Urinary liver-type fatty acid-binding protein levels may be associated with the occurrence of acute kidney injury induced by trauma

Introduction

Acute kidney injury (AKI), with a fatality rate of 8.6%, is one of the most common types of multiorgan failure in the intensive care unit (ICU). Thus, AKI should be diagnosed early, and early interventions should be implemented. Urinary liver-type fatty acid-binding protein (L-FABP) could aid in the diagnosis of AKI.

Methods

In this prospective, single-center, observational study, we included 100 patients with trauma. Urinary L-FABP levels were measured using a semi-quantitative rapid assay kit 6 and 12 h after injury. Negative, weakly positive, and strongly positive urinary L-FABP levels were examined using two protocols. Using protocol 1, measurements were performed at 6 h after injury negative levels were considered "negative," and weakly positive and strongly positive levels were considered "positive." Using protocol 2, strongly positive levels at 6 h after injury were considered "positive," and negative or weakly positive levels at 6 h after injury were considered "positive" if they were weakly positive or positive at 12 h after injury.

Results

Fifteen patients were diagnosed with AKI. Using protocol 1, the odds ratio (OR) was 20.55 (p = 0.001) after adjustment for the injury severity score (ISS), contrast media use, and shock index. When the L-FABP levels at 6 and 12 h were similarly adjusted for those three factors, the OR was 18.24 (p < 0.001). The difference in ORs for protocols 1 and 2 was 1.619 (p = 0.04).

Discussion

Associations between urinary L-FABP and AKI can be examined more precisely by performing measurements at 6 and 12 h after injury than only one time at 6 h.

Prospective study examining the probability of cerebral fat embolism based on magnetic resonance imaging

Purpose

Cerebral fat embolism (CFE) is a rare syndrome caused by the embolization of fat particles into the brain circulation. This prospective single-center observational study investigated the incidence of CFE in long-bone or pelvic fractures based on magnetic resonance imaging (MRI) findings. The purpose of this study was to investigate the incidence of CFE by MRI findings with or without symptoms suggestive of CFE.

Methods

Eligible patients were consecutive, aged 15 years or older, with high-energy traumas, including pelvic or femur fractures. Excluded patients were those who died, could not undergo MRI resulting from medical conditions, or had insufficient mental capacity and no consultee to provide consent. The MRI was scheduled within 4 weeks of the injury, and the images were reviewed by one of the three neuroradiologists who were unaware of the patient's clinical information. Patient data regarding demographics, preceding trauma, injury severity score (ISS), presentation and examination timing of MRI, management including surgery, and outcome were collected.

Results

Sixty-two patients were recruited, and three patients were excluded. All patients were injured by blunt trauma. The median patient age was 44 years. The median ISS was 13, and 53 patients needed surgical fixation. There were 22 patients with long-bone fractures, all of whom received external fixation or intramedullary nailing on admission day. MRI was performed after a median hospital day of 18 days. Using MRI imaging, three (5.0%) patients were diagnosed with CFE, and three patients were suspected of CFE.

Conclusions

This is the first study to prospectively examine the probability of CFE based on MRI. Since fat embolism syndrome (FES) is confirmed in patients without clinical symptoms, CFE may be more common in patients with trauma than currently believed. Therefore, studies to determine the diagnostic criteria combined with symptoms, MRI, or other objective findings are required in the future.

Clinical characteristics of patients with snow sports trauma transported to a trauma care center: A retrospective observational study

BACKGROUND

Snow sports are a popular recreational activity; however, the incidence of injury of snow sports can be high for skiers and snowboarders. Our hospital receives severe trauma cases from snow resorts and hospitals throughout the region. This study aimed to determine whether the risk of snow sports-related major trauma that requires emergency surgery under general anesthesia varies by the equipment and injury mechanism.

METHODS

This retrospective cohort study included patients with snow sports trauma referred to Gifu University Hospital, Japan between November 2010 and March 2020. We analyzed the need for emergency operation under general anesthesia within 24 h using Fisher's exact test. We identified 106 patients: (1) 90 in the snowboarders' group and 16 in the skiers' group or (2) 46 in the fall after jumping group (jumping group), 27 in the collide with other people and obstacle group (collision group), and 33 in the fall during gliding group (gliding group).

RESULTS

Snowboarders were nearly twice as likely as skiers to require emergency surgery under general anesthesia (44% vs. 25%; p = 0.236]. No significant associations were found between emergency surgery under general anesthesia and injury mechanism, but half of the patients in the jumping group required emergency surgery.

CONCLUSIONS

Snowboard as equipment and falls after jumping as a mechanism of injury tended to be associated with emergency surgery under general anesthesia, with no significant differences. In order to provide adequate resources for snow sports trauma, the cause of the patient's injury is strongly related to the urgency of the condition, and transport to a trauma center should be actively considered. Further studies are warranted with respect to the effects of personal protective equipment and skill level.

Recombinant thrombomodulin may protect cardiac capillary endothelial glycocalyx through promoting Glypican-1 expression under experimental endotoxemia

Introduction

Myocardial dysfunction occurs in patients with sepsis due to vascular endothelial injury. Recombinant human thrombomodulin (rhTM) attenuates vascular endothelial injuries through endothelial glycocalyx (eGC) protection.

Hypothesis

We hypothesized that rhTM attenuates myocardial dysfunction via the inhibition of vascular endothelial injury during sepsis.

Methods

Ten-week-old male C57BL6 mice were injected intraperitoneally with 20 mg/kg of lipopolysaccharide (LPS). In rhTM-treated mice, rhTM was injected intraperitoneally at 3 and 24 h after LPS injection. Saline was injected intraperitoneally as control. To assess for eGC injury, intensity score was measured 48 h after the LPS injection. To confirm vascular endothelial injuries, ultrastructural analysis was performed using scanning (SEM) and transmission electron microscopy (TEM).

Results

The survival rate of the rhTM group at 48 h after LPS injection was significantly higher than that of the control group (68% vs. 17%, p < 0.05). The serum level of troponin I in the rhTM group was lower than that in the control (2.2 ± 0.4 ng/dL vs 9.4 ± 1.1 ng/dL, p < 0.05). The expression of interleukin-6 (IL-6) was attenuated in the rhTM-treated group than in the control (65.3 ± 15.3 ng/mL vs 226.3 ± 19.4 ng/mL, p < 0.05). The serum concentration of syndecan-1, a marker of glycocalyx damage, was significantly decreased 48 h post-administration of LPS in the rhTM-treated group than in the control group. In ultrastructural analysis using SEM and TEM, eGC peeled off from the surface of the capillary lumen in the control. Conversely, the eGC injury was attenuated in the rhTM group. Gene set enrichment analysis revealed that osteomodulin, osteoglycin proline/arginine-rich end leucine-rich repeat protein, and glypican-1, which are proteoglycans, were preserved by rhTM treatment. Their protein expression was retained in endothelial cells.

Conclusion

rhTM attenuates sepsis-induced myocardial dysfunction via eGC protection.

