Effects of acoustic overstimulation on 2f1-f2 distortion product in the cochlear microphonics

The cochlear microphonics (CM) in response to two-tone stimuli as well as the threshold of compound action potential (CAP) were measured before and after exposure to 4 kHz pure tone at 100 dB SPL for 10 min. Although the loss of CM output at the primary frequencies was limited to around 2 dB, the 2f1-f2 distortion products in the CM (CM-DPs) were markedly reduced immediately after the exposure, especially at low primary levels (i.e. less than 65 dB). The low level CM-DPs recovered gradually near the initial level within 7 days from the exposure. The elevation of CAP threshold closely paralleled with the reduction of CM-DPs in not only the acute phase but also in the recovery phase from the exposure. These results show that the active transduction process in the cochlea was affected by acoustic overstimulation. This impairment of the active transduction was postulated to play an important role in developing the noise induced temporary threshold shift.

[MR imaging of the anterior spinal artery in a case of bilateral vertebral arterial occlusion]

A 66-year-old woman, who had been suffering from frequent episodes of vertebro-basilar insufficiency for 10 years, was admitted because of brainstem ischemic symptoms. Magnetic resonance (MR) images were almost normal, but small flow voids were observed in front of the medulla oblongata and the upper cervical spinal cord. Cerebral angiography revealed that both of the vertebral arteries were completely occluded after branching off the respective posterior inferior cerebellar arteries. The basilar artery was fed only by a retrograde collateral flow via the anterior spinal artery which, arising from the left vertebral artery at the level of the fifth to sixth cervical vertebra, ascended the ventral aspect of the cord. These findings clarified that the flow voids on the MRI were from the anterior spinal artery, and were unusually prominent, as a collateral flow to the basilar artery. To the best of our knowledge, an anterior spinal flow void found on routine brain MR imaging has not been documented in the literature. Our case suggested that the flow void, a very small finding on the MRI, could be a useful sign in the diagnosis of serious vertebral arterial diseases.

Detection of green algae (Chlorophyceae) for the diagnosis of drowning

The plankton test (generally, diatom test) is one of the methods available to diagnose the cause of death of submerged bodies. The solubilization method using tissue solubilizer Soluene-350 was used in this study to detect not only diatoms but also green algae, based on the fact that the solubilizer does not digest the cell walls of green algae which are made from cellulose. Detection of green algae from organs of submerged cadavers is very informative to determine drowning in fresh water, and also in cases where only few diatoms are detected in the organs.

Portal and peripheral endotoxins in patients with esophageal varices undergoing surgery

Under the hypothesis that portal endotoxemia, which has been considered evidence of endogenous endotoxemia, is actually a false-positive reaction of the Limulus test, the conventional method of determination, Toxicolor (TOX) and a new endotoxin-specific method, Endospecy (ES) were investigated, whereby portal endotoxemia was reexamined. Peripheral and portal blood samples were collected from 12 patients at various intervals during surgery for esophageal varices, and then evaluated by TOX and ES, the normal values of which are under 60.0 pg/ml and under 9.8 pg/ml, respectively. The mean peripheral and portal endotoxin (Et) levels by TOX were 23.1 pg/ml and 38.9 pg/ml, 1.5 h after the start of surgery, which continued to increase thereafter, the corresponding levels being 48.1 pg/ml and 58.7 pg/ml 8 h after the start of surgery, respectively. The portal Et levels were significantly higher by ES, indicating portal endotoxemia, the mean peripheral and portal Et levels being 6.9 pg/ml, and 6.5 pg/ml, 1.5 h after the start of surgery, these levels showing changes within a similar range. The levels determined by the conventional TOX method increased with time, to a portal Et level of 5.0 pg/ml 8 h after the start of surgery, whereas those determined by ES changed within the same range suggesting that the onset of portal endotoxemia primarily involves the G-factors and that endogenous endotoxemia does not occur.

