Histological changes in the olfactory bulb and rostral migratory stream due to interruption of olfactory input

OBJECTIVE

Periglomerular and granule cells in the adult mammalian olfactory bulb modulate olfactory signal transmission. These cells originate from the subventricular zone, migrate to the olfactory bulb via the Rostral Migratory Stream (RMS), and differentiate into mature cells within the olfactory bulb throughout postnatal life. While the regulation of neuroblast development is known to be affected by external stimuli, there is a lack of information concerning changes that occur during the recovery process after injury caused by external stimuli. To address this gap in research, the present study conducted histological observations to investigate changes in the olfactory bulb and RMS occurring after the degeneration and regeneration of olfactory neurons.

METHODS

To create a model of olfactory neurodegeneration, adult mice were administered methimazole intraperitoneally. Nasal tissue and whole brains were removed 3, 7, 14 and 28 days after methimazole administration, and EdU was administered 2 and 4 h before removal of these tissues to monitor dividing cells in the RMS. Methimazole-untreated mice were used as controls. Olfactory nerve fibers entering the olfactory glomerulus were observed immunohistochemically using anti-olfactory marker protein. In the brain tissue, the entire RMS was observed and the volume and total number of cells in the RMS were measured. In addition, the number of neuroblasts and dividing neuroblasts passing through the RMS were measured using anti-doublecortin and anti-EdU antibodies, respectively. Statistical analysis was performed using the Tukey test.

RESULTS

Olfactory epithelium degenerated was observed after methimazole administration, and recovered after 28 days. In the olfactory glomeruli, degeneration of OMP fibers began after methimazole administration, and after day 14, OMP fibers were reduced or absent by day 28, and overall OMP positive fibers were less than 20%. Glomerular volume tended to decrease after methimazole administration and did not appear to recover, even 28 days after recovery of the olfactory epithelium. In the RMS, EdU-positive cells decreased on day 3 and began to increase on day 7. However, they did not recover to the same levels as the control methimazole-untreated mice even after 28 days.

CONCLUSION

These results suggest that the division and maturation of neuroblasts migrating from the RMS was suppressed by olfactory nerve degeneration or the disruption of olfactory input.

Efficacy of tokishakuyakusan and mecobalamin on post-infectious olfactory dysfunction: A prospective multicenter study

OBJECTIVE

To determine if tokishakuyakusan (TSS) is effective for treating post-infectious olfactory dysfunction (PIOD) compared with vitamin B12 (mecobalamin).

METHODS

We conducted a randomized, nonblinded clinical trial. Patients with PIOD enrolled in 17 hospitals and clinics from 2016 to 2020 were randomly divided into two groups, and we administered TSS or mecobalamin for 24 weeks. Their olfactory function was examined using interviews and T&T olfactometry. The improvement of olfactory dysfunction was assessed following the criteria of the Japanese Rhinologic Society.

RESULTS

Overall, 82 patients with PIOD were enrolled in this study. In the TSS and mecobalamin groups, 39 patients completed the medication regimen. In the TSS and mecobalamin groups, olfactory dysfunction was significantly improved based on self-reports and olfactory test results. The improvement rate of olfactory dysfunction was 56% in the TSS group and 59% in the mecobalamin group. Early intervention within 3 months produced a better prognosis than the treatment initiated after 4 months. Furthermore, age and sex differences were not observed. Both medications produced no severe adverse events.

CONCLUSION

The present study showed that TSS and mecobalamin might be useful for treating PIOD.

Olfactory and taste dysfunctions caused by COVID-19: a nationwide study

BACKGROUND

Olfactory dysfunctions (OD) and taste dysfunctions (TD) are widely recognized as characteristic symptoms of COVID-19; however, the frequency and mode of occurrence has varied depending on the viral mutation. The prevalence and characteristics of OD/TD in Japan have not been definitively investigated. The purpose of this study is to assess the prevalence of OD/TD in Japan during the Alpha variant epidemic, and measure symptom prolongation at 6 months and 1 year later following initial infection.

METHODS

Patients treated for COVID-19 between February to May 2021 were evaluated for OD/TD symptoms and provided with a QOL questionnaire. Olfactory tests and taste tests were performed using Open Essence and Taste Strips, respectively.

RESULTS

Among the 251 COVID-19 patients who participated, 119 underwent both olfactory and taste tests. Prevalence of subjective OD and TD at the time of survey was 57.8% and 40.2%, respectively. After 12 months, the prevalence fell to 5.8% for OD and 3.5% for TD. Among the OD/TD patients, 36.6% experienced parosmia, and 55.4% experienced parageusia. Prevalence of parosmia and parageusia was higher at 6 and 12 months than at the time of survey. Patients with long-lasting disease reported qualitative dysfunctions and scored significantly higher in food-related QOL problems. Most patients who were aware of their hyposmia had low scores on the olfactory test (83.1%). In contrast, only 26.7% of patients who were aware of their hypogeusia had low scores on the taste test.

CONCLUSIONS

The prevalence of COVID-19-related OD and TD at the time of survey was 57.8% and 40.2%, respectively. Subjective symptoms of OD and TD persisted for one year in 5.8% and 3.5% of patients, respectively. More than half of the patients with OD or TD complained of qualitative dysfunction and a decrease in their QOL related to eating and drinking. Most patients with TD did not have true TD, but rather developed flavour disorders associated with OD. This conclusion is supported by the finding that patients with subjective OD had low scores on the olfactory test, whereas most patients with subjective TD had normal scores on the taste test.

Sarcopenia and decline in appendicular skeletal muscle mass are associated with hypoperfusion in key hubs of central autonomic network on 3DSRT in older adults with progression of normal cognition to Alzheimer's disease

AIM

Although sarcopenia is common in patients with Alzheimer's disease (AD), the neural substrates involved remain unclear. We investigated the relationship between sarcopenia, as well as its definition components, and regional cerebral blood flow (rCBF) in older adults with progression of normal cognition to AD.

