Frequency analysis of arterial pulse transmission in the cranial cavity]

The changes of intracranial and arterial pulse shape under functional loads (hypervolemia and intracranial hypertension) were compared. The logarithmic amplitude-frequency characteristics were found and used for the synthesis of equivalent electrical circuit of arterial pressure pulses transmission on cerebrospinal fluid (CSF) in the cranial cavity. The model obtained points to the necessity of taking into account the induction which was not performed in the earlier models of the CSF-system. It is found that the attenuation factor permitted to estimate the stability of the intracranial circulation system to input influences under different functional conditions.     

On the cavity size distribution in water and n-hexane

The cavity size distribution functions in water and n-hexane were determined by Pohorille and Pratt, in a series of important works, from molecular dynamics simulations. These functions are considered as experimental data. In the present investigation the ability of scaled particle theory in reproducing such distributions is tested. In the case of water the scaled particle theory results compare favorably with the experimental distribution if a proper choice of the size to be assigned to water molecules is performed. Specifically, a slight size increase from 2.70 to 2.80 A is necessary to reach agreement for the largest cavities detected by Pohorille and Pratt. In the case of n-hexane the scaled particle theory results do not agree with the experimental distribution especially in the region of small cavities. This deficiency is because a n-hexane molecule cannot be realistically treated as a single spherical exclusion volume. The implications of such findings are analyzed and discussed in depth.     

幽门螺杆菌在口腔中的特征性分布

目的:研究幽门螺杆菌(Helicobacterpylori,Hp)在慢性胃炎患者口腔中的分布.方法:依据Hp尿素酶C基因和细胞毒素相关基因(cagA)设计引物建立PCR方法,从32例慢性胃炎患者口腔内多部位采集标本,检测和鉴定牙菌斑(每人采集6个牙的龈上和龈下菌斑)、含漱液、舌背黏膜、颊黏膜及腭黏膜表面中的Hp.结果:32例患者中有29例(90.6%)从口腔内牙菌斑、含漱液、舌背黏膜、颊黏膜及腭黏膜至少一处检测出Hp,其中28例(87.5%)从胃和口腔内同时检出Hp,口腔内各部位标本中Hp检出率依次为牙菌斑84.4%,口腔含漱液56.2%,舌背黏膜43.8%,颊黏膜28.1%,腭黏膜9.4%;在384份牙菌斑中,磨牙的牙菌斑Hp的检出率高于前牙(33.2%vs21.9%,P＜0.01);而上下牙的牙菌斑Hp的阳性率差异无显著性(29.7%vs29.2%,P＞0.05);在PD＞4 mm的牙周袋,菌斑Hp检出率显著高于PD＜4 mm的袋(P＜0.05),龈下菌班Hp的阳性率显著高于龈上菌斑(P＜0.01).结论:口腔多部位存在Hp,牙菌斑中居多,并呈一定的分布规律;口腔Hp可能是胃Hp感染的重要来源.     

Pressure distribution on mattresses

Measurements of pressure distribution are usually performed on a hard base, such as those in gait analysis or tire research; measurements on soft surfaces are avoided because of technical problems. A sensor mat was developed which consists of 512 pressure sensors, glued to arbitrary locations of a fabric. The mat can be bent to spherical and saddle shapes so that it can be utilised on soft and flexible surfaces like chairs and beds. Performance of eight hospital mattresses concerning decubitus prophylactics and support in supine and side position was studied in four subjects representing extreme body build. It was found that one particular mattress served well for three subjects, whereas no mattress was suitable for the high and heavy type. It was concluded that measurement of pressure distribution is a valuable tool for designing and selecting.     

The development and distribution of the cranial neural crest in the rat embryo

Summary The head region of rat embryos was investigated by scanning electron microscopy after removal of the surface ectoderm with adhesive tape. Observations were made in embryos from 6-somite to 11-somite stages of development, in order to determine: (1) the sequence of emigration of neural crest cells from the different regions of the future brain; (2) the appearance of crest cells before, during, and after their conversion from an epithelial to a mesenchymal form; (3) the migration pathways.Emigration occurs first from the midbrain, and next from the rostral hindbrain; crest cells from these two regions migrate into the first visceral arch. Subsequently cells emigrate from the caudal hindbrain, but not in a rostrocaudal sequence. At the time of crest cell emigration, the neural fold morphology varies from a slightly convex, widely open plate (midbrain) to a closed tube (caudal hindbrain). Thus the timing of emigration is related neither to age (as reflected in rostrocaudal levels) nor to morphology of the neural epithelium.     

