Glutamate toxicity induced degeneration of outer hair cells with a temporal increase of nitric oxide production in the guinea pig cochlea

The aim of this study was to examine the roles of glutamate (GLU) toxicity and involvement of nitric oxide (NO) in the pathogenesis of cochlear degeneration. We examined guinea pig cochleae following chronic exposure to GLU. Trypan blue extrusion and transmission electron microscopy were performed to evaluate degeneration in the organ of Corti. In parallel, nitric oxide synthase (NOS) activity was demonstrated by histochemical staining of NADPH diapholase. GLU treatment caused time-dependent degeneration of outer hair cells (OHCs) in conjunction with a temporal increase of NOS activity in the organ of Corti. This suggests that GLU may be involved in OHC degeneration under toxic conditions, with NO production possibly playing a role in this process.

Nuclear transport of the major capsid protein is essential for adeno-associated virus capsid formation

Adeno-associated virus capsids are composed of three proteins, VP1, VP2, and VP3. Although VP1 is necessary for viral infection, it is not essential for capsid formation. The other capsid proteins, VP2 and VP3, are sufficient for capsid formation, but the functional roles of each protein are still not well understood. By analyzing a series of deletion mutants of VP2, we identified a region necessary for nuclear transfer of VP2 and found that the efficiency of nuclear localization of the capsid proteins and the efficiency of virus-like particle (VLP) formation correlated well. To confirm the importance of the nuclear localization of the capsid proteins, we fused the nuclear localization signal of simian virus 40 large T antigen to VP3 protein. We show that this fusion protein could form VLP, indicating that the VP2-specific region located on the N-terminal side of the protein is not structurally required. This finding suggests that VP3 has sufficient information for VLP formation and that VP2 is necessary only for nuclear transfer of the capsid proteins.

Comparison of the levels of hepatocyte growth factor and vascular endothelial growth factor in aqueous fluid and serum with grades of retinopathy in patients with diabetes mellitus

AIMS

To determine the relation between the stages of diabetic retinopathy (DR) and the levels of hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) in aqueous fluid and serum.

METHODS

Levels of HGF and VEGF in serum and aqueous humour obtained during ocular surgery were measured by enzyme linked immunosorbent assay in 58 diabetic patients with 32 non-diabetic patients (NDM) as controls. The patients with diabetes were classified into three groups according to the stage of DR: no DR (NDR; 15 cases), non-proliferative DR (NPDR; six cases), and proliferative DR (PDR; 37 cases).

RESULTS

No significant differences were found between any of the groups in serum concentrations of HGF or VEGF. The aqueous HGF levels increased with the stage of DR: NDM, median 397 pg/ml, range 133-930 pg/ml; NDR, 371 pg/ml, 142-1536 pg/ml; NPDR, 455 pg/ml, 162-1007 pg/ml; and PDR, 638 pg/ml, 187-2222 pg/ml. The aqueous VEGF levels in PDR (median 212 pg/ml, range 14-1216 pg/ml) were significantly higher than in NDM (105 pg/ml, 9-203 pg/ml), but aqueous HGF concentrations were unrelated to those of VEGF.

CONCLUSION

The results of the present study suggest that both HGF and VEGF present in the ocular tissues may play important roles in the progression of DR.

Acute and chronic effects of hyperosmolality on mRNA and protein expression and the activity of Na-K-ATPase in the IMCD

We investigated acute and chronic effects of hyperosmolality on mRNA and protein expressions of Na-K-ATPase alpha and beta isoforms and Na-K-ATPase activity in the rat inner medullary collecting duct (IMCD). Incubation of IMCD in hypertonic medium for 30 min reduced the Na-K-ATPase activity by 50%. The Na-K-ATPase activity of dehydrated rats measured in isotonic medium was decreased, and incubation in hypertonic medium did not further decrease the activity. Incubation of IMCD in hypertonic medium for 6 h did not change alpha(1) mRNA. In contrast, dehydration decreased alpha(1) subunit mRNA and protein and beta(1) protein expressions without changing beta(1) mRNA. These data show (1) that acute hyperosmolality decreases Na-K-ATPase activity in IMCD without changing alpha(1) and beta(1) mRNA and (2) that 2 days of dehydration decreased Na-K-ATPase activity by reducing alpha(1) and beta(1) proteins. Thus, the mechanisms for the inhibition of the Na-K-ATPase activity in IMCD is different between acute and chronic exposure to hyperosmolality.

