Cardiovascular changes during and after arousal from hibernation in golden hamsters

This thesis examines the plasticity of cardiovascular control of golden hamsters {Mesocricetus auratus) in four physiological conditions, normal controls at euthermy, cold controls (cold-exposed animals that did not undergo hibernation), hibernating animals and animals aroused from hibernation for 2 h. There were two main areas of study 1) the endothelium and perivascular innervation of mesenteric and renal arteries using electron-immunocytochemical techniques and 2) gap junctions in the left ventricle and aorta using immunohistochemistry combined with laser confocal microscopy. During hibernation, the percentages of both nitric oxide synthase (NOS)- positive and endothelin (ET)-positive endothelial cells in the superior mesenteric artery and renal artery were markedly lower than in the controls. In the mesenteric artery, the percentage of NOS and ET positive endothelial cells fell from 22% and 17%, respectively, in the normal controls to 1% and 6%, respectively, during hibernation. In the renal artery 23% and 43% of endothelial cells contained NOS and ET, respectively in the normal controls but only 5% contained NOS and ET in the hibernating group. On arousal, the percentages of NOS and ET immunopositive endothelial cells were similar to the normal control values (18% and 13%, respectively, in the mesenteric artery and 21% and 30%, respectively, in the renal artery). In perivascular nerves, there was an increase in the percentage of axon profiles positive for sympathetic nerve markers, tyrosine hydroxylase (from 17% to 57% during hibernation in the mesenteric artery and from 20% to 76% during hibernation in the renal artery) and neuropeptide Y (from 30% to 65% during hibernation in the mesenteric artery and from 25% to 77% in the renal artery). There was also a hibernation-associated decrease in the percentage of axon profiles containing a parasympathetic nerve marker, vasoactive intestinal polypeptide (from 14% to 4% during hibernation) in the mesenteric artery. These changes are consistent with increased peripheral vascular resistance during hibernation. The endothelial and neural changes reported may reflect a predominantly sympathetic vasoconstrictor control during hibernation concomitant with a reduced endothelial contribution to the maintenance of vascular tone. The density of immunoreactive connexin (Cx) 43 gap junctions was significantly increased in left ventricular cardiomyocytes in hibernating hamsters (area and numerical density were 9.73±1.4 and 16.11 ±1.6 µm2/1000 µm2, respectively, in hibernation compared to 4.03±0.93 and 10.68±1.7 µm2/1000 µm2 in normal control, hibernation compared to 4.03±0.93 and 10.68±1.7 µm2/1000 in normal control, P<0.05). Cx43 plaque size was larger in cold controls and hibernating animals (0.52+0.04 and 0.58±0.03 µm2, respectively, compared to normal controls, P<0.05). Cx40 immunoexpression at the endothelium lining coronary arterioles of the ventricle was increased in the cold control group only: Cx40 area density was 38.99±4.19 µm2/1000 µm2 in cold controls compared to 25.26±3.2 µm2/1000 µm2 in normal controls and was significantly greater than during hibernation (23.04±3.1 µm2/1000 µm2, P<0.05). There were no changes in Cx40 levels in the aortic endothelium or in levels of Cx43 in smooth muscle of the aorta. The increase in cardiomyocyte gap junction proteins in the cold controls may represent a compensatory response to prepare the animal for hibernation avoiding ventricular fibrillation, while during hibernation, increased connexin expression may facilitate intercellular transfer of selected signals in readiness for arousal. The elevation of gap junction channels in coronary arteriolar endothelium corresponds with the requirement of increased intercellular communications during the prolonged circulatory changes required to maintain core temperature. In summary, cardiovascular changes during hibernation operate at several different levels, neural, endothelial and at the level of cell to cell communication via gap junctions. These changes emphasise the active rather than passive nature of the process of hibernation and arousal

