3D turbo spin-echo sequence with motion-sensitized driven-equilibrium preparation for detection of brain metastases on 3T MR imaging

BACKGROUND AND PURPOSE

MSDE preparation is a technique for black-blood imaging. Our purpose was to evaluate the usefulness of a 3D TSE sequence with MSDE preparation in detecting brain metastases by comparing it with conventional sequences.

MATERIALS AND METHODS

Postcontrast images of 227 patients who were suspected of having brain metastasis were prospectively obtained by using 3 T1-weighted 3D sequences: a gradient-echo sequence (MPRAGE), TSE-noMSDE, and TSE-MSDE. The number of visualized blood vessels and the lesion-to-normal CNR were compared among the 3 sequences. An observer test involving 9 radiologists was performed, and their diagnostic performance by using TSE-MSDE, MPRAGE, and combined TSE-MSDE and MPRAGE was compared by means of an FOM as an index of diagnostic performance derived by the JAFROC analysis, sensitivity, FP/case, and reading time.

RESULTS

TSE-MSDE resulted in significantly better vessel suppression than the other 2 methods. TSE with and without MSDE resulted in significantly higher CNRs than MPRAGE. In the observer test, significantly higher sensitivity and FOM as well as significantly shorter reading time were achieved by TSE-MSDE compared with MPRAGE, but FP/case was significantly higher with TSE-MSDE. Combined TSE-MSDE/MPRAGE resulted in significantly higher sensitivity and FOM and similar FP/case and reading time compared with MPRAGE alone.

CONCLUSIONS

With blood vessel suppression and increased CNR, TSE-MSDE improves radiologists' performances in detecting brain metastases compared with MPRAGE, but it may increase FP results. Combined with MPRAGE, TSE-MSDE achieves high diagnostic performance while maintaining a low FP rate.

Diagnosis of Alzheimer's Disease: Two MRI-Based Approaches

Imaging has been increasingly recognized as a powerful tool for diagnosing Alzheimer's disease (AD). Magnetic resonance imaging (MRI) is advantageous over other imaging modalities due to its non-invasiveness and multi-parametric capabilities. In addition to the morphological assessment, several new MR imaging approaches have shown potential for improved AD diagnosis. This paper focuses on two of these advanced MRI-based approaches: diffusion-weighted imaging and arterial spin labeling.

Simultaneous measurement of arterial transit time, arterial blood volume, and cerebral blood flow using arterial spin-labeling in patients with Alzheimer disease

BACKGROUND AND PURPOSE

Cerebral hemodynamics abnormality in Alzheimer disease (AD) is not fully understood. Our aim was to determine whether regional hypoperfusion due to AD is associated with abnormalities in regional arterial blood volume (rABV) and regional arterial transit time (rATT) as measured by quantitative arterial spin-labeling (ASL) with multiple-delay time sampling.

MATERIALS AND METHODS

Nineteen patients with AD (9 men and 10 women; mean age, 74.5 +/- 8.6 years) and 22 cognitively healthy control subjects (11 men and 11 women; mean age, 72.8 +/- 6.8 years) were studied by using a quantitative ASL method with multiple-delay time sampling. From the ASL data, maps of regional cerebral blood flow (rCBF), rABV, and rATT were generated. A region of hypoperfusion due to AD was determined by statistical parametric mapping (SPM) analysis. Mean rCBF, rABV, and rATT values within the hypoperfused region were compared between the AD and control groups.

RESULTS

Despite the significantly lower rCBF (P = .0004) in patients with AD (27.8 +/- 7.1 mL/100 g/min) in comparison with control subjects (36.7 +/- 6.3 mL/100 g/min), no significant difference in rATT was observed between the control (0.48 +/- 0.09 seconds) and AD (0.47 +/- 0.10 seconds) groups. Mean rABV was lower in the AD group (0.22 +/- 0.10%) than in the control group (0.27 +/- 0.12%), though the difference did not reach the level of statistical significance.