Involvement of nitric oxide in aminoglycoside vestibulotoxicity in guinea pigs

Involvement of nitric oxide (NO) has been reported in physiological and pathological conditions in the inner ear. Recently, the presence of nitric oxide synthase (NOS) was demonstrated in the vestibular epithelium. In this study we used nicotinamide adenine dinucleotide phosphate-diapholase staining to monitor NOS activity during degeneration of guinea pig vestibular epithelia affected by streptomycin. Increased NOS activity was observed in affected epithelia in a dose- and time-dependent manner and a NOS inhibitor could protect hair cells from apoptosis. Additionally, cycloheximide significantly reduced NOS activity and the occurrence of apoptosis. These findings suggest that NO is involved in the degenerative process of vestibular epithelia caused by aminoglycosides.

Expression of telomerase subunits and localization of telomerase activation in hydatidiform mole

Activation of telomerase compensating for the loss of telomeres has been implicated in human cell immortalization and carcinogenesis. Telomeric repeat amplification protocol (TRAP) assay can be used to detect telomerase activity in a variety of malignant tumours, including those of the female reproductive tract which have been found to have high levels of telomerase activity. However, it is unclear whether all the cells or only a subset of cells within a tumour have telomerase activity. To determine the regulation mechanism of telomerase activity in hydatidiform moles, we studied telomerase activity at the single cell level (using an in situ TRAP assay), and expression of TLP1 (telomerase protein 1), TERC (telomerase RNA component) and TERT (telomerase reverse transcriptase component). Expression of TERC and TLP1 was observed in all normal chorionic villi, as well as in trophoblastic diseases, and various cell lines irrespective of telomerase activity. TERT expression was observed in trophoblastic diseases and normal chorionic villi with telomerase activity but not in normal chorionic villi without telomerase activity, except in some cases in the present series, indicating that TERT expression is closely associated with telomerase activity. Upregulation of TERT expression may thus play an important role in telomerase reactivation.

[Survey of infective endocarditis in the last 10 years: analysis of clinical, microbiological and therapeutic features]

Infective endocarditis still presents problems with early diagnosis, selection of antibiotics and timing of surgical procedure despite modern antibiotics and investigative procedures. A retrospective study was performed to clarify the clinical and microbiological spectrum of recent infective endocarditis in the Japanese population in 38 patients with infective endocarditis (mean age 42.7 +/- 12.5 years) treated from March 1986 to March 1996. The portal of entry to bacteremia was unknown in most cases (57.9%), but the commonest identified portal was dental procedure (18.4%). Overall, the aortic valve was infected most frequently (44.7%) and followed by the mitral valve (36.8%). The most common complication of infective endocarditis were emboli (11/38, 28.9%) and congestive heart failure, NYHA class III and IV (14/38, 36.8%). Organisms were isolated from 26 of the 38 (68.4%) patients. Streptococcus viridans was the most frequent organism (34.2%), and then Staphylococcus aureus (13.2%). The blood culture positivity of microorganism was significantly higher in patients not receiving antibiotics than in those the received antibiotics (87.5% vs 50%, p < 0.05). The prevalence of streptococcal endocarditis decreased in the 1990s (1992-1996) in comparison with those in the 1980s (1986-1988). Multiple antibiotics were used frequently in 1990s and the sensitivity titer to piperacillin reduced from 3.0 in the 1980s to 1.8 in the 1990s. In contrast to reduction of streptococcal endocarditis, Staphylococcus aureus endocarditis has increased recently from 12.5% to 30.8%. The most common clinical features are valve destruction, low sensitivity of penicillin, and significantly higher in-hospital mortality. Surgical treatment was indicated most commonly in cases of uncontrollable heart failure, and infected valves were replaced during the active stage in 11/23 cases (47.8%). In-hospital mortality was higher in the medical treatment group than in the surgical group, but a long-term mortality of mean observation term 4.2 +/- 3.2 years was identical in the chronic phase. In patients with infective endocarditis and successful treatment in the acute stage, a long-term survival rate in medically treated patients was found almost comparable to surgically treated patients in our series. However, it should be emphasized that streptococcal endocarditis is being replaced by infection by Staphylococcus aureus, which is resistant to penicillin and requires intensive chemotherapy and proper decision at suitable timing for surgical therapy in the early stage.