The Surgical Landmark for Facial Foramen

ABSTRACTObjectiveTo study the localization and relative of the supratrochlear, supraorbital, infraorbital and mental foramen in Thai cadavers to external landmarks for helps the surgeon to easily and practically identify these foramen.Materials and methodsThe localization of the supratrochlear, supraorbital, infraorbital and mental foramen in adult Thai cadavers were studied in 110 cadevers (220 sides) from 2008 until 2012. The analyses were also performed to compare differences between sexes and sides.ResultsMean length of supraorbital foramen from nasal midline on the right side was 2.76 cm, left side 2.75 cm, above supraorbital rim right side 0.23 cm, left side 0.23 cm. Mean length of supratrochlear foramen from nasal midline on the right side was 1.77 cm, left side 1.76 cm. Mean length of infraorbital foramen from maxillary midline on the right side was 3.06 cm, left side 3.07 cm, from infraorbital rim on the right side was 0.94 cm, left side 0.92 cm. Mean length of mental foramen measurement straight to symphysis menti on the right side was 3.19 cm, left side 3.18 cm. Measurement along curvature of the mandible on the right side was 3.49 cm, left side 3.49 cm.ConclusionThe knowledge gained from this study is quite important, since it helps the surgeon to easily and practically identify supraorbital notch/foramen, supratrochlea foramen, infraorbital foramen and mental foramen. This will help avoid injury of the neurovascular bundles passing though these sets of foramen.How to cite this articleTungkeeratichai J, Bhongmakapat T, Saitongdee P, Orathai P. The Surgical Landmark for Facial Foramen. Int J Otorhinolaryngol Clin 2013;5(3):121-124.</jats:sec

A New External Landmark for Mental Foramen

ABSTRACTPurposeThe purpose of this study was to establish a new external landmark of mental foramen to help facilitate prediction of the location during local anesthesia and during surgery of mandibular region.Materials and methodsOne hundred and ten adult Thai cadavers of 61 males and 49 females from Department of Anatomy, Faculty of Science, Mahidol University were included in this study. The anatomy of mental foramen in 110 adult Thai cadavers (220 sides) was studied from 2008 until 2011. Measurements in vertical plane were made: (i) From gingival sulcus to mental foramen = A, (ii) from mental foramen to inferior border of mandible = B, and (iii) the ratio of A/A + B = D.Measurements in horizontal plane were also made: (i) From symphysis menti to the mental foramen = S (in straight line and not related to mandibular curvature), and (ii) from symphysis menti to the mental foramen = C (in curved line related to mandibular curvature), and (iii) in relation to position of lower tooth/teeth, and (iv) in relation to cheilions (corners of the mouth).ResultsThe results included 61 male and 49 female cadavers. On the right side, the proportion of A/A + B (D) of male and female was 0.50 and 0.46. On the left side, the proportion of A/A + B (D) of male and female was 0.50 and 0.46. The location of right and left cheilion was related with the position of mental foramen, mostly at center (male: 63.93 and 70.49%, female: 61.22 and 73.47%). If center ± 0.3 cm it was possible to find the mental foramen more easily than the point of the center (male: 95.08 and 91.80%, female: 87.76 and 93.88%). If center ± 0.5 cm, it could find the mental foramen more easily than the point of the center ± 0.3 cm (male: 98.36 and 98.36%, female: 95.92 and 97.96%).ConclusionThe knowledge gained from this study is quite important, since it helps the surgeon to easily identify the mental foramen prior to surgery which is halfway between gingival sulcus and inferior border of mandible in vertical plane and at the cheilion position in horizontal plane.</jats:sec

