Role of amino acids in cochlear degeneration: morphological changes in cochlear outer hair cells following glutamate application

Glutamate is an excitatory neurotransmitter in the cochlea and has toxic effects on the organ of Corti in various pathological conditions. The toxic effects of glutamate have not been determined in detail. In this study, we examined morphological changes in the organ of Corti of guinea pigs following local application of glutamate. Morphological changes were noted in outer hair cells. Degeneration of outer hair cells was found 24 h after glutamate treatment. The extent of degeneration depended on exposure time. Inner hair cells did not exhibit any degeneration. In addition, no degenerative changes were detected in nerve endings attached to hair cells. These findings suggest that outer hair cells are the initial site of degeneration caused by application of excess glutamate to the inner ear.

Surgical treatment of cancer extending from the retromolar fossa to the masticator space

Cancer extending from the retromolar fossa to the masticator space with neck metastasis (T4N2M0, Stage IV) was surgically removed en bloc by maxillectomy using a mandibular swing technique. This approach allowed a wide surgical view and was useful as handling the external and internal pterygoid muscles and upper neck dissection could be combined. Though there have been several surgical approaches to the masticator space, in the case of tumors which are commonly malignant there, this approach is useful and satisfactory.

Cleavage product from the NO donor NOC-5 and inner ear hair cell damage

Nitric oxide (NO) is a neurotoxic gas which causes neuronal cell death. NO ototoxicity has also been reported, 1-Hydroxy-2-oxo-3-(3-aminopropyl)-3-isopropyl-1-triazene (NOC-5), NO donor, was used for studying NO. In this in vitro study, we examined whether NOC-5 and the cleavage products arising from it after production of No have ototoxic effects on the cochlea. The temporal bones of 55 guinea pigs were dissected and incubated in Dulbecco Modified Eagle's Medium (DMEM) with low glucose and 10% foetal bovine serum (FBS) perfused with various concentrations (100, 50, 10, 1 mM, 100 microM) of NOC-5 (pH 7.4) or the same concentrations of N-isopropyl 1-3 propanildiamine (R-NH2). Hair cell death was assessed using trypan blue staining. With NOC-5, percentages of outer hair cell death were 99.2, 98.0, 45.2, 40.5, and 20%, respectively, and percentages of inner hair cell death were 69.3, 70.2, 22.5. 11.1 and 0%, respectively. With R-NH2, percentages of outer hair cell death were 90.3, 81.1, 29.8, 21.0 and 19.3%, respectively, and percentages of inner hair cell death were 61.4, 48.1, 10.2, 5.4 and 0%, respectively. Ultramicroscopic examination showed that hair cell death was necrotic. Although NOC-5 is useful for study of NO, its cleavage products are also ototoxic.

Autologous blood donation preceding coronary artery bypass graft operation in a hemodialysis patient

A 67-year-old male hemodialysis patient with abdominal aortic aneurysm and triple vessel coronary heart disease required autologous blood donation because of his blood type of Rh(-) before cardiovascular surgery. We performed autologous red blood cell and plasma collection by the switch back method with recombinant human erythropoietin therapy during the 5 weeks before the operation. Autologous platelet collection was also made the day before the operation. These autologous blood donations were safely and successfully performed along with hemodialysis. There was some caution taken for these procedures. The ultrafiltration rate had to be adjusted for blood collection or blood transfusion during hemodialysis in order not to disturb fluid balance. It was necessary to monitor the hyperkalemia of the stored autologous packed red blood cells. For platelet collection, blood in the extracorporeal circuit had to be concentrated because of the presence of renal anemia. Coronary artery bypass graft was safely and successfully performed with the autologous blood only.

