GABA-activated whole-cell currents in isolated retinal ganglion cells

1. We have begun to analyze neurotransmitter-activated conductances in retinal ganglion cells by measuring the response of single voltage-clamped adult goldfish ganglion cells to gamma-aminobutyric acid (GABA). Here we describe 1) our method of identifying ganglion cells in vitro after their dissociation from papain-treated retinas, and 2) the response of these cells to GABA in the tight-seal whole cell configuration of the patch-clamp method (cf. 41) after 1-4 days of primary cell culture. 2. Ganglion cell somata were backfilled in situ by injections of horseradish peroxidase (HRP) into the optic nerve. After dissociation of the retinas containing these cells, HRP reaction product was localized to cells that retained the size, shape, and an intracellular organelle characteristic of ganglion cells in situ. These features enabled us thereafter to identify ganglion cells in vitro without retrograde marker transport. 3. GABA (3-10 microM) elicited inward currents and substantial noise increases in almost all ganglion cells at negative holding potentials. Reversal potential measurements in salines containing different chloride concentrations indicated that GABA produces a chloride-selective conductance increase in ganglion cells. Bicuculline (10 microM) reversibly inhibited ganglion cell GABA responses. Baclofen (10 microM) alone elicited no responses in ganglion cells. 4. Noise analysis of GABA-activated whole cell currents yielded elementary conductance estimates of 16 pS, with a slow time constant of 30 ms plus a faster component of 1-2 ms. No significant voltage dependence of these values was observed between -20 and -80 mV. 5. We have thus devised a means of identifying ganglion cells dissociated from adult retinas, identified GABAA receptors (cf. 16) on these cells, and found that the responses mediated by these receptors resemble those found in other regions of central nervous system (CNS). These results are consistent with the notion that GABA may function as an inhibitory transmitter at synapses on ganglion cells.     

Present and future status of noninvasive selective deep heating using RF in hyperthermia

To achieve hyperthermia using electromagnetic energy, RF of under 100 MHz is basically suitable for the external heating of the deep portions of the body. For applicators using such RF, the following types are considered: capacitive, inductive, radiative and hybrid. With radiative applicators, the intensity of the EM waves radiated from the applicator decreases with propagation into the material to be heated, but the phased annular array of radiative applicators potentially increases the intensity of the EM energy in the deep portion owing to the interference of the waves. Using this method, the focusing of EM energy depends on the dielectric properties of the material to be heated. With respect to RF heating at a lower frequency than the RF used for the annular phased array, some devices have been said to concentrate EM energy in the deep portions, where the characteristics of ‘wave’ are not utilised. To this end, some methods using capacitive electrodes, an inductive coil, or a combination of both, are being designed. The results of using such methods have shown that it is possible to supply sufficient EM energy to the muscle layers deep in the material to be heated, without heating the fat layers excessively.     

Effects of acute hypoxia on ventilatory response at the onset of submaximal exercise

In order to investigate the effects of acute hypoxia and accompanying hypocapnia on the ventilatory response at the onset of dynamic exercise, four healthy adult men performed 50W rectangular loads on a cycle-ergometer in normoxic (FIO2 = 0.21) and hypoxic (FIO2 = 0.11) conditions. No statistically significant differences in the initial ventilatory responses to exercise (both delta VI and delta VE assessed on a breath-by-breath basis) were found between eucapnic normoxia (PETO2 approximately 95, PETCO2 approximately 42 Torr) and hypocapnic hypoxia (PETO2 approximately 45, PETCO2 approximately 35 Torr). The present findings support the contention that the neurogenic ventilatory drive at the onset of early exercise is independent from PO2 and PCO2.     

Digital image processing: effect on detectability of simulated low-contrast radiographic patterns

Detection studies of simulated low-contrast radiographic patterns were performed with a high-quality digital image processing system. The original images, prepared with conventional screen-film systems, were processed digitally to enhance contrast by a "windowing" technique. The detectability of simulated patterns was quantified in terms of the results of observer performance experiments by using the multiple-alternative forced-choice method. The processed images demonstrated a significant increase in observer detection performance over that for the original images. These results are related to the displayed and perceived signal-to-noise ratios derived from signal detection theory. The improvement in detectability is ascribed to a reduction in the relative magnitude of the human observer's "internal" noise after image processing. The measured dependence of threshold signal contrast on object size and noise level is accounted for by a statistical decision theory model that includes internal noise.     

