Comparative study on chemical pretreatments to accelerate enzymatic hydrolysis of aquatic macrophyte biomass used in water purification processes.

In this study, enzymatic hydrolysis of two floating aquatic plants which are suitable for water purification, water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes L.), was performed to produce sugars. Twenty chemical pretreatments were comparatively examined in order to improve the efficiency of enzymatic hydrolysis. As a result, the alkaline/oxidative (A/O) pretreatment, in which sodium hydroxide and hydrogen peroxide were used, was the most effective pretreatment in terms of improving enzymatic hydrolysis of the leaves of water hyacinth and water lettuce. The amount of reducing sugars in enzymatic hydrolysate of water lettuce leaves was 1.8 times higher than that of water hyacinth leaves, therefore water lettuce seems to be more attractive as a biomass resource than water hyacinth. Although roots of these plants contained large amounts of polysaccharides such as cellulose and hemicellulose, they generated less monosaccharides than from leaves, no matter which chemical pretreatment was tested.

Presence of Streptococcus infection in extra-oropharyngeal head and neck squamous cell carcinoma and its implication in carcinogenesis.

To investigate the involvement of S. anginosus infection in head and neck cancer in the extra-oropharyngeal cavity, we analyzed 3 DNA samples prepared from squamous cell carcinoma of the external auditory canal and one from squamous cell carcinoma of the skin using polymerase chain reaction (PCR) analysis and Southern blot analysis to detect the DNA sequence of S. anginosus. We also examined these four specimens by Gram's stain to detect the streptococcal bacterial bodies. By PCR analysis, the DNA sequence of S. anginosus was found in 4 out of 4 (100%) DNA samples obtained from these tumors. By Southern blot analysis, positive bands were detected in one out of the 3 (33%) samples from the tumor taken from the external auditory canal. We detected streptococcal bacterial bodies in one of the three specimens from the tumor obtained from cancer of the external auditory canal and in the one specimen from the skin cancer by the method of Gram's stain. Contrary to our expectations, these bacterial bodies were located in the middle of the tumor. Since S. anginosus is thought to exist in the mouth as a normal flora and to be located mainly in the gingiva and dental plaque, these data strongly indicate that S. anginosus infection is implicated in the carcinogenesis of head and neck squamous cell carcinoma.

Thermal conductivity of a self-frequency-doubling laser crystal measured by use of optical methods.

We present a new all-optical technique to measure the thermal conductivity of laser crystals. This technique can be used for crystals that are too small for direct measurement of thermal conductivity. We used this technique to measure the thermal conductivities of Nd:LYAB, with the result of 44 +/- 6% compared with that of Nd:YAG thermal conductivity.

Development of a routine analytical procedure for nonylphenol polyethyoxylates and their biodegradation products in sludge from sewage treatment plants.

A method of quantitative analysis of nonylphenol polyethoxylates (NPnEOs) and their biodegration products (NPE-BDPs) in sewage sludge, which is effective, economical, and applicable to a high performance liquid chromatography was developed and actual sludge samples collected from Japanese sewage treatment plants (STPs) were analyzed using the method to confirm its effectiveness. Soxhlet extraction showed better recovery in a spike and recovery test than shaking extraction. Among the four pretreatments for Soxhlet extraction tested, the condition in which samples were freeze-dried, ultrasonicated, and extracted with methanol showed the best recovery efficiency. Quantitative analysis of NPE-BDPs in STP sludge resulted in 6.1 microg/g, 4.3 microg/g, and 8. microg/g in average concentration for NPnEOs (n=1-3), NPnEOs (n=4-18), and nonylphenol ethoxycarboxylates (NPnECs (n=1-3)), respectively, and the values of concentration were 100-1000 times higher than those in effluent at Japan's STPs. The results implied importance of quantitation of NPE-BDPs in sewage sludge to assess the risk to the environment.

A clinical study of oral tongue cancer.