Syndecan-1 as a severity biomarker for patients with trauma

Tissue injury and hemorrhage induced by trauma lead to degradation of the endothelial glycocalyx, causing syndecan-1 (SDC-1) to be shed into the blood. In this study, we investigated whether serum SDC-1 is useful for evaluating trauma severity in patients. A single-center, retrospective, observational study was conducted at Gifu University Hospital. Patients transported to the emergency room for trauma and subsequently admitted to the intensive care unit from January 2019 to December 2021 were enrolled. A linear regression model was constructed to evaluate the association of serum SDC-1 with injury severity score (ISS) and probability of survival (Ps). A total of 76 trauma patients (54 men and 22 women) were analyzed. ISS was significantly associated with serum SDC-1 level in trauma patients. Among the six body regions defined in the AIS used to calculate the ISS score, “chest” and “abdominal or pelvic contents” were significantly associated with serum SDC-1 level, and “extremities or pelvic girdle” also tended to show an association with serum SDC-1 level. Moreover, increasing serum SDC-1 level was significantly correlated with decreasing Ps. Serum SDC-1 may be a useful biomarker for monitoring the severity of trauma in patients. Further large-scale studies are warranted to verify these results.

Hypergranulation over a meshed split-thickness skin graft, a complication of negative-pressure wound therapy: a case report

Background

We present a case of a rare complication of negative-pressure wound therapy (NPWT) wherein there was fixation of a meshed split-thickness skin graft (STSG), suspected as a failure by hypergranulation. However, the meshed STSG was integrated within 5 days of NPWT cessation.

Case presentation

A 22-year-old Asian man sustained 25% total-body-surface-area flame burns. After multiple operations, an ulcer was present on the proximal left thigh. On day 37 after admission, the ulcer was debrided, and an 11/1000-inch (0.28 mm) skin graft was taken from the ipsilateral thigh and meshed, using a 1:1.5 ratio. NPWT was applied to the donor and recipient sites with a continuous negative pressure of 125 mmHg. On day 43, NPWT was discontinued. The skin grafts were not identified on the surface of the granulation tissue. With topical ointment therapy, rapid epithelialization of the ulcer was observed as the granulation tissue regressed. On day 48, the recipient site had completely epithelialized.

Conclusions

The hypergranulation tissue rarely covered the meshed STSGs when the grafts were fixed by NPWT. In that case, immediate debridement should be avoided, and conservative treatment should be initiated.

Leriche syndrome diagnosed due to polytrauma: a case report

Background

Leriche syndrome is caused by atherosclerosis and is often characterized by symptoms such as intermittent claudication and numbness and coldness of the lower limbs. Its exact prevalence and incidence are unknown because it is a rare disease. We report a case of Leriche syndrome diagnosed incidentally on trauma pan-scan computed tomography (CT).

Case presentation

A 61-year-old Asian male was driving a passenger car and had a head-on collision with a dump truck that required an emergency call. The patient was transported to our hospital in a doctor’s helicopter. Physical examination revealed the following vital signs: respiratory rate, 23 breaths per min; SpO₂, 98% under a 10-L administration mask; pulse rate, 133 beats per min; blood pressure, 142/128 mmHg; Focused Assessment with Sonography for Trauma, positive; Glasgow Coma Scale assessment, E3V5M6; and body temperature, 35.9 °C.

Trauma pan-scan CT showed bilateral mandibular fractures, bilateral multiple rib fractures, bilateral pneumothorax, sternal fractures, hematoma around thoracic spine, small bowel perforation, mesenteric injury, right clavicle fracture, right ankle debridement injury, and thrombotic occlusion from just above the abdominal aortic bifurcation to the bilateral common iliac arteries. Although thrombotic occlusion needed to be differentiated from traumatic aortic injury, the presence of collateral blood vessels led to the diagnosis of Leriche syndrome, and conservative treatment was performed.

Damage control surgery was required for the small bowel injuries. From the second day of admission, the patient was treated with continuous intravenous heparin and prostaglandin preparations. However, impaired blood flow and reperfusion injury in the right lower extremity progressed. On the fifth day of admission, right thigh amputation was performed. The patient required renal replacement therapy for 2 weeks starting from the third day of admission.

Conclusions

In this case, conservative therapy was initially chosen for Leriche syndrome. However, the complex factors in the acute phase of trauma led to development of hemorrhagic necrosis, requiring amputation of the lower extremity. Our findings indicate the need to carefully consider the unique factors affecting Leriche syndrome patients when considering treatment indications and choices for trauma.

Measuring the Concentration of Serum Syndecan-1 to Assess Vascular Endothelial Glycocalyx Injury During Hemodialysis

Glycocalyx is present on the surface of healthy endothelium, and the concentration of serum syndecan-1 can serve as an injury marker. This study aimed to assess endothelial injury using serum syndecan-1 as a marker of endothelial glycocalyx injury in patients who underwent hemodialysis. In this single-center, retrospective, observational study, 145 patients who underwent hemodialysis at the Gifu University Hospital between March 2017 and December 2019 were enrolled. The median dialysis period and time were 63 months and 3.7 h, respectively. The serum syndecan-1 concentration significantly increased from 124.6 ± 107.8 ng/ml before hemodialysis to 229.0 ± 138.1 ng/ml after hemodialysis (P &lt; 0.001). Treatment with anticoagulant nafamostat mesylate inhibited hemodialysis-induced increase in the levels of serum syndecan-1 in comparison to unfractionated heparin. Dialysis time and the change in the syndecan-1 concentration were positively correlated. Conversely, the amount of body fluid removed and the changes in the syndecan-1 concentration were not significantly correlated. The reduction in the amount of body fluid removed and dialysis time inhibited the change in the syndecan-1 levels before and after hemodialysis. In conclusion, quantitative assessment of the endothelial glycocalyx injury during hemodialysis can be performed by measuring the serum syndecan-1 concentration, which may aid in the selection of appropriate anticoagulants, reduction of hemodialysis time, and the amount of body fluid removed.

Serum syndecan-1 concentration in hospitalized patients with heart failure may predict readmission-free survival

Syndecan-1 is found in the endothelial glycocalyx and is released into the bloodstream during stressed conditions, including severe diseases such as acute kidney injury, chronic kidney disease, and cardiovascular disease. This study investigated the prognostic value of serum syndecan-1 concentration in patients with heart failure upon admission. Serum syndecan-1 concentration was analyzed in 152 patients who were hospitalized for worsening heart failure from September 2017 to June 2018. The primary outcome of the study was readmission-free survival, defined as the time from the first admission to readmission for worsened heart failure or death from any cause, which was assessed at 30 months after discharge from the hospital. The secondary outcome of the study was survival time. Blood samples and echocardiogram data were analyzed. Univariate and multivariable time-dependent Cox regression analyses adjusted for age, creatinine levels, and use of antibiotics were conducted. The serum syndecan-1 concentration was significantly associated with readmission-free survival. Subsequently, the syndecan-1 concentration may have gradually decreased with treatment. The administration of human atrial natriuretic peptide and antibiotics may have modified the relationship between readmission-free survival and serum syndecan-1 concentration (p = 0.01 and 0.008, respectively). Serum syndecan-1 concentrations, which may indicate injury to the endothelial glycocalyx, predict readmission-free survival in patients with heart failure.

