Purification,Crystallization and Properties of Tyrosine Phenol Lyase from Erwinia herbicola

Crystalline tyrosine phenol lyase was prepared from the cell extract of Erwinia herbicola grown in a medium supplemented with l-tyrosine. The crystalline enzyme was homogeneous by the criteria of ultracentrifugation and acrylamide gel electrophoresis. The molecular weight was determined to be approximately 259,000. The crystalline enzyme catalyzed the conversion of l-tyrosine into phenol, pyruvate and ammonia, in the presence of added pyridoxal phosphate. The enzyme also catalyzed pyruvate formation from d-tyrosine, S-methyl-l-cysteine, 3, 4-dihydroxyphenyl-l-alanine, l- and d-serine, and l- and d-cysteine, but at lower rates than from l-tyrosine. l-Phenyl-alanine, l-alanine, phenol and pyrocatechol inhibited pyruvate formation from l-tyrosine.

Crystalline tyrosine phenol lyase from Erwinia herbicola is inactive in the absence of added pyridoxal phosphate. Binding of pyridoxal phosphate to the apoenzyme is accompanied by pronounced increase in absorbance at 340 and 425 mμ. The amount of pyridoxal phosphate bound to the apoenzyme was determined by equilibrium dialysis to be 2 moles per mole of enzyme. Addition of the substrate, l-tyrosine, or the competitive inhibitors, l-alanine and l-phenyl-alanine, to the holoenzyme causes appearance of a new absorption peak near 500 mμ which disappears as the substrate is decomposed but remains unchanged in the presence of the inhibitor.     

Influence of bite force and tongue pressure on oro-pharyngeal residue in the elderly

Objective: To investigate the influence of maximal bite force, maximal tongue pressure, number of mastications and swallowing on the oro‐pharyngeal residue in the elderly. Background: Oro‐pharyngeal residue in the elderly is an indication of dysphagia. Pharyngeal residue is especially critical as it may cause aspiration pneumonia, which is one of the major causes of death in elderly. Materials and methods: Videofluorographic recordings were performed on 14 elderly volunteers (six males, eight females, age range 65–93 years) without any history or symptoms of dysphagia. The subjects were instructed to consume 9 g of barium containing bread in two manners; free mastication and swallow (FMS: masticate and swallow freely), and limited mastication and swallow (LMS: swallow once after 30 chewing actions). The amount of oral and pharyngeal residue was evaluated using a 4‐point rating scale. Maximal occlusal force was measured by a pressure sensitive sheet, and maximal tongue pressure using a handy probe. Multiple regression analysis was performed to examine the influence of these items on the amount of oral and pharyngeal residue in FMS and LMS. Results: In FMS, age was found to be a factor which increased oral residue (p = 0.053), and the number of swallowing (p = 0.017) and the state of the prosthesis (p = 0.030) reduced the pharyngeal residue. In LMS, tongue pressure was a factor which reduced oral residue (p = 0.015) and increased pharyngeal residue (p = 0.008). Conclusion: It is suggested that in the elderly tongue pressure contributed to propulsion of the food bolus from oral cavity into the pharynx, and multiple swallowing contributed to the reduction in the amount of pharyngeal residue.     

Clinical and pathologic manifestation of oesophagostomosis in African great apes: does self‐medication in wild apes influence disease progression?

Nodular worms (Oesophagostomum spp.) are common intestinal parasites found in cattle, pig, and primates including humans. In human, they are responsible for serious clinical disease called oesophagostomosis resulting from the formation of granulomas, caseous lesions or abscesses in intestinal walls. In wild great apes, the fecal prevalence of this parasite is high, but little information is available concerning the clinical signs and lesions associated. In the present study, we describe six cases of multinodular oesophagostomosis in free-ranging and ex-captive chimpanzees and captive gorillas caused by Oesophagostomum stephanostomum. While severe clinical signs associated with this infection were observed in great apes raised in sanctuaries, nodules found in wild chimpanzees do not seem to affect their health status. One hypothesis to explain this difference would be that in wild chimpanzees, access to natural environment and behavior such as rough leaves swallowing combined with ingestion of plants having pharmacological properties would prevent severe infection and decrease potential symptoms.     