METHODS

99m Tc-ethyl-cysteinate-dimer single-photon emission computed tomography was carried out in 95 older adults with progression of normal cognition to AD (40 men and 55 women, mean ± SD age 80.9 ± 6.8 years). The associations of rCBF determined by 3-D stereotactic region of interest template software, with sarcopenia and its definition components, slower gait speed, weaker grip strength, and decline in appendicular skeletal muscle mass index (ASMI) were analyzed.

RESULTS

Logistic regression analysis adjusted by age, sex, mini-mental state examination score and education showed that sarcopenia as well as ASMI less than the cut-off (men 7.0 kg/m2 , women 5.7 kg/m2 ) were associated with significantly reduced rCBF in the key hub of the central autonomic network, including the insula, anterior cingulate cortex, subcallosal area, rectal gyrus, hypothalamus, amygdala and caudate head. Sarcopenia and ASMI decline were associated with hypoperfusion in the aforementioned cortical hubs of the central autonomic network in men, but with hypoperfusion of the hypothalamus in women. Linear regression analysis showed significant correlations of ASMI/cut-off with rCBF in the bilateral medial frontal cortex, as well as rCBF in the aforementioned key hubs.

CONCLUSIONS

Hypoperfusion in key hubs of central autonomic network is implicated in the emergence of sarcopenia, probably through ASMI decline in vulnerable older adults. Geriatr Gerontol Int 2023; 23: 16-24.

The Impact of Ovariectomy on Olfactory Neuron Regeneration in Mice

Estrogen has been shown to affect differentiation and proliferation as a mitogen in various neural systems. Olfactory receptor cells are unique within the nervous system, and have the ability to regenerate even after an individual has reached maturity. Olfactory receptor cells also regenerate after experimentally induced degeneration. The purpose of this study is to observe the influence of estrogen depletion induced by ovariectomy on olfactory nerve regeneration. Female mice underwent bilateral ovariectomy at 8 weeks of age and received intraperitoneal administration of methimazole 1 week later. At 2, 4, and 6 weeks after methimazole administration, the olfactory mucosa was analyzed histochemically to determine olfactory epithelium (OE) thickness, olfactory marker protein distribution, and Ki-67 immunoreactivity. Furthermore, 2 weeks after ovariectomy, trkA protein distribution in the OE and nerve growth factor (NGF) levels in the olfactory bulb were determined by immunohistochemistry and enzyme-linked immunosorbent assay, respectively. Our results showed that in ovariectomized mice OMP, Ki-67, and trkA-immunopositive cells expression decreased at 2 weeks after methimazole injection, a time point at which regeneration is underway. At this same time point, although NGF production in the olfactory bulb had increased before methimazole administration, no differences were observed between the ovx and control groups. These results suggest that estrogen depletion induces a suppressive effect on regeneration of olfactory neurons, and that estrogen may have a potential use in the treatment of sensorineural olfactory dysfunction.

Effects of Tokishakuyakusan on Regeneration of Murine Olfactory Neurons In Vivo and In Vitro

Post-upper respiratory tract infection related olfactory dysfunction typically occurs due to neural damage after an upper respiratory tract infection associated with a common cold or influenza. At present, Tokishakuyakusan, a Japanese traditional Kampo medicine, has been found to be effective for post-viral olfactory dysfunction. However, the pharmacodynamics of Tokishakuyakusan in the treatment of post-viral olfactory dysfunction remains unresolved. We investigated the effects of Tokishakuyakusan on the regeneration of olfactory neurons and expression of nerve growth factor (NGF) in neural systems, using in vivo murine studies and in vitro cell culture studies. Eight-week-old BALB/C female mice were fed a pellet diet with or without Tokishakuyakusan. Degeneration of cells in olfactory epithelium was induced by intraperitoneal methimazole injection. Regeneration of olfactory neurons was observed by histological and immunohistochemical procedures. NGF expression in the olfactory bulb was measured by enzyme-linked immunosorbent assay. NGF gene and protein expression were measured using rat primary cultured astrocytes by real-time polymerase chain reaction and enzyme-linked immunosorbent assay. We found that olfactory marker protein, Ki-67, and NGF were more highly expressed in the olfactory epithelium during the regeneration period in mice receiving Tokishakuyakusan. In cultured astrocytes, Tokishakuyakusan as well as its individual components, Atractylodes lancea rhizome and Japanese angelica root, increased NGF expression. Screening assays revealed that NGF production was increased by atractylodin and levistolide A, which are ingredients in Atractylodes lancea rhizome and Japanese angelica root, respectively. These results suggest that Tokishakuyakusan promotes regeneration of olfactory neurons by increasing NGF expression in the olfactory bulb.

Thallium-201 Imaging in Intact Olfactory Sensory Neurons with Reduced Pre-Synaptic Inhibition In Vivo

In this study, we determined whether the ²⁰¹Tl (thallium-201)-based olfactory imaging is affected if olfactory sensory neurons received reduced pre-synaptic inhibition signals from dopaminergic interneurons in the olfactory bulb in vivo. The thallium-201 migration rate to the olfactory bulb and the number of action potentials of olfactory sensory neurons were assessed 3 h following left side nasal administration of rotenone, a mitochondrial respiratory chain complex I inhibitor that decreases the number of dopaminergic interneurons without damaging the olfactory sensory neurons in the olfactory bulb, in mice (6–7 animals per group). The migration rate of thallium-201 to the olfactory bulb was significantly increased following intranasal administration of thallium-201 and rotenone (10 μg rotenone, p = 0.0012; 20 μg rotenone, p = 0.0012), compared with that in control mice. The number of action potentials was significantly reduced in the olfactory sensory neurons in the rotenone treated side of 20 μg rotenone-treated mice, compared with that in control mice (p = 0.0029). The migration rate of thallium-201 to the olfactory bulb assessed with SPECT-CT was significantly increased in rats 24 h after the left intranasal administration of thallium-201 and 100 μg rotenone, compared with that in control rats (p = 0.008, 5 rats per group). Our results suggest that thallium-201 migration to the olfactory bulb is increased in intact olfactory sensory neurons with reduced pre-synaptic inhibition from dopaminergic interneurons in olfactory bulb glomeruli.

