CBCT location of the fusion between the buccal and lingual cortical in the mandibular ramus: importance to sagittal split osteotomy.

BACKGROUND: Mandibular Sagittal Split Osteotomy (MSSO) is a popular technique in orthognathic surgery used both to advance and to retreat the mandible. However, MSSO may incur in important complications, such as bad splits and sensorineural injuries. Knowing the location of the fusion between the buccal and lingual cortical (FBLC) in the mandibular ramus and the bone thickness in the region where osteotomies will be performed is determinant in MSSO planning to avoid complications. The aim of this study was to document and evaluate possible differences between sexes regarding the location of the FBLC in relation to the superior cortical of mandibular foramen (MF) and bone thickness in the region of interest for MSSO in a Brazilian population. MATERIAL AND METHODS: Eighty five cone-beam Computed Tomography (CBCT) scans were used to perform linear measurements to determine the location of the FBLC. Bone thickness from the mandibular canal (MC) to the cortical external surfaces and the diameter of the MC were measured at three different points: mandibular ramus (A), mandibular angle (B) and mesial of the second molar (C). RESULTS: The FBLC was located at a mean distance of 8.3 mm from the superior cortical of the MF in males and 8.1 mm in females. There was no difference between males and females regarding the mean bone thickness from the MC to the buccal external surface at all the points investigated (p>0.05). Bone thickness from the lingual external surface to the MC was bigger among females than males in regions B and C (p < 0.05). The diameter of the MC was bigger among males in regions B and C. CONCLUSION: Sexual dimorphism regarding mandibular bone thickness but not regarding the location of FBLC was present. This fundamental knowledge may assist to the panning of MSSO.

How to assess tonsilloliths and styloid chain ossifications on cone beam computed tomography images.

OBJECTIVE: The aim of this study was to establish an anatomical guideline in cone beam computed tomography (CBCT) images to discriminate soft-tissue calcifications, specifically, tonsilloliths, and styloid chain ossification (SCO) in the multiplanar reconstruction screen of the i-CAT Vision. MATERIALS AND METHODS: We analyzed 100 pairs of CBCT images and panoramic digital radiographies regarding the presence or absence of tonsilloliths and SCO. The intraobserver agreement varied from excellent to good. The statistical analyses included Mann-Whitney test, chi-square test, Spearman test, Student's t-test, and Wilcoxon test. The analyses were repeated without the guideline to verify its effectiveness. RESULTS: A total of 25 tonsilloliths were found in panoramic images while CBCT images revealed 60. Panoramic and CBCT images showed 42% and 63% of patients positive to SCO, respectively. We found a statistically significant difference when comparing the presence of tonsilloliths and SCO between panoramic and CBCT images (Wilcoxon test P < 0.05). The analyses without the guideline showed that the observer tended to diagnoses more false-positive SCO. CONCLUSION: Based on the results, we can suggest that CBCT images are more suitable to differentiate tonsilloliths and SCO than panoramic images. The guideline was more important to diagnosis SCO than tonsilloliths. SCO was misclassified in 34% without the guideline.

Influence of hypobaric hypoxia on bispectral index and spectral entropy in volunteers.

BACKGROUND: Hypoxia has been shown to change electroencephalogram parameters including frequency and amplitude, and may thus change bispectral index (BIS) and spectral entropy values. If hypoxia per se changes BIS and spectral entropy values, BIS and spectral entropy values may not correctly reflect the depth of anaesthesia during hypoxia. The aim of this study was to examine the changes in BIS and spectral entropy values during hypobaric hypoxia in volunteers. METHODS: The study was conducted in a high-altitude chamber with 11 volunteers. After the subjects breathed 100% oxygen for 15 min at the ground level, the simulated altitude increased gradually to the 7620 m (25,000 ft) level while the subjects continued to breathe oxygen. Then, the subjects discontinued to breath oxygen and breathed room air at the 7620 m level for up to 5 min until they requested to stop hypoxic exposure. Oxygen saturation (SpO2), heart rate, 95% spectral edge frequency (SEF), BIS, response entropy (RE), and state entropy (SE) of spectral entropy were recorded throughout the study period. RESULTS: Of the 11 subjects, seven subjects who underwent hypoxic exposure for 4 min were analysed. SpO2 decreased to 69% at the 7620 m level without oxygen. However, SEF, BIS, RE, and SE before and during hypoxic exposure were almost identical. CONCLUSION: These data suggest that hypoxia of oxygen saturation around 70% does not have a strong effect on BIS and spectral entropy.

