Stress signaling through Ca2+/calmodulin-dependent protein phosphatase calcineurin mediates salt adaptation in plants

Calcineurin (CaN) is a Ca²⁺- and calmodulin-dependent protein phosphatase (PP2B) that, in yeast, is an integral intermediate of a salt-stress signal transduction pathway that effects NaCl tolerance through the regulation of Na⁺ influx and efflux. A truncated form of the catalytic subunit and the regulatory subunit of yeast CaN were coexpressed in transgenic tobacco plants to reconstitute a constitutively activated phosphatase in vivo. Several different transgenic lines that expressed activated CaN also exhibited substantial NaCl tolerance, and this trait was linked to the genetic inheritance of the CaN transgenes. Enhanced capacity of plants expressing CaN to survive NaCl shock was similar when evaluation was conducted on seedlings in tissue culture raft vessels or plants in hydroponic culture that were transpiring actively. Root growth was less perturbed than shoot growth by NaCl in plants expressing CaN. Also, NaCl stress survival of control shoots was enhanced substantially when grafted onto roots of plants expressing CaN, further implicating a significant function of the phosphatase in the preservation of root integrity during salt shock. Together, these results indicate that in plants, like in yeast, a Ca²⁺- and calmodulin-dependent CaN signal pathway regulates determinants of salt tolerance required for stress adaptation. Furthermore, modulation of this pathway by expression of an activated regulatory intermediate substantially enhanced salt tolerance.     

Invited. Fukuyama congenital muscular dystrophy: A neuroradiologic review

We reviewed neuroradiologic findings of Fukuyama congenital muscular dystrophy (FCMD) and correlated them with the known neuropathology. All patients showed thick and bumpy cortices with shallow sulci corresponding to polymicrogyria, and approximately half of the patients showed pachygyric cortex with smooth surface corresponding to type II lissencephaly. The two types of cortical dysplasias presented characteristic distributions: the former demonstrated frontal lobe involvement in all and parietotemporal lobe involvement in some, whereas the latter involved the temporo-occipital lobes. Most patients showed prolonged T1 and T2 signal in the white matter, which was indistinct in neonates and infrequently seen in adolescents. Cerebellar polymicrogyria depicted as disorganized cerebellar foliation accompanying cysts were found more than 90% of the patients. In conclusion, brain MRI demonstrates findings consistent with the known neuropathology of FCMD. The detection of the two types of cerebral cortical dysplasia with characteristic distribution and cerebellar abnormalities is helpful in the differential and early diagnosis.     

Immunology: Diversity of the blocking effects of antisperm antibodies on fertilization in human and mouse

The blocking effects of complement-dependent sperm immobilizingantibodies in the sera of infertile women and monoclonal antispermantibodies against humans and mice on fertilization were investigated.The hemizona assay (HZA) and sperm penetration assay (SPA) wereused to study the inhibitory effects of sera from 22 infertilepatients positive for sperm immobilizing antibodies. Use ofthese tests allowed us to differentiate whether the antibodyblocked sperm—zona pellucida tight binding and/or spermpenetration into the ooplasm. The zona pellucida penetrationassay (ZPA) was also used to study the effects of four monoclonalantibodies (mAbs) on human sperm penetration into the zona pellucida.Seven mAbs against murine spermatozoa were tested for theirinhibitory effects on in-vitro fertilization (IVF) and HZA inmice. Of 22 patient sera with sperm immobilizing antibodies,21 (95.5%) inhibited HZA attachment and penetration, whereasthis did not occur in any of 13 patient sera without these antibodies.However, 19 of 22 (86.4%) patient sera with sperm immobilizingantibodies and eight of 13 (61.5%) patient sera without theseantibodies inhibited the SPA. Two (2C6, 1G12) of four mAbs againsthuman spermatozoa showed strong inhibitory effects in all theassays (HZA, ZPA and SPA). One mAb (3B10) did not inhibit HZAbut blocked ZPA and SPA. Another mAb (H6-3C4) seemed to haveno inhibitory effects on fertilization. Two (Vx 5 and Vx 8)of seven mAbs against murine spermatozoa inhibited IVF in micebut did not block mouse HZA. These findings suggest that antispermantibodies block fertilization at specific stages. Some of themmay inhibit sperm capacitation and thus prevent all processesof fertilization that follow. Some other antibodies may notaffect capacitation and sperm binding to zona pellucida butinhibit the acrosome reaction, followed by the blocking of spermpenetration through zona pellucida and ooplasm.     

Thyroplasty Type I with Ceramic Shim

Abstract: To prevent side effects from a silicone shim in Isshiki thyroplasty type I, we used a ceramic shim in 10 patients with unilateral recurrent laryngeal nerve paralysis. No published reports have described the use of ceramic in this type of surgery. According to the degree of glottic insufficiency, ceramic shims of various heights were inserted into the fenestration made in the thyroid ala. All patients experienced subjective improvement of voice postoperatively. Laryngoscopies in most cases showed that glottic insufficiency improved postoperatively. In the postoperative examination, the maximum phonation time improved an average of 3.7 s, and the mean flow rate improved an average of 331 ml/s. We have analyzed the relationship of these improvements to the degree of glottic insufficiency and have compared our results with those of other investigators.     

