Satoshi Ikeda

Effect of menthol on detrusor smooth-muscle contraction and the micturition reflex in rats.

OBJECTIVESnTo investigate the effects of menthol, an activator of the temperature-sensitive transient receptor potential family member TRPM8, on detrusor smooth-muscle contraction and the micturition reflex in rats.nnnMETHODSnWe evaluated the effect of intravesical infusion of 1 or 3 mM menthol by cystometry in conscious female Sprague-Dawley rats. Some of the animals were pretreated with 125 mg/kg capsaicin subcutaneously 4 days earlier. The parameters measured were voided volume (VV), residual volume (RV), volume threshold for inducing micturition (VT), voiding efficiency (VE), micturition pressure (MP), and pressure threshold for inducing micturition (PT). Strips of detrusor muscle were mounted in organ baths to study the effect of menthol on the contractile response to 0.01 mM carbachol.nnnRESULTSnIntravesical infusion of 3 mM menthol reduced VV by 20%, VT by 19%, and PT by 31%. RV, VE, and MP were unaltered. Capsaicin pretreatment had no effect on baseline cystometric parameters, and 3 mM menthol caused similar reductions in VV (24%), VT (22%), and PT (30%), while having no effect on RV, VE, and MP. Menthol at 0.1, 0.3, and 1 mM inhibited carbachol-induced contractions by 10.7%, 36.7%, and 97.3%, respectively.nnnCONCLUSIONSnOur results demonstrated that intravesical infusion of menthol facilitated the micturition reflex, and capsaicin pretreatment had no effect on this response. Menthol inhibited carbachol-induced contraction of the detrusor smooth muscle. This suggests that intravesically infused menthol cannot relax detrusor muscle, and acts on capsaicin-resistant afferents (probably through TRPM8 in urothelium or sensory nerve endings) to facilitate the micturition reflex.

Induction of myogenin messenger ribonucleic acid in rat skeletal muscle after 1 hour of passive repetitive stretching

OBJECTIVEnTo investigate the effect of repetitive passive stretch of living rat muscle on myogenin messenger ribonucleic acid (mRNA) expression.nnnDESIGNnCase-controlled study.nnnSETTINGnUniversity laboratory.nnnANIMALSnSeventeen female 8-week-old Wistar rats.nnnINTERVENTIONSnRepetitive stretch (15 times/min) was performed manually on gastrocnemius muscle of anesthetized rats for 15, 30, and 60 minutes.nnnMAIN OUTCOME MEASURESnTotal RNA was extracted, after the animals were killed, from the gastrocnemius muscle, and Northern blotting was performed using oligonucleotide complementary to myogenin.nnnRESULTSnRepetitive stretch to gastrocnemius muscles of anesthetized rats for 1 hour induced a 21.5% increase in the expression of myogenin mRNA.nnnCONCLUSIONSnRepetitive passive stretch of the rat skeletal muscle for 60 minutes induced the expression of myogenic transcription factor myogenin mRNA. These findings suggest the clinical utility of passive repetitive stretch to maintain muscle strength in patients who are unconscious or paralyzed.

Functional recovery and expression of GDNF seen in photochemically induced cerebral infarction.

Glial cell line-derived neurotrophic factor (GDNF) is a potent neurotrophic factor involved in the survival and proliferation of neurons. However, there have been few reports examining the relationship between GDNF and functional recovery after cerebral infarction. The authors investigated the change in the expression of GDNF proteins during functional recovery in rats following photochemically induced cerebral infarctions. Functional recovery for the first 14 days after the infarction was evaluated using a beam-walking test. The number of GDNF-like immunoreactive cells around the infarction were counted at various times (24 h, 72 h, 7 days, and 14 days) post-infarction. Immunohistochemical analysis of brain sections showed that the expression of GDNF-like immunoreactive cells was significantly increased in the temporal cortex until 7 days on the side ipsilateral to the infarction, and had decreased by 14 days. Likewise, the functional recovery of paralysis was substantial until 7 days post-infarction, after which the improvement was mild. Therefore, the expression of GDNF protein might have some relationship with the functional recovery of paralysis. There are great hopes that GDNF could be used as a therapeutic agent for cerebral infarction.