CONCLUSIONS

Our results revealed that regional hypoperfusion in AD is not associated with rATT prolongation, suggesting that the mechanism of hypoperfusion is distinct from that in cerebrovascular diseases.

Perfusion imaging of brain tumors using arterial spin-labeling: correlation with histopathologic vascular density

BACKGROUND AND PURPOSE

We investigated the relationship between tumor blood-flow measurement based on perfusion imaging by arterial spin-labeling (ASL-PI) and histopathologic findings in brain tumors.

MATERIALS AND METHODS

We used ASL-PI to examine 35 patients with brain tumors, including 11 gliomas, 9 meningiomas, 9 schwannomas, 1 diffuse large B-cell lymphoma, 4 hemangioblastomas, and 1 metastatic brain tumor. As an index of tumor perfusion, the relative signal intensity (SI) of each tumor (%Signal intensity) was determined as a percentage of the maximal SI within the tumor per averaged SI within normal cerebral gray matter on ASL-PI. Relative vascular attenuation (%Vessel) was determined as the total microvessel area per the entire tissue area on CD-34-immunostained histopathologic specimens. MIB1 indices of gliomas were also calculated. The differences in %Signal intensity among different histopathologic types and between high- and low-grade gliomas were compared. In addition, the correlations between %Signal intensity and %Vessel or MIB1 index were evaluated in gliomas.

RESULTS

Statistically significant differences in %Signal intensity were observed between hemangioblastomas versus gliomas (P < .005), meningiomas (P < .05), and schwannomas (P < .005). Among gliomas, %Signal intensity was significantly higher for high-grade than for low-grade tumors (P < .05). Correlation analyses revealed significant positive correlations between %Signal intensity and %Vessel in 35 patients, including all 6 histopathologic types (rs = 0.782, P < .00005) and in gliomas (rs = 0.773, P < .05). In addition, in gliomas, %Signal intensity and MIB1 index were significantly positively correlated (rs = 0.700, P < .05).

CONCLUSION

ASL-PI may predict histopathologic vascular densities of brain tumors and may be useful in distinguishing between high- and low-grade gliomas and in differentiating hemangioblastomas from other brain tumors.

Risk evaluation for staphylococcal food poisoning in processed milk produced with skim milk powder

The growth of S. aureus and the production of staphylococcal enterotoxin A (SEA) in skim milk concentrates stored at inappropriate temperatures in a recovery milk tank (tank for excess concentrated skim milk) used in the manufacture of skimmed milk powder were investigated. Also, it was estimated if a possible outbreak of food poisoning would occur if the contaminated skimmed milk powder was used in the manufacture of processed milk. Skim milk concentrates with milk solid content of 15, 25, and 35% were inoculated with S. aureus at 1-2 log CFU/ml and incubated at 15, 25, or 35 degrees C for 0 to 24 h with or without shaking. Bacterial growth and the level of SEA production were measured. At 35 degrees C with shaking, there was a significant difference (p<0.05) in one way layout analysis of variance, and it was demonstrated that the growth of S. aureus and SEA production could be milk solid content-dependent. Shaking accelerated the growth of S. aureus and SEA production at 35 degrees C. Generally, skim milk powder is produced by mixing a set percentage of skim milk concentrates (recovery milk) from the recovery milk tank into raw milk. If recovery milk contaminated with S. aureus at levels of 1-2 log CFU/ml is kept at 15 to 35 degrees C due to a power failure, it was estimated that processed milk consumption of 670-1200 ml, 420-1500 ml and 18-83 ml would trigger the onset of food poisoning symptoms when skim milk concentrates (recovery milk) are stored at 25 degrees C for 24 h, 35 degrees C for 10 h, and 35 degrees C for 24 h, respectively, during the production of the skim milk powder. Based on these consumption levels, it was concluded that, if recovery milk cannot be refrigerated and is stored at room temperature (25 to 35 degrees C), it must be used within 8 h and preferably within 6 h.