Utilization of computerized tomography for the determination of the volume of the cranial cavity of the galgo hound

The volumetry of the cranial cavity of 30 galgo hounds (15 males and 15 females) has been studied by computerized axial scanning tomography and biostatistical methods. The serial tomodensitometric sections of heads were 5 mm thick and 5 mm distant, taken in sagittal and transverse planes. Results demonstrate a sexual differentiation, with a security of 99.99%. The discussion turns to zootechnical and osteoarcheological applications.     

Effect of hyaluronidase treatment on the distribution of cranial neural crest cells in the chick embryo

The cranial paraxial mesoblast is patterned into segmental units termed somitomeres. Recently we demonstrated the morphological relationship between the migratory pathways of cranial neural crest cells and the patterned primary mesenchyme of chick embryos (Anderson and Meier, '81). Since extracellular matrix, particularly hyaluronate, is also distributed in cranial crest pathways, embryos were given sub-blastodisc injections of hyaluronidase just prior to neural tube fusion and neural crest migration to remove matrix. Histological sections of enzyme-treated embryos showed that Alcian blue staining of hyaluronate was significantly reduced. Surface ectoderm appeared collapsed on the subjacent mesoderm as well. Examination of embryos with the scanning electron microscope (SEM) revealed that paraxial mesoderm remained segmentally patterned even though it appeared more condensed because of a reduction in intercellular space between mesenchymal cells. In enzyme-treated embryos, the rostral crest cells spread over the dorsal surfaces of the first four somitomeres, as they would do normally. This distribution of neural crest cells occurs even when enzyme treatment interferes with neural tube fusion at that level. We conclude that 1) neural tube fusion is not a prerequisite for the timely release of cranial crest in the chick embryo and 2) that much of the organized hyaluronate-rich matrix that lies in the path of cranial crest is not essential for crest emigration or patterned distribution.     

Studies on the frequency distribution of Pythium-induced cavity spot of carrots

Data on Pythium-induced cavity spot from experimental plots and commercial fields were collated to study the frequency distribution of cavities on carrots. It was shown that cavities tended to occur in clusters with strong evidence that they followed a Polya-Aeppli distribution rather than the Negative Binomial distribution often associated with clustering. Possible biological interpretations of the Polya-Aeppli distribution are discussed, also their implications for estimation of inoculum potential and analysis of cavity spot field trials.     

健康人群口腔酵母菌的分离及菌种分布

目的调查健康人群口腔酵母菌的分布。方法将来源于健康人的口腔拭子接种于改良SDA培养基,37℃培养14d,分到的酵母菌通过菌落形态、革兰染色作初步鉴定．芽管形成试验、厚膜孢子生成及假菌丝产生试验、YBC酵母鉴定卡作菌种鉴定。结果酵母菌在健康人口腔中总分离率为8．78％(86／979),其中较多的为白色假丝酵母菌37株,占43．02％,近平滑假丝酵母菌和季也蒙假丝酵母菌各9株,各占10．47％,葡萄牙假丝酵母菌6株,占6．98％,其他25株。结论健康人口腔中有多种条件致病酵母菌的寄生。     

小鼠腹腔内腺病毒介导的基因表达和分布

本文报道了重组腺病毒－带有报道基因ｌａｃＺ的Ａｄ／ＲＳＶ－β－ｇａｌ注入小鼠腹腔后,在胃、小肠、大肠、等均出现被Ｘ－ｇａｌ染色蓝色的细胞,腹膜下面未见染色细胞。结果表明重组腺病毒可广泛感染腹腔内的组织并使外源基因表达,但不扩散出体腔。     

Pressure distribution over the palm region during forward falls on the outstretched hands