Postmortem diagnosis of pulmonary tumor thrombotic microangiopathy with rapid exacerbation in a patient with gastric cancer: a case report

Background

Pulmonary tumor thrombotic microangiopathy (PTTM) is a condition that involves the development of pulmonary hypertension due to the presence of microscopic tumor emboli of the peripheral pulmonary arteries. Here, we report a case of rapidly exacerbating PTTM associated with gastric cancer that was identified postmortem through pathological autopsy.

Case presentation

A 52-year-old Asian woman who experienced anterior chest pain while coughing visited the orthopedic department of the Gifu University Hospital. She was diagnosed as having multiple osteolytic bone metastases throughout her body and was subsequently scheduled to undergo combined positron emission tomography and computed tomography (CT) to search for a primary lesion. However, 4 days after her visit to the orthopedic department, she was unable to stand up and thus visited the emergency department. At the time of admission, physical examination results revealed that she had a percutaneous oxygen saturation level of 90% (on room air) and cyanosis and that she was in a state of hemodynamic shock. Laboratory test results revealed elevated levels of fibrin degradation products and D-dimer in her blood. Chest CT results were normal. She was admitted to the hospital’s general ward for follow-up but soon entered a gradually worsening state of shock and respiratory failure. Electrocardiography revealed findings associated with right heart strain; however, contrast-enhanced CT did not reveal the presence of pulmonary embolism. She was admitted to the intensive care unit and was treated for pulmonary hypertension; however, 45 h after her arrival at the hospital, she died of respiratory failure. A pathological autopsy revealed the presence of gastric cancer, tumor microemboli, and fibrous intimal thickening of the peripheral arteries of both lungs; thus, a diagnosis of PTTM was made.

Conclusions

In patients with carcinoma of unknown primary site and pulmonary hypertension with pulmonary embolism ruled out by CT, emergency physicians and intensivists must consider the possibility of PTTM, which represents an oncologic emergency, and initiate chemotherapy administration as soon as possible.

Serum syndecan-1 reflects organ dysfunction in critically ill patients

Syndecan-1 (SDC-1) is found in the endothelial glycocalyx and shed into the blood during systemic inflammatory conditions. We investigated organ dysfunction associated with changing serum SDC-1 levels for early detection of organ dysfunction in critically ill patients. To evaluate the effect of SDC-1 on laboratory parameters measured the day after SDC-1 measurement with consideration for repeated measures, linear mixed effects models were constructed with each parameter as an outcome variable. A total of 94 patients were enrolled, and 831 samples were obtained. Analysis using mixed effects models for repeated measures with adjustment for age and sex showed that serum SDC-1 levels measured the day before significantly affected several outcomes, including aspartate aminotransferase (AST), alanine transaminase (ALT), creatinine (CRE), blood urea nitrogen (BUN), antithrombin III, fibrin degradation products, and D-dimer. Moreover, serum SDC-1 levels of the prior day significantly modified the effect between time and several outcomes, including AST, ALT, CRE, and BUN. Additionally, increasing serum SDC-1 level was a significant risk factor for mortality. Serum SDC-1 may be a useful biomarker for daily monitoring to detect early signs of kidney, liver and coagulation system dysfunction, and may be an important risk factor for mortality in critically ill patients.

Severe heat stroke complicated by multiple cerebral infarctions: a case report

Background

Heat-related illnesses include symptoms such as heat syncope/cramps, heat exhaustion, and life-threatening heat stroke. Usually, a heat stroke causes cerebellar ataxia, cognitive impairment, dysphagia, and aphasia. We report a very rare case of a patient who developed severe heat stroke complicated by multiple cerebral infarctions.

Case presentation

An 80-year-old Asian woman was found lying unconscious at her house, with no air conditioner and closed windows; the highest outside temperature was 36.1 °C. She was brought to our hospital unconscious with a high bladder temperature (42.5 °C) and disseminated intravascular coagulation (DIC score 4). She was diagnosed with severe heat stroke and managed with rapid cooling, intravenous fluids therapy, antibiotic therapy, and anti-coagulation therapy for DIC. Anti-coagulation therapy consisted of treatment with recombinant thrombomodulin for 4 days (days 1–4) and recombinant antithrombin for 1 day (day 1). A head computed tomography (CT) and magnetic resonance imaging (MRI) examination were performed on day 3, because she was still unconscious. Diffuse-weighted imaging showed high-signal intensities, indicating multiple lesions. An intracranial magnetic resonance angiography showed normal results. Imaging indicated new multiple cerebellar infarctions complicated with DIC. A tracheotomy was performed on day 9 because her conscious condition had not improved. She was transferred to another hospital for subacute care on day 23.

Conclusions

Early management of heat stroke using anti-DIC, anti-bacterial, and fluid resuscitation therapy can help prevent complications such as intracranial hemorrhaging.

Possible involvement of Syndecan-1 in the state of COVID-19 related to endothelial injury

BACKGROUND

The coronavirus infection 2019 (COVID-19) is associated with microvascular endothelial injury. Here, we report that syndecan-1, a component of endothelial glycocalyx, may reflect the disease state of COVID-19 related to endothelial injury.

CASE PRESENTATION

A patient with COVID-19 was transferred to the intensive care unit of our hospital. Computed tomography of the chest showed bilateral ground glass opacities, which was diagnosed as acute respiratory syndrome. The PaO₂/F_IO₂ ratio gradually increased from 158 on hospitalization to 300 on Day 11, on which day the ventilator was withdrawn. However, serum syndecan-1 (SDC-1) level gradually decreased from 400.5 ng/ml at hospitalization to 165.1 ng/ml on Day 5. On Day 6, serum SDC-1 level increased to 612.9 ng/ml owing to a systemic thrombosis with an increase in D-dimer. Serum SDC-1 level then decreased until 206.0 ng/ml on Day 11 after a decrease in D-dimer. The patient was transferred to another hospital on Day 21 after hospitalization.

CONCLUSIONS

In this case report, changes in serum SDC-1 level closely reflected the change in disease condition in a patient with COVID-19. Serum SDC-1 may be a useful biomarker for monitoring the disease state of critically ill patients with COVID-19.

Emphysematous cholecystitis during the treatment of heat stroke

Background

During a heat stroke, microvascular injury may occur as a result of thermal damage and systemic hypoperfusion. We present a case of an older woman who experienced emphysematous cholecystitis during a treatment of heat stroke.

Case presentation

A 91-year-old woman presented unconscious with a blood pressure, pulse, and core temperature of 73/48 mmHg, 135 bpm, and 39.8°C, respectively. The patient was diagnosed with heat stroke. Twenty-two hours after arrival, the patient fell into septic shock. We diagnosed emphysematous cholecystitis and performed an emergency cholecystectomy. As the bile culture was positive for Clostridium perfringens, meropenem was administered. The patient was transferred for rehabilitation 32 days after admission.