[Potential role of primary hypercoagulability and antiphospholipid antibody as a risk factor of acute pulmonary thromboembolism]

To examine whether primary hypercoagulable states, such as protein C and protein S deficiencies and antiphospholipid antibody, are associated with an increased risk, severity and recurrence of acute pulmonary thromboembolism, the blood levels of antithrombin III, protein C, protein S, lupus anticoagulant, anticardiolipin antibodies were measured in 23 patients with acute pulmonary thromboembolism, 7 men and 16 women (mean age +/- SD, 52 +/- 5 years), admitted to Nippon Medical School Hospital from January, 1990 through December, 1997. Four patients (17.4%) had protein C deficiency, one had protein S deficiency (4.3%), 10 had lupus anticoagulant (43.5%), and 2 had anticardiolipin antibodies (8.7%). Hemodynamic evaluation by Swan-Ganz catheter and venography of the lower extremity to detect deep venous thrombi were carried out in 20 and 21 patients, respectively. There were no differences between the patients with and without primary hypercoagulable states in age (52 +/- 14 vs 52 +/- 19 years), gender, or percentage of patients with deep venous thrombi in the lower extremity (91.7% vs 88.9%). Mean pulmonary arterial pressure (38 +/- 9 vs 26 +/- 4 mmHg, p < 0.05) and total pulmonary vascular resistance (10 +/- 5 vs 6 +/- 2 Wood unit, p < 0.1) were higher in the 13 patients with primary hypercoagulable states compared with the 10 patients without primary hypercoagulable states. Recurrence of pulmonary thromboembolism tended to be higher in the 13 patients with primary hypercoagulable states compared with the 10 patients without primary hypercoagulable states (46.2% vs 10.0%, p < 0.1). These findings suggest that primary hypercoagulable states, such as protein C and S deficiencies and antiphospholipid antibody, are associated with the severity and increased risk and recurrence of acute pulmonary thromboembolism.

Effect of nasal continuous positive airway pressure on pulmonary edema complicating acute myocardial infarction

Cardiogenic pulmonary edema is a frequent cause of reparatory failure. We investigated the effects of nasal continuous positive airway pressure (CPAP) in patients with severe pulmonary edema associated with acute myocardial infarction. Twenty-nine consecutive patients were divided into 3 groups: firstly, 7 intubated patients who received mechanical ventilation at study entry comprised the intubation group. The rest of the patients were randomly assigned to either of the following 2 groups: 11 patients who received oxygen plus CPAP delivered by a nasal mask (CPAP group), and 11 patients who received oxygen only via face mask (oxygen group). All patients in the intubation group had cardiogenic shock. Two patients (18%) in the CPAP group and 8 patients (73%) in the oxygen group required mechanical ventilation with endotracheal intubation (p=0.03). The hospital mortality rate in the CPAP group (9%) was significantly lower than the oxygen group (64%, p=0.02). The pulmonary artery wedge pressure and heart rate were significantly lower in the CPAP group than in the oxygen group 24 h after study entry (p<0.05 and p<0.01). The mean pulmonary artery pressure 48 h after study entry was 18+/-5 mmHg in the CPAP group and 25+/-8 mmHg in the oxygen group (p<0.05). The PaO2/FiO2 ratio increased in the intubation group (168+/-69 to 240+/-57, p<0.05) and the CPAP group (137+/-17 to 253+/-67, p<0.01) 24 h after study entry. Arterial plasma endothelin-1 concentrations decreased significantly earlier in the CPAP group than in the oxygen group (p<0.05). In patients without cardiogenic shock, nasal CPAP lead to an early improvement in oxygenation and hemodynamics, and decreased the mortality rate. Early and active respiratory management is recommended in patients with pulmonary edema associated with acute myocardial infarction.

[Nutritional intake by the oldest elderly Japanese. Tokyo Centenarian Study 6]

Rapid demographic aging has made caring for the elderly an increasingly important social issue in Japan. To study current conditions of the oldest elderly citizens, we investigated the dietary practices of centenarians in the Tokyo metropolitan area. First, we compared the food intake of centenarians with that of octogenarians. Next, to identify dietary trends, we investigated whether food intake by centenarians had changed significantly between 1981 and 1995. Nutritional intake by the centenarians and octogenarians in 1995 was about 60% and 75% that of the control, respectively. However, the nutritional intake of well nourished centenarians was similar to that of the octogenarians. Cognitive function and daily activity have an influence on nutritional intake. The centenarians were similar to the control subjects in their consumption of dairy products, sweets, and fruit. However, their intake of cereals, meat, fish, and fatty oils was loss than 60% that of the control, which indicates their preference for soft and sugary foods. The pattern of dietary practices of centenarians in 1981 was similar. Although the total food intake of centenarians amounted to 60% of the control in 1995 energy intake per kilogram of body weight averaged over 30 kcal. As to dietary trends, centenarians in 1981 are more cereals, eggs, algae products, and legumes than did their 1995 counterparts. This finding seems to reflect a generational difference in dietary habits.