Thirty-nine previously untreated patients with squamous cell carcinoma of the oral tongue treated with curative intent in our hospital from 1993 through 1998 are reviewed. Of these patients, those in the early stage (stages I and II) constituted 64%. The over all 5-year survival rate of all the patients was 60%. The 5-year survival rate of the patients with early stage cancers was unsatisfactory (stage I: 73%; II: 56%). This was thought to be related to the absence of elective neck dissection and the administration of chemotherapy in the patients with early stage cancer. We concluded that elective neck dissection for levels I, II and III is the first choice of treatment strategy for patients with stage II cancer. Our data indicate that chemotherapy in patients with early stage cancer was not beneficial and might have increased the risk of late lymph node metastasis in the clinically NO patients without neck dissection. There were 9 patients younger than 40 years of age and their survival rate at 5 years was 80%, which was better than that of the older patients. The treatment strategy for patients younger than 40 years of age was similar to that of older patients.

Streptococcus anginosus in head and neck squamous cell carcinoma: implication in carcinogenesis.

It has been suggested that Helicobacter pylori (H. pylori) infection might be associated with not only gastric ulcers but also gastric malignancies. Recently, it was reported that the Streptococcus anginosus (S. anginosus) DNA sequence was found in DNA samples extracted from esophageal cancers. Because smoking and alcohol abuse are regarded as risk factors for both esophgeal cancer and head and neck cancer, infection of S. anginosus might be associated with carcinogenesis of head and neck cancer. To investgate the involvement of S. anginosus infection in head and neck cancer, we analyzed 217 DNA samples prepared from head and neck squamous cell carcinomas. We performed PCR analysis with S. anginosus-16S ribosomal DNA-specific primers, and Southern blot analysis. For detection of S. anginosus in the oral and pharyngeal cavities, we used oropharyngeal bacteriological culture and PCR analysis of gingival smears of the patients. By PCR analysis, the S. anginosus DNA sequence was found in 217 out of 217 (100%) DNA samples obtained from head and neck cancers. By Southern blot analysis, positive bands were detected in 41 out of 125 (33%) samples. We could find no S. anginosus colony in oropharyngeal bacteriological culture dishes of 53 patients with and without head and neck cancer. On the other hand, we found the S. anginosus DNA fragment in 8 out of 8 DNA samples obtained from gingival smears by PCR analysis. These data indicate that the upper aerodigestive environment of the patients permitting S. anginosus infection was implicated in the carcinogenesis of head and neck squamous cell carcinoma.

Tunable phase conjugation by intracavity degenerate four-wave mixing in an injection-seeded solid dye laser.

We demonstrate efficient degenerate four-wave mixing in a laser injection-seeded solid dye laser. Phase-conjugate energy of as much as 140 times the total energy injected externally into the phase conjugator was extracted. Moreover, efficient phase-conjugate energy was obtained in the broad wavelength region from 558 to 567 nm.

Launched pulse-shape dependence of the power spectrum of the spontaneous brillouin backscattered light in an optical fiber.

We theoretically analyze the relationship between the electric field envelope shape of an optical pulse launched into an optical fiber and the power spectrum of the spontaneous Brillouin backscattered light it produces. The electric field envelope is characterized by the pulse width, leading-trailing time, and steepness. The peak power of the launched, pulsed-light power spectrum is proportional to the square of the pulse width regardless of the pulse leading-trailing time and steepness, and the power spectrum broadens in inverse proportion to the pulse width. The peak power of the spontaneous Brillouin backscattered light produced by the launched, pulsed light is proportional to the pulse width when it is above approximately 100 ns and is proportional to the square of the pulse width when it is below approximately 1 ns. The power spectrum of the spontaneous Brillouin backscattered light also broadens rapidly corresponding to the pulse width, when the pulse width falls below approximately 30 ns. As the pulse leading-trailing time is shortened or the pulse leading-trailing part becomes steep, the Brillouin backscattered-light power spectrum broadens greatly, even if the launched pulse width remains constant. Our analysis showed that an optical pulse with a triangular-shaped electric field envelope forms the Brillouin backscattered-light power spectrum with the narrowest profile and consequently gives the minimum error in measuring the peak-power frequency, when the pulse width is below approximately 50 ns. The measurement error with the triangular-shaped pulsed light is 1/square root(2) times smaller than that for a rectangular-shaped pulsed light, when the pulse width falls below several nanoseconds. By contrast, the rectangular-shaped envelope gives the minimum error when the pulse width exceeds approximately 50 ns.

[An adult case of asymptomatic congenital tracheal stenosis].