The Role of Zinc in the Treatment of Taste Disorders

In the 1990s the number of patients diagnosed with taste disorders in the USA and Japan was over one million people each year, and the number is increasing annually. Taste disorders are caused by several factors such as genetic disease, head trauma, structural changes, glossodynia, cancer, change of lifestyle, and more. The role of zinc in the treatment of taste disorders has been studied since the oral administration of zinc by patients was reported to improve their taste disorders. Carbonic anhydrase (CA), a zinc metalloenzyme, has also been studied in association with taste disorders, since the regulation of serum CA levels was shown to influence the effect of orally administrated zinc in the treatment of taste disorders. Zinc is an essential trace element that contributes to the active center of approximately 300 enzymes. Studies have revealed that zinc is involved in various physiological functions. Moreover, some medications have been shown to induce a zinc deficiency, which has been associated with a variety of clinical conditions. Hence, since the relationship between taste disorder and serum zinc concentration has been discussed for long time, taste disorder may be useful in diagnosing zinc deficiency. Moreover, it appears that medicines of the zinc-containing supplement type contribute to the treatment of taste disorders caused by zinc deficiency. Orally administered zinc has been shown to directly stimulate food intake via neuropeptide in the hypothalamus. Therefore, zinc administration may potentially be used to treat taste disorders, as well as several other diseases by stimulating feeding. The article presents some promising patents on the role of zinc in the treatment of taste disorders.

Combined effects of repeated sauna therapy and exercise training on cardiac function and physical activity in patients with chronic heart failure.

Abstract Purpose: We investigated the combined effects of repeated sauna therapy and exercise training on subjective symptoms, cardiac function, daily activities and ambulation capacity in patients with chronic heart failure. Methods: Fifty four patients including 26 patients with repeated sauna therapy and exercise training (combined therapy group) and 28 patients with repeated sauna therapy (monotherapy group) participated in the study. Repeated sauna therapy and exercise training were performed once a day, 5 days a week. Clinical symptoms, brain natriuretic peptide concentration, cardiac functions evaluated by echocardiography, cardiac size on chest radiography, Barthel Index (BI) and ambulation capacity were examined and compared between the time of hospital admission and the time of discharge. Results: Both the groups showed significantly improved New York Heart Association functional class, cardiothoracic ratio, brain natriuretic peptide concentration, left ventricular ejection fraction, BI score and ambulation capacity grade. The changes of New York Heart Association functional class, BI score and ambulation capacity in the combined therapy group were a higher level of statistical significance than those in monotherapy group. Notably, significant between group difference was observed in the changes of BI score. Conclusions: The addition of exercise training programs to repeated sauna therapy may be efficient and effective for improvement of cardiac function and daily activities for patients with chronic heart failure. Implications of Rehabilitation Repeated sauna therapy is an effective means of improving cardiac, vascular function and mental health in CHF patients. Exercise training is an effective means of improving exercise capacity, thus improving ADL. Combination of repeated sauna therapy and exercise training may be recommended as a comprehensive treatment to improve cardiac function, ambulation capacity, and ADL in CHF patients.

Passive Repetitive Stretching for a Short Duration within a Week Increases Myogenic Regulatory Factors and Myosin Heavy Chain mRNA in Rats' Skeletal Muscles

Stretching is a stimulation of muscle growth. Stretching for hours or days has an effect on muscle hypertrophy. However, differences of continuous stretching and repetitive stretching to affect muscle growth are not well known. To clarify the difference of continuous and repetitive stretching within a short duration, we investigated the gene expression of muscle-related genes on stretched skeletal muscles. We used 8-week-old male Wistar rats (N = 28) for this study. Animals medial gastrocnemius muscle was stretched continuously or repetitively for 15u2009min daily and 4 times/week under anesthesia. After stretching, muscles were removed and total RNA was extracted. Then, reverse transcriptional quantitative real-time PCR was done to evaluate the mRNA expression of MyoD, myogenin, and embryonic myosin heavy chain (MyHC). Muscles, either stretched continuously or repetitively, increased mRNA expression of MyoD, myogenin, and embryonic MyHC more than unstretched muscles. Notably, repetitive stretching resulted in more substantial effects on embryonic MyHC gene expression than continuous stretching. In conclusion, passive stretching for a short duration within a week is effective in increasing myogenic factor expression, and repetitive stretching had more effects than continuous stretching for skeletal muscle on muscle growth. These findings are applicable in clinical muscle-strengthening therapy.