Dose-dependent response of vestibular hair cells of guinea pigs following streptomycin ototoxiation

Although the involvement of apoptosis has been suggested in the loss of vestibular hair cells due to aminoglycosides, dose-dependent effects of aminoglycosides have not been determined. We therefore examined dose-dependent effects of streptomycin on the degeneration of hair cells of guinea pig ampullar cristae using TUNEL stain and Hoechst nuclear stain. Streptomycin induced apoptosis of hair cells in a dose-dependent manner. Even following high-dose applications, most of the affected cells showed apoptotic features. Apoptosis may therefore play a predominant role in the deletion of vestibular hair cells affected by aminoglycosides.

A spectrometric method for determining the capability of intermolecular interaction: mono- and dideoxynucleotides

A method for detecting the dimer of mono- and oligodeoxynucleotides is presented by using fast atom bombardment mass spectrometry (FAB-MS). The mass spectrum of a mononucleotide dpC showed an intense peak of the dimeric ion dpC:::dpC, compared with those of dpA, dpG and dpT. The mass spectrum of an equimolar mixture of dpC and dpG showed the highest peak of the dimeric ion dpC:::dpG, compared with all other combinations. The dimeric ion peaks in the mass spectra of dinucleotides d(ApT) and d(CpG) were relatively high and it may reflect the base-pairing energy due to hydrogen bonding. The degradation patterns of each dimers for d(ApT) and d(CpG) obtained by using the collision-induced dissociation (CID) technique which reflected the strength of each base-pairing.

[Evaluation of whole blood rapid troponin T assay: cooperative study of general practitioners and office cardiologists in Tokyo]

The recently developed whole blood rapid assay for cardiac troponin T (TROP T) was evaluated by a cooperative study of general practitioners and office cardiologists in the Tokyo area (Tokyo TROP T Trial). Seventy patients with suspected acute myocardial infarction treated at 14 medical clinics were enrolled in this study. The diagnostic efficacy of troponin T was compared with that of electrocardiographic evaluations and clinical standards for diagnosis of acute myocardial infarction. Twelve of the 70 patients (17.1%) had final diagnoses of acute myocardial infarction or severe unstable angina necessitating emergency coronary intervention. Troponin T was judged as positive when simultaneously measured serum troponin T was more than 0.25 ng/ml. Sensitivity, specificity, positive predictive value, and negative predictive value were 100%, 58.6%, 33.3%, and 100% for electrocardiographic evaluation, and 58.3%, 100%, 100%, and 92.1% for troponin T, respectively. Presence of bundle branch block (11/70 cases) or previous myocardial infarction (14/70 cases) caused false positive readings on electrocardiography, and resulted in the lower positive predictive value. In contrast, troponin T was false in patients admitted within 4 hours after the onset, or patients with smaller infarct. The Tokyo TROP T Trial by general practitioners and office cardiologists concluded that the combination of electrocardiographic evaluation and use of troponin T is a rapid and efficient diagnostic method for the evaluation of patients with suspected acute myocardial infarction.