We report an adult case of asymptomatic congenital tracheal stenosis. A 42-year-old woman was admitted to our hospital, whose chief complaint was tongue pain. Clinical examination revealed a tumor 35 x 20 mm in diameter along the middle, right edge of the tongue, and histopathological examination determined a diagnosis of squamous cell carcinoma of the tongue. She had no history of dyspnea, stridor nor recurrent pneumonia, and enjoyed playing table tennis in her daily life. Physical examination, electrocardiogram, spirogram and laboratory data showed no abnormal signs although chest roentgenogram revealed a narrowed trachea 6 mm in diameter, however, the tracheal stenosis was not noted at the time. On the 10th hospital day, radical operation for cancer of the tongue including right hemiglossectomy and supraomohyoid neck dissection, were performed. Oral intubation was not successful, and a tracheostomy was conducted. The trachea was incised, and revealed that complete tracheal rings existed without posterior membraneous tissue. The operation time was limited because of high airway pressure for a narrow tracheal tube (5 mm in diameter). The main postoperative complication was one crust formation in the tracheal lumen that resulted in CO2 narcosis due to check valve obstruction of the trachea on the 4th postoperative day. A nebulizer provided continuous moisture and was effective in preventing recurrence of the crust attachment to the tracheal membrane thus, the tracheostoma was closed by the 17th postoperative day. This case indicates that among healthy people there are extremely rare patients with congenital tracheal stenosis who survive their postnatal and infantile periods, and who experience no trouble in their daily lives. As physicians, we must be aware of this disease in adult patients in our clinics.

[Multiple primary cancers of oral cavity and pharynx].

Multiple primary cancers were found in 23 of 68 patients (34%) with an index cancer in the oral cavity or pharyngeal area treated in our institute from June 1995 to July 1998. Four cases had triple primary cancers. All 68 cases underwent upper and lower gastrointestinal endoscopy as well as ultrasonography of the liver. Lung CT was performed in cases with abnormal findings on chest roentgenograms. Multiple cancers were found in 5 of 25 oral cavity cases (20%), 6 of 14 mesopharynx cases (43%) and 12 of 29 hypopharynx cases (41%). Nine of 23 cases (39%) were synchronous and 14 (61%) were metachronous. Eighteen of 27 (69%) secondary cancers occurred in the upper aerodigestive tract with an especially high incidence (22%) in the esophagus. Gastroendoscopy also revealed 7 neoplastic lesions, aside from cancers, with the total abnormal rate of 24% (24/68). Thus, gastroendoscopy is useful for the diagnosis of multiple primary cancers. The frequency of multiple primary cancers in males (33%) was not different from that in females (35%). The average age of multiple primary cancer patients (65.1 years) was a little higher than that of single cancer patient (62.7 years). Smoking or drinking was not related to the incidence of multiple cancers. The interval between the first and the second cancer in metachronous cancer cases was 25.5 months on average, and within 4 years in 71% (10/14) of the cases. This result suggests that close follow-up including endoscopy should be required for at least 4 years after treatment of oral or pharyngeal cancer. Radical treatment for each of the multiple cancer lesions was performed in 22 of 23 cases, and the mortality rate of multiple primary cancer cases was not significantly different from that of single cancer cases. Among 7 cases who died of disease, 5 cases died of distant metastasis, suggesting that control of distant metastasis is an important issue in the treatment of multiple primary cancers.

[Indication of tracheostomy for advanced oral or mesopharyngeal cancer resection].

In advanced oral or mesopharyngeal cancer requiring reconstruction, preventive tracheostomy have been performed to insure an airway postoperatively. However, tracheostomy often causes difficulty in swallowing and stress in the postoperative period for the patients. We have devised a strategy to avoid tracheostomy as much as possible in the cases requiring reconstruction except for the cases with over 2/3 resection of the base of the tongue or with prospective difficulty of re-intubation. Eleven cases were treated without tracheostomy out of 20 cases operated on with reconstruction in our hospital from 1995 through 1997. These patients were managed under nasal intubation for less than 2 days on average with careful observation postoperatively. In 11 non-tracheostomized cases, 1 case experienced venous thrombosis of a free flap and tracheostomy was performed at the salvage operation. Other 10 non-tracheostomized case were compared with 10 tracheostomized cases who were treated from 1991 though 1995. It was revealed that non-tracheostomized cases tended to have shorter periods until they could speak or eat, and also have a shorter postoperative admission term. In these cases, we have not experienced serious complications such as aspiration pneumonia or dyspnea, instead, special care in the postoperative period was needed. Thus, certain advanced cases who undergo curative resection followed by reconstruction can be managed without tracheostomy. The indication of tracheostomy in surgery for oral or mesopharyngeal cancer should be decided carefully.