Utilization behavior after right thalamic infarction

We report a patient who showed exaggerated responses to external cues (utilization behavior), motor impersistence, and a right-hand-predominant instinctive grasp reaction after right thalamic infarction. High-resolution computed tomography with stereotaxic lesion localization revealed almost complete destruction of the ventroanterior nucleus and intralaminar nuclei of the right thalamus; the dorsomedial nucleus was only partially involved. Single photon emission computed tomography revealed hypoperfusion in the right thalamus and over the entire right cerebral cortex with some prominence in the frontal area. From these observations, we believe that the utilization behavior in our case was caused by the disturbance in maintaining cortical tone of the right hemisphere as well as by the dysfunction of the right frontal lobe, both secondary to the damage to the right ventroanterior nucleus and intralaminar nuclei.

Lesser sac herniation through the greater omentum and gastro-pancreatic ligament: report of a case

We report herein the case of a woman who developed a lesser sac hernia which was especially unusual in that the small bowel prolapsed through a defect in the greater omentum and was thereafter strangulated by a hole in the gastro-pancreatic ligament. The gastro-pancreatic ligament has never before been documented as causing an internal hernia. In our patient, a plain abdominal X-ray demonstrated as soft-tissue mass displacing the stomach to the left while abdominal computed tomography and ultrasonography showed a sac-like encapsulation of the small bowel loops between the liver and stomach. Careful evaluation of these radiographic findings allowed for the preoperative diagnosis of a lesser sac hernia to be made.

Nucleotide sequence of a highly repetitive element isolated from Opsariichthys uncirostris (Osteichthyes). O. uncirostris repetitive sequence

A highly repetitive DNA element has been isolated from Opsariichthys uncirostris. It contains several oligo-dA tracts and potential regions for the secondary structures.

Detection of gamma-aminobutyric acid in a living rat brain using in vivo microdialysis-capillary electrophoresis/mass spectrometry

Coupling of in vivo microdialysis with capillary electrophoresis/mass spectrometry (MD-CE/MS) was demonstrated. A microdialysis probe was inserted in the striatum of a rat brain and gamma-aminobutyric acid (GABA) in the brain was detected by CE/MS without any chemical treatment of the sample. MD-CE/MS is expected to be a useful technique for analyzing brain substances, because of the relatively small damage it causes to a living structure and the high selectivity of the analytical technique.

Comparative pharmacodynamic analysis of TAT-59 and tamoxifen in rats bearing DMBA-induced mammary carcinoma

TAT-59 suppressed the growth of DMBA-induced mammary tumors in rats earlier and more strongly than tamoxifen (TAM). After oral administration of the drugs, DP-TAT-59, one of the main metabolites of TAT-59, was found in 10- to 15-fold higher concentrations in both the tumor and blood compared to 4-OH-TAM, an active metabolite of TAM. In a 3-day antiuterotrophic test, every detected metabolite of TAT-59 showed stronger antiestrogenic activity than did TAM. In a competition assay, the affinity of the metabolites for estrogen receptors ranged from that of estradiol to that of TAM. These results suggest that the superior antiestrogenic activity of TAT-59 compared to TAM was either due to its higher penetration into tumor tissue or to the stronger antiestrogenic activity of its metabolites.

Involvement of endothelin in peripheral circulatory change induced by hand-arm vibration

Physiologic mechanisms involving local vasoregulating factor, endothelium-derived relaxing factor (EDRF) and endothelium-derived constricting factors (EDCF) have been postulated to play a role in VWF. Recent evidence that endothelin is a potent vasoconstrictor peptide indicates that it may play a role in vasoregulation during vibration exposure through the local actions of EDRF or EDCF. Therefore, we examined the effects of grasping (50 N) and hand-arm vibration with an unweighted acceleration of 50 m/s2 rms at a frequency of 120 Hz in the direction of X-axis on digital blood flow (DBF) and on the level of plasma endothelin in 7 healthy male office workers. DBF was measured by an apparatus based on the thermal diffusion method where the thermal diffusion flow probe was incorporated in the Peltier's stack. In the grasping test, DBF decreased by about 40% from resting level within 1 minute after the grasping was begun, and was maintained at almost the same level during grasping, but increased immediately after cessation of grasping. In the vibration exposure test, initial decrease in DBF due to grasping was the same as that observed in the grasping test, but DBF gradually increased when exposure to vibration was performed simultaneously. No significant change in plasma endothelin level was induced by grasping. Endothelin was significantly lower after exposure to vibration than at rest and after grasping. The grasping-induced decrease in DBF seemed to be due to mechanical compression of the vessels. The negative correlation between DBF and endothelin during vibration exposure suggests that a reduction in release of endothelin from smooth muscle into the vessel cavity during vibration leads to vasodilatation, possibly attributable to the local axon reflex.