Immunohistochemical study of adenohypophysial gonadotropes in the musk shrew, Suncus murinus L. (Insectivora)

Most gonadotropes in the pituitary of male Suncus murinus L. are immunostained with both LH beta and FSH antisera, whereas only a few gonadotropes are positive only for LH beta. The former gonadotropes consist of polygonal or polyhedral cells of medium size, and can be identified by the presence of two types of secretory granules of low density: smaller ones (about 150-250 nm in diameter) which are spherical in shape, and larger ones of irregular form with a maximum diameter of about 1,500 nm. The endoplasmic reticulum is not prominent, while the Golgi apparatus is distinct. Mitochondria are found throughout the cytoplasm but are often concentrated in and around the region of the Golgi apparatus. These fine structural features are somewhat similar to those of the classical Barnes "FSH cells" and Kurosumi-Oota "FSH cells".     

Calcium uptake in the skin of a freshwater teleost.

The skin, particularly the opercular membrane of some teleosts, contains mitochondrion-rich "chloride" cells and has been widely used as a model to study branchial salt-extrusion mechanisms in seawater fish. Skin isolated from the operculum of the freshwater Nile tilapia (Oreochromis niloticus) can transport Ca2+ against an ionic and electrical gradient. Adaptation of Nile tilapia to a low-Ca2+ environment increased the capacity of the opercular membrane to transport Ca2+. The density of mitochondrion-rich cells increased in parallel with Ca2+ transport capacity. The results demonstrate net Ca2+ uptake by vertebrate skin and strongly implicate mitochondrion-rich cells as the site of Ca2+ uptake in fresh water.     

Spinal cord lesions block seizures or delay their onset in myelin-deficient rats: evidence that generalized tonic seizures can be triggered by abnormal spinal cord activity

The myelin-deficient mutant rat develops generalized tonic seizures and dies during the fourth postnatal week. Surgical constriction of the lower thoracic spinal cord, performed either after the seizures have appeared or before, eliminates the seizures, or delays their onset, and prolongs the life of the animals. These observations support the view that the seizures in these animals can be triggered by abnormal activity originating in the myelin-deficient spinal cord and can be blocked by preventing that activity from ascending to higher levels. Similar seizures and "paroxysmal" phenomena occur in other myelin-deficient conditions including multiple sclerosis.     

Change of blood pressure and pulse rate in intravenous urography

We monitored the blood pressure and pulse rate during routine excretory urography in 3002 patients (4832 examinations) using high osmolality contrast medium. After injection of contrast medium, the blood pressure was changed more than 20% of the pre-injection blood pressure lasting for more than 1 minute in 27 patients (27 examinations, 0.56%), including 8 patients with a hypertensive reaction (0.17%) and 19 patients with a hypotensive reaction (0.39%). In all 27 patients, transient tachycardia was seen along with the progress of blood pressure change. Bradycardia was associated with a severe hypotensive reaction in 2 patients. In 19 patients with a hypotensive reaction, the blood pressure was progressively decreased beyond 60 mmHg in 9 patients (0.18%) while the blood pressure was remained above 60 mmHg in 10 patients (0.21%). Treatment was not necessary in 8 patients with a hypertensive reaction as well as in 10 patients with a mild hypotensive reaction (above 80 mmHg). In these 18 patients, the examination would have been finished without a suspicion of the blood pressure change unless the blood pressure was monitored. In 9 patients with a severe hypotensive reaction (below 60 mmHg), the subjective or objective symptoms were present during the examination in 7 patients. They should be considered to have had "severe adverse reaction". In remaining 2 patients, there was no subjective or objective symptoms. We discussed possible mechanisms regarding the change of blood pressure and pulse rate after injection of contrast medium.     

Clinical experiences with a new membrane oxygenator with low priming volume (D702 MASTER FLO 51), studies during pulsatile and constant flow perfusion

The newly developed oxygenator "D702" is a compact hollow fiber membrane oxygenator with a priming volume of 170 ml. The maximum flow allowance is 4 liters per/minute. We used this oxygenator in 16 patients (11 infants and children, and 5 adults) undergoing various open heart surgery, and function of this oxygenator was studied. Pulsatile cardiopulmonary bypass was performed in 8 patients and nonpulsatile constant flow perfusion was employed in the remaining 8 patients. Our clinical experience showed excellent maintenance of PaO2 and PaCO2 during both pulsatile and constant flow bypasses. A low pressure drop was encountered across the membrane oxygenator, and therefore, this oxygenator is applicable for pulsatile cardiopulmonary bypass. The D702 is a very useful and applicable for a wide range of patients from infants to adults with a small body structure.