Minoru Hattori

Retinoic Acid Stimulates 17β-Estradiol and Testosterone Synthesis in Rat Hippocampal Slice Cultures

The hippocampus is essentially involved in learning and memory processes. Its functions are affected by various neuromodulators, including 17beta-estradiol, testosterone, and retinoid. Brain-synthesized steroid hormones act as autocrine and paracrine modulators. The regulatory mechanism underlying brain steroidogenesis has not been fully elucidated. Synthesis of sex steroids in the gonads is stimulated by retinoic acids. Therefore, we examined the effects of retinoic acids on estradiol and testosterone biosynthesis in the rat hippocampus. We used cultured hippocampal slices from 10- to 12-d-old male rats to investigate de novo steroidogenesis. The infant rat hippocampus possesses mRNAs for steroidogenic enzymes and retinoid receptors. Slices were used after 24 h of preculture to obtain maximal steroidogenic activity because steroidogenesis in cultured slices decreases with time. The mRNA levels for P450(17alpha), P450 aromatase and estrogen receptor-beta in the slices were increased by treatment with 9-cis-retinoic acid but not by all-trans-isomer. The magnitude of stimulation and the shape of the dose-response curve for the mRNA level for P450(17alpha) were similar to those for cellular retinoid binding protein type 2, the transcription of which is activated by retinoid X receptor signaling. 9-cis-Retinoic acid also induced a 1.7-fold increase in the protein content of P450(17alpha) and a 2-fold increase in de novo synthesis of 17beta-estradiol and testosterone. These steroids may be synthesized from a steroid precursor(s), such as pregnenolone or other steroids, or from cholesterol, as so-called neurosteroids. The stimulation of estradiol and testosterone synthesis by 9-cis-retinoic acid might be caused by activation of P450(17alpha) transcription via retinoid X receptor signaling.

Single-port laparoscopic colectomy versus conventional laparoscopic colectomy for colon cancer: a comparison of surgical results

BackgroundSingle-port laparoscopic surgery is a new technique that leaves no visible scar. This new technique has generated strong interest among surgeons worldwide. However, single-port laparoscopic colon surgery has not yet been standardized. Our aim in this study was to evaluate the feasibility of single-port laparoscopic colectomy compared with conventional laparoscopic colectomy for colon cancer.MethodsWe conducted a case-matched, controlled study comparing single-port laparoscopic colectomy to conventional laparoscopic colectomy for right-sided colon cancer.ResultsA total of ten patients were included for the single-port laparoscopic colectomy (S-LAC) group and ten patients for the conventional laparoscopic colectomy (C-LAC) group. The length of the skin incision in the S-LAC group was significantly shorter than that of the C-LAC group.ConclusionOur early experiences indicated that S-LAC for right-sided colon cancer is a feasible and safe procedure and that S-LAC results in a better cosmetic outcome.

Social isolation stimulates hippocampal estradiol synthesis

17beta-estradiol is synthesized de novo in the rat hippocampus. However, the regulatory mechanism of hippocampal estradiol synthesis has remained unclear. We investigated the effects of social isolation on rat hippocampal estradiol synthesis. Rats were divided into two groups: social isolation and pair housed group. Socially isolated rats were housed individually while pair housed rats were housed two per cage for 8 weeks. Social isolation activated the transcription of neurosteroidogenic molecules, including steroidogenic acute regulatory protein (StAR) and CYP19 (cytochrome P450arom). These two molecules are involved in the regulatory step for steroidogenesis and final step of estradiol synthesis. In contrast, the mRNA levels were not affected in rat olfactory bulb. The hippocampal estradiol content was increased in accordance with the increased mRNA levels. The hippocampal estradiol content exhibited correlations with the StAR and P450arom mRNA levels. These data suggest that social isolation may enhance de novo estradiol synthesis in the hippocampus.