Stimulation of transcription in cultured cells by high mobility group protein 1: essential role of the acidic carboxyl-terminal region

Several in vitro studies have suggested that high mobility group (HMG) protein 1 has a role in gene regulation as a trans activator or quasi-transcription factor. However, data on the molecular functions of HMG1 protein in these reactions are contradictory or obscure. In order to assess whether HMG1 protein does, in fact, have transcriptional activation potential, two assay systems in cultured cells were employed. HMG1 protein introduced into COS-1 cells as a complex with a reporter plasmid carrying the lacZ gene enhanced the level of the gene expression. Cotransfection of an expression plasmid carrying HMG1 cDNA into the cells with the reporter plasmid enhanced the activity of beta-galactosidase 2-3-fold in comparison with that of the control effector plasmid. The enhancement was proved to be dependent not on the replication but on the transcription of the reporter plasmid. In the cotransfection experiments, an expression plasmid the HMG1 molecule lacking the acidic carboxyl terminus repressed the expression of the reporter gene. The binding of an HMG1 protein variant lacking the acidic carboxyl terminus to DNA gave an extremely large shift of gel retardation in comparison with the complete HMG1 molecule. Together, these results indicate that HMG1 protein can enhance expression in cells in culture at the step of gene transcription and that the DNA binding domains comprising two-thirds of the HMG1 protein molecule are responsible for the inhibition property. Also, the acidic terminus of the HMG1 molecule is essential for the enhancement of gene expression in addition to elimination of the repression caused by the DNA binding. (ABSTRACT TRUNCATED AT 250 WORDS)

Relationship between plasma levels of type II phospholipase A2, PAF acetylhydrolase, endothelin-1, and thrombomodulin in patients with infected burns

The relations between type II phospholipase A2 (PLA2) and PAF acetylhydrolase (PAFAH) levels and those of endothelin-1 (ET-1) and thrombomodulin (TM) were examined in samples containing the maximum amount of TNF-alpha detected over the clinical course for each patient with burn wound infection. The study included 23 patients with a total burn surface area of > 20%. Plasma levels of tumor necrosis factor-alpha (TNF-alpha), type II PLA2, PAFAH, TM, and ET-1 were 174.1 +/- 239.5 pg/ml, 229.5 +/- 190.8 ng/ml, 22.68 +/- 7.07 nmol/min per ml, 6.62 +/- 2.78 ng/ml, and 7.45 +/- 2.99 pg/ml, respectively. There were significant correlations between plasma levels of type II PLA2 and TM (r = 0.767, p < 0.0001), between PAFAH and TM (r = 0.542, p = 0.0076), between type II PLA2 and ET-1 (r = 0.688, p = 0.0003), and between PAFAH and ET-1 (r = 0.516, p = 0.0117). These results suggest that the increases in plasma type II PLA2 and PAFAH are related to vascular endothelial disorders in patients with infected burns.

Sustained release of hCG minipellet for newt experiment in space

Sustained release formulation of hCG, hCG minipellet, was applied to induce oviposition of newt. Period of egg spawning was prolonged with a certain delay of its initiation. When hCG minipellet was injected to newt that was hibernating, it induced egg spawning even after one month of hibernation. Results suggest that minipellet keeps steady concentration of hCG at the effective level for longer period. For the study on early development of newt egg, it is essential to obtain egg on orbit. hCG minipellet makes it possible even at launch slip or early "late access".