Comparison between ultrafiltration and trichloroacetic acid precipitation method for concentration of Staphylococcus aureus enterotoxin in dairy samples

Staphylococcus aureus enterotoxin that may be contained at low concentrations in milk and dairy products can cause food poisoning. To detect this enterotoxin at low concentrations, samples should be concentrated. We evaluated the performance of centrifugal ultrafiltration method (UF) in comparison with trichloroacetic acid precipitation method (TCA) for the concentration of S. aureus enterotoxin in milk and dairy products. S. aureus enterotoxin A (SEA) were added at various concentrations to ultra high-temperature heating process (UHT) milk, UHT concentrated skim milk, UHT skim milk powder, low heat-treated (LH) skim milk powder, and raw milk. SEA was concentrated by TCA and UF once a day on a total of 3 days by different researchers to prepare test solutions. The fluorescence value (TV) of test solutions was determined using an immunofluorescence autoanalyzer (miniVIDAS), and the linearity and slope of the regression line, relative standard deviation (RSD(RW)) at each added concentration, detection limit (DL), quantification limit (QL), and the recovery rate by each concentration method were obtained according to the guidelines of the International Conference on Harmonization (ICH). The slope of the regression line obtained by UF was steeper than that by TCA for all dairy samples excluding LH (74 degrees C, 20 s) skim milk powder. RSDRW, DL, and QL obtained by UF were comparable to or more excellent than those obtained by TCA. The procedure of UF was simpler than that of TCA. The recovery rate and rapidity were similar between the two methods. The DL and QL of enterotoxins other than SEA in dairy products by UF or TCA were estimated based on the DL and QL of SEA. In this estimation, consideration was given to reactions between each enterotoxin and its antibody, and also to the immunoactivity maintenance rate of each enterotoxin after addition of trichloroacetic acid in TCA. The estimated values were similar to those obtained by experiments using enterotoxin C1 (SEC1). UF using a centrifugal ultrafiltration membrane can be more readily performed and similar to or more reliable than TCA. UF combined with a miniVIDAS can be used for quantitative routine analysis.

Rapid determination of bovine lactoferrin in dairy products by an automated quantitative agglutination assay based on latex beads coated with F(ab )2fragments

This study evaluated an automated immunoassay for bovine lactoferrin (LF) in dairy products based on latex beads coated with F(ab')2 fragments.

METHODS

F(ab')2 fragments were obtained by pepsin digestion of rabbit anti-bovine LF (IgG fraction) and polystyrene latex beads were coated with the F(ab')2 fragments. We used the beads to develop a rapid and homogeneous light scatter immunoassay employing an autoanalyzer (the Automated Latex assay). The Automated Latex assay was easy to perform and could rapidly determine bovine lactoferrin in lactoferrin-supplemented products. It was sensitive enough for testing products and showed good precision.

Gluteal muscular and sciatic nerve metastases in advanced urinary bladder carcinoma: case report

We present a case of gluteal muscular and sciatic nerve metastases from urinary bladder carcinoma. T2-weighted magnetic resonance images demonstrated diffuse swelling and an increase in the signal of the right gluteus maximus muscle without destruction of the original arrangement of muscular fibers. Further, remarkable thickening of the right sciatic nerve showing a relatively hypointense signal was detected. Postcontrast T1-weighted images showed strong enhancement of these structures. Fine-needle aspiration biopsy with ultrasonographic guidance confirmed metastatic carcinoma cells in the right gluteal muscle and the sciatic nerve. These radiologic findings may represent a rare pattern of metastasis from urinary bladder carcinoma.