[Loss of heterozygosity of 3p21 and 9p21 in head and neck squamous cell carcinomas and its prognostic implication].

To examine whether genetic factors influence the prognosis of cancer patients, several microsatellite markers were used to determine the allelic loss of certain areas of the genome. Three microsatellite markers, D3S1067, IFNA and D9S171 were used to study the loss of heterozygosity (LOH) of 3p21 and 9p21 in 93 head and neck squamous cell carcinomas. Of 57 informative cases, LOH was detected in 27 of 57 (47%) DNA samples obtained from cancer specimens when at least one marker was used. The frequency of LOH was not correlated with the clinical factors. However, the frequency of LOH was significantly higher in the recurrent cases than in the non-recurrent cases, and patients with 3p21 and/or 9p21 LOH tended to survive for a shorter period of time. These results suggested that the allelic loss at 3p21 and/or 9p21 could be correlated with the prognosis of the patients, and that it was a novel prognostic factor independent of other clinical factors concerning head and neck cancers. LOH at 3p21 and/or 9p21 may help to identify head and neck cancer patients with a poor prognosis, who need an intensive postoperative follow-up protocol, or who are suitable for novel investigational therapeutic approaches.

[Simultaneous reconstruction of pharyngoesophagus and phonetic shunt following laryngopharyngoesophagectomy].

Because of its many advantages, free jejunal transfer has gained wide acceptance for pharyngoesophageal reconstruction after ablative surgery. Because the jejunum is well vascularized, it facilitates good wound healing, and has a low incidence of anastomotic insufficiency, fistula formation and stricture. However, voice rehabilitation in this group of patients can be difficult. Therefore, we performed primary tracheojejunal shunt operations for voice restoration with jejunum siphons using Nozaki's method (type 3). In this procedure, after dividing a section of the jejunum into two segments, the reconstructed neopharyngoesophagus is anastomosed in a side-to-end fashion to the fabricated shunt using the other segment of the jejunum, as an "elephant nose shunt" so called because of its appearance. Voice restoration can be achieved in patients who undergo laryngopharyngoesophagectomy through these reconstructive procedures. We performed this surgery for nine hypopharyngeal cancer patients after total pharyngo-laryngo-esophagectomy. Following placement of the shunt, no special care was required. Only one patient developed a severe aspiration. No leakage was seen and the swallowing function was preserved in all patients. Four of nine patients could speak well following these procedures. A vibratory source is created in the neoesophagus, above the elephant shunt. During speech production, narrowing of the inside and vibration of the jejunal mucosa can be observed using a laryngeal fiber scope. In order to study the acoustical characteristics of shunt speech, voice analysis was performed in patients with restored phonatory function using Computerized Speech Lab Model 4300 (KAY). Irregularities of pitch periods in the voice sample were measured using Jita (the pitch period) and Jitt (relative evaluation of the pitch) for the very short term (cycle-to-cycle), and PPQ (pitch period pertubation quotient) for the short term (cycle-to-cycle with a smoothing factor of 5 periods). Irregularities of the peak-to-peak amplitude were measured using ShdB (evaluation in dB of the peak-to-peak amplitude) and Shim (relative evaluation of the peak-to-peak amplitude) for the very short term (cycle-to-cycle), and APQ (amplitude perturbation quotient) for the short term (cycle-to-cycle with a smoothing factor of 11 periods). The pertubation parameters of shunt speech are larger than normal ones not only in terms of the period but also in terms of the amplitude. These results are similar to those of laryngeal polyps, recurrent nerve palsy and esophageal speech. Recovery of phonation using Nozaki's type 3 method with the elephant nose shunt appears promising for pharyngo-laryngo-esophagectomized patients.