Stromal-type Nephroblastoma with or without Anaplasia in Two Hedgehogs (Atelerix albiventris).

We describe the clinical and histological characteristics of stromal-type nephroblastomas that developed in two hedgehogs (Atelerix albiventris). In case 1, the tumour was composed of a proliferation of anaplastic stromal cells with ductal structures resembling the epithelium of nephroblastoma. In case 2, spindle-shaped cells that were somewhat larger than nephroblasts were frequently seen surrounding the cell cluster, and there was proliferation of stromal cells with collagen fibres at the periphery. Immunohistochemically, the tumour cells labelled weakly to strongly for the nephroblast marker Wilms' tumour-1 and were positive for Ki67 with rates of 5% and 10% for cases 1 and 2, respectively. Based on the above, the diagnosis was of stromal-type nephroblastoma with anaplasia in case 1 and without anaplasia in case 2. Our findings suggest that stromal-type nephroblastomas arise in adult hedgehogs and are clinically benign, and that histological anaplasia does not affect the prognosis.

Clearance of atrial natriuretic factor by lung, liver, and kidney in human subjects and the dog.

We determined human and canine plasma clearance of atrial natriuretic factor (ANF) by lung, liver, and kidney from arteriovenous differences in plasma ANF and measured organ plasma flow. Human subjects had lower plasma ANF concentrations in the pulmonary vein or the pulmonary capillary wedge position when compared with the pulmonary artery, and both sites yielded pulmonary ANF extraction ratios of 24%. Canine lung ANF extraction was 19 +/- 3% and pulmonary ANF clearance was 328 +/- 78 ml/min per m2 vs. 357 +/- 53 ml/min per m2 in man. Hepatic plasma ANF clearance was 216 +/- 26 ml/min with an extraction ratio of 30 +/- 3% in humans and 199 +/- 89 ml/min and 36 +/- 6% in the dog. Renal plasma ANF clearance in human subjects was 78 +/- 12 ml/min per kidney and correlated well with each kidney's creatinine clearance (r = 0.58, P less than 0.05). The mean renal ANF extraction ratio was 35 +/- 4% in human subjects and 42 +/- 6% in the dog. These data quantitate the specific organ ANF clearances by lung, liver, and kidney in human subjects and in dogs and provide a rationale for elevated plasma ANF levels in cirrhosis, renal failure, and diseases accompanied by reduced perfusion of these organs. These findings support the conclusion that plasma ANF concentrations are dependent upon both the stimuli for ANF secretion as well as the specific organ clearances of ANF.

Impact of different husbandry conditions on contact and airborne transmission of H5N1 highly pathogenic avian influenza virus to chickens.

Typically highly pathogenic avian influenza (HPAI) viruses spread very rapidly among chickens within sheds. However, the spread was slower than expected for the initial 10 days of the index farm in Japan during 2004. This slow spread, as well as the lack of gross lesions, clinical signs, or high mortality, hindered the field veterinarian from reporting a suspected HPAI outbreak to the veterinary office. To understand the field conditions for the slow virus spread, we examined contact and airborne transmission of the H5N1 virus to chickens in a negative-pressure isolator using various numbers of infected chickens and separate compartments. We found that the contact transmission did occur inefficiently when one or two chickens were infected, whereas the transmission was efficient when four chickens were infected. Airborne transmission of the HPAI virus was also dependent on the number of infected chickens and was less efficient than contact transmission. These data together with field observations suggested that number of infected chickens, chicken house types, and amount of environmental contamination might affect the virus transmission efficiency to chickens.