Conclusions

Emphysematous cholecystitis can present during a treatment of heat stroke. An abdominal X-ray examination should be performed during treatment of heat stroke in the acute phase regardless of the physical assessment.

Ultrastructural alteration of pulmonary tissue under conditions of high oxygen concentration

OBJECTIVE

To determine the structure of pulmonary tissue under conditions of high oxygen concentration.

METHODS

Ten-week-old C57BL male mice and control mice were exposed to 100% oxygen and to room air for 72 hours, respectively. To follow the progression of lesions, the mice were sacrificed at 6, 12, 24, 48, and 72 hours after 100% oxygen administration. Lung specimens obtained from these mice underwent morphologic analysis and immunofluorescence studies. We used scanning and transmission electron microscopy to determine the ultrastructure of the pulmonary capillaries, including the endothelial glycocalyx. To visualize the endothelial glycocalyx, we performed lanthanum nitrate staining.

RESULTS

The survival rate of the 100% oxygen administration group was 5% (2/40) and that of the control group was 100%. Perivascular cavity enlargement was detected 12 hours after 100% oxygen administration and expanded over time. Ultrastructural analysis using electron microscopy revealed collapsed alveoli and pulmonary capillary wall and alveolar wall thickening in the 100% oxygen group. The pulmonary capillary endothelial glycocalyx was injured in the 100% oxygen group. The perivascular cavity decreased in mice that were returned to room air after 48 hours of 100% oxygen administration.

CONCLUSION

High-concentration oxygen causes perivascular cavity enlargement; this is thought to be a special characteristic of high oxygen damage. In addition, high-concentration oxygen may be involved in pulmonary endothelial glycocalyx injury.

1320Effectiveness of atrial flutter ablation line selection using SOUNDSTAR catheter

Background

Cavotricuspid isthmus (CTI) ablation for atrial flutter (AFL) shows a high success rate and effective for patients. However, operators experience difficulties in CTI ablation in some cases and need additional ablation for repeated recurrence. We investigated whether the SOUNDSTAR® (Biosense. Webster, Diamond Barr, CA, USA) catheter would be effective to select a CTI line of high therapeutic effect.

Methods

We have investigated the anatomy of around CTI by SOUNDSTAR® catheter and decided the CTI line using the anatomical information in AFL ablation (Figure1). We assumed two CTI lines of medial and lateral line. Medial CTI (M-CTI) line was more common and shorter line. Lateral CTI (L-CTI) line was uncommon and slightly longer line. We use 3.5mm tip catheter with NxT steerable introducer. The target Ablation Index (AI) was 400, and the target VisTtag™ interval was 6 mm or less.

Results

A total 30 of AFL ablated cases were investigated retrospectively. We surveyed 15 cases in M-CTI group and 15 cases in L-CTI group. Comparing the length of CTI in all cases, the length of M-CTI line was shorter than L-CTI line (M-CTI 32.1 ± 6.6mm vs. L-CTI 38.4 ± 8.3mm, n = 30, p &lt;0.01). The atrial wall thickness of midsection and tricuspid valve (TV) side were thicker in M-CTI line (Midsection: M-CTI 4.0 ± 1.2mm vs. L-CTI 3.3 ± 0.8mm, n = 30, p &lt;0.05, TV side: M-CTI 5.4 ± 1.4mm vs. L-CTI 4.3 ± 1.1mm, n = 30, p &lt;0.05,). There was no difference in the required number of points to complete initial line (M-CTI 8.4 ± 1.6 vs. L-CTI 8.1 ± 1.7, n = 15, ns). Eustachian ridge in IVC side was thicker and higher in the M-CTI group (3.4 ± 3.3mm vs. 0.9 ± 1.9mm, n =30, p &lt;0.01) and ablation on the Eustachian ridge showed instability of catheter placement. A lot of RF delivery was required on Eustachian ridge in M-CTI (2.6 ± 0.6 vs. 2.1 ± 0.7, n =15, p &lt;0.05) and AI had resulted lower in M-CTI (351 ± 42.8 vs. 381 ± 27.1, n =15, p &lt;0.05). Recurrence is more common in M-CTI group (9/15, 60% vs. 3/15, 20%). Recurrence sites in M-CTI group were distributed ((IVC side 3/9 (33%), midsection 5/9 (56%), TV side 5/9 (56%)) and multiple recurrences occurred in 3/9 (33%). Recurrence sites in L-CTI were only midsection of CTI (3/3, 100%).

Conclusions

CTI ablation at the shorter distance M-CTI, which is commonly selected, resulted in more recurrences due to the unevenness including Eustachian ridge and the myocardium thickness. However, ablation at slightly longer L-CTI line showed lower recurrence and effective for CTI ablation.

Abstract Figure 1

Diffuse midline glioma in the spinal cord with rapid respiratory deterioration

Background

Neurogenic acute respiratory failure is usually caused by either infection or vascular insufficiency. We report the case of a patient who developed acute respiratory failure secondary to a spinal tumor.

Case Presentation

A 32‐year‐old man, presenting with numbness and muscle weakness in his legs for 2 weeks, was transferred to our hospital with worsening quadriplegia and development of respiratory symptoms. We carried out emergent spinal decompression and initiated steroid pulse therapy, with no resolution of symptoms; a tumor incision biopsy after contrast cervical magnetic resonance imaging revealed an intraspinal tumor with a pathological diagnosis of World Health Organization grade IV glioma. The patient developed bradycardia, severe sepsis, status epilepticus, and cardiopulmonary arrest due to hypoxemia and was treated with chemoradiotherapy under mechanical ventilation. He was later transferred to another hospital for subacute care.

Conclusion

Acute respiratory failure caused by spinal tumors is uncommon. However, acute care practitioners should be mindful of neoplastic lesions as a potential cause.

Herpes zoster and meningitis in an immunocompetent child: a case report

Background

Development of neurological complications of varicella zoster virus reactivation is relatively uncommon, particularly in an immunocompetent child.

Case presentation

An 11-year-old Asian girl presented with headache and skin rash on her left chest. She was diagnosed with meningitis, and herpes zoster was confirmed by polymerase chain reaction using cerebrospinal fluid. Acyclovir was administered intravenously. Given the favorable evolution of the clinical course, she was discharged from the hospital on day 8 of her illness. She had no apparent sequelae or comorbidities at the time of the 6-week follow-up.

Conclusions

Neurological complications such as meningitis due to varicella zoster virus reactivation are uncommon, especially in an immunocompetent child; no specific immune deficiency was identified in our patient. We conclude that, although rare, varicella zoster virus should be recognized as a potential cause of viral meningitis in immunocompetent children.

Effect of high-flow high-volume-intermittent hemodiafiltration on metformin-associated lactic acidosis with circulatory failure: a case report

Background

Metformin-associated lactic acidosis is a well-known life-threatening complication of metformin. We here report the case of a patient who developed metformin-associated lactic acidosis without organ manifestations, due to the simultaneous ingestion of an overdose of metformin and alcohol, and who recovered with high-flow high-volume intermittent hemodiafiltration.