Falls on the outstretched hands are the cause of over 90% of wrist fractures, yet little is known about bone loading during this event. We tested how the magnitude and distribution of pressure over the palm region during a forward fall is affected by foam padding (simulating a glove) and arm configuration, and by the faller's body mass index (BMI) and thickness of soft tissues over the palm region. Thirteen young women with high (n=7) or low (n=6) BMI participated in a "torso release experiment" that simulated falling on both outstretched hands with the arm inclined either at 20° or 40° from the vertical. Trials were acquired with and without a 5 mm thick foam pad secured to the palm. Outcome variables were the magnitude and location of peak pressure (d, θ) with respect to the scaphoid, total impact force, and integrated force applied to three concentric areas, including "danger zone" of 2.5 cm radius centered at the scaphoid. Soft tissue thickness over the palm was measured by ultrasound. The 5mm foam pad reduced peak pressure, and peak force to the danger zone, by 83% and 13%, respectively. Peak pressure was 77% higher in high BMI when compared with low BMI participants. Soft tissue thickness over the palm correlated positively with distance (d) (R=0.79, p=0.001) and force applied outside the danger zone (R=0.76, p=0.002), but did not correlate with BMI (R=0.43, p=0.14). The location of peak pressure was shunted 4 mm further from the scaphoid at 20° than that of 40° falls (d=25 mm (SD 8), θ=-9° (SD 17) in the 20° falls versus d=21 mm (SD 8), θ=-5° (SD 24) in the 40° falls). Peak force to the entire palm was 11% greater in 20° compared with 40° falls. These results indicate that even a 5 mm thick foam layer protects against wrist injury, by attenuating peak pressure over the palm during forward falls. Increased soft tissue thickness shunts force away from the scaphoid. However, soft tissue thickness is not predicted by BMI, and peak pressures are greater in high individuals than that of low BMI individuals. These results contribute to our understanding of the mechanics and prevention of wrist and hand injuries during falls.     

Trematode metacercariae from the cranial cavity of African catfish Clarias gariepinus (Burchell, 1822) from Lake Tana,Ethiopia

Metacercariae of two species of trematodes from the fam. Diplostomidae from the cranial cavity of the African catfish Clarias gariepinus are described. The metacercaria Tylodelphys grandis n. sp. is described for the first time. Data are presented on the infection rate of catfishes in Lake Tana.     

Developments in cranial morphometrics

This paper sets out to describe a number of traditional and novel approaches to craniometry. These include linear and angular measurements, indices, shape factors, least squares, and Fourier analysis. A study is presented in which these different techniques are applied to a phenetic analysis of the crania of a variety of living and extinct hominoids, with the aim of assessing the relative merits of different approaches. The results allow an appraisal of the stability of phenetic groupings in the face of different data and suggest that the choice of data can considerably influence the observed pattern of between-group relationships. The choice of craniometric method should be made with due regard for the questions at hand and the interpretation of phenetic relationships should allow for the particular data.     

Anatomical structure and surface epithelial distribution in the nasal cavity of the common cotton-eared marmoset (Callithrix jacchus).

To validate use of the common cotton-eared marmoset (Callithrix jacchus) in inhalation toxicity studies, its nasal morphology was examined. The nasal turbinates each consisted of one maxilloturbinate and one ethmoturbinate: these were more planar in structure than the comparable structures of rodents or dogs. The nasal cavity epithelia comprised squamous epithelium (SE), nasal transitional epithelium (NTE), respiratory epithelium (RE) and olfactory epithelium (OE), listed in order of occurrence from anterior to posterior positions. NTE was distributed as a narrow band lying between SE and RE. OE was limited to the dorsal part of the cavity, which was structurally similar to that of the macaque or man. Overall, this study revealed structural the similarity of the whole nasal cavity in the marmoset to that of macaques or humans. Prediction of nasal cavity changes in man based on extrapolation from experimentally induced changes in the common marmoset therefore seems likely to be feasible, making it a useful animal model for inhalation studies.     

Effects of annular cranial vault modification on the cranial base and face

Artificial modification of the cranial vault was practiced by a number of prehistoric and protohistoric populations, frequently during an infant's first year of life. We test the hypothesis that, in addition to its direct effects on the cranial vault, annular cranial vault modification has a significant indirect effect on cranial base and facial morphology. Two skeletal series from the Pacific Northwest Coast, which include both nonmodified and modified crania, were used: the Kwakiutl (62 nonmodified, 45 modified) and Nootka (28 nonmodified, 20 modified). Three-dimensional coordinates of 53 landmarks were obtained using a diagraph, and 36 landmarks were used to define nine finite elements in the cranial vault, cranial base, and face. Finite element scaling was used to compare average nonmodified and average modified crania, and the significance of the results were evaluated using a bootstrap test. Annular modification of the cranial vault produces significant effects on the morphology of the cranial base and face. Annular modification in the Kwakiutl resulted in restrictions of the cranial vault in the medial-lateral and superior-inferior dimensions and an increase in anterior-posterior growth. Similar dimensional changes are observed in the cranial base. The Kwakiutl face is increased anterior-posteriorly and reduced anterior-laterally to posterior-medially. Similar effects of modification are observed in the Nootka cranial vault and cranial base, though not in the face. These results demonstrate the developmental interdependence of the cranial vault, cranial base, and face. © 1993 Wiley-Liss, Inc.