Increased heterogeneity of chromosome 17 aneuploidy in endometriosis

OBJECTIVE

Endometriosis is a complex gynecologic disorder that may display features similar to malignancy, including aggressive growth and localized invasion of the myometrium or spread to various organs outside the uterus. Molecular studies of cancer have demonstrated that genomic instability involving chromosome 17 plays a role in the development and progression of various tumor types. These involve gain and/or loss, deletions, and mutations of candidate tumor suppressor genes (eg, BRCA1 and p53 ) on chromosome 17.

STUDY DESIGN

We used a 2-color fluorescence in situ hybridization method for analysis of endometriotic and normal archival tissue. Centromere-specific and locus-specific p53 probes localized to chromosome 17 were selected to study 8 patients with late-stage (severe) endometriosis. Single cells localized to endometriotic lesions or normal endometrial glands were analyzed and identified as normal or abnormal on the basis of the distribution of fluorescence in situ hybridization signals.

RESULTS

Overall, chromosome 17 aneuploidy was significantly greater (P <.05) in the endometriosis specimens (mean of 65%) than in normal endometrial cells (mean of 25%). No significant difference (P =.1071) in the distribution of fluorescence in situ hybridization signals was observed among the 5 normal endometrial specimens. However, significant differences (P <. 0001) were observed between the 8 endometriosis tissue specimens.

CONCLUSION

We found increased heterogeneity of chromosome 17 aneuploidy in endometriosis. These findings support a multistep pathway involving somatic genetic alterations in the development and progression of this common disease.

Loss of protection by hypoxic preconditioning in aging Fischer 344 rat hearts related to myocardial glycogen content and Na+ imbalance

OBJECTIVES

The objective of this study was to determine whether hypoxic preconditioning (HP) could lessen the myocardial increase in [Na+]i, thus protecting the aging myocardium against ischemia.

BACKGROUND

A decrease in ischemic tolerance with aging is associated with an accelerated increase in [Na+]i during ischemia. Ischemic preconditioning fails to protect the middle-aged and senescent myocardium against ischemia.

METHODS

Isolated hearts of young adult (12-week-old), middle-aged (50-week-old) and senescent (100-week-old) Fischer 344 rats were subjected to 25 min of ischemia with or without HP followed by 30 min of reperfusion. Left ventricular (LV) function, myocardial energy metabolites and [Na+]i were measured.

RESULTS

In the older groups, the recovery of LV function and high-energy phosphates (HEPs) was lower with an increased release of creatine kinase (CK) during reperfusion than in the young group. The increased [Na+]i at the end of ischemia was greater in the former groups than in the young group. HP decreased myocardial glycogen and lessened the increased [Na+]i in the young group, resulting in an improved recovery of LV function and HEPs, as well as decreased CK release. However, the levels of glycogen before HP in the older groups were higher than in the young group and its levels after HP were similar to that before HP in the young group. HP did not affect the [Na+]i, exacerbated CK release and inhibited the recovery of LV function and HEPs in the older groups.

CONCLUSIONS

HP failed to lessen the increased [Na+]i or to protect the aging hearts, probably due to the preexistence of increased glycogen level.

Epithelial-myoepithelial carcinoma: An unusual tumor of the paranasal sinus

A 65-year old woman presented with nasal obstruction and on examination was found to have a huge mass in the maxillary sinus. This was removed, and histological examination revealed a mixture of trabecular structures consisting of inner dark cells, outer clear cells and solid structures consisting of only clear cells. Immunohistochemical examination showed the clear cells to be positive for alpha-smooth muscle actin. Ultrastructural examination confirmed the myoepithelial cell origin. The characteristic morphological, immunohistochemical and ultrastructural features aided in the diagnosis of epithelial-myoepithelial carcinoma.

Induction of macrophage exudation in the inner ear by OK432 treatment

OK432, a heat- and penicillin-treated lyophilized powder of a low virulent Su strain of Streptococcus pyogenes, was injected into the perilymphatic space of guinea pigs in order to determine the kinetics of exudation of inflammatory cells into the cochlea over a 7-day period. OK432 induced exudation of many neutrophils and Asialo GM1-positive cells into the scala tympani. The numbers of these cells peaked on the first day after OK432 treatment, and then gradually decreased. Four days after treatment very few of either of these types of cells were observed in the scala tympani. Asialo GM1-positive cells were confirmed to be activated macrophages. In ears treated with physiological saline or with the additive included in OK432 in control studies, no notable changes in the inner ear were recognized. These findings suggest that the inner ear can undergo induction of macrophage rapidly exudation by OK432 treatment as has previously been observed for other organs.

