, (1-[4-[4-(2- maleimidoethoxy)succinamido]benzyl]ethylenediamine-N,N,N',N' -tetraacetic acid; MESS-Bz-EDTA), was developed. MESS-Bz-EDTA was coupled with a thiolated monoclonal antibody (OST7, IgG1) prepared by reducing its disulfide bonds to introduce the ester bond close and proximal to the antibody molecule. For comparison, 1-[4-(5- maleimidopentyl)aminobenzyl]ethylenediamine-N,N,N',N'-tetraacetic acid (EMCS-Bz-EDTA) and meleimidoethyl 3-[131I]iodohippurate (MIH) was coupled to OST7 under the same conjunction chemistry. When incubated in 50% murine plasma or a buffered-solution of neutral pH, OST7-MESS-Bz-EDTA-111In rapidly released the radioactivity, and more than 95% of the initial radioactivity was liberated after a 24 h incubation in both solutions, due to a cleavage of the ester bond. On the other hand, only about 20% of the radioactivity was released from OST7-MIH-131I in both solutions during the same incubation period. In mice biodistribution studies, while a slightly faster radioactivity clearance from the blood with less radioactivity levels in the liver and kidneys was observed with OST7-MIH-131I than with OST7-EMCS-Bz-EDTA-111In, OST7-MESS-Bz-EDTA-111In indicated radioactivity clearance from the blood much faster than and almost comparable to that of OST7-MIH-131I and succinamidobenzyl-EDTA-111In, respectively. These findings as well as previous findings on radiolabeled antibodies with ester bonds suggested that while an introduction of an ester bond close to an antibody molecule stabilized the ester bond against esterase access, chemical structures of the linkages and radiolabels attached to the ester bonds play a significant role in the chemical stability of the ester bond. This may explain the different stability of the ester bonds in radioimmunoconjugates so far reported.

Hormonal regulation of aldose reductase in rat ovary during the estrous cycle

The physiological roles of aldose reductase [alditol:NAD(P)+1-oxidoreductase] have not been fully elucidated yet, although it has been implicated in the pathogenesis of diabetic complications. In the rat ovary we found remarkable changes in the enzyme level during the 4-day estrous cycle. After diestrus, the activity and protein content of aldose reductase increased to the maximum level on proestrous morning and rapidly fell off to the lowest level on the early morning of estrus. At this time its mRNA level in the ovary was significantly decreased compared with that on the morning of proestrus. Immunohistochemical staining of the diestrous ovary demonstrated localization of the enzyme protein in the granulosa cells and in the oocytes. At the end of proestrus when its level was low, immunoreactive aldose reductase in the granulosa cells was localized preferentially to the antrum side, with lesser staining in the cells lining the follicles. Administration of chlorpromazine to the rats on proestrus significantly restored the enzyme level on the following morning of the expected estrus. This effect of chlorpromazine was abolished when human chorionic gonadotropin was administered to the chlorpromazine-treated rats. When chlorpromazine was administered to the rats treated with bromocriptine, an inhibitor of pituitary prolactin secretion, aldose reductase activity in the ovary was significantly elevated compared with that in the rats treated with chlorpromazine alone. These findings suggest that in the rat ovary it is under hormonal regulation during the estrous cycle. The enzyme may possess a new functional role in the reproductive system of the female rat, which can be disordered under diabetic conditions.

Seroepidemiological study of human herpesvirus-6 and -7 in children of different ages and detection of these two viruses in throat swabs by polymerase chain reaction

The presence of human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7) in throat swabs of 62 children of different age groups (group I, ages 0-5 month; group II, ages 6-11 months, group III, ages 12-23 months, group IV, age 2-8 years) and 28 adults was detected by polymerase chain reaction. The detection rate of HHV-6 DNA was the highest (87%) in children aged 1-year-old and decreased with age, whereas the detection rate of HHV-7 increased with age and reached a maximum in adults. HHV-6B was detected in almost all samples except for two children who secreted only HHV-6A. When the antibody prevalence was determined in the four groups of children, HHV-6 antibody was detected in 8/12 (66.7%), 10/12 (83.3%), 15/16 (93.8%), and 13/14 (92.9%), respectively. Antibody to HHV-7 in these groups was detected in 6/12 (50.0%), 4/12 (33.3%), 12/16 (75.0%), and 13/14 (92.9%), respectively. Detection of HHV-6 DNA in throat swabs of triplets who had the sequential onset of exanthem subitum was attempted by using samples sequentially collected from these children after the onset of the disease in the first patient. HHV-6 DNA with high copy numbers was detectable during the acute and convalescent phases of the disease in all patients, but no DNA was detected in samples collected before the onset of disease.