Highly efficient degenerate four-wave mixing with multipass geometries in a polymer laser dye saturable amplifier.

We demonstrate the use of highly efficient degenerate four-wave mixing for phase conjugation with multipass geometries in a polymer laser dye saturable amplifier. Phase-conjugate energy reflectivity of as much as 20,000% with a four-pass geometry in the longitudinally pumped polymer dye was obtained at 564 nm.

Trade-off between the spatial and the frequency resolutions in measuring the power spectrum of the Brillouin backscattered light in an optical fiber.

We theoretically analyze the relation between the pulse width of light launched into an optical fiber and the resultant power spectrum of spontaneous Brillouin backscattered light. Through this analysis, we determine numerically that the bandwidth of the Brillouin backscattered light becomes wider, and thus the measurement accuracy in determining the peak-power frequency degrades in approximately inverse proportion to the launched pulse width. Experimental results with various pulse widths are in good agreement with the derived theoretical results.

pH regulation of the globular substance in the otoconial membrane of the guinea-pig inner ear.

Physiological and pharmacological characteristics of the globular substance, a precursor of otoconia, are not well understood. In the present study, we investigated the variations and regulation of internal pH (pHi) of the globular substance of the guinea-pig inner ear. The otoconial membrane was dissected out from the utricular macula and loaded with the pH-sensitive fluorophore, carboxyseminaphthorhodafluor-1. Dynamic changes of fluorescence were directly observed under a confocal laser scanning microscope, and pHi was calculated from dual emission ratio. In the NaCl standard solution buffered with 5 mM HEPES/Tris at pH 7.4, the pHi of the globular substance varied from 6.26 to 8.55 with an average of 7.21 (n = 270). Exposure to 25 mM NH+4 induced a rapid increase of the pHi followed by a slow relaxation. The, wash-out of NH+4 caused a prompt and pronounced acidification followed by a gradual pHi recovery to the initial level. This gradual pHi recovery was significantly inhibited by the absence of external Na+, indicating the presence of an external Na(+)-dependent H+ extrusion mechanism. This pHi recovery was also inhibited by 1 mM amiloride and 10 microM 3-amino-N-(aminoiminomethyl)-6-[ethyl(2-propyl)amino]pyrazine-2-ca rboxamide. These results suggest the presence of an Na(+)-H+ exchanger in the globular substance of the guinea pig. However, HCO3(-)-transporting mechanisms were not determined. The working hypothesis for the otoconial formation is discussed.

Tunable, visible phase conjugator with a saturable-amplifier polymer laser dye.

We present the first report to the best of our knowledge of highly efficient phase conjugation in a laser-pumped polymer-dye saturable amplifier. Phase-conjugate reflectivity of as much as 210% at 560 nm has been obtained. Moreover, efficient reflectivity has been obtained in the broad wavelength region from 556 to 567 nm.

Spectral-linewidth broadening in synchronous Raman fiber amplification caused by cross-phase modulation effects and its suppression.

When coherent light is amplified by a synchronous Raman fiber amplifier pumped by output pulses from a high-power erbium-doped fiber amplifier operating in an unsaturated gain regime, the detection efficiency with the heterodyne method is degraded. This degradation is caused mainly by cross-phase modulation effects. It is confirmed that using power-flattened pump pulses can suppress these effects.

Mode-coupling analysis in axisymmetric birefringent waveguides.

Axisymmetric periodic media such as annular layers have axi-symmetric birefringence. I report the theoretical analysis of mode coupling in axisymmetric birefringent waveguides. Any of the LP(11) modes in a perturbed system can couple with a corresponding LP(11) mode that is orthogonal to the original mode with respect to both the polarization direction and the node line of an electric field. The coupling beat length depends on the amount of birefringence, which can be as short as 5 mm for a practical structure.

Measurement of distributed strain due to laying and recovery of submarine optical fiber cable.

Strain distribution due to cable laying and recovery is measured, using Brillouin optical fiber time domain analysis in a 3.7-km long submarine optical fiber cable. We believe this is the first time that the residual strain distribution in the recovered submarine cable has been measured. The residual strains measured in some cable sections due to the cable laying and recovery are found to be as small as 0.02 and 0.04%, respectively.