Effect of Seihai-to, a Kampo medicine, in relapsing aspiration pneumonia an open-label pilot study

Two published case reports described palliation of disease after Seihai-to therapy for refractory aspiration pneumonia caused by recurrent laryngeal nerve paralysis and cerebrovascular disease. We undertook an open-label trial in patients with relapsing aspiration pneumonia. Fifteen patients with relapsing aspiration pneumonia were randomly divided into conventional therapy group (n = 8) or Seihai-to group (n = 7). In Seihai-to group, patients were treated with Seihai-to in addition to conventional therapy (Western medicines). Frequency of feverish days and antibiotics-use, CRP value and chest CT or X-ray findings were compared between the two groups during the study period of 16 weeks. In the Seihai-to group, the latency of swallowing reflex was measured in 6 patients before and after administration of Seihai-to. The mean values of fever index, CRP value and antibiotics-use in the Seihai-to group were decreased significantly, compared with those of the conventional therapy group. However, the latency of the swallowing reflex after 4 weeks of treatment was not significantly changed (p = 0.249), compared with the latency before administration of Seihai-to. No adverse reaction was observed in either group. Seihai-to was effective in reducing relapse of aspiration pneumonia in this small group. Seihai-to might not improve the swallowing reflex, but might instead improve a defense mechanism or excessive inflammation caused by pneumonia in the lower airway. Further evaluation of Seihai-to therapy for patients with aspiration pneumonia in a larger population is warranted.     

How tetrapods feed in water: a functional analysis by paradigm

Mechanical theory is used to erect a paradigm predicting the manipulations used by carnivorous aquatic amphibians, reptiles, birds and mammals to catch, subdue, process and swallow their prey. These predictions are confirmed by observational evidence. Most aquatic predatory tetrapods use long, prehensile tooth-armed jaws as pincer jaws to snap shut onto the prey and catch and kill it, although some use the flexibility of long necks in spear fishing and some odontocetes may stun prey with sonar. Most do not have cutting or nipping dentitions as these cannot be used on prey which is freely floating. They use caniniform dentition to hold and kill prey, or in some cases crushing dentition to break open hard-shelled prey. They dismember prey by dynamic loading, snatching bites so quickly that the prey tears. They use shake feeding, shaking the prey apart from side to side above the water. If the prey is too large to lift above the water they use twist feeding, twisting pieces off. Small pieces are easily swallowed but larger pieces are held above the water and swallowed by tilting the head back in gravity feeding, or by jerking the head back and forth in incrtial feeding. Some animals use mobile jaws to pull prey back into the mouth in ratchet feeding. Filter feeding evades these problems by feeding on very small prey. The use of paradigms in functional analysis is discussed with special reference to this work. The paradigm method is shown to be the most suitable one. There has been repeated convergent and parallel evolution of adaptations to feed in water.     

Decreased Hardness of Dietary Fiber-Rich Foods by the Enzyme-Infusion Method

A novel technique is reported for softening plant tissues while retaining their shape by impregnating them with macerating enzymes under reduced pressure after defrosting the frozen plants. Samples were removed immediately from the enzyme solution after the freeze-infusion treatment, and the hardness was measured. Six enzymes and three enzymes were respectively chosen from 18 commercial enzymes for softening burdock roots and bamboo shoots. The tissue degradation due to impregnation of the tissues with the enzymes and the reaction time were investigated. Burdock roots and bamboo shoots were progressively softened during the reaction: the hardness reached 1.0×10⁴ N/m² or less. The water-soluble dietary fiber contents increased as a result of the freeze-infusion treatment. This softening technique, which retained the food shape, could enhance the production of food products for elderly persons and those under nursing care. Foods produced by this method can replace current minced and liquid dietary components.     

Effect of ill-fitting dentures on the swallowing duration in patients using polygraphy

doi: 10.1111/j.1741‐2358.2011.00536.x Effect of ill‐fitting dentures on the swallowing duration in patients using polygraphy Background: Surface electromyography (SEMG) has been widely used in the recent years to study swallowing physiology, offering a valid and reliable tool for identifying normal swallowing. The goal of our study was to assess the contribution of denture fitness in the age‐related increase of swallowing duration. Methods: Twenty denture wearers and 20 dentate individuals were analysed using SEMG and a computerised kinesiography of mandibular movement. Three spontaneous saliva swallowings were recorded for each patient with both their old and new prostheses. Three spontaneous saliva swallowings were recorded for each dentate person in two different recording sessions. Results: Old prosthesis mean swallowing time was 1.84 (SD ± 0.85) seconds while the new well‐fitting prostheses needed a 1.28 (SD ± 0.55) (p = 0.0009) swallowing time. The difference in swallowing time was significant (p = 0.01) between dentate subjects and individuals wearing an old prosthesis. No significant difference was found between dentate subjects and the same prosthesis wearers when a new well‐fitting prosthesis was worn. Conclusion: Data presented in this work suggest that part of the increased duration of swallowing showed by elderly and healthy people is because of incorrect an dental prosthesis. Prolongation of swallowing duration in the elderly population could be reconsidered in the light of the quality of dental device worn by the aged population.