Approaching time is important for assessment of endoscopic surgical skills

Abstract This study aimed to verify whether the approaching time (the time taken to reach the target point from another point, a short distance apart, during point-to-point movement in endoscopic surgery), assessed using the Hiroshima University Endoscopic Surgical Assessment Device (HUESAD), could distinguish the skill level of surgeons. Expert surgeons (who had performed more than 50 endoscopic surgeries) and novice surgeons (who had no experience in performing endoscopic surgery) were tested using the HUESAD. The approaching time, total time, and intermediate time (total time – approaching time) were measured and analyzed using the trajectory of the tip of the instrument. The approaching time and total time were significantly shorter in the expert group than in the novice group (p < 0.0001). The intermediate time did not significantly differ between the groups (p > 0.05). The approaching time, which is a component of the total time, is very mportant in the measurement of the total time to assess endoscopic surgical skills. Further, the approaching time was useful for skill assessment by the HUESAD for evaluating the skill of surgeons performing endoscopic surgery.

Transient decline in rats' hippocampal theta power relates to inhibitory stimulus-reward association.

The hippocampus is important in learning during a discrimination-reversal task. In this task, animals first learn to emit the go response to one stimulus and the no-go response to another stimulus (S1+, S2-) during the discrimination phase, and then they learn to reverse these relationships between stimulus and response during the reversal phase (S1-, S2+). To emit a no-go response for non-reinforced trial during the reversal phase, animals needed to inhibit the previously learned response pattern. This study examined the relationship between the reversal phase of the discrimination-reversal task and hippocampal electric activity in operant conditioning. The results revealed that hippocampal theta power transiently declined during the non-reinforced trial in the reversal phase compared with that during the discrimination phase. This decrease was observed during the 400-600-ms epoch after the onset of stimulus presentation. This study suggested that transient decline in hippocampal theta power is related to negative memory retrieval.

Environmental enrichment alters gene expression of steroidogenic enzymes in the rat hippocampus

Neuroactive steroids are synthesized in the central and peripheral nervous systems. The purpose of this study was to analyze the effects of environmental enrichment on neuroactive steroidogenesis in the rat hippocampus. Environmental enrichment rats were housed in a group of nine in a large cage and three groups of pair-housed rats were housed in a standard cage for 8 weeks. The levels of mRNAs for steroidogenic enzymes and proteins in hippocampus were quantified by real-time RT-PCR. Environmental enrichment increased the mRNA expression levels of 5α-reductase-1 and 3α-hydroxysteroid dehydrogenase, which catalyze synthesis of allopregnanolone from progesterone. Hence, environmental enrichment appears to affect allopregnanolone synthesis.

Hippocampal theta wave activity during configural and non-configural tasks in rats

This study examined hippocampal theta power during configural and non-configural tasks in rats. Experiment 1 compared hippocampal theta power during a negative patterning task (A+, B+, AB−) to a configural task and a simple discrimination task (A+, B−) as a non-configural task. The results showed that hippocampal theta power during the non-reinforcement trial (non-RFT) of the negative patterning task was higher than that during the simple discrimination task. However, this hippocampal power may reflect sensory processing for compound stimuli that have cross-modality features (the non-RFT of the negative patterning task was presented together with visual and auditory stimuli, but the non-RFT of the simple discrimination task was presented with visual or auditory stimulus alone). Thus, in experiment 2, we examined whether the experiment 1 results were attributable to sensory processing of a compound stimulus by comparing hippocampal theta power during negative patterning (A+, B+, AB−), simultaneous feature-negative (A+, AB−), and simple discrimination tasks (A+, B−). Experiment 2 showed that hippocampal theta activity during the non-RFT in the negative patterning task was higher than that in the simultaneous feature-negative and simple discrimination tasks. Thus, we showed that hippocampal theta activity increased during configural tasks but not during non-configural tasks.