Technique and assessment of sentinel lymph node biopsy usefulness in laparoscopy-assisted distal gastrectomy.

BACKGROUND: Recently, some studies have suggested that sentinel node biopsy also can be applied to gastric cancer. The authors apply sentinel lymph node biopsy in laparoscopy assisted distal gastrectomy to perform it as safe limited surgery. Limited surgery is a procedure in which the extent of lesion resection and lymph node dissection is reduced. The authors demonstrate that intraoperative diagnosis of lymph node metastasis is useful in this respect. METHODS: The study was conducted with 38 patients (29 men and 9 women) who had a preoperative diagnosis of T1 tumor invasion. The patients had a mean age of 66.2 years. Patent blue (1%) was injected submucosally into four or five different sites around the primary tumor at 1 ml per site. Blue-stained lymphatics and lymph nodes could be seen by turning over the greater omentum and the lesser omentum extraperitoneally. If blue nodes were found, biopsy was performed. RESULTS: The mean number of blue nodes dissected was 2.5 +/- 1.9. Intraoperative identification and biopsy of blue nodes could be performed for 35 (92.1%) of the 38 patients. Of the 35 patients in whom blue nodes were identified, 4 (9.7%) had metastases in blue nodes confirmed by intraoperative frozen-section diagnosis. Intraoperative frozen-section diagnosis was negative for blue node metastasis in 31 patients. Postoperative permanent section diagnosis also showed no evidence of lymph node metastasis in these 31 patients (100% accuracy, 0% false-negative rates). CONCLUSION: The reported method allows observation of blue-stained lymphatics up to 2 h after patent blue injection. Sentinel node biopsy was performed in laparoscopy assisted distal gastrectomy, making it technically equivalent to open gastrectomy. Sentinel node biopsy can serve as a method to determine the appropriate use of laparoscopy assisted distal gastrectomy for management of T1 gastric cancer.

Distribution of viral antigens and development of lesions in chicken embryos inoculated with nipah virus.

An isolate of Nipah virus was injected into fertile eggs via the allantoic cavity or yolk sac. Allantoic inoculation resulted in considerable pathological variation and only partial mortality. Dead embryos showed severe necrosis in the brain and congestion in the kidney and the subcutis of limbs. In contrast, yolk sac inoculation led to uniform infection and mortality, the dead embryos exhibiting the same lesions as those described above but without the subcutaneous congestion. Histological lesions in dead embryos inoculated by either route were similar and particularly severe in the central nervous system. Viral antigens were detected mainly in the vasculature and neurons. The results indicated that Nipah virus is highly pathogenic to chicken embryos, and that the route of inoculation is an important determinant of the course of disease. The findings also suggested that yolk sac inoculation can be used for viral titration, and that the chicken embryo represents a useful model for studying the vascular and neuronal tropisms of Nipah virus.

Atrial pressure and secretion of atrial natriuretic factor into the human central circulation.

Atrial natriuretic factor, a peptide found in mammalian cardiac atria, has natriuretic and vasodilatory properties that may be important in the regulation of intravascular volume. To study factors related to its release in human subjects, intracardiac pressures and plasma atrial natriuretic factor concentrations in the central circulation were measured in 34 patients with a variety of cardiovascular disorders. Plasma atrial natriuretic factor concentration increased from the inferior vena cava to the right atrium (76 +/- 24 to 162 +/- 37 pg/ml, p less than 0.001) and from the vena cava to the aorta (76 +/- 24 to 177 +/- 46 pg/ml, p less than 0.001). Mean right atrial pressure was positively correlated with atrial natriuretic factor concentration in the pulmonary artery (r = 0.58, p less than 0.001), and mean pulmonary capillary wedge pressure was positively correlated with concentration in the aorta (r = 0.64, p less than 0.001). In six patients whose atrial natriuretic factor concentrations were measured at two different levels of atrial pressure, increased atrial pressure was accompanied by increased atrial natriuretic factor concentration in the pulmonary artery (p less than 0.01) and aorta (p less than 0.01). Atrial natriuretic factor levels measured in fresh myocardium from a patient undergoing cardiac transplantation showed tissue concentrations in the atria 500-fold higher than tissue concentrations in the ventricles. These data document that atrial natriuretic factor is found in human atrial myocardium and suggest that it may be released in response to increased atrial pressure. Such a secretory release mechanism is consistent with the hypothesis that atrial natriuretic factor plays a role in the regulation of circulatory volume.