Relationship Between Olfactory Disturbance After Acute Ischemic Stroke and Latent Thalamic Hypoperfusion

Odor detection, recognition, and identification were assessed in 19 acute ischemic stroke patients who had no magnetic resonance imaging-detectable thalamic lesions but in whom technetium-99m ethyl cysteinate dimer single photon emission tomography revealed thalamic hypoperfusion. Although these patients were unaware of reduced olfactory function, they exhibited significantly lower scores in tests for odor identification and recognition threshold as compared with 9 ischemic stroke controls that had normal thalamic hypoperfusion. However, absolute odor detection thresholds were similar in the 2 groups. These results demonstrate the usefulness of cerebral perfusion scintigraphy in assessing sensory loss after ischemic stroke and provide further evidence for the role of the thalamus in olfaction.

Nasal thallium-201 uptake in patients with parosmia with and without hyposmia after upper respiratory tract infection

BACKGROUND

In this study, we aimed to determine whether nasal thallium-201 uptake of the olfactory cleft and olfactory bulb (OB) differs between patients with parosmia with and without hyposmia after upper respiratory tract infection (URTI).

METHODS

Twenty patients with parosmia after URTI were enrolled in this study (15 women and 5 men, 28 to 76 years old). Nasally administered thallium-201 migration to the OB, nasal thallium-201 uptake ratio in the olfactory cleft, and OB volume were determined in 10 patients with normal T&T olfactometry (Daiichi Yakuhin Sangyo, Tokyo, Japan) odor recognition thresholds (≤2.0) who still complained of parosmia (parosmia group), and 10 patients with T&T odor recognition thresholds >2.0 (parosmia and hyposmia group).

RESULTS

The nasal thallium-201 uptake ratio in the olfactory cleft was significantly higher in the parosmia group than in the parosmia and hyposmia group (p = 0.0015). Thallium-201 migration to the OB was not significantly different between the 2 groups (p = 0.31). The OB volume was significantly larger in the parosmia group than that in the parosmia and hyposmia group (p = 0.029); however, the mean OB volume in both the groups was lower than the normal threshold value in healthy individuals.

CONCLUSION

Our results signify the recovery of the olfactory epithelium; however, the olfactory neural projections to the OB and regeneration of OB were not complete in patients with parosmia with normal T&T recognition thresholds after URTI.

Clinical practice guidelines for the management of olfactory dysfunction - Secondary publication

OBJECTIVE

To provide an evidence-based recommendation for the management of olfactory dysfunction in accordance with the consensus reached by the Subcommittee of the Japanese Clinical Practice Guideline for olfactory dysfunction in the Japanese Rhinologic Society.

METHODS

Seven clinical questions (CQs) regarding the management of olfactory dysfunction were formulated by the subcommittee of the Japanese Clinical Practice Guideline for olfactory dysfunction. We searched the literature published between April 1990 and September 2014 using PubMed, the Cochrane Library, and Ichushi Web databases. The main search terms were "smell disorder," "olfactory dysfunction," "olfactory loss," "olfactory disturbance," "olfactory impairments," "olfaction disorder," "smell disorder," "anosmia," "cacosmia," and "dysosmia." Based on the results of the literature review and the expert opinion of the Subcommittee, 4 levels of recommendation, from A-strongly recommended to D-not recommended, were adopted for the management of olfactory dysfunction.

RESULTS

Both oral and locally administered corticosteroids have been strongly recommended for patients with olfactory dysfunction due to chronic rhinosinusitis. Nasal steroid spray and antihistamine drugs have been moderately recommended for patients with allergic rhinitis. Although no drugs have been deemed to be truly effective for post-viral olfactory dysfunction by randomized-controlled trials (RCTs) or placebo-controlled trials, olfactory training using odorants has been reported to be effective for improving olfactory function. There is considerable evidence that olfactory testing is useful for differential diagnosis, prediction of disease progression, and early detection of cognitive decline in neurodegenerative diseases.

CONCLUSION

The Clinical Practice Guideline has developed recommendations for the management of various aspects of olfactory dysfunction.

Association of olfactory impairment with indexes of sarcopenia and frailty in community-dwelling older adults

AIM

Individuals with olfactory or gustatory impairment often have associated difficulties with food-related activities. As both functions decline in older adults, we investigated the association of these impairments with sarcopenia/frailty indexes in community-dwelling older adults.

METHODS

A total of 141 participants (69 men and 72 women, mean age 73.0 years) were enrolled. Odor identification was examined using the Open Essence test. Salty and sweet tastes were assessed using a whole-mouth gustatory test. Participants underwent evaluation of the appendicular skeletal muscle mass index (ASMI) by InBody720 and grip strength, and determination of the Study of Osteoporotic Fractures frailty index.

RESULTS

Participants with olfactory impairment (Open Essence ≤7), but not with gustatory impairment, showed a significantly higher prevalence of ASMI and grip strength less than the cut-off values recommended by the Asian Working Group for Sarcopenia, and Study of Osteoporotic Fractures frailty and/or pre-frailty status, compared with those without impairment. Multivariate logistic regression analysis showed a significant association of olfactory impairment with ASMI less than the cut-off value, grip strength less than the cut-off value, Asian Working Group for Sarcopenia sarcopenia and pre-frailty/frailty in the Study of Osteoporotic Fractures index in the whole population, and with ASMI less than the cut-off value and Asian Working Group for Sarcopenia sarcopenia in women, after adjustment. Three (Japanese cypress, wood and roasted garlic) and four (Japanese orange, India ink, menthol and curry) Open Essence odorants were elucidated as the "sarcopenia subset" and "frailty subset," respectively, and showed higher ability to identify sarcopenia and frailty status, compared with the remaining five odorants.

CONCLUSIONS

These findings suggest that olfactory impairment is closely associated with sarcopenia and/or frailty in community-dwelling older adults. Geriatr Gerontol Int 2019; 19: 384-391.