Case presentation

A 44-year-old Asian woman with type 2 diabetes attempted suicide by ingesting 10 tablets of metformin 500 mg and drinking approximately 600 mL of Japanese sake containing 15% alcohol. She was transferred to our emergency department because of disturbed consciousness. Continuous intravenous administration of noradrenalin (0.13 μg/kg per minute) was given because she was in shock. Laboratory findings included a lactate level of 119 mg/dL (13.2 mmol/L), bicarbonate of 14.5 mmol/L, and serum metformin concentration of 1138 ng/mL. She was diagnosed as having metformin-associated lactic acidosis worsened by alcohol. After 4560 mL of bicarbonate ringer (Na⁺ 135 mEq/L, K⁺ 4 mEq/L, Cl⁻ 113 mEq/L, HCO₃⁻ 25 mEq/L) was administered, high-flow high-volume intermittent hemodiafiltration.

(dialysate flow rate: 500 mL/min, substitution flow rate: 3.6 L/h) was carried out for 6 h to treat metabolic acidosis and remove lactic acid and metformin. Consequently, serum metformin concentration decreased to 136 ng/mL and noradrenalin administration became unnecessary to maintain normal vital signs. On hospital day 12, she was moved to the psychiatry ward.

Conclusions

HFHV-iHDF may be able to remove metformin and lactic acid efficiently and may improve the condition of hemodynamically unstable patients with metformin-associated lactic acidosis.

Thyrotoxic and pheochromocytoma multisystem crisis: a case report

Background

Thyrotoxic crisis and pheochromocytoma multisystem crisis are rare, life-threatening, emergency endocrine diseases with various clinical manifestations. Here we report a case of a patient who simultaneously developed thyrotoxic crisis and pheochromocytoma multisystem crisis and required intensive cardiovascular management.

Case presentation

A 60-year-old Asian man experienced nausea and vomiting, and subsequently developed dyspnea and cold sweats while farming. His serum free thyroxine, free triiodothyronine, and thyrotropin receptor antibody levels were elevated at 2.9 ng/dL, 7.2 pg/dL, and 4.7 IU/L, respectively. Serum thyrotropin levels were suppressed at less than 0.01 μIU/mL. Thyroid echography demonstrated no thyroid swelling (23 × 43 mm).

A whole body computed tomography was performed for systemic evaluation. This revealed exophthalmos and a mass of size 57 × 64 mm in the anterior pararenal space. Based on these findings, we made an initial diagnosis of thyrotoxic crisis secondary to exacerbation of Grave’s hyperthyroidism. Treatment was begun with an iodine agent at a dose of 36 mg/day, thiamazole at a dose of 30 mg/day, and hydrocortisone at a dose of 300 mg daily for 3 consecutive days. To control tachycardia, continuous intravenously administered propranolol and diltiazem infusions were given. At the same time, small doses of doxazosin and carvedilol were used for both alpha and beta adrenergic blockade. On hospital day 5, his blood pressure and serum catecholamine concentrations (adrenalin 42,365 pg/mL, dopamine 6409 pg/mL, noradrenalin 72,212 pg/mL) were still high despite higher beta blocker and calcium channel blocker doses. These findings contributed to the diagnosis of pheochromocytoma multisystem crisis with simultaneous thyrotoxic crisis. We increased the doses of doxazosin and carvedilol, which stabilized his hemodynamic status. On hospital day 16, metaiodobenzylguanidine scintigraphy showed high accumulation in the right adrenal gland tumor. After retroperitoneal laparoscopic adrenalectomy on hospital day 33, his condition stabilized. He was discharged on hospital day 58.

Conclusions

Since he required more intensive cardiovascular management for thyrotoxic crisis, beta blockade was increased under intensive care unit monitoring even though initial alpha blockade is recommended in pheochromocytoma. When these crises occur simultaneously, cardiovascular management can be very challenging.

Suspected Metallic Embolism following Endovascular Treatment of Intracranial Aneurysms

We describe a case series of suspected metallic embolism after coil embolization for intracranial aneurysms. Between January 2012 and December 2014, 110 intracranial aneurysms had been treated by coil embolization in our institution. In 6 cases, the postprocedural MR imaging revealed abnormal spotty lesions not detected on the preprocedural MR imaging. The lesions were also undetectable on the postprocedural CT scan. They were demonstrated as low-intensity spots on T1WI, T2WI, DWI, and T2*-weighted imaging. On DWI, they were accompanied by bright "halo," and on T2*-weighted imaging, they showed a "blooming" effect. In 3 of the 6 cases, follow-up MR imaging was available and all the lesions remained and demonstrated no signal changes. Although histologic examination had not been performed, these neuroradiologic findings strongly supported the lesions being from metallic fragments. No specific responsible device was detected after reviewing all the devices used for the neuroendovascular treatment in the 6 cases.

Four Sporadic Pediatric Cases of Yersinia enterocolitica O:8 Infection in a Rural Area of Japan

In the spring of 2015, we experienced a cluster of 4 sporadic cases of yersiniosis in children in Nagano prefecture, a rural area of Japan. Two patients developed appendicitis-like episodes; one had acute gastroenteritis, and the other had bacteremia associated with liver abscess. The causative agent of these infections was Yersinia enterocolitica serogroup O:8. None of the patients had an underlying illness, and all have recovered completely. The patients were neither socially nor geographically related to each other. These 4 consecutive cases suggest that Y. enterocolitica O:8 has spread substantially in the middle part of Japan, and that this virulent strain might be more common than previously reported in our country.

Recurrent peritoneal inclusion cysts successfully treated with oral contraceptives: a report of two cases

OBJECTIVE

To examine whether conservative treatment with oral contraceptives is effective in the shrinkage of a peritoneal inclusion cyst (PIC). This is a case report of two patients with a PIC that developed after gynecological surgery.

CASES

Both cases were suspected of a PIC based on the medical history, laboratory data, and image findings. It was difficult in differentiate a PIC from an ovarian tumor. Surgery was chosen at first. However, PICs in both cases recurred after surgery and were treated with oral contraceptives as a conservative treatment. PICs shrank after the treatment of oral contraceptives in both cases.

CONCLUSION

Due to the high rate of recurrence following surgery, conservative treatment is recommended to treat PICs. Hormone therapy using oral contraceptives seems to have some therapeutic benefit for the PICs.

Decontamination of outdoor school swimming pools in Fukushima after the nuclear accident in March 2011

Because of radioactive fallout resulting from the Fukushima Daiichi Nuclear Power Plant (NPP) accident, water discharge from many outdoor swimming pools in Fukushima was suspended out of concern that radiocesium in the pool water would flow into farmlands. The Japan Atomic Energy Agency has reviewed the existing flocculation method for decontaminating pool water and established a practical decontamination method by demonstrating the process at eight pools in Fukushima. In this method, zeolite powder and a flocculant are used for capturing radiocesium present in pool water. The supernatant is discharged if the radiocesium concentration is less than the targeted level. The radioactive residue is collected and stored in a temporary storage space. Radioactivity concentration in water is measured with a NaI(Tl) or Ge detector installed near the pool. The demonstration results showed that the pool water in which the radiocesium concentration was more than a few hundred Bq L was readily purified by the method, and the radiocesium concentration was reduced to less than 100 Bq L. The ambient dose rates around the temporary storage space were slightly elevated; however, the total increase was up to 30% of the background dose rates when the residue was shielded with sandbags.