Use of microcoil probehead for determination of the structure of oriented silk fibers by solid-state NMR.

A microcoil probehead for solid-state NMR was developed with a two-channel radio-frequency circuit, and 13C observation with a proton-decoupling probehead was performed to obtain information on the distribution of the orientation of silk fibroin molecules in the fiber. The coil (1 mm (diameter) x 5 mm (length)) of the probehead was placed at the angles 90 degrees and 30 degrees , relative to the static magnetic field. Only 70 mug of [1-13C]Gly silk fibroin fiber was used in a magnet of 9.4 T (400 MHz for proton channel).

Sodium loading and posture modulate human atrial natriuretic factor plasma levels.

Atrial natriuretic factor is postulated to act through atrial stretch receptors as a volume regulatory hormone that stimulates diuresis and natriuresis in response to increased atrial pressure. To characterize the stimuli associated with the release of atrial natriuretic factor in humans, we studied 14 normal subjects, both in the supine position and after 10 minutes in an upright posture, while they were on a regular diet (Day 0) and during 3 days of supplemental sodium chloride intake (8 g/day). Radioimmunoassay of plasma atrial natriuretic factor was performed with rabbit antibody to the human hormone amino acids (102-126). Urinary sodium excretion increased from 111 +/- 13 mEq/day (mean +/- SEM) on Day 0 to 275 +/- 15 mEq/day by the third day (Day 3) of high sodium intake. The level of atrial natriuretic factor in the supine position rose from 17 +/- 4 pg/ml (Day 0) to 76 +/- 13 pg/ml on Day 3 (p less than 0.001) and after 10 minutes in an upright posture on Day 3, the level fell to 32 +/- 10 (p less than 0.005). Plasma concentrations of atrial natriuretic factor correlated positively with spot and 24-hour urinary sodium excretion and weight gain, and correlated negatively with plasma aldosterone and renin activity. We conclude that the response of atrial natriuretic factor to sodium loading and posture change in humans is appropriate for a volume regulatory hormone.

Structure and physiological actions of rat atrial natriuretic factor.

Natriuretic substances were purified from rat atrium (atrial natriuretic factor, ANF) and were shown to be identical with the inhibitor of norepinephrine-induced contraction of smooth muscle. Four native forms were isolated and their amino acid sequences were determined. The presence of a high-molecular-weight prohormone was shown. Complementary DNA (cDNA) encoding for the precursor was cloned and used to deduce the amino acid sequence of the prohormone. Genomic DNA for ANF was cloned and two introns were found. Several ANF peptides were synthesized. Structure-function studies showed that the ring structure was essential for the activity. Antibodies produced against the synthetic 25-amino acid residue ANF were used to develop a radioimmunoassay. The presence of ANF in rat plasma demonstrated that ANF is a circulating hormone. ANF was also found in the hypothalamus of rats. The ANF in plasma was found to be a low-molecular form, whereas that in atria and hypothalamus consisted of both the high-molecular-weight precursor and low-molecular-weight active ANF. The presence of messenger RNA for ANF was determined using ANF cDNA as a probe and was considered as evidence for ANF synthesis in the brain, atrium, and ventricles. ANF was shown to be released from the brain. ANF administered intracerebroventricularly was shown to inhibit angiotensin II and thirst-induced dipsogenesis. In vitro and in vivo experiments showed ANF inhibits release of vasopressin from posterior pituitary and renin from the kidneys. The hypotensive effect of ANF was examined at various doses.(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis, structure-activity relationships, and pharmacokinetic profiles of nonpeptidic alpha-keto heterocycles as novel inhibitors of human chymase.