Rapamycin downregulates thymidylate synthase and potentiates the activity of pemetrexed in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) accounts for 80-85% of lung cancer cases, and almost half of newly diagnosed patients have metastatic disease. Pemetrexed is a widely used drug for NSCLC and inhibits several folate-dependent enzymes including thymidylate synthase (TS). Increased expression of TS confers resistance to pemetrexed in vitro and predicts poor response to pemetrexed. Rapamycin is an mTOR inhibitor and suppresses cap-dependent synthesis of specific mRNA species. Here, we show that the combination of rapamycin and pemetrexed synergistically inhibits proliferation of NSCLC cells. Although pemetrexed as a single agent induced TS, pretreatment with rapamycin suppressed pemetrexed-induced TS expression. In vivo, the combination of rapamycin and pemetrexed inhibited growth of NSCLC xenografts, which correlated with decreased mTOR activity and suppression of pemetrexed-induced TS expression. The ability of rapamycin to enhance the efficacy of pemetrexed and prevent TS expression has implications for the design of Phase I and/or Phase II NSCLC clinical trials with mTOR inhibitors in combination with pemetrexed.

Combinations of two odorants of smell identification test for screening of olfactory impairment

OBJECTIVE

To determine whether combinations of two odorants of the Open Essence smell identification test can be used to screen for olfactory impairment in Japanese people.

METHODS

A total of 243 Japanese subjects (142 males, 101 females; mean age, 37.5 years; age range, 20-62 years) were enrolled in the study. The main outcome measures were the results of olfactory testing by using the full 12 odorants (condensed milk, cooking gas, curry, cypress wood (Japanese cypress, hinoki), India ink, Japanese orange (mikan), menthol, perfume, roasted garlic, rose, sweaty-smelling clothes, and wood) of the Open Essence test as well as combinations of two odorants of the Open Essence test, and the results of self-reported questionnaires addressing awareness of a smell disorder, history of sinunasal disease, self-reported nasal obstruction, and history of smoking.

RESULTS

In screening with combinations of two odorants, the highest positive likelihood ratio (19.1) was obtained with the cypress wood and India ink odorants. All subjects correctly identified the curry odorant. Combinations of other odorants also had high positive likelihood ratios (India ink and sweaty-smelling clothes, 17.6; perfume and sweaty-smelling clothes, 14.7; cypress wood and roasted garlic, 14.1; cypress wood and rose, 13.2; cypress wood and perfume, 11.0; cypress wood and wood, 10.7).

CONCLUSION

The combination of cypress wood and India ink odorants may be useful for detecting individuals with olfactory impairment among subjects who can correctly identify the curry odorant.

Reduced nasal transport of insulin-like growth factor-1 to the mouse cerebrum with olfactory bulb resection

Although the olfactory nerve is involved in nasal transport of insulin-like growth factor-1 (IGF-1) to the brain, to our knowledge there have been no direct assessments of the effects of olfactory nerve damage on this transport. To determine whether olfactory bulb resection resulted in reduced transport of nasally administered human recombinant IGF-1 (hIGF-1) to the cerebrum, we measured the uptake of nasally administered iodine-125 hIGF-1 ((125)I-hIGF-1) in the cerebrum as a percentage of that in the blood in male ICR mice subjected to left olfactory bulb resection (model mice) and in sham-operated male ICR mice (control mice). Phosphorylated extracellular signal-regulated kinase (ERK) 1/2 (Thr202/Tyr204)/(Thr185/Tyr187) as a percentage of total ERK 1/2 in the left cerebrum was also assessed by using enzyme-linked immunosorbent assay after nasal administration of hIGF-1. Uptake of nasally administered (125)I-hIGF-1 in the cerebrum as a percentage of that in the blood was significantly lower in the model group than in the control group 30min after nasal administration of hIGF-1. Unilateral olfactory bulb resection prevented nasally administered hIGF-1 from increasing the phosphorylation of ERK 1/2 in the mouse cerebrum in vivo. These findings suggest that olfactory bulb damage reduces nasal transport of hIGF-1 to the brain in vivo.

Risk factors for Clostridium difficile-associated diarrhea and the effectiveness of prophylactic probiotic therapy

Measures for prevention of Clostridium difficile-associated diarrhea, a common nosocomial infection, in hospital settings are urgently needed. This study was conducted to identify the risk factors contributing to C. difficile-associated diarrhea and to evaluate the clinical benefit of probiotics in its prevention. The study included 2716 patients at least 20 years old who received an injected antibiotic at any time between February 2010 and February 2011; a total of 2687 patients (98.9%) were assigned to the non-C. difficile-associated diarrhea group, and 29 patients (1.1%) were assigned to the C. difficile-associated diarrhea group. Univariate analysis revealed a significant difference between the two groups for the following factors: antibiotic therapy for > or = 8 days; enteral nutrition; intravenous hyperalimentation; fasting; proton pump inhibitor use; H2 blocker use; and serum albumin < or = 2.9g/dL (p<0.05). Multivariate logistic regression analysis revealed a significant difference between the two groups for several factors. Antibiotic therapy for > or = 8 days, intravenous hyperalimentation, proton pump inhibitor use, and H2 blocker use were therefore shown to be risk factors for C. difficile-associated diarrhea. Prophylactic probiotic therapy was not shown to suppress the occurrence of C. difficile-associated diarrhea.

Risk factors contributing to urinary protein expression resulting from bevacizumab combination chemotherapy

Proteinuria following administration of bevacizumab is reported to be a specific adverse effect, but the risk factors for proteinuria have not been elucidated. In this study, the risk factors for urinary protein expression resulting from bevacizumab combination chemotherapy were investigated. The subjects were 47 patients aged > or = 20 years who had received bevacizumab combination chemotherapy at Gifu Municipal Hospital between February 2010 and February 2011. A total of 13 patients were excluded based on exclusion criteria; of the remaining 34 patients, 24 (70.6%) were assigned to the urinary protein non-expression group, and 10 (29.4%) were assigned to the urinary protein expression group. The results of multivariate logistic regression analysis revealed a significant difference in systolic blood pressure (> or =130 mmHg) between the two groups (OR: 14.499, 95%CI: 1.326-158.577, p=0.028). This finding shows that systolic blood pressure (> or =130 mmHg) is a risk factor for urinary protein expression resulting from bevacizumab combination chemotherapy.