Additional possible tools for identification of proteins on one- or two-dimensional electrophoresis

Additional, essentially chemical, identification methods of proteins in polyacrylamide gel electrophoresis are described. Two cleavages of peptide bonds were used at the C-side of aspartic acid with a 0.2% pentafluoropropionic acid (PFPA) aqueous vapor at 90 degrees C for 4-16 h, and the N-side of serine/threonine with an S-ethyl trifluorothioacetate vapor at 50 degrees C for 6-24 h. The products were analyzed by mass spectrometry-peptide mass fingerprinting. A new type of C-terminal sequencing at multisites of protein was introduced. An aqueous vapor of 90% PFPA at 90 degrees C for 2-16 h provided cleavages at the C-side of aspartic acid and the N-side of serine/threonine and simultaneous successive truncation at the C-termini of the cleaved fragments. The product resulted in C-terminal sequences at multisites in proteins by mass spectrometric analysis. The following chemical deblocking methods were used. Anhydrous hydrazine vapor at -5 degrees C for 8 h deblocked the N-formyl group, and the vapor at 20 degrees C for 4 h deblocked pyrrolidone carboxylate. N-acetylserine/threonine was deblocked by aqueous vapor of 75% PFPA at 50 degrees C for 1 h, followed by reaction with p-sulfophenylisothiocyanate at pH 6.0. These methods were applied to a variety of protein spots on polyacrylamide gels. A new stepwise C-terminal sequencing of protein from polyacrylamide gels is also described.

Apoptosis of guinea pig cochlear hair cells following chronic aminoglycoside treatment

Although aminoglycosides have been investigated for their cochleotoxicity, it has still not been determined whether apoptosis or necrosis results in cochlear hair cell death following aminoglycoside treatment. To study possible mechanisms of cell death, we used in situ DNA break-labeling to examine guinea pig cochleae affected by Kanamycin ototoxicity. Chronic kanamycin treatment induced DNA fragmentation that was detectable in both outer and inner hair cells, suggesting the occurrence of apoptosis. These findings suggest that apoptosis achieves deletion of affected hair cells without disrupting tissue architecture in the organ of Corti.

Low concentrations of adenosine receptor blocker decrease protection by hypoxic preconditioning in ischemic rat hearts

A role for adenosine in ischemic preconditioning and hypoxic preconditioning (HP) has been established in several species but is controversial in rats, due in part to the inconsistency of the data from the different experimental design. Our objective was to investigate the role of adenosine in the protection of the ischemic myocardium by HP in rats.

METHODS

perfused hearts isolated from Sprague-Dawley rats were exposed to 5 min of hypoxic perfusion before 25 min of global ischemia followed by 20 min of reperfusion. The effects of adenosine receptor antagonist, 8-(p-sulfophenyl)-theophylline (8SPT) on HP-based changes in left-ventricular function, energy metabolites, and release of creatine kinase and lactate dehydrogenase were determined. To minimise non-specific effects of 8SPT, low concentrations of agent (0.5 or 1.0 micro mol/l) were used.

RESULTS

8SPT alone had no deleterious effects on normoxically perfused hearts or on ischemic/reperfused hearts. HP improved the recovery of LV function and creatine phosphate, and reduced the release of enzymes during reperfusion. 8SPT (1.0 micromol/l) ameliorated the beneficial effect of HP on cardiac function, but did not reverse the reduction in release of enzymes by HP completely.

CONCLUSION

results suggest that the protective effect of HP on myocardial contractile function may be mediated by receptor(s) that can be inhibited by low concentrations of antagonist but may not have a primary role in the reduction of cellular damage by HP in rats.

Purulent pericarditis with tamponade caused by Salmonella enteritidis

The incidence of purulent pericarditis has declined. However, mortality remains high. We describe a case of purulent pericarditis with tamponade caused by Salmonella enteritidis, and emphasize the importance of early recognition, prompt institution of appropriate antibiotic therapy, and early surgical drainage for survival.

Comparison of telomerase activity in normal chorionic villi to trophoblastic diseases

Trophoblasts are derived from the normal placenta, and they infiltrate into the endometrium and the maternal blood vessels under strict control but, unlike malignant cells, never metastasize. To understand the proliferative characteristics of trophoblasts and its related disorders, we assessed telomerase activity in chorionic villi obtained from 27 normal individuals, 9 hydatidiform moles, and 2 choriocarcinomas. Telomerase activity was detected in 13/27 (48%) normal chorionic villi samples. The detectability and the level of telomerase activity depended on gestational age; 8/10 (80%) villi samples in the first trimester (relative telomerase activity; 1.77 +/- 1.37), whereas 2/8 (25%) villi samples in the second trimester (0.78 +/- 1.52) and 3/9 (33%) in the third trimester (0.28 +/- 0.43) had telomerase activity. Telomerase activity of normal chorionic villi in the first trimester was higher than that of the third trimester (P = 0.0251). In contrast, all mole samples had increased telomerase activity compared to normal villi (3.17 +/- 2.81, P = 0.0152). Thus, a relationship may exist among cell proliferation, telomerase activity, and progression to trophoblastic disease.