Dietary Olive Oil Intake Improves Running Endurance with Intramuscular Triacylglycerol Accumulation in Mice

Olive oil is a functional food shown to have a variety of bioactive effects. Therefore, we expect it to be a novel functional food with an exercise-mimetic effect on skeletal muscles. This study aimed to investigate the effect of olive oil on the endurance capacity and muscle metabolism in mice. Mice fed a 7% (w/w) olive oil diet for eight weeks showed improved treadmill running endurance and increased intramuscular triacylglycerol (IMTG) accumulation in the gastrocnemius muscle compared to soybean oil diet-fed controls. The increase in running endurance with olive oil intake was independent of the muscle fiber type. To elucidate underlying the mechanism of elevated IMTG levels, we examined the expression levels of the genes related to lipid metabolism. We found that the expression of diacylglycerol O-acyltransferase1 (DGAT1) was significantly upregulated in the muscle of olive oil diet-fed mice. In addition, the olive oil diet-fed mice showed no metabolic impairment or differences in growth profiles compared to the controls. These results suggest that dietary olive oil intake affects muscle metabolism and muscle endurance by increasing energy accumulation.     

Clinical results of arthroscopic rotator cuff repair in diabetic and non-diabetic patients

BackgroundAlthough the clinical outcomes of arthroscopic rotator cuff repair (ARCR) have been reported, few studies have focused on diabetic patients. We investigated and compared the clinical results of ARCR in patients with and without diabetes.MethodsThis retrospective study involved 195 consecutive patients who underwent ARCR from 2015 to 2018 in our hospital. Twenty-seven and 168 shoulders were assigned to diabetes and non-diabetes groups, respectively. Diabetic patients with poor control were preoperatively hospitalized for perioperative diabetic control. We evaluated range of motion (ROM), Japanese Orthopaedic Association shoulder (JOA) score, Constant Shoulder Score, and University of California, Los Angeles (UCLA) score preoperatively and at 6 months and 1 year post-ARCR. Rates of rotator cuff retear 1 year post-ARCR and preoperative and postoperative stiff shoulder were also evaluated. We compared the results between groups and analyzed them statistically. A p-value of <0.05 was considered statistically significant.ResultsPreoperative ROM, JOA score, Constant Shoulder Score and UCLA scores showed significant improvement at post-ARCR in both groups (p < 0.05). On comparing the groups, although preoperative JOA score and Constant Shoulder Score were significantly lower in diabetes group than in non-diabetes group (diabetic/non-diabetic group; 60.0/65.3 for JOA score; p = 0.003, 59.7/64.2 for Constant Shoulder Score; p = 0.003), there was no significant difference postoperatively (6 months post-ARCR; 88.0/89.7 for JOA score; p = 0.783, 88.1/88.6 for Constant Shoulder Score; p = 0.597, 1 year post-ARCR; 96.7/95.4 for JOA score; p = 0.238, 96.6/95.4 for Constant Shoulder Score; p = 0.248). Furthermore, preoperative and postoperative stiff shoulder and retear rates were not significantly different between groups (p = 0.152, p = 0.344, p = 0.347, and p = 0.563, respectively).ConclusionDiabetic patients showed comparable clinical results with non-diabetic patients post-ARCR. Perioperative diabetic control may be recommended for preoperatively uncontrolled diabetic patients.     

How Are Indeterminate Pulmonary Nodules at Diagnosis Associated with Survival in Patients with High-Grade Osteosarcoma?