[Clinical diagnosis of the olfactory nerve transport function]

Nasal administration of macromolecular drugs (peptides, nanoparticles) has a possibility to enable a drug delivery system beyond the blood brain barrier via olfactory nerve transport. Basic research on nasal drug delivery to the brain has been well studied. However, evaluation of the olfactory nerve transport function in patients with olfactory disorders has yet to be done, although such an evaluation is important in selecting candidates for clinical trials. Current olfactory function tests are useful for the analysis of olfactory thresholds in olfaction-impaired patients. However, the usefulness of using the increase in olfactory thresholds in patients as an index for evaluating olfactory nerve damage has not been confirmed because of the difficulty in directly evaluating the viability of the peripheral olfactory nerves. Nasally administered thallium-201 migrates to the olfactory bulb, as has been shown in healthy volunteers. Furthermore, transection of olfactory nerve fibers in mice significantly decreases migration of nasally administered thallium-201 to the olfactory bulb. The migration of thallium-201 to the olfactory bulb is reduced in patients with impaired olfaction due to head trauma, upper respiratory tract infections, and chronic rhinosinusitis, relative to the values in healthy volunteers. Nasally administrating thallium-201 followed by single photon emission computed tomography, X-ray computed tomography and magnetic resonance imaging might be useful in choosing candidates for clinical trials of nasal drug delivery methods to the brain.

Evaluation of the olfactory nerve transport function by SPECT-MRI fusion image with nasal thallium-201 administration

PURPOSE

The aim of this study was to visualize the human olfactory transport pathway to the brain by performing imaging after nasal thallium-201 ((201)Tl) administration.

PROCEDURES

Healthy volunteers were enrolled in this study after giving informed consent (five males, 35-51 years old). The subjects were nasally administered (201)TlCl into either the olfactory cleft. Twenty-four hours later, uptake of (201)Tl was detected by a single photon emission computed tomography (SPECT)/X-ray computed tomography hybrid system. For each subject, an MRI image was obtained and merged with the SPECT image.

RESULTS

The peak of the (201)Tl uptake entered into the olfactory bulb in the anterior skull base through the cribriform lamina 24 h after nasal administration of (201)Tl. No participant had olfactory disturbance after treatment.

CONCLUSIONS

Nasal (201)Tl administration was safely used to assess the direct pathway to the brain via the nose in healthy volunteers with normal olfactory threshold.

Use of thallium transport to visualize functional olfactory nerve regeneration in vivo

OBJECTIVE

To image olfactory nerve regeneration in vivo using a high-resolution gamma cam- era and radiography after nasal administration of thallium-201 (olfacto-scintigraphy).

METHODS

Six Wistar rats were trained to avoid the smell of cycloheximide as a test of olfactory function. The olfactory nerve fibers of 3 rats were then carefully transected bilaterally with a Teflon knife, avoiding damage to the olfactory bulbs. The remaining 3 rats underwent sham operations and were used as controls. Steel wires were implanted in the left olfactory bulb of each rat for locating the bulbs with plain X-rays. The rats were assessed 2, 14, 28, and 42 d after the olfactory nerve transection or sham operation for their ability to detect odours and for transport of 201Tl to the olfactory bulb area 8 h after nasal administration of 201Tl.

RESULTS

Both transport of 201Tl to the olfactory bulb area (p < 0.04) and ability to detect odours (p < 0.04) significantly increased with a time course after olfactory nerve transection.

CONCLUSION

201Tl transport to the olfactory bulb may be useful to visually assess olfactory ability in vivo. We plan to test olfacto-scintigraphy clinically by nasal administration of 201Tl in patients with posttraumatic olfactory loss.

ING2 is upregulated in colon cancer and increases invasion by enhanced MMP13 expression

Inhibitor of growth 2 (ING2) is associated with chromatin remodeling and regulation of gene expression by binding to a methylated histone H3K4 residue and recruiting HDAC complexes to the region. The aim of our study is to investigate the regulation of ING2 expression and the clinical significance of upregulated ING2 in colon cancer. Here, we show that the ING2 mRNA level in colon cancer tissue increased to more than twice than that in normal mucosa in the 45% of colorectal cancer cases that we examined. A putative NF-kappaB binding site was found in the ING2 promoter region. We confirmed that NF-kappaB could bind to the ING2 promoter by EMSA and luciferase assays. Subsequent microarray analyses revealed that ING2 upregulates expression of matrix metalloproteinase 13 (MMP13), which enhances cancer invasion and metastasis. ING2 regulation of MMP13 expression was confirmed in both ING2 overexpression and knock down experiments. MMP13 expression was further induced by coexpression of ING2 with HDAC1 or with mSin3A, suggesting that the ING2-HDAC1-mSin3A complex members regulates expression of MMP13. In vitro invasion assay was performed to determine functional significance of ING2 upregulation. ING2 overexpressed cells exhibited greater invasive potential. Taken together, upregulation of ING2 was associated with colon cancer and MMP13-dependent cellular invasion, indicating that ING2 expression might be involved with cancer invasion and metastasis.

Usefulness of curry odorant of odor stick identification test for Japanese in olfactory impairment screening

CONCLUSION

The curry odorant of the odor stick identification test for Japanese (OSIT-J) is useful in screening for olfactory impairment in Japanese subjects.

OBJECTIVE

The present study was designed to determine the most useful odorant of the OSIT-J in screening for olfactory impairment in Japanese subjects.

SUBJECTS AND METHODS

We studied olfactory impairment screening with the OSIT-J in 83 participants (49 male, 34 female; average age 50 years) in an executive check-up at NTT West Kanazawa Hospital. Olfactory discrimination acuity was evaluated with three odorants of the OSIT-J (rose, curry, and sweaty-smelling clothes), each known to be significantly correlated with the assessment of the Japanese standard olfaction test (T&T olfactometer). Those participants who did not score full marks in tests with the three odors were assessed with another nine odorants of the OSIT-J.

