M2 Stage Research Articles

Early Detection of Delayed Myelination in Preterm Infants

Myelination of the central nervous system can be demonstrated with magnetic resonance imaging. The influence of periventricular-intraventricular hemorrhage and periventricular leukomalacia on cerebral myelination was studied using magnetic resonance imaging. The subjects were 33 preterm infants of less than 30 weeks' gestation studied at 44 weeks' postmenstrual age: 11 infants with periventricular-intraventricular hemorrhage, 7 with periventricular leukomalacia, and 15 without periventricular-intraventricular hemorrhage or periventricular leukomalacia. There were no differences in mean gestational age and birth weight between the three groups. However, infants without periventricular-intraventricular hemorrhage or periventricular leukomalacia had significantly less respiratory distress syndrome. At 44 weeks postmenstrual age, infants with periventricular leukomalacia had a significantly delayed myelination pattern (stage M2) in comparison with infants without periventricular-intraventricular hemorrhage or periventricular leukomalacia and infants with periventricular-intraventricular hemorrhage (stages M3 and M4). The latter two groups had myelination stages that were similar to those of healthy term infants at 44 weeks' postmenstrual age. The results demonstrate that periventricular leukomalacia causes delayed myelination of the cerebrum, whereas periventricular-intraventricular hemorrhage does not.

Ethidium bromide (EB) induced mutants in gingelly (Sesamum indicum L.) cultivar ‘Vinayak’

One eight-loculed mutant was isolated from Sesamum indicum L. cv. 'Vinayak' in the M2 stage using 0.05% ethidium bromide. The breeding behaviour of this mutant was followed up to M6 through selfing and reciprocal crosses with a control. The nutritional value of this mutant was assayed in terms of oil, protein, PUFA and a-globulin content. Two variants from this mutant could be distinguished: one with a monostem (in M3) (Fig. 2) and another with a broad and flat stem (in M~) (Fig. 3). Supernumerary floral parts (Fig. 5) and vivipary (Fig. 4) were also recorded. Chemical induced mutants o f a similar range have been reported by earlier workers in gingelly and other crops (ZiaUlthasam 1987, in gingelly; Kamala and Nagamani 1980, in Brassica; Mallikarjuna Radhaya and Channabyregowda 1981, in safflower). The mutant could be stabilised for 8 locules by the M6 stage through selfing although some 6 loculed plants also occured as segregants up to IVI4. Progenies from the six and eight loculed plants showed segregations o f 1 : 5 and 1 : 11, respectively of the two types in M3 and M4 but the latter showed stabilised behaviour from M5 onwards. Reciprocal crosses of six and eight loculed plants with the 4 loculed control showed a lack of any maternal influence. Capsules with up to 24 locules were also occasionally observed (Fig. 6, 6a) although unstable. These results suggest the influence of modifying factors on the number o f locules as against the single recessive inheritance o f the 8 loculed condition recorded earlier (Kumar and Rao 1945). Increase in the number of floral parts and locules, and broad and flat stems can also be accounted for by the Chemical induced fasciation or somatic mutations (White 1945). Supression or inhibition of the lateral growing points result in monostems and removal or deactivation of inhibitors present in the seed or in associated structures (Baburao and Bhalla 1979). Unfavourable action of rains or humidity (Reddy and Rao 1977) results in vivipary. Seed yield per plant and the nutritional value of the seed and of the seed oil of the 8 loculed mutant showed a significant improvement in the present project. Yield, level of important fatty acids as oleic and linoleic (Table 1), and the a-globulin fraction registered a

Junctional complexes in the inner cyst tissue of the cysticercoid of Hymenolepis diminuta (Cestoda).

The inner cyst tissue development is anteriad and centripetal. The cells produce lamellar extensions which assume parallel alignment. The first contact points (approximately 4 days post-infection) establish heptalaminar (gap) junctions. Lamellar attenuation results in a decreased intercellular space, and at 5-6 days pentalaminar junctions (with fused outer plasmalemma leaflets to give an electron-dense, approximately 3 nm wide O-O line) occur. This is the first maturation (M1) stage. The O-O lines are permeable to lanthanum, and evidence of their possible transformation from heptalaminar junctions is presented. Continued lamellar attenuation, associated with scolex retraction and subsequent growth, results in cytoplasmic occlusion and contact between the inner leaflets of the same lamella. The resultant electron-dense I-I line is approximately 3 nm wide; the O-O line is now less electron-dense and thinner (approximately 2 nm). This final maturation (M2) stage, resembling vertebrate myelin, occurs over limited areas; closely adjacent regions either remaining at the M1 stage, or not displaying junctional complexes. Since in vivo and in vitro excystment can occur before the M2 stage, the inner cyst tissue is not considered to be protective against the definitive host. That the tissue may function in limiting nutrient flow, thus regulating the size of the presumptive adult, is discussed.