Differences in recombination frequencies during female and male meioses of the sex chromosomes of the medaka, Oryzias latipes

In the medaka, Oryzias latipes, sex is determined chromosomally. The sex chromosomes differ from those of mammals in that the X and Y chromosomes are highly homologous. Using backcross panels for linkage analysis, we mapped 21 sequence tagged site (STS) markers on the sex chromosomes (linkage group 1). The genetic map of the sex chromosome was established using male and female meioses. The genetic length of the sex chromosome was shorter in male than in female meioses. The region where male recombination is suppressed is the region close to the sex-determining gene y, while female recombination was suppressed in both the telomeric regions. The restriction in recombination does not occur uniformly on the sex chromosome, as the genetic map distances of the markers are not proportional in male and female recombination. Thus, this observation seems to support the hypothesis that the heterogeneous sex chromosomes were derived from suppression of recombination between autosomal chromosomes. In two of the markers, Yc-2 and Casp6, which were expressed sequence-tagged (EST) sites, polymorphisms of both X and Y chromosomes were detected. The alleles of the X and Y chromosomes were also detected in O. curvinotus, a species related to the medaka. These markers could be used for genotyping the sex chromosomes in the medaka and other species, and could be used in other studies on sex chromosomes.

Characterization of the cathepsin B-like proteinases of Trichomonas tenax ATCC 30207

An oral parasite Trichomonas tenax ATCC 30207 synthesizes and secretes various proteinases. By gelatin-SDS-PAGE, we found five proteinases bands (30, 37, 46, 51 and 60 kDa) in cell lysate and four bands (37, 45, 52 and 60 kDa) in culture filtrate. The proteinases hydrolyzed acid soluble type I collagen as well as gelatin. The enzymes were suggested to possess typical characteristics of cysteine proteinases based on the patterns of inhibition and activation by various factors. Based on relative efficiencies of synthetic substrates, most of them were most likely cathepsin B-like enzymes.

Two distinct hemolysins in Trichomonas tenax ATCC 30207

An oral protist Trichomonas tenax ATCC 30207 was investigated for the ability to lyse erythrocytes of sheep, rabbits, horses and humans. Five fractions, including intact cells, culture supernatant, culture filtrate, cell debris and lipid-enriched fractions, were prepared from the protozoan cells, and their hemolytic activities were assayed under various conditions. All the samples except culture supernatant had hemolytic activities, which were due to two different kinds of hemolysins. One hemolysin was protein-like and mainly found in cell-free fractions: culture supernatant and culture filtrate. It was heat-labile and inhibited by various cysteine-proteinase inhibitors. The other hemolysin was lipid-like and found in cell-associated fractions: intact cells, cell-debris and lipid-enriched fractions. It was heat-stable, organic solvent-tolerant and unaffected by various proteinase inhibitors and stimulators. These results suggested that T. tenax ATCC 30207 possessed two distinct hemolysins, protein and lipid.

[Guideline for the treatment of Hansen's disease in Japan]

Ad hoc committee of Japanese Leprosy Association recommends standard treatment protocol of leprosy in Japan, which is a modification of World Health Organization's multidrug therapy (WHO/MDT, 1997). For paucibacillary (PB) leprosy, 6 months treatment by rifampicin and dapsone (MDT/PB) is enough. However, for high bacterial load multibacillary (MB) leprosy, 12 months treatment seems insufficient. Thus, (A) For MB with bacterial index (BI) > or = 3 before treatment, 2 years treatment by rifampicin, dapsone and clofazimine (MDT/MB) is necessary. (A-1) When satisfactory decrease of BI (BI value decrease > or = 2 steps, or final BI < 3) is obtained after completion of 2 years MDT/MB, maintenance therapy by dapsone and clofazimine is recommended until BI negativity and loss of active lesions. (A-2) When BI decrease is not satisfactory (BI value decrease < 2 steps, or final BI > or = 3), MDT/MB should be continued until BI negativity and loss of active lesions. (B) For MB with BI < 3 or fresh MB (less than 6 months after the onset of the disease) with BI > or = 3, 1 year treatment by rifampicin, dapsone and clofazimine (MDT/MB) is necessary. (B-1) When BI become negative and active lesion is lost within one year, no maintenance therapy is necessary. (B-2) When BI is still positive or active lesion is remaining, additional therapy with MDT/MB for one more year is recommended. Brief summary of diagnosis, purpose of therapy, character of drugs, and prevention of deformity is also described.