RESULTS

The positive predictive value was 100% in the screening with the curry odorant. In 38 participants who did not identify all three odors correctly, the identification of the curry odor was significantly correlated with the scores for all 12 odors (p<0.005). Identification of the curry odor was not significantly correlated with identification of the menthol odor of OSIT-J.

Relationship between pattern of masticatory path and state of lateral occlusal contact

The purpose of this study is to clarify whether the state of occlusal contact on lateral excursion is related to the pattern of masticatory movement path. The masticatory movement during mastication of softened chewing gum and the occlusal contact on lateral sliding of the mandible by 1 mm (L1), 2 mm (L2) and 3 mm (L3) were recorded in 50 healthy subjects. The path of masticatory movement was classified into one of seven patterns. The number of teeth involved in the occlusal contact in each pattern was investigated and compared among different lateral occlusal positions. The occlusal contact was then classified into 15 types based on one or a combination of the following four regions; incisal region, canine region, premolar region and molar region. The number of occlusal contact type for each pattern was investigated and compared among patterns. The number of teeth involved in occlusal contact decreased as the degree of lateral excursion increased, and significant differences were observed among the lateral occlusal positions (P < 0.001). The occlusal contact tended to decrease in the molar region and increase in the canine or premolar regions as the degree of the lateral excursion increased. When comparing among patterns, significant differences were observed at L2 and L3 (L2; P < 0.001, L3; P = 0.030) but not at L1 (P = 0.318). The difference was remarkable at L2. It was suggested that the state of occlusal contact at L2 and L3, particularly at L2 was related to the masticatory path pattern.

Odor detection ability and thallium-201 transport in the olfactory nerve of traumatic olfactory-impaired mice

Although olfactory nerve damage is a contributing factor in the diagnosis of posttraumatic olfactory loss, at present, there are no methods to directly assess injury to these nerves. We have shown that following olfactory nerve injury in mice, thallium-201 (201 Tl) transport from the nasal cavity to the olfactory bulb decreases. To determine if olfactory function after nerve injury could be assessed with nasal administration of 201 Tl, we measured the correlation between odor detection ability (ODA) and the rate of transport of 201 Tl in olfactory nerves. Both ODA and 201 Tl transport were measured after bilateral olfactory nerve transection for a 4-week period. Cycloheximide solution was used for ODA against tap water. 201 Tl transport was measured as the ratio of radioactivity in the nasal cavity and olfactory bulb with gamma spectrometry. There was a significant correlation between ODA and the rate of 201 Tl transport in the olfactory nerve. These findings suggest that olfactory function after nerve injury can be objectively evaluated with the nasal administration of 201 Tl.

Thallium Transport and the Evaluation of Olfactory Nerve Connectivity between the Nasal Cavity and Olfactory Bulb

Little is known regarding how alkali metal ions are transported in the olfactory nerve following their intranasal administration. In this study, we show that an alkali metal ion, thallium is transported in the olfactory nerve fibers to the olfactory bulb in mice. The olfactory nerve fibers of mice were transected on both sides of the body under anesthesia. A double tracer solution (thallium-201, (201)Tl; manganese-54, (54)Mn) was administered into the nasal cavity the following day. Radioactivity in the olfactory bulb and nasal turbinate was analyzed with gamma spectrometry. Auto radiographic images were obtained from coronal slices of frozen heads of mice administered with (201)Tl or (54)Mn. The transection of the olfactory nerve fibers was confirmed with a neuronal tracer. The transport of intranasal administered (201)Tl/(54)Mn to the olfactory bulb was significantly reduced by the transection of olfactory nerve fibers. The olfactory nerve transection also significantly inhibited the accumulation of fluoro-ruby in the olfactory bulb. Findings indicate that thallium is transported by the olfactory nerve fibers to the olfactory bulb in mice. The assessment of thallium transport following head injury may provide a new diagnostic method for the evaluation of olfactory nerve injury.

[Olfactory disturbance screening with the odor stick identification test (OSIT-J) in executive checkups]

The odor stick identification test for Japanese (OSIT-J) has been shown to be useful for detecting and evaluating olfactory disturbances in Japanese people. We studied the usefulness of OSIT-J in screening for olfactory disturbances in 83 Japanese participants (49 male, 34 female) participating in an executive checkup at NTT West Kanazawa Hospital in Japan. The olfactory ability was self-reported on a grade scale. Olfactory function was then evaluated with a three-odors OSIT-J (rose, curry and sweaty socks). Participants with low self-reported olfactory ability or less-than-full scores in the three-odor test were evaluated with an additional 10 odors of OSIT-J. Eight or less points are considered to be lower than average in the 13-odor test of OSIT-J (Saito S, et al.). Eleven of the 83 participants had low self-reported olfactory ability. Four participants with a full score in the three odors test with low self-reported olfactory ability scored more than eight points in the 13-odor test. Thirty-eight participants scored less than three points in the three-odor test. Seven of 29 participants with two points in the three-odor test scored eight or less in the 13-odor test. In the 29 participants, subjects with low self-reported olfactory ability scored significantly lower scores than those without a low self-reported olfactory ability in the 13-odor test. The self-reported olfactory ability was not related to the score in the 13-odor test in the nine participants with one point or less in the three-odor test. Males scored significantly lower scores than females in the three-odor test. However, gender was not significantly related to the rate of olfactory disability estimated based on the 13-odor test. Use of a three-odor OSIT-J along with a self-administered questionnaire pertaining to olfactory disability is useful for olfactory disturbance screening during executive health checkups.

GAP junctional channel inhibition alters actin organization and calcium propagation in rat cultured astrocytes

Astrocytes are connected by gap junctions, which provide intercellular pathways that allow a direct exchange of ions and small metabolites including second messengers and the propagation of electric currents. The roles of gap junctional communication on whole-cell morphology, cytoskeletal organization, and intercellular communication in astrocytes are not yet clear even in vitro, though there are many studies that have examined the active relation between gap junctions and actin filaments in astrocytes. Here we examined the effects of gap junction inhibitors, which do not interrupt the formation but rather the function of gap junctions, on whole-cell morphology, cytoskeletal organization, and intercellular communication in rat cultured astrocytes. Functional blockade of gap junctions during the formation of an astrocytic monolayer resulted in discordance of actin stress fibers between neighboring cells, even though whole-cell morphology of these cells did not change by such treatment. Mechanical stimulation-induced calcium wave propagation was significantly reduced in these actin-discordance cells even after thorough wash out. Differentiation of astrocytes in the presence of gap junction inhibitors was associated with morphological disarrangement among neighboring cells due to disordered alignment of actin stress fibers between cells.Our results indicate that gap junctional communication enables cell-to-cell coordination of actin stress fibers in astrocytes, thus enhancing intercellular communication through calcium spread.