Assessment of hair cell death using the dye extrusion method

We examined the usefulness of the dye extrusion method for assessing cochlear hair cell death in guinea pigs. Unilateral temporal bones were incubated in sterile Dulbecco modified Eagle's medium for 1-6 h and then perfused with PBS/0.3% trypan blue to determine hair cell viability. Cells with nuclei stained with trypan blue were assumed to have died. The contralateral temporal bones of each animal were incubated with the same medium for 1-6 h and examined by transmission electron microscopy (TEM). This method revealed that hair cell viability under these conditions was maintained for at most 3 h. After incubation for more than 3 h, hair cell injury began and increased. After 6 h incubation, TEM revealed apoptotic death of outer hair cells. The results with this method agreed with the TEM findings. The dye extrusion method is simple, easy and useful for screening hair cell death in the cochlea under pathological conditions.

Apoptotic cell death in Kikuchi's disease: a TEM study

The pathogenesis of Kikuchi's disease (Kikuchi-Fujimoto disease, histiocytic necrotizing lymphadenitis) remains unclear. However, some previous studies have suggested that a disorder in cellular immunity is responsible for this disease, and apoptotic cell death appears to be the principal finding in the histogenesis of this disease. In the present study, a lymph node from a female patient with Kikuchi's disease was examined by transmission electron microscopy (TEM). TEM revealed specific morphological features of apoptotic cells, such as nuclear chromatin condensation and fragmentation along the nuclear membrane with intact organelles, and the presence of histiocytes phagocytosing karyorrhectic debris (apoptotic bodies) in areas affected by Kikuchi's disease. Although neither the role nor the trigger of apoptosis in Kikuchi's disease has been clearly determined, our findings show that apoptotic cell death clearly plays a role in the pathogenesis of Kikuchi's disease.

Time-dependent response of vestibular hair cells of guinea pigs following high-dose applications of streptomycin

Apoptosis has been reported to occur in vestibular hair cells following aminoglycoside treatment and is suggested to play a predominant role in deletion of affected hair cells. However, the type of cell death occurring during an acute phase of vestibular damage following high-dose application of streptomycin has not yet been determined. Hence, in this study we examined the cell death mode of vestibular hair cells during the acute phase. The numbers of hair cell nuclei stained by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling (TUNEL) method and residual hair cells were quantitatively analysed. Hoechst nuclear staining was used for analysis of the nuclear morphology of affected hair cells. TUNEL staining of hair cell nuclei and lost hair cells began to appear 6 h after streptomycin treatment and increased with more exposure time. Apoptotic nuclear features could also be found from 6 h after streptomycin treatment. These findings support the thesis that apoptosis is a predominant cell death mode in degeneration of vestibular hair cells due to streptomycin ototoxicity.

Local substances regulating cochlear blood flow

The regulation of cochlear lateral wall blood flow was investigated in rats using histochemistry, immunohistochemistry and transmission electron microscopy. The contractile protein, tropomyosin (TM) was localized in the pericyte around the vessels of spiral ligament but little was seen around strial capillaries. Prostaglandin I2 (PGI2) is a vasodilatory substance produced by PGI2 synthase (PGI2S), which is present in the endothelium of the vessels of spiral ligament but not much is present around strial capillaries. Endothelial nitric oxide synthase (eNOS) was present in the endothelium of both the vessels of spiral ligament and strial capillaries. These findings indicate that the blood flow of the cochlear lateral wall is regulated mainly in the spiral ligament by locally produced substances and that strial blood flow is not significantly regulated by pericytes responsible for enlargement or constriction of capillaries.