C-arm CT measurement of cerebral blood volume using intra-arterial injection of contrast medium: an experimental study in canines

BACKGROUND AND PURPOSE

Measurement of perfusion parameters is typically done using an intravenous injection of contrast medium. This purpose of this study was to evaluate the feasibility of measuring regional and global CBV using C-arm CT with IA injections of contrast medium.

MATERIALS AND METHODS

Twelve canines were studied. CBV measurement was performed using standard PCT, and then using C-arm CT with IV and IA contrast. Values obtained using C-arm CT were compared with those using PCT.

RESULTS

C-arm CT CBV maps using IA injections required less contrast than ones with IV injections. PCT and C-arm CT using IV and AA injections provided comparable maps. In controls, C-arm CT with a CCA or VA injection provided comparable maps to PCT. In animals with a stroke, a CCA or VA injection did not provide maps comparable to ones made with PCT. IV and AA C-arm CT showed excellent quantitative agreement with PCT, while CCA and VA C-arm CT studies did not.

CONCLUSIONS

Measurement of global CBV using C-arm CT in conjunction with either an IV or an AA injection was feasible in controls and dogs with a stroke. Measurement of regional CBV with C-arm CT using either CCA or VA injection, in normal canines, provided CBV maps qualitatively comparable with those obtained with PCT; the absolute CBV values from these maps were in poor agreement with PCT measurements. Valid measurement of CBV using C-arm CT requires all tissue in a target region to be fully and equally opacified during any acquisition. Using CCA or VA injections, it was impossible to document if and when this had been achieved. CBV measurements using these routes of injection were therefore not reliable.

Adult rat hepatocytes cultured on an oxygen-permeable film increases the activity of albumin secretion

Primary culture of rat hepatocyte was performed in an oxygen-permeable film dish (F-dish), which would be expected to give an oxygen-rich culture condition. In the conventional culture dish in which the depth of medium was 2 mm, the oxygen tension (pO(2)) in the medium decreased from 19% (144 mmHg) to 0.3% (2.3 mmHg) within 2 hr, while the pO(2) in the F-dish maintained 8.5% (64.6 mmHg) even after 2 hr. The adverse effect of the oxygen-deficiency appeared in the albumin secretion activity of the hepatocytes and it was more remarkable in the early period of culture. The average rate of albumin secretion for the initial 48 hr was 2.0 mug ml(-1) hr(-1) or 96 mug 10(6) cells(-1) day(-1) in the F-dish. The average rate of albumin secretion for the initial 12 hr was only 0.36 mug ml(-1) hr(-1) in the conventional culture dish. The activity of ammonia elimination in the F-dish was 20-50% higher than the conventional culture dish. Three-dimensional aggregate was formed only in the F-dish. The advantage of three-dimensional aggregate for albumin secretion was not clear compared with two-dimensional monolayer.

Aneurysm ostium angle: a predictor of the need for stent as assistance for endovascular aneurysm coiling in internal carotid artery sidewall aneurysms

BACKGROUND AND PURPOSE

There is no satisfactory parameter that can predict the need for assistant devices for endovascular aneurysm coiling. Our aim was to evaluate the utility of MOA as a predictor of the need for stent-assisted coiling in ICA sidewall aneurysms.

MATERIALS AND METHODS

From a retrospective review of an internal data base, 55 consecutive ICA sidewall aneurysms were identified. Thirty-two of the aneurysms were treated by using endovascular techniques. Because 23 of the 55 aneurysms were either untreated or clipped, 3 experienced interventionalists reviewed the 3D images of these aneurysms and then made a decision as to whether stent-assisted coiling would have been required. Thirty-one of the 55 aneurysms would have required stent-assisted coiling, while 24 would not. Neck width, DNR, AR, and MOA were obtained from each aneurysm by using prototype software. These parameters were then correlated with the requirement of stent-assisted coiling.

RESULTS

MOA and neck width of aneurysms requiring stent-assisted coiling were significantly larger than those not requiring stent-assisted coiling (P < .001 and <0.001, respectively). Although the DNR and AR of aneurysms requiring stent-assisted coiling were smaller than those not requiring it, the difference was not significant (P = .22 and 0.12, respectively). ROC analysis revealed that MOA was the parameter that best correlated with the need for stent-assisted coiling. Inclusion of MOA with the rest of the parameters significantly increased the predictive performance regarding the need for stent-assisted coiling (P = .005).

CONCLUSIONS

In this small study, MOA was a useful parameter to predict the need for stent-assisted coiling in ICA sidewall aneurysms. Further prospective study of this parameter for aneurysms at multiple locations is required to determine its ultimate value.

A method for serial selective arterial catheterization and digital subtraction angiography in rodents

BACKGROUND AND PURPOSE

Imaging is a key element in the study of many rodent models of human diseases. The application of DSA has been limited in these studies in part because of a lack of a method that allows serial intra-arterial examinations to be performed during an extended period of time. It was our intent to develop and test a method for performing sequential arterial catheterizations and DSA in rats.

MATERIALS AND METHODS

Using a transfemoral approach, we subjected 12 adult male Harvey rats to 3 sequential DSA examinations during a 6- to 8-week period. At each examination, 2 selective arterial catheterizations and a DSA were performed. Animals were monitored for ill effects, and images from the 3 examinations were compared for quality and the presence of any arterial injury.

RESULTS

Ten of the 12 rats survived all 3 examinations. There were no adverse effects noted and no evidence of arterial injury from the examinations.

CONCLUSIONS

With the technique described, it is possible to perform serial arterial catheterizations and DSA in rats. This technique will be useful as an adjunct in the use of rodents for the study of human diseases.

C-arm CT measurement of cerebral blood volume in ischemic stroke: an experimental study in canines

BACKGROUND AND PURPOSE

CBV is a key parameter in distinguishing penumbra from ischemic core. The purpose of this study was to compare CBV measurements acquired with standard PCT with ones obtained with C-arm CT in a canine stroke model.

MATERIALS AND METHODS

Under an institutionally approved protocol, unilateral MCA strokes were created in 10 canines. Four hours later, DWI was used to confirm the presence of an infarct. CBV maps acquired with PCT were compared with ones acquired by using C-arm CT. Three experienced observers, blinded to the technique used for acquisition, evaluated the CBV maps.

RESULTS

An ischemic stroke was achieved in 9 of the 10 animals. Areas of reduced CBV were detected in 70%-75% of the PCT studies and in 83%-87% of the C-arm CT examinations, with false-positives in 1.7% and 3.3%, respectively. False-negatives were found in 25% of the PCT and 12.2% of the C-arm CT studies. In all studies, there was a significant difference between the absolute CBV values in normal and abnormal tissue (P < .005) and no significant difference between PCT and C-arm CT CBV values in either the normal or the abnormal parenchyma (P > .05).