Kinetic analysis of the bactericidal action of heated scallop-shell powder

Shell powder of scallop (Patinopecten yessoensis) was exposed to heat treatment at between 200 and 1000 degrees C, and the bactericidal action of the powder slurry was investigated. Shell powder heated at 700 degrees C or higher exhibited bactericidal action against Escherichia coli, Salmonella typhimurium, Staphylococcus aureus and Bacillus subtilis (vegetative cells). The death of bacteria in the shell powder slurry followed first-order reaction kinetics, and the apparent death rate constant (k) was determined. An increase in exposure temperature enhanced the bactericidal action. The bactericidal action is due to calcium oxide that is converted from calcium carbonate, which is the main component of the shell powder, by heat treatment. The slurry temperature is found to significantly affect the bactericidal action of the shell powder. The slope of the Arrhenius plot of k for E. coli and S. aureus that were grown at 37 degrees C exhibited a discontinuous point at approximately 22 degrees C, at which the values of activation energy for the death of bacteria in the powder slurry changed. This temperature corresponds to that of the phase transition of cell membrane lipids. The bactericidal action of the shell powder is greater than that of a NaOH solution of identical pH. Although the pH of the shell powder slurry is high, the slurry was considered to possess other antibacterial mechanisms in addition to that of alkalinity.

The effect of bolus size on the chewing cycle in humans

No general agreement exists regarding the effect that bolus size has on masticatory movement, probably because both the size and texture of food change during mastication. In this experiment, in order to clarify the effect of bolus size on masticatory movement, a food that does not change in size and texture--chewing gum--was chosen, and the relationship between bolus size and the chewing cycle was analyzed. Ten healthy subjects in their twenties were asked to chew pieces of softened chewing gum of four different sizes. For ten cycles, beginning with the fifth cycle of mastication, gape and masticatory width were calculated for the spatial parameter of the chewing cycle, and cycle time was calculated as the temporal parameter. The relationship between these parameters and the bolus size was investigated. As the bolus size increased, the spatial and temporal parameters increased. In addition, there was a positive correlation between the bolus size and each parameter. The influence of the bolus size was as follows: gape, r = 0.91; masticatory width, r = 0.79; and cycle time, r = 0.74 (all, P < 0.001). From these results it was concluded that the shape of the chewing cycle was altered by the size of the food bolus, and that the changes in sensory input from the peripheries greatly affected the masticatory movement.

Heated scallop-shell powder slurry treatment of shredded cabbage

The main component of scallop-shell powder is calcium carbonate (CaCO3). Through heat treatment, CaCO3 in the shell is converted to CaO, which exhibits antibacterial activity. The disinfecting effect of heated scallop-shell powder on shredded cabbage was investigated for various powder concentrations (0.1 to 1.0 g dm(-3)) and treatment temperatures (10 to 40 degrees C). Scallop-shell powder treatment was found to reduce the aerobic bacteria count in cabbage, with increasing effectiveness at higher powder concentrations and treatment temperatures. Coliforms were completely eliminated within 5 min with as little as 0.1 g dm(-3) powder treatment. During storage at 4 degrees C, aerobic bacterial counts did not increase after powder treatment, whereas counts increased with water-washing or sodium hypochlorite treatment at 200 microg dm(-3). The inactivation pattern of bacterial cells in shredded cabbage involved an accelerated decline followed by an extended tail at powder concentrations of 0.1 and 0.5 g dm(-3). We postulate that a fraction of bacterial cells in the initial population becomes tolerant to the shell powder. A proposed model accurately predicts the reducing bacterial counts on shredded cabbage by scallop-shell powder treatment. The decrease in the L-ascorbic acid content of shredded cabbage was approximately 20 to 30% for scallop-shell powder treatment at 0.1 and 0.5 g dm(-3) (20 degrees C), which is almost identical to that by sodium hypochlorite treatment at 200 micorg dm(-3).

Ca2+ signaling regulated by an ATP-dependent autocrine mechanism in astrocytes

Although the mechanisms of Ca2+ wave propagation in astrocytes induced by mechanical stimulation have been well studied, it is still not known how the [Ca2+]i increases in the stimulated cells. Here, we have analyzed the mechanisms of [Ca2+]i increase in single, isolated astrocytes. Our results showed that there was an autocrine mechanism of Ca2+ regulation mediated by ATP in mechanically stimulated astrocytes. This autocrine mechanism induced the activation of phospholipase C via a G-protein, resulting in Ca2+ release from intracellular Ca2+ stores. A second pathway mediating a [Ca2+]i increase was via a Ca2+ influx from the extracellular space, which, interestingly, suppressed an intracellular Ca2+ oscillation. These two different Ca2+ cascades are involved in signal transduction and may function separately during intercellular communication.

Current topics on cytokine removal technologies

It has been widely accepted that cytokines play important roles in the development of organ failure in various pathophysiological conditions of critically ill patients. Various new technologies, including continuous renal replacement therapy, have been developed for the removal of causative humoral mediators in sepsis or other critical conditions. Nonselective blood purification technologies, such as hemofiltration and plasma exchange, are applied in cytokine removal technology. However, the more selective blood purification technologies, such as adsorption, and the combination of those technologies, should be considered in future applications. Only through a prospective randomized controlled study can it be elucidated whether or not these technologies have efficacy in the treatment of sepsis and critically ill patients with hypercytokinemia. We should join and discuss the design of future clinical trials with a standardized strategy for the evaluation of the technologies.