We designed nonpeptidic chymase inhibitors based on the structure of a peptidic compound (1) and demonstrated that the combination of a pyrimidinone skeleton as a P3-P2 scaffold and heterocycles as P1 carbonyl-activating groups can function as a nonpeptidic chymase inhibitor. In particular, introduction of heterobicycles such as benzoxazole resulted in more potent chymase-inhibitory activity. Detailed structure-activity relationship studies on the benzoxazole moiety and substituents at the 2-position of the pyrimidinone ring revealed that 2r (Y-40079) had the most potent chymase-inhibitory activity (K(i) = 4.85 nM). This compound was also effective toward chymases of nonhuman origin and showed good selectivity for chymases over other proteases. Pharmacokinetic studies in rats indicated that 2r was absorbed slowly after oral administration and showed satisfactory bioavailability (BA) (T(max) = 6.0 +/- 2.3 h, BA = 19.3 +/- 6.6%, t(1/2) = 35.7 +/- 13.3 h). In conclusion, 2r is a novel, potent, and orally active chymase inhibitor which would be a useful tool in elucidating the pathophysiological roles of chymase.

Synthesis, structure-activity relationships, and pharmacokinetic profiles of nonpeptidic difluoromethylene ketones as novel inhibitors of human chymase.

Potent human chymase inhibitors with high enzymatic selectivity and satisfactory metabolic stability were obtained by replacing the Val-Pro (P3-P2) dipeptide portion of the previously described inhibitor 1 with a nonpeptidic pyrimidinone skeleton. The potency of the novel compounds was further enhanced by the introduction of carbamoyl-substituted difluoromethylene ketone moieties. The most potent chymase inhibitor of the newly created series was 2u (Y-40018), which had a K(i) of 2.62 nM. Compound 2u possessed high selectivity for human chymase since it lacked significant activity toward other representative human proteolytic enzymes. Moreover its strict specificity for human chymase suggested that 2u strongly inhibited human and canine chymases but not rat and mouse ones. Pharmacokinetic studies in rats and dogs indicated that 2u was absorbed rapidly after oral administration and had satisfactory bioavailability in these experimental animal species (rat, 17%; dog, 32%). In conclusion, 2u is a novel, potent, and orally active chymase inhibitor which would prove very useful in revealing the precise roles of the latter in various pathophysiological processes.

Postoperative functional evaluation of pylorus-preserving gastrectomy for early gastric cancer compared with conventional distal gastrectomy.

BACKGROUND: Malnutrition, gallbladder dysfunction, dumping syndrome, reflux esophagitis, and gastritis of the remnant stomach are unfavorable sequelae in patients undergoing gastrectomy. Operative procedures should be improved to ensure such patients a satisfactory quality of life. METHODS: After operation, gallbladder function, reflux gastritis, gastric emptying, and caloric intake were evaluated in 20 patients with early gastric cancer undergoing pylorus-preserving gastrectomy (PPG) and 25 patients undergoing conventional distal gastrectomy (CDG). RESULTS: The resting gallbladder area increased significantly after CDG. In contrast, after PPG the gallbladder area showed no significant change and the contraction rate decreased slightly. After CDG, emptying was much more rapid for the first 30 minutes after ingestion of a meal. Although delayed emptying was observed early after PPG, the rate of emptying increased with time. Gastric pH was lower and gastric mucosal injury was milder in patients undergoing PPG. These results are attributed to preserved pyloric function. The caloric intake and changes in body weight after operation were similar in both the CDG and PPG groups. CONCLUSIONS: PPG has advantages over CDG in terms of gallbladder function, the condition of the remnant stomach, and gastric emptying, PPG should be used in carefully selected patients with early gastric cancer to improve their quality of life.