BackgroundPulmonary metastases are a poor prognostic factor in patients with osteosarcoma; however, the clinical significance of subcentimeter lung nodules and whether they represent a tumor is not fully known. Because the clinician is faced with decisions regarding biopsy, resection, or observation of lung nodules and the potential impact they have on decisions about resection of the primary tumor, this remains an area of uncertainty in patient treatment. Surgical management of the primary tumor is tailored to prognosis, and it is unclear how aggressively patients with indeterminate pulmonary nodules (IPNs), defined as nodules smaller than 1 cm at presentation, should be treated. There is a clear need to better understand the clinical importance of these nodules.Questions/purposes(1) What percentage of patients with high-grade osteosarcoma and spindle cell sarcoma of bone have IPNs at diagnosis? (2) Are IPNs at diagnosis associated with worse metastasis-free and overall survival? (3) Are there any clinical or radiologic factors associated with worse overall survival in patients with IPN?MethodsBetween 2008 and 2016, 484 patients with a first presentation of osteosarcoma or spindle cell sarcoma of bone were retrospectively identified from an institutional database. Patients with the following were excluded: treatment at another institution (6%, 27 of 484), death related to complications of neoadjuvant chemotherapy (1%, 3 of 484), Grade 1 or 2 on final pathology (4%, 21 of 484) and lack of staging chest CT available for review (0.4%, 2 of 484). All patients with abnormalities on their staging chest CT underwent imaging re-review by a senior radiology consultant and were divided into three groups for comparison: no metastases (70%, 302 of 431), IPN (16%, 68 of 431), and metastases (14%, 61 of 431) at the time of diagnosis. A random subset of CT scans was reviewed by a senior radiology registrar and there was very good agreement between the two reviewers (κ = 0.88). Demographic and oncologic variables as well as treatment details and clinical course were gleaned from a longitudinally maintained institutional database. The three groups did not differ with regard to age, gender, subtype, presence of pathological fracture, tumor site, or chemotherapy-induced necrosis. They differed according to local control strategy and tumor size, with a larger proportion of patients in the metastases group presenting with larger tumor size and undergoing nonoperative treatment. There was no differential loss to follow-up among the three groups. Two percent (6 of 302) of patients with no metastases, no patients with IPN, and 2% (1 of 61) of patients with metastases were lost to follow-up at 1 year postdiagnosis but were not known to have died. Individual treatment decisions were determined as part of a multidisciplinary conference, but in general, patients without obvious metastases received (neo)adjuvant chemotherapy and surgical resection for local control. Patients in the no metastases and IPN groups did not differ in local control strategy. For patients in the IPN group, staging CT images were inspected for IPN characteristics including number, distribution, size, location, presence of mineralization, and shape. Subsequent chest CT images were examined by the same radiologist to reevaluate known nodules for interval change in size and to identify the presence of new nodules. A random subset of chest CT scans were re-reviewed by a senior radiology resident (κ = 0.62). The association of demographic and oncologic variables with metastasis-free and overall survival was first explored using the Kaplan-Meier method (log-rank test) in univariable analyses. All variables that were statistically significant (p < 0.05) in univariable analyses were entered into Cox regression multivariable analyses.ResultsFollowing re-review of staging chest CTs, IPNs were found in 16% (68 of 431) of patients, while an additional 14% (61 of 431) of patients had lung metastases (parenchymal nodules 10 mm or larger). After controlling for potential confounding variables like local control strategy, tumor size, and chemotherapy-induced necrosis, we found that the presence of an IPN was associated with worse overall survival and a higher incidence of metastases (hazard ratio 1.9 [95% CI 1.3 to 2.8]; p = 0.001 and HR 3.6 [95% CI 2.5 to 5.2]; p < 0.001, respectively). Two-year overall survival for patients with no metastases, IPN, or metastases was 83% [95% CI 78 to 87], 65% [95% CI 52 to 75] and 45% [95% CI 32 to 57], respectively (p = 0.001). In 74% (50 of 68) of patients with IPNs, it became apparent that they were true metastatic lesions at a median of 5.3 months. Eighty-six percent (43 of 50) of these patients had disease progression by 2 years after diagnosis. In multivariable analysis, local control strategy and tumor subtype correlated with overall survival for patients with IPNs. Patients who were treated nonoperatively and who had a secondary sarcoma had worse outcomes (HR 3.6 [95% CI 1.5 to 8.3]; p = 0.003 and HR 3.4 [95% CI 1.1 to 10.0]; p = 0.03). The presence of nodule mineralization was associated with improved overall survival in the univariable analysis (87% [95% CI 39 to 98] versus 57% [95% CI 43 to 69]; p = 0.008), however, because we could not control for other factors in a multivariable analysis, the relationship between mineralization and survival could not be determined. We were unable to detect an association between any other nodule radiologic features and survival.ConclusionThe findings show that the presence of IPNs at diagnosis is associated with poorer survival of affected patients compared with those with normal staging chest CTs. IPNs noted at presentation in patients with high-grade osteosarcoma and spindle cell sarcoma of bone should be discussed with the patient and be considered when making treatment decisions. Further work is required to elucidate how the nodules should be managed.Level of EvidenceLevel III, prognostic study.     

Abdominal angiography is associated with reduced in-hospital mortality among pediatric patients with blunt splenic and hepatic injury: A propensity-score-matching study from the national trauma registry in Japan

PurposeThe aim of this study was to assess the association between the implementation of abdominal angiography and outcome among pediatric patients with blunt splenic or hepatic injury.MethodsThis was a retrospective observational study, with a study period of 14 years, from January 2004 to December 2017. Blunt-trauma patients with splenic or hepatic injury who were less than 19 years old were included in this study. We used propensity-score-(PS) matching analysis to assess the relationship between abdominal angiography and in-hospital mortality.ResultsIn total, 639 patients were eligible for analysis, with 257 patients included in the abdominal-angiography group and 382 patients in the no-abdominal-angiography group. After PS matching, 224 patients from each group were selected. In the PS matched patients, in-hospital mortality was lower in the abdominal-angiography group than in the no-abdominal-angiography group (4.9% vs. 11.2%, odds ratio 0.416, 95% confidence interval 0.177–0.903).ConclusionIn this population, the implementation of abdominal angiography was significantly associated with lower in-hospital mortality among pediatric patients with blunt splenic or hepatic injury compared with nonimplementation of abdominal angiography.Type of studyPrognosis study.Level of evidenceIII