Usefulness of plasma exchange plus continuous hemodiafiltration to reduce adverse effects associated with plasma exchange in patients with acute liver failure

OBJECTIVE

To efficiently remove middle-molecular-weight substances such as hepatic toxins and minimize adverse effects associated with plasma exchange implementation, we have performed plasma exchange slowly in combination with continuous hemodiafiltration. This study was designed to determine the usefulness of plasma exchange with continuous hemodiafiltration in reducing the adverse effects associated with implementation of plasma exchange alone.

DESIGN

A retrospective clinical study.

SETTING

University teaching hospital.

PATIENTS

The study involved 90 patients with liver failure who had been treated with plasma exchange in our department over the past 12 yrs. We examined these patients by dividing them into two groups (48 patients treated with plasma exchange alone and 42 patients treated with plasma exchange plus continuous hemodiafiltration at the time of plasma exchange implementation).

MEASUREMENTS AND MAIN RESULTS

Baseline blood Na+ concentration, HCO3- concentration, and colloid osmotic pressure were followed after implementation of plasma exchange to compare the frequency of development of three adverse effects (hypernatremia, metabolic alkalosis, and sharp decrease in colloid osmotic pressure) in the two groups. Hypernatremia was found in 26.7% of treatments in the group with plasma exchange alone and 3.3% in the group of plasma exchange plus continuous hemodiafiltration, and metabolic alkalosis was found in 30.6% of treatments in the group with plasma exchange alone and 4.9% in the group of plasma exchange plus continuous hemodiafiltration; both percentages were significantly higher in the group with plasma exchange alone (p <.001). A sharp decrease in colloid osmotic pressure occurred in 13.3% of treatments in the group with plasma exchange alone but was not observed at all in the patients treated with plasma exchange plus continuous hemodiafiltration.

CONCLUSIONS

We conclude that adverse effects associated with plasma exchange for artificial liver support for liver failure can be alleviated with use of plasma exchange plus continuous hemodiafiltration instead of plasma exchange alone.

Comparison of Sepsis-related Organ Failure Assessment (SOFA) score and CIS (cellular injury score) for scoring of severity for patients with multiple organ dysfunction syndrome (MODS)

OBJECTIVE

To evaluate the usefulness of cellular injury score (CIS) and Sepsis-related Organ Failure Assessment (SOFA) score for determination of the severity of multiple organ dysfunction syndrome (MODS).

DESIGN

A prospective observational study.

SETTING

A medical and surgical intensive care unit (ICU) of a teaching hospital.

PATIENTS

Forty-seven consecutive MODS patients.

MEASUREMENTS AND RESULTS

SOFA score and CIS were measured every day for 12 months for 47 MODS patients. Comparison was made of the SOFA score and CIS for usefulness in the scoring of severity of MODS in 26 survivors and 21 non-survivors. In addition, receiver operating characteristics (ROC) analysis was used to determine the usefulness of these two indexes as predictors of prognosis. No significant differences were found on admission between the survivors and non-survivors, but significant differences between the two subgroups (p < 0.001) were found in maximum value within 1 week after admission and maximum value during the course of treatment for both indexes. Analysis of changes after admission indicated that significant differences between survivors and non-survivors began to appear on day 3 of admission for both indexes; at that time SOFA score began to deteriorate in the non-survivors while CIS began to improve in the survivors. ROC analysis demonstrated that the area under the ROC curve was 0.769 for SOFA scores and 0.760 for CIS.

CONCLUSIONS

Both SOFA score and CIS sequentially reflected the severity of MODS. Furthermore, they were comparable in diagnostic value as predictors of prognosis. These findings may indicate the possibility that MODS is a summation of effects of cellular injury. In addition, sequential evaluation of both SOFA score and CIS would provide a more accurate prediction of prognosis than conventional methods.

Prognostic value of c-erbB2 and other markers in patients treated with chemotherapy for recurrent head and neck cancer

BACKGROUND

Chemotherapy is widely used in patients with recurrent head and neck cancer, but no clear markers are available that can predict response to treatment or survival in these patients.

METHODS

Twenty-nine patients evaluated in this study had recurrent head and neck squamous carcinomas, previously treated with surgery and/or radiotherapy. Patients received either cisplatin and 5-fluorouracil (5-FU) (n = 15) or cisplatin and paclitaxel (Taxol) (n = 14). Expression of c-erbB2, p53, glutathione S-transferase pi, multidrug resistance-associated protein, thymidylate synthase, and glutathione synthetase were evaluated in biopsy tissues.

RESULTS

Response to chemotherapy was significantly correlated with improved survival (progression-free survival, p =.0005; overall survival, p =. 007). Of the factors examined, expression of c-erbB2 was associated with significantly decreased progression-free survival (p =.023) and overall survival (p =.029). This was seen in patients treated with cisplatin/taxol but not in patients treated with cisplatin/5-FU.

CONCLUSION

Expression of c-erbB2 may be a clinically useful predictor of survival in this group of patients.

Quantitative analyses of topography and elasticity of living and fixed astrocytes

The topography and elasticity of living and fixed astrocytes cultured from the rat cerebra were studied quantitatively by atomic force microscopy (AFM). Ridge-like structures reflecting F-actin beneath the cell membrane were prominent in the contact-mode images of living astrocytes. Many of these ridges became unclear after fixation (2% glutaraldehyde). In addition, the ridge-like structures were invisible in the topography of living cells observed at zero-loading force in the force mapping mode, which is considered to show the real cell surface not pressed down by an AFM tip. The topography of fixed cells observed both in the contact mode and at zero-loading force in the force mapping mode was similar to that of living cells observed at zero-loading force in the force mapping mode, although some deformed areas were detected in the fixed cells. The elasticity map images of living astrocytes showed that the cell membrane above the nucleus was softer (2-3 kPa) than the surroundings, and that the cell membrane above F-actin was stiffer (10-20 kPa) than the surroundings. In the elasticity map images of fixed astrocytes, on the other hand, the elasticity of the cells was found to be relatively uniform (200-700 kPa) irrespective of the inner structures of cells. These results show that images observed by AFM should be carefully examined in consideration of the force introduced to specimens and the elasticity of specimens to find out the real surface topography.