High incidence of breakthrough varicella observed in healthy Japanese children immunized with live attenuated varicella vaccine (Oka strain)

In order to know the rate of occurrence of varicella among vaccinees (breakthrough varicella: BV), questionnaire postcards were sent to 593 healthy children who had received varicella vaccine (Oka strain) from March 1987 to December 1989. The questionnaire survey was repeated once a year until January 1996. The annual attack rate from the 1st to 3rd questionnaire was approximately 12%: however, from the 5th to 8th one it was 1-4%. To February 1996, the cumulative attack rate was 157/459 (34.2%). This rate was comparable to that among vaccinees who had confirmed seroconversion; namely, 51/132 (38.6%). These rates are much higher than those reported by other authors. All BV cases were clinically mild; even subjects who had received the vaccine 7 years prior to the disease showed mild symptoms. The high incidence may be partly explained by the regional epidemiology of varicella. The decrease in annual incidence with time after vaccination may be due to the following reasons: some vaccinees remained free from BV owing to reinforcement of their immunity from subclinical infection of varicella-zoster virus (VZV) and others from diminution of opportunity for exposure to VZV with increasing age. Varicella vaccine seems to be effective in modifying the symptoms of varicella, but not potent enough in protecting from VZV infection.

Decrease in ischemic tolerance with aging in isolated perfused Fischer 344 rat hearts: relation to increases in intracellular Na+ after ischemia

While the ischemic tolerance of the myocardium has been reported to decrease with senescence, it is not known when and how this occurs. Our objectives were to determine whether the tolerance to myocardial ischemia in rats decreased before the onset of senescence and whether an increase in myocardial ionic imbalance was associated with an enhanced myocardial injury with aging. Hearts were isolated from Fischer 344 rats categorized as young (12 weeks old), mature adult (24 weeks), middle-aged (50 weeks) or senescent (100 weeks). Hearts were perfused isovolumically by the Langendorff procedure and subjected to 25 min of global ischemia followed by 30 min of reperfusion. In the 50- and 100-week-old rats, the recovery of ventricular function and high-energy phosphate levels was lower and there was increased incidence of ventricular fibrillation after 25 min of global ischemia followed by reperfusion. The release of creatine kinase and lactate dehydrogenase during reperfusion was greater in the 50-and 100-week-old rats than in the 12- and 24-week-old rats, indicating the irreversible myocardial damage due to ischemia-reperfusion increased by middle-age. Intracellular levels of Na+ and K+ before ischemia were higher in the 50- or 100-week-old rats than in the 12-week-old rats. The increase in intracellular Na+ at end of ischemia was greater in the older (50-week-old, 215% of the pre-ischemic value; 100-week-old, 232% of the pre-ischemic value) than in the younger rats (12-week-old, 158% of the pre-ischemic value). Results indicated that the rat heart becomes more vulnerable to ischemia in middle-age. This decrease in ischemic tolerance may be caused by an acceleration of myocardial ionic imbalance with aging.

Two modes of auditory hair cell loss following acoustic overstimulation in the avian inner ear

To determine the type of cell death occurring and how the removal of damaged cells proceeds following overstimulation, we examined chick basilar papillae using an in situ DNA nick end labeling method and transmission electron microscopy. Two distinct modes of hair cell loss were identified. First, hair cells which had not progressed into typical cell death processes, apoptosis or necrosis, were deleted by extrusion from the epithelium just after sound exposure. Second, hair cells manifested degeneration through the process of apoptosis, then further deterioration within the epithelium after the beginning of the process of hair cell regeneration. The latter mode may contribute to the following repair processes.