Cellular aggregates in bone marrow cultures of patients with acute myeloid leukemia.

We describe the incidence and morphology of cellular aggregates which may develop in 8 day bone marrow (BM) cultures of patients with acute myeloid leukemia (AML). Aggregates formed in at least one BM culture from 50% (20/39) of the AML group. They developed irrespective of the patient's status (i.e. stages M1-M4), FAB type, and presence of colony stimulating factor (CSF). All aggregates were composed of macrophages, plasma cells, and cells of the myelocyte series surrounding a core of adipocytes and collagen fibrils. The percentage of blasts and promyelocytes in the plated BM aspirate governed the final composition of the aggregate. Patients in Stages M3 or M4 with FAB types M1 or M2 formed aggregates with a high proportion of myelocytic cells; aggregates of all other AML patients were composed predominantly of macrophages and plasmacytes. Aggregates appeared to form as a result of attraction of cells in the medium toward the stroma cell core. Furthermore, the development of aggregates in the absence of exogenous CSF, suggested that stromal cells excreted a factor with CSF-like activity. The results indicate that cellular aggregates in AML-BM cultures reflect the important role of BM stroma in creating microenvironments which enhance the development of hemopoietic stem cells.

Observations écologiques sur le Néotrague de Bates (Neotragus batesi du Nord-Est du Gabon

Bates’s Pygmy Antelope Neotragus batesi was studied for 15 consecutive months in North East Gabon. Fourteen animals were individually marked and six of them (5 ♀ ♀ and 1 ♂) monitored by radio-tracking. During the same period, 128 specimens were collected outside the study area, to examine the stages of growth of their jugal teeth, tooth wear and reproductive condition. Four age-categories can be recognized among young animals, and five among adults. In the mature rain forest Neotragus batesi is commonly found in tree falls and along riversides. It thrives in secondary growth vegetation and native plantations where it reaches its highest population densities. Both its morphology and habits are well adapted to locomotion through dense undergrowth. Bates’s Pigmy Antelope is active by day as well as by night, with peaks in the morning and the evening. It rests in the middle of the day, and in the beginning and middle of the night. The home ranges are small (1 to 3 ha for females ; 2 to 4 ha for males). This area is not used evenly throughout the year ; the core-area of the range changes in keeping with the seasons. Furthermore, every home range includes areas which are used only by day and others which are visited only by night, vegetation structure differing accordingly. The more regularly tended native plantations are those which produce the most food for Neotragus batesi, but periodical clearing of the undergrowth also disturbs the animals. Bates’s Pygmy Antelope has therefore to make use of both well managed native plantations and neglected ones or secondary growth to ensure its food supply and shelter. About 200 species of plants are eaten by Neotragus batesi in N.E. Gabon. Usually this pigmy antelope makes use of a given area when its plant food is most readily available, thus quickly adapting to new situations. Some of the most actively sought plant species, however, may definitely be scarce. On the whole this animal tends to browse upon the most nutritious parts of the plants it selects. Bates’s Pigmy Antelope is a solitary animal ; 76 % of the individuals encountered were alone. More than one female can share a single home range, whereas males never do so. Interindividual communication is mostly achieved through short groans (between a young animal and its mother, or between adult males and females), and through olfactory marking by the secretion of males’ anteorbital glands. Females do not display any territorial behaviour, whereas males might do so. Males are apparently polygamous, their large home ranges overlapping those of several females. Females give birth throughout the year, with peaks at the end of each of the two rainy seasons. In this way the young animals are weaned at a time when fresh grass is readily available. Mortality rate among males apparently increases at the M² stage, when the young leave their mothers’ ranges, and also among the oldest adults. Among females mortality seems to be the highest amongst subadults, at the onset of the reproductive period. Females, as usual, outlive males. Competition with sympatric ungulates is avoided by differences in size, a protracted activity rythm, and a strictly folivorous diet.