A New Non-Human Primate Model of Photochemically Induced Cerebral Infarction

Background and Purpose Rat models of photochemically induced cerebral infarction have been readily studied, but to date there are no reports of transcranial photochemically induced infarctions in the marmoset. In this report, we used this non-human primate as a model of cerebral thrombosis and observed the recovery process. Methods Five common marmosets were used. Cerebral ischemia was produced via intravascular thrombosis induced by an intravenous injection of Rose Bengal and irradiation with green light. After inducing cerebral infarction, we observed the behavior of marmosets via a continuous video recording. We evaluated maximum speed, mean speed, and distance traveled in 1 min. In addition, we evaluated scores for feeding behavior, upper limb grip, and lower limb grip. We confirmed the infarct area after cerebral infarction using 2,3,5-triphenyltetrazolium chloride staining in a separate marmoset. Results We found functional decreases 2 days after creating the cerebral infarction in all measurements. Total distance traveled, average speed, upper limb score, and feeding behavior score did not recover to pre-infarction levels within 28 days. Maximum speed in 1 min and lower limb score recovered 28 days after infarction as compared to pre-infarction levels. We confirmed the infarct area of 11.4 mm×6.8 mm as stained with 2,3,5-triphenyltetrazolium chloride. Conclusion We were able to create a primate photothrombosis-induced cerebral infarction model using marmosets and observe functional recovery. We suggest that this is a useful model for basic research of cerebral infarction.

Spinal cord transection induced c-Fos protein in the rat motor cortex

Spinal cord transection at the middle thoracic level induced the expression of c-Fos protein in the rat motor cortex detected with the immunohistochemical study. At 1 h after transection, maximal expression of c-Fos was seen in the frontal cortex and hindlimb area of the cortex. c-Fos-like immunoreactive neurons were recognized in the second to sixth layers of these cortices, although the axotomized neurons were located only in the fifth layer of these cortices. A significant difference of c-Fos-like protein expression was observed between the spinal transected group and the sham operated group 1 h after the operation. These results indicate that each layer of the motor cortical column is activated and that there is a correlation between alteration of the neuronal network and functional plasticity.

Impaired visuo-motor skills in the unaffected lower limb of patients with stroke.

To study the motor skills of the unaffected lower limb of patients with stroke, the visuo-motor skills of the unaffected lower limb in patients with stroke was compared with those in healthy control subjects using a computerized motor skill analyzer that calculated the accuracy in the tracking task in terms of lap time and trajectory error. Trajectory errors in the task by the unaffected lower limb in the patients with stroke were significantly greater than those in the lower limb of healthy control subjects. These results suggest that patients with stroke have impaired visuo-motor skills of the unaffected lower limb.

Temperature changes caused by the difference in the distance between the ultrasound transducer and bone during 1 MHz and 3 MHz continuous ultrasound: A phantom study

[Purpose] This study aimed to use a thermograph to observe temperature changes caused by different distances between an ultrasound transducer and bone during 1u2005MHz and 3u2005MHz continuous ultrasound emission on a phantom. [Materials and Methods] We observed the distribution of temperature elevations on a phantom consisting of pig ribs and tissue-mimicking material. One megahertz and 3u2005MHz ultrasound were delivered at 2.0u2005W/cm2 for 5 minutes. To record the temperature changes on the phantom, we took a screenshot of the thermograph with a digital camera every 20 seconds. [Results] With 1u2005MHz ultrasound at the distances of 2 and 3u2005cm, the temperature elevation near the bone was higher than that near the transducer. However, with 3u2005MHz ultrasound, the temperature elevation was higher near the transducer rather than near the bone. At this point, we consider that there is a possibility of heat injury to internal organs in spite of there being no elevation of skin temperature. [Conclusion] When performing ultrasonic therapy, not only should the frequency be taken into consideration, but also the influence of the absorption coefficient and the reflection of the tissue. We visually confirmed the thermal ultrasound effect by thermography. Special attention to the temperature elevation of the internal organs is necessary to avoid injuries.