Structure determination of [Arg8]vasopressin methylenedithioether in dimethylsulfoxide using NMR

The structure of [Arg8]vasopressin methylenedithioether ([AVP]CH2) has been determined in dimethylsulfoxide-d6. Two-dimensional DQF-COSY and NOESY spectra were measured and used to derive angle and distance constraints for restrained molecular dynamics (MD) calculations. In the MD trajectory, two types of beta-turn structure were found in the region from Tyr2 to Asn5, suggesting an equilibrium between type-I and type-II' beta-turn structures. When Halpha chemical shifts were used as an additional constraint, the type-I turn was favoured. To validate this result, an independent energy minimization procedure was used, using differences between calculated and observed chemical shifts. The two approaches gave essentially identical results. It is therefore concluded that the type-I turn predominates in solution. Analysis of calculated chemical shift contributions suggests that the beta-turn structure found in AVP is well preserved in [AVP]CH2, although the pressin ring size is expanded.

Plasmodium falciparum-infected erythrocytes: qualitative and quantitative analyses of parasite-induced knobs by atomic force microscopy

We used the combination of an atomic force microscope and a light microscope equipped with epifluorescence to serially image Plasmodium falciparum-infected erythrocytes. This procedure allowed us to determine unambiguously the presence and developmental stage of the malaria parasite as well as the number and size of knobs in singly, doubly, and triply infected erythrocytes. Knobs are not present during the ring stage of a malaria infection but a lesion resulting from invasion by a merozoite is clearly visible on the erythrocyte surface. This lesion is visible into the late trophozoite stage of infection. Knobs begin to form during the early trophozoite stage of infection and have a single-unit structure. Our data suggest the possibility that a two-unit structure of knobs, which was reported by Aikawa et al. (1996, Exp. Parasitol. 84, 339-343) using atomic force microscopy, appears to be a double-tipped image. The number of knobs per unit of host cell surface area is directly proportional to parasite number in both early and late trophozoite stages. These results indicate that knob formation by one parasite does not influence knob formation by other parasites in a multiply infected erythrocyte. In addition, knob volume is not influenced by either parasite stage or number at the late trophozoite stage, indicating that the number of component molecules per knob is constant throughout the parasite maturation process.

The application of the atomic force microscope to studies of medically important protozoan parasites

Both living and fixed specimens of the medically-important parasitic protozoa, Trypanosoma cruzi, Toxoplasma gondii, Giardia lamblia, Entamoeba histolytica, and Acanthamoeba spp. were studied by atomic force microscopy (AFM). The preparation of fixed specimens was similar to methods used for either scanning or transmission electron microscopy. AFM scanning was performed using both contact and tapping modes. A classical fixation procedure utilizing glutaraldehyde followed by ethanol dehydration was not suitable for all parasite species. AFM images could not be obtained from fixed samples of T. cruzi, T. gondii or E. histolytica. However, excellent topographic images could be obtained from specimens of G. lamblia and Acanthamoeba under identical conditions. Critical point drying permitted AFM imaging of both trypomastigote and epimastigote stages of T. cruzi. Phase imaging of T. cruzi elucidated unique surface details at a level of resolution not visible using any other imaging modalities. AFM elasticity map imaging of T. cruzi-infected and T. gondii-infected cells demonstrated that both parasites were markedly firmer than the surrounding host cell cytoplasm. The parasitophorous vacuole surrounding replicating T. gondii tachyzoites was also visualized by elasticity map imaging. These data suggest that although much remains to be learned about preparing parasitic protozoa for AFM imaging, the technique has the potential of providing unique and important insights into these disease causing organisms.

The cell biological application of carbon nanotube probes for atomic force microscopy: comparative studies of malaria-infected erythrocytes

We describe the first cell biological