On the Occurrence of Palaeoloxodon naumanni (MAKIYAMA) from Kamibessho, Sakura-shi, Chiba Prefecture, Central Japan

In 1973, fossil elephant bones were yielded from the sandy formation, at Kamibessho, Sakura-shi, Chiba Prefecture, Kwanto Regeon of Central Japan.The formation, belonging to the lower part of Narita Formation also yielded many other molluscan fossils characterized by Glycymeris yessoensis, Diplodonta usta etc. The molluscan assemblage is closely related to that of Kamiiwahashi fossil beds of Narita Formation in other area except for a few remarkable characteristics, that is; containing less number of the genera than the other Kamiiwahashi beds and being found in thin fossil beds.The fossil materials of the elephant include a lower jaw with the left second molar in situ, and a right tusk separated into three pieces. The mandible is rather large as P. naumanni of M2 stage and the shape of it generally resembles to the holotype of P. naumanni. The features observed on the grinded tooth indicate that the materials belong to the molar of P. naumanni, which is steno-crown type with distinct loxodont plica. The incisor is more thick and stout, suggesting that it belongs to male individual.

Geology of the Kwanto Area, with an Introduction to Exploration and Developmet of Its Natural Gas Deposits

Judging from the complicated structures of the pre-Miocene rocks, they are treated as the basement rocks. The Yorii conglomerate, which has been generally considered to be an Aquitanian formation, must be correlated with the Cretaceous Atokura formation, and then, it is a member of the basement rocks. The Miocene formations of this area are time-stratigraphically divided into four stages, that is, M1, M2, M3 and M, from lower to upper. The M1a stage is subdivided into two substages, M1a (lower) and M1b (upper). The rocks of M1a substage are characterized by molluscan and foraminiferal faunas, which contain proper Miocene and survived Oligocene elements, and Aniai flora. On the other hand, the rocks of M1b substage are characterized by the first occurrence of the Lepidocyclina-Miogypsina fauna and Daijima flora, and the Oligocene elemens of Mollusca and Foraminifera are rare in these rocks. The rocks of M2 stage are characterized by the Kadonosawa and Shirikonai molluscan faunas -of proper Micene type, and some of these contain Lepidocyclina, Miogypsina, Desnzostylus and Cornwallius. The rocks of M3 stage are also characterized by the Kadonosawa molluscan fauna, but Lepidocyclina has not been found in these rocks. The lowermost horizon of this stage is marked by the Miogypsina-Operculina fauna and pyroclastic rocks. The rocks of M4 stage are characterized by the Higashi-Tanagura and Zushi molluscan faunas. These faunas contain both Miocene and Pliocene elements. Globigerina nepenthes has been found in some rocks of this stage. Judging from Kasukabe GS-1, a stratigraphic well, the Kazusa group in the middle part of the Kwanto plain area contains two sedimentary cycles corresponding to lower and middle parts of this group in the type area. In the northern part of the Kwanto plain area, the Kazusa group contains only one cycle, that is, the upper cycle in Kasukabe GS-1. In this well, the Pleistocene formation between Kazusa group and Alluvium is very thick, but this formation is considered to represent only one inter-glacial age, that is, Mindel-Riss. In the Kwanto area, six diastrophic phases since middle Tertiary have been recognized by the writers. Of these phases, the Kadono, Fuji-Yoshida, Higashi-Matsuyama and Kurotaki phases correspond respectively to Savian, old Styrian, new Styrian and Rhodanic phases in Europe. The ages of remaining two phases, that is, Minami-Tama and Kasukabe, are middle Pliocene and Mindel-Riss inter-glacial age respectively. The distribution of sea and land in this area had been largely changed by the crustal deformation of the Higashi-Matsuyama phase. In the Kwanto area, all developed gas reservoirs except those of Mobara type belong to normal dissolved-in-water type. Permeability of reservoirs is generally lower than that in the Niigata gas-field, and then, the wells of large diameter are not always favourable for the southern Kwanto gas-producing region. In the Mobara type gas deposits, gas-water ratio rapidly increases with the progress of devel-opment. Development methods suitable to natural condition are especially important in case of Mobara type gas deposits. It is also very important to clarify the extension of reservoirs of this type. On the other hand, detailed gravimetric survey and facies studies are effective for exploration of the normal dissolved-in-water type gas deposits. As to Miocene formations, we cannot expect too much of free gas pools in the region except the area of thick lower and middle Miocene deposits.

Aspetti del secreto vaginale in ♀♀ gravide di topo domestico

Summary In the house mouse the histological picture of the vaginal secret during the two first weeks of pregnancy is very similar to the Allen's M2 stage (Mctaocstrus II). In all the studied individuals the macroscopic aspect of the vaginal fluid shows a quite peculiar character, as a result of the started pregnancy.