Dynamic cortical activation in mental image processing revealed by biomagnetic measurement.

The mental rotation task has been reported to activate the human parietal and extra-striate areas, based on the results of fMRI and PET analysis. In the present study, we investigated the dynamic properties of the distributed cortical activity related to mental rotation processes at high temporal resolution by means of brain magnetic field measurements and a linear inversion algorithm. Distributed neural activities during the mental rotation and control tasks were estimated for six subjects, and the differences in the activity distribution were analyzed. Statistically significant differences in the parietal and lateral posterior temporal region were detected 200-300 ms after the visual stimulus, indicating that the dorsal and ventral pathway were included in the mental image processing.

Are there discrete distal-proximal representations of the index finger and palm in the human somatosensory cortex? A neuromagnetic study.

OBJECTIVE: The distal-proximal representations of the finger and palm in the first somatosensory cortex (SI) were studied in humans. METHODS: Somatosensory evoked magnetic fields (SEFs) from 11 subjects were measured, following mechanical stimulation of the skin by using a 122 channel whole head SQUID system. Sensory stimulus comprising of a 10 ms vibration at the frequency of 200 Hz was delivered to 6 successive sites in 3 cm increments, along the distal-proximal direction over the volar surface of the right index finger and palm. Using a single dipole model, the sources of the magnetic fields were estimated and mapped onto magnetic resonance images of each subject. ANOVA was used for statistics. RESULTS: Source localization was determined on the main peak (M50) of the SEFs. All of the sources were located in the area 3b of SI. Contrary to the well-defined distal-proximal representations in the hand area of simian SI cortex, there was no statistically significant differences between the locations of the dipoles in human SI cortex evoked by stimulation of different sites. CONCLUSION: The result, however, should be interpreted with caution, because it cannot be denied that the spatial separation of sources in the distal-proximal somatotopy is beyond the resolving capacity of magnetoencephalography (MEG). In addition, at variance with the discrete distal-proximal gradient in the mechanoreceptor density, there was no statistically significant differences between the signal strengths of the dipoles for stimulation of the different locations.

Agonist-specific refractory states of bovine platelets-disappearance of synergism in aggregation.

The specificity of refractory state of bovine platelets developed by various agonists was examined. When bovine unwashed platelets were preincubated with 5-hydroxytryptamine (5HT) (or ADP), they became non responding to that agonist (refractory) but they responded quite normally to collagen, thrombin and ADP (or 5HT). When platelets became refractory to 5HT, the synergistic aggregation normally obtained with this agonist plus ADP was lost, but that with ADP plus thrombin was not changed. Platelets made refractory to ADP (or 5HT) after the aggregation and disaggregation cycle by the agonist responded normally to 5HT (or ADP). These results strongly indicate that platelets become refractory to one agonist without impairing the sensitivity to any other agonists.

Specific desensitization in the cytoskeletal assembly of platelet by receptor-dependent activations.

Cytoskeletal assembly induced by receptor-dependent or independent activation of bovine platelets was investigated. When platelets were preactivated with receptor-dependent stimulus, ADP or thrombin, cytoskeletal assembly was not induced repeatedly by the same agonist. However, in the case of receptor-independent stimulus, cryo-activation, the assembly was induced not only by receptor-dependent but also by independent stimulus. The desensitization, therefore, lies in the transmission of stimuli from receptors to cytoskeletal proteins.

Agonist-specific desensitization of shape change of platelets.

Using scanning electron microscopy and light scattering we have investigated the shape change of bovine platelets. The extents of shape change obtained by ADP and 5-hydroxytryptamine(5HT) increased in dose-dependent manner, and the maximum obtained by these agonists were additive. The agonist-specific desensitization in shape change was observed with ADP, 5HT and thrombin. The extent of desensitization by pre-exposure to ADP was dependent upon the concentration of ADP. It was strongly indicated that receptors or their subsequent stimuli-transmission apparatus became unable to respond to further stimulation after the exposure to the initial stimulation.