Cycloheximide blocks the toxic effect of streptomycin in guinea pig vestibular hair cells

Apoptosis has been suggested to be a predominant cell death process for streptomycin-induced degeneration of vestibular hair cells. However, the biochemical aspects of this have not been studied. The purpose of this study was to examine the biochemical aspects of apoptosis of vestibular hair cells caused by streptomycin. Cycloheximide is a widely used protein synthesis inhibitor in studies of apoptosis. We therefore investigated cycloheximide effects on degeneration of vestibular hair cells following streptomycin applications. Supplements of cycloheximide significantly prevented DNA fragmentation in hair cell nuclei and reduced the loss of hair cells. This suggests that cycloheximide possibly inhibits apoptosis of hair cells and attenuates streptomycin-induced degeneration of the vestibular epithelium.

Study of tuberculosis in the field of otorhinolaryngology in the past 10 years

Over the 10 years from 1988 to 1997, a total of 18 cases of tuberculosis of the head and neck (8 of the cervical lymph node, 5 of the larynx, 2 of the salivary glands, and 1 each of the hypopharynx, tongue and middle ear) were diagnosed in our department. Four cases were diagnosed in 1996 and 8 in 1997, indicating a rapid increase over these 2 years. Definitive diagnosis was based on histopathological examination in 14 cases, detection of M. tuberculosis in 1 case and exclusion diagnosis, mainly using the tuberculin skin test, in 3 cases. The length of time from the first examination to obtaining a definitive diagnosis was 14.2 +/- 6.5 days in five subjects in whom tuberculosis was suspected from the beginning or in whom tuberculosis was suggested by the physician in making a differential diagnosis, 25.3 +/- 17.2 days in the group in whom malignant tumour was suspected and 64.3 +/- 57.3 days in other cases. Although no significant difference was found (p = 0.077), the length of time until diagnosis tended to be shorter in the cases that were suspected of having tuberculosis from the beginning. Family history and past history of tuberculosis, contact with a tuberculous patient and abnormal findings at chest X-ray were examined as background factors, and some of these were present in nine out of the 18 cases. In the five cases diagnosed in the early stage, some of the background factors were found in four cases. However, no significant difference in the time until definitive diagnosis was found between the groups with or without background factors in all cases (p = 0.675). These results suggest the importance of considering tuberculosis when performing differential diagnoses.

Role of amino acids in cochlear degeneration: deprivation of cystine induces death of cochlear hair cells of guinea pigs in vitro

Redox regulation reportedly plays a role in maintaining cochlear homeostasis. However, little is known about the roles of oxidation-reduction systems in the cochlea. We examined the role of the cystine/cysteine oxidation-reduction system in survival of cochlea hair cells in vitro. The survival of hair cells was evaluated in cochlea specimens following incubation with the medium supplemented with various concentrations of cystine. Dying hair cells were detected by the trypan blue extrusion method. The rates of cell death for both outer and inner hair cells increased significantly with a decrease in the concentration of cystine. In addition, the rate of cell death of IHCs tended to be higher than that of OHCs. These findings suggest that the cystine/cysteine system might be required for maintenance of homeostasis in cochlear hair cells, especially in IHCs.

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.

External high-frequency oscillation for hypercapnia after upper abdominal surgery

The purpose of this study was to evaluate the efficacy of external high-frequency oscillation (EHFO) in patients with hypercapnia following upper abdominal surgery. Seven patients were ventilated with EHFO for 2 hr at 60 oscillations/min, with cuirass pressures of 36 cm H2O (-26 to +10), and an inspiratory to expiratory ratio of 1:1. Blood gases and cardiac functional parameters were examined during the 2 hr on EHFO. Pulmonary functional parameters were analyzed prior to the institution and after the termination of EHFO. PaCO2 significantly decreased from 61 +/- 8 mmHg to 48 +/- 7 mmHg after 10 min on EHFO (p < 0.01). PaO2 significantly increased from 74 +/- 10 mmHg 95 +/- 26 mmHg after 1 hr on EHFO (p < 0.01). The heart rate decreased significantly from 108 +/- 27 beats/min to 101 +/- 24 beats/min after 30 min on EHFO (p < 0.05). The FEV1 and FVC significantly increased from 1.09 +/- 0.54 L to 1.50 +/- 0.46 L (p < 0.01) and from 1.90 +/- 0.74 L to 2.18 +/- 0.60 L (p < 0.05), respectively. The other parameters of lung function also significantly improved after the termination of EHFO. The significant changes in all of the pulmonary functional parameters continued for 1 hr after the termination of EHFO. EHFO is an effective method of gas exchange which is associated with earlier return to preoperative lung function.