CONCLUSIONS

CBV measurements made with C-arm CT compare well with ones made with PCT. While further work is required both to fully validate the technique and to define its ultimate clinical value, it appears that it offers a feasible method for assessing CBV in the angiography suite.

F1-ATPase: a highly efficient rotary ATP machine

A single molecule of F1-ATPase is by itself a rotary motor in which a central subunit, gamma, rotates against a surrounding stator cylinder made of alpha 3 beta 3 hexamer. Driven by the three beta subunits that hydrolyse ATP sequentially, the motor runs with discrete 120 degrees steps at low ATP concentrations. Over broad ranges of load and speed, the motor produces a constant torque of 40 pN.nm. The mechanical work the motor does in the 120 degrees step, or the work per ATP hydrolysed, is also constant and amounts to 80-90 pN.nm, which is close to the free energy of ATP hydrolysis. Thus this motor can work at near 100% efficiency.

Pause and rotation of F(1)-ATPase during catalysis

F(1)-ATPase is a rotary motor enzyme in which a single ATP molecule drives a 120 degrees rotation of the central gamma subunit relative to the surrounding alpha(3)beta(3) ring. Here, we show that the rotation of F(1)-ATPase spontaneously lapses into long (approximately 30 s) pauses during steady-state catalysis. The effects of ADP-Mg and mutation on the pauses, as well as kinetic comparison with bulk-phase catalysis, strongly indicate that the paused enzyme corresponds to the inactive state of F(1)-ATPase previously known as the ADP-Mg inhibited form in which F(1)-ATPase fails to release ADP-Mg from catalytic sites. The pausing position of the gamma subunit deviates from the ATP-waiting position and is most likely the recently found intermediate 90 degrees position.

Purine but not pyrimidine nucleotides support rotation of F(1)-ATPase

The binding change model for the F(1)-ATPase predicts that its rotation is intimately correlated with the changes in the affinities of the three catalytic sites for nucleotides. If so, subtle differences in the nucleotide structure may have pronounced effects on rotation. Here we show by single-molecule imaging that purine nucleotides ATP, GTP, and ITP support rotation but pyrimidine nucleotides UTP and CTP do not, suggesting that the extra ring in purine is indispensable for proper operation of this molecular motor. Although the three purine nucleotides were bound to the enzyme at different rates, all showed similar rotational characteristics: counterclockwise rotation, 120 degrees steps each driven by hydrolysis of one nucleotide molecule, occasional back steps, rotary torque of approximately 40 piconewtons (pN).nm, and mechanical work done in a step of approximately 80 pN.nm. These latter characteristics are likely to be determined by the rotational mechanism built in the protein structure, which purine nucleotides can energize. With ATP and GTP, rotation was observed even when the free energy of hydrolysis was -80 pN.nm/molecule, indicating approximately 100% efficiency. Reconstituted F(o)F(1)-ATPase actively translocated protons by hydrolyzing ATP, GTP, and ITP, but CTP and UTP were not even hydrolyzed. Isolated F(1) very slowly hydrolyzed UTP (but not CTP), suggesting possible uncoupling from rotation.

Large-scale cDNA analysis of the maternal genetic information in the egg of Halocynthia roretzi for a gene expression catalog of ascidian development

The ascidian egg is a well-known mosaic egg. In order to investigate the molecular nature of the maternal genetic information stored in the egg, we have prepared cDNAs from the mRNAs in the fertilized eggs of the ascidian, Halocynthia roretzi. The cDNAs of the ascidian embryo were sequenced, and the localization of individual mRNA was examined in staged embryos by whole-mount in situ hybridization. The data obtained were stored in the database MAGEST (http://www.genome.ad.jp/magest) and further analyzed. A total of 4240 cDNA clones were found to represent 2221 gene transcripts, including at least 934 different protein-coding sequences. The mRNA population of the egg consisted of a low prevalence, high complexity sequence set. The majority of the clones were of the rare sequence class, and of these, 42% of the clones showed significant matches with known peptides, mainly consisting of proteins with housekeeping functions such as metabolism and cell division. In addition, we found cDNAs encoding components involved in different signal transduction pathways and cDNAs encoding nucleotide-binding proteins. Large-scale analyses of the distribution of the RNA corresponding to each cDNA in the eight-cell, 110-cell and early tailbud embryos were simultaneously carried out. These analyses revealed that a small fraction of the maternal RNAs were localized in the eight-cell embryo, and that 7.9% of the clones were exclusively maternal, while 40.6% of the maternal clones showed expression in the later stages. This study provides global insights about the genes expressed during early development.

Resolution of distinct rotational substeps by submillisecond kinetic analysis of F1-ATPase

The enzyme F1-ATPase has been shown to be a rotary motor in which the central gamma-subunit rotates inside the cylinder made of alpha3beta3 subunits. At low ATP concentrations, the motor rotates in discrete 120 degrees steps, consistent with sequential ATP hydrolysis on the three beta-subunits. The mechanism of stepping is unknown. Here we show by high-speed imaging that the 120 degrees step consists of roughly 90 degrees and 30 degrees substeps, each taking only a fraction of a millisecond. ATP binding drives the 90 degrees substep, and the 30 degrees substep is probably driven by release of a hydrolysis product. The two substeps are separated by two reactions of about 1 ms, which together occupy most of the ATP hydrolysis cycle. This scheme probably applies to rotation at full speed ( approximately 130 revolutions per second at saturating ATP) down to occasional stepping at nanomolar ATP concentrations, and supports the binding-change model for ATP synthesis by reverse rotation of F1-ATPase.

Methicillin-resistant coagulase-negative staphylococci isolated from healthy horses in Japan

OBJECTIVE

To determine patterns of methicillin-resistant staphylococci isolated from apparently healthy horses.

SAMPLE POPULATION

44 horses from 8 riding clubs in Japan.

PROCEDURE

Methicill in-resistant staphylococci were isolated from the skin or nares, using a selective medium containing a beta-(symboric) lactam antibiotic, ceftizoxime. Clonality of isolates was determined by use of pulsed-field gel electrophoresis. Detection of mecA, mecl, and mecR1 genes was accomplished by use of polymerase chain reactions.

RESULT

Of the 44 horses, 13 (29.5%) yielded 15 isolates of methicillin-resistant staphylococci. The 15 isolates were identified as 6 species (Staphylococcus epidermidis, S lentus, S saprophyticus, S xylosus, S sciuri, and S haemolyticus). However, methicillin-resistant S aureus was seldom isolated. Each isolate contained the mecA gene and had a high resistance to beta-lactam antibiotics. Some isolates also were resistant to other antibiotics such as erythromycin and kanamycin.

CONCLUSIONS AND CLINICAL RELEVANCE

Methicillin-resistant coagulase-negative staphylococci that were highly resistant to various antibiotics were isolated from apparently healthy horses in Japan. These organisms must be considered a potential threat to horses and veterinarians who care for them.