[Effect of nitric oxide on central dopaminergic neurons]

Neuronal damage induced by ischemia involves various changes in neurotransmission. Nitric oxide (NO), a putative neurotransmitter and/or neuromodulator has some role in this neuronal damage. In the present study, the effect of NO on the terminal site of dopamine (DA) neurons in the rat striatum was examined using the microdialysis technique. First perfusion with sodium nitroprusside (SNP) as an NO donor increased extracellular DA (10 mM, 460%; 1 mM, 140%) in the striatum and decreased its metabolites. Pretreatment with tetrodotoxin (TTX, 5 microM), (+)-5-methyl-10,11-dihydro-5H-dibenzo [a,d] cyclohepten-5,10-imine hydrogen maleato (MK801, 1 microM) or muscimol (1 microM) inhibited SNP-induced increases in extracellular DA and decreases in DOPAC (TTX, complete block; MK801, 75% inhibition; muscimol, 80% inhibition). Second, extracellular NO, DA and DOPAC were measured in the gerbil striatum following 10 minutes of forebrain ischemia produced by occluding both carotid arteries. Occlusion of the carotid arteries also caused increases in extracellular NO and DA in the gerbil striatum (NO, 3000%; DA, 2800%). These findings suggest that NO-facilitated DA release occurs via interaction between glutamatergic and dopaminergic neurons. These changes are probably partially involved in the neurodegenerative phenomena following ischemia. It is also shown that simultaneous measurements of NO and DA using this technique may be useful in assessing ischemic changes in vivo.

Tetravalent platinum complexes with ammine/amine carrier ligand configuration: circumvention of platinum resistance in vivo

A platinum(II) and three platinum(IV) ammine/cycloalkylamine homologous series, the latter possessing either chloro, acetato or hydroxo axial ligands, were evaluated for efficacies in mice bearing tumor cells sensitive (leukemia L.1210/0 and reticulosarcoma M5076) or resistant to cisplatin (L1210/DDP) and tetraplatin (L1210/DACH). Within each series, which contained four homologs, potency increased (optimal dose decreased) as alicyclic ring size increased incrementally from cyclopropane to cyclohexane. All analogs were active at maximally tolerated doses against L1210/0 (%T/C = 125-426), with good associated therapeutic ratios of 2 to > 8 that, like the therapeutic index, provided indications of the drug's safety margin. Most complexes had activities that were similar to cisplatin (%T/C = 239) and tetraplatin (%T/C = 310). Antitumor activities were seen for all four platinum(II) complexes against L1210/DDP cells (%T/C = 133-167). In the three platinum(IV) series, on the other hand, only cyclopentane (C5) and cyclohexane (C6) analogs met or exceeded the minimum criterion for activity. These activities were similar to that seen with the positive control agent tetraplatin (%T/C = 133), but higher than that of cisplatin (%T/C = 94). Long-term survivors, which were frequently observed with these complexes in the L1210/0 model, were also seen in the L1210/DDP model, but to a lesser extent. Against L1210/DACH cells, which were sensitive to cisplatin (%T/C = 155), but resistant to tetraplatin (%T/C = 113), the C5 and C6 congeners in the platinum(IV) series were effective with %T/C in the range 148-189, while corresponding members in the platinum(II) series were only marginally active. In the solid M5076 model, complexes C5 in platinum(II) and in the acetato- and hydroxoplatinum(IV) series, and C6 from the hydroxo-platinum(IV) series, were as effective or more effective than cisplatin, which itself gave a tumor growth delay of 27.5 days. In summary, the results indicate that alicyclic ring size and, in the platinum(IV) series, axial ligand, are important modulators of efficacies of ammine/cycloalkylamine platinum congeners in both sensitive and platinum-resistant models. However, the cyclopentylamine or cyclohexylamine carrier ligand with acetato or hydroxo axial ligands in the platinum(IV) configuration are optimal combinations for circumventing both cisplatin and tetraplatin resistances.