The Importance of Stressing the Use of Laparoscopic Instruments in the Initial Training for Laparoscopic Surgery Using Box Trainers: A Randomized Control Study

BACKGROUND The goal of this study was to improve the efficiency of initial box training for laparoscopic surgery. MATERIALS AND METHODS The study used the following task: suturing and knot tying task under a combination of four conditions. (1) The C (use of conventional instruments)-D (direct vision); (2) the C-V (indirect vision via a video monitor); (3) the L (use of laparoscopic instruments)-D; and (4) the L-V (the standard laparoscopic suturing and knot tying). The first study assessed 11 medical students undergoing L-V training. The time to complete each of the four assessment tasks was recorded pre- and post-training. The second study was a randomized, controlled trial involving 36 students grouped according to three types of training methods: the L-D, the C-V, and the L-V group. The improvement in the time to complete the L-V task was assessed and the Hiroshima University Endoscopic Surgical Assessment Device (HUESAD) was used for assessment as well. RESULTS In the first study, a significant improvement in the performance time between pre- and post-training for the L-D task was found, but not for the C-V task. The second study found that the improvement rate of the L-D trained group was significantly greater than that of the C-V and L-V groups. The HUESAD assessment also showed the similar results. CONCLUSIONS A training program stressing the use of laparoscopic instruments and compensating for the fulcrum effect is more effective for novices using box trainers in the initial laparoscopic surgery instruction than one emphasizing performing the tasks via a video monitor.

Initial experiences of robotic versus conventional laparoscopic surgery for colorectal cancer, focusing on short-term outcomes: a matched case-control study.

BackgroundRobotic surgery is a new technique with the benefits of a three-dimensional view, the ability to use multi-degree-of-freedom forceps, the elimination of physiological tremors, and a stable camera view. The aim of this study was to evaluate the feasibility and short-term outcomes of robotic surgery for colorectal cancer as initial cases, compared with conventional laparoscopic surgery.MethodsFrom July 2010 to June 2013, ten patients with left-sided colon and rectal cancer underwent robotic surgery, and 121 received conventional laparoscopic surgery. Both groups were balanced in terms of age, gender, American Society of Anesthesiologists (ASA) score, body mass index (BMI), operative history, TNM staging, and tumor location. Moreover, in order to improve objectivity and approximate a randomized controlled study, we used the propensity score matching method. The matching was successful because the ROC analysis showed a well-balanced curve (C = 0.535).ResultsFollowing propensity score matching, ten patients were included in the robotic surgery group and 20 patients were included in the conventional laparoscopic surgery group. There were no significant differences in the short-term clinicopathologic outcomes between the robotic surgery group and the conventional laparoscopic surgery group. However, the operative time was significantly longer in the robotic surgery group than in the conventional laparoscopic surgery group.ConclusionsThere were no significant differences between the robotic surgery group and the conventional laparoscopic surgery group with respect to short-term clinicopathologic outcomes, with the exception of the operative time. Our early experience indicates that robotic surgery is a promising tool, particularly in patients with rectal cancer.

Evaluating the correlation between the HUESAD and OSATS scores: Concurrent validity study

Abstract Background: The aim of this study was to determine whether a correlation exists between the HUESAD and both the OSATS checklist and the global rating score. Material and methods: Fourteen participants were recruited, ranging from residents to consultants. The HUESAD measured three different parameters: Visual spatial ability, smoothness and accuracy. The OSTAS measured the endoscopic surgical skills by the checklist and the global rating score. Results: A significant relationship was thus identified between the OSATS checklist (p < 0.0001), the OSATS global rating score (p < 0.05) and the HUESAD assessment in the evaluation of visual-spatial ability. In terms of smoothness, there was also a significant relationship between the OSATS checklist (p < 0.05), the OSATS global rating score (p < 0.05) and the HUESAD assessment. Moreover, there was a significant relationship between the OSATS checklist (p < 0.05), the OSATS global rating score (p < 0.05) and the HUESAD assessment for accuracy. Conclusions: There was strong correlation between the motion analysis in the HUESAD assessment and OSATS checklist and the global rating score. Moreover, the visual spatial ability, smoothness and accuracy analyzed by the HUESAD were reliable parameters when assessing the endoscopic surgical skills.