Regional and strain-specific gene expression mapping in the adult mouse brain

To determine the genetic causes and molecular mechanisms responsible for neurobehavioral differences in mice, we used highly parallel gene expression profiling to detect genes that are differentially expressed between the 129SvEv and C57BL/6 mouse strains at baseline and in response to seizure. In addition, we identified genes that are differentially expressed in specific brain regions. We found that approximately 1% of expressed genes are differentially expressed between strains in at least one region of the brain and that the gene expression response to seizure is significantly different between the two inbred strains. The results lead to the identification of differences in gene expression that may account for distinct phenotypes in inbred strains and the unique functions of specific brain regions.

Stepping rotation of F1-ATPase visualized through angle-resolved single-fluorophore imaging

Orientation dependence of single-fluorophore intensity was exploited in order to videotape conformational changes in a protein machine in real time. The fluorophore Cy3 attached to the central subunit of F(1)-ATPase revealed that the subunit rotates in the molecule in discrete 120 degrees steps and that each step is driven by the hydrolysis of one ATP molecule. These results, unlike those from the previous study under a frictional load, show that the 120 degrees stepping is a genuine property of this molecular motor. The data also show that the rate of ATP binding is insensitive to the load exerted on the rotor subunit.

Hyaluronan exists in the normal stratum corneum

Hyaluronan is well known to exist as a water-sorbed macromolecule in the extracellular matrix. We here examined whether hyaluronan exists in the normal stratum corneum. High performance liquid chromatography was used to quantify hyaluronan content in the stratum corneum, epidermis (including stratum corneum), and dermis of mice, with the resulting dry weights being 22.3 +/- 2.9, 15.1 +/- 1.5, and 738.6 +/- 31.6 microg per g, respectively. Normal mouse skin was then labeled with [3H]-glucosamine in an organ culture, and accumulation of [3H]-labeled hyaluronan and its molecular mass were determined separately for the stratum corneum, epidermis, and dermis. In the stratum corneum, [3H]-labeled hyaluronan was accumulated linearly over the 3-d culture period. After the 3-d culture period, the epidermis synthesized twice the amount (expressed as dpm per mg dry weight) of [3H]-labeled hyaluronan as the dermis, whereas the stratum corneum and dermis showed nearly the same content of [3H]-labeled hyaluronan. The molecular mass of [3H]-labeled hyaluronan was highest (>1.0 x 106) in the dermis and clearly lower (<6.0 x 104) in the stratum corneum. Based on these results, we here confirm that hyaluronan is supplied from keratinocytes beneath the stratum corneum layer, and is present in the normal stratum corneum. We speculate that hyaluronan may play a role in moisturizing the stratum corneum and/or regulating its mechanical properties.

The role of the DELSEED motif of the beta subunit in rotation of F1-ATPase

F(1)-ATPase is a rotary motor protein, and ATP hydrolysis generates torque at the interface between the gamma subunit, a rotor shaft, and the alpha(3)beta(3) substructure, a stator ring. The region of conserved acidic "DELSEED" motif of the beta subunit has a contact with gamma subunit and has been assumed to be involved in torque generation. Using the thermophilic alpha(3)beta(3)gamma complex in which the corresponding sequence is DELSDED, we replaced each residue and all five acidic residues in this sequence with alanine. In addition, each of two conserved residues at the counterpart contact position of gamma subunit was also replaced. Surprisingly, all of these mutants rotated with as much torque as the wild-type. We conclude that side chains of the DELSEED motif of the beta subunit do not have a direct role in torque generation.

A rotary molecular motor that can work at near 100% efficiency

A single molecule of F1-ATPase is by itself a rotary motor in which a central gamma-subunit rotates against a surrounding cylinder made of alpha3beta3-subunits. Driven by the three betas that sequentially hydrolyse ATP, the motor rotates in discrete 120 degree steps, as demonstrated in video images of the movement of an actin filament bound, as a marker, to the central gamma-subunit. Over a broad range of load (hydrodynamic friction against the rotating actin filament) and speed, the F1 motor produces a constant torque of ca. 40 pN nm. The work done in a 120 degree step, or the work per ATP molecule, is thus ca. 80 pN nm. In cells, the free energy of ATP hydrolysis is ca. 90 pN nm per ATP molecule, suggesting that the F1 motor can work at near 100% efficiency. We confirmed in vitro that F1 indeed does ca. 80 pN nm of work under the condition where the free energy per ATP is 90 pN nm. The high efficiency may be related to the fully reversible nature of the F1 motor: the ATP synthase, of which F1 is a part, is considered to synthesize ATP from ADP and phosphate by reverse rotation of the F1 motor. Possible mechanisms of F1 rotation are discussed.

Genomic organization of the family of CNR cadherin genes in mice and humans

The cadherin-related neuronal receptor (CNR) family is localized to the synaptic junction, and their cytoplasmic domains interact with Fyn-tyrosine kinase. Here, we describe the chromosomal locations and the orthologous genomic structures of CNR family members in mice and humans. In the genomic organization, distinct exons, each of which encodes the N-terminus of a different CNR ("variable region"), are clustered in a tandem array, and these exons are spliced to a common region composed of three exons ("constant region"). We also discovered three alternative versions of the transcripts; a single variable exon connects with three different C-terminal tails, comparable to class-switching in the immunoglobulin heavy chain. Thus the CNR family in the central nervous system has similarities to the immunoglobulin and T-cell receptor genes in the immune system.

Rotation of F(1)-ATPase and the hinge residues of the beta subunit

Rotation of a motor protein, F(1)-ATPase, was demonstrated using a unique single-molecule observation system. This paper reviews what has been clarified by this system and then focuses on the role of residues at the hinge region of the beta subunit. We have visualised rotation of a single molecule of F(1)-ATPase by attaching a fluorescent actin filament to the top of the beta subunit in the immobilised F(1)-ATPase, thus settling a major controversy regarding the rotary catalysis. The rotation of the beta subunit was exclusively in one direction, as could be predicted by the crystal structure of bovine heart F(1)-ATPase. Rotation at low ATP concentrations revealed that one revolution consists of three 120 degrees steps, each fuelled by the binding of an ATP to the beta subunit. The mean work done by a 120 degrees step was approximately 80 pN nm, a value close to the free energy liberated by hydrolysis of one ATP molecule, implying nearly 100% efficiency of energy conversion. The torque is probably generated by the beta subunit, which undergoes large opening-closing domain motion upon binding of AT(D)P. We identified three hinge residues, betaHis179, betaGly180 and betaGly181, whose peptide bond dihedral angles are drastically changed during domain motion. Simultaneous substitution of these residues with alanine resulted in nearly complete loss (99%) of ATPase activity. Single or double substitution of the two Gly residues did not abolish the ATPase activity. However, reflecting the shift of the equilibrium between the open and closed forms of the beta subunit, single substitution caused changes in the propensity to generate the kinetically trapped Mg-ADP inhibited form: Gly180Ala enhanced the propensity and Gly181Ala abolished the propensity. In spite of these changes, the mean rotational torque was not changed significantly for any of the mutants.