The Surgical Landmark for Facial Foramen

ABSTRACTObjectiveTo study the localization and relative of the supratrochlear, supraorbital, infraorbital and mental foramen in Thai cadavers to external landmarks for helps the surgeon to easily and practically identify these foramen.Materials and methodsThe localization of the supratrochlear, supraorbital, infraorbital and mental foramen in adult Thai cadavers were studied in 110 cadevers (220 sides) from 2008 until 2012. The analyses were also performed to compare differences between sexes and sides.ResultsMean length of supraorbital foramen from nasal midline on the right side was 2.76 cm, left side 2.75 cm, above supraorbital rim right side 0.23 cm, left side 0.23 cm. Mean length of supratrochlear foramen from nasal midline on the right side was 1.77 cm, left side 1.76 cm. Mean length of infraorbital foramen from maxillary midline on the right side was 3.06 cm, left side 3.07 cm, from infraorbital rim on the right side was 0.94 cm, left side 0.92 cm. Mean length of mental foramen measurement straight to symphysis menti on the right side was 3.19 cm, left side 3.18 cm. Measurement along curvature of the mandible on the right side was 3.49 cm, left side 3.49 cm.ConclusionThe knowledge gained from this study is quite important, since it helps the surgeon to easily and practically identify supraorbital notch/foramen, supratrochlea foramen, infraorbital foramen and mental foramen. This will help avoid injury of the neurovascular bundles passing though these sets of foramen.</jats:sec

Levels of Gap Junction Proteins in Coronary Arterioles and Aorta of Hamsters Exposed to the Cold and During Hibernation and Arousal

There are marked changes in vascular dynamics during prolonged periods in the cold, entrance into hibernation, and arousal to euthermy. Cell-to-cell communication through gap junction channels plays a pivotal role in the control of vasomotor function. Multiple gap junction proteins are expressed in blood vessels, including connexins 37 (Cx37), 40 (Cx40), 43 (Cx43), and 45 (Cx45). Using immunolabeling techniques combined with confocal microscopy, we quantitated the levels of these connexins in coronary arterioles and the thoracic aorta of the golden hamster in four physiological conditions: normal control animals at euthermy; cold-exposed animals (before entrance into hibernation); during hibernation; and after 2-hr arousal from hibernation. In all groups, Cx37 was localized between endothelial cells of the aorta and Cx40 was observed between endothelial cells of coronary arterioles and the aorta. Cx43 was confined to smooth muscle cells of the aorta. Labeling for Cx45 was detected in the endothelium of the ascending aorta. The expression of Cx37 was significantly reduced in cold-exposed, hibernating, and aroused animals. Immunolabeling for Cx40 was increased in the coronary arteriolar endothelium of the cold-exposed group compared with normal controls, hibernating, and aroused animals, perhaps to facilitate intercellular communication during the prolonged circulatory changes to vascular dynamics required to maintain core temperature during cold adaptation. Cx40 expression was unchanged in the aorta. Cx43 immunoexpression in the aorta remained constant under all conditions examined. These changes in connexin expression did not occur during the rapid circulatory changes associated with arousal from hibernation. </jats:p

Is the Silicone Implant actually in the Subperiosteal Pocket in Augmented Rhinoplasty?

ABSTRACTPurposeTo identify the right plane in augmented rhinoplasty to help facilitate the facial plastic surgeons in creating more natural look in oriental noses.Materials and methodsOne hundred and ten adult Thai cadavers comprising 61 males and 49 females from Department of Anatomy, Faculty of Science, Mahidol University were included in this study. Augmentation rhinoplasty with the closed technique was performed by using silicone prosthesis; then, surgical incision was done at midline from nasion to nasal tip to identify the correlation between silicone and periosteum in the area of rhinion and nasion.ResultsThis study included 61 male and 49 female cadavers. At the rhinion, silicones were placed in subperiosteal plane of 65 cadavers (59.1%) and above periosteum of 45 cadavers (40.9%). In nasion area, silicones were successfully inserted below periosteum of 109 cadavers (99.1%). However, silicone was placed in the supraperiosteum of only one cadaver (0.9%).ConclusionSilicone can be inserted into subperiosteal layer in the area of nasion easier than in the area of rhinion. Augmented rhinoplasty by using silicone insertion in subperiosteal plane, at lease in the nasion area, makes it more natural look, stable and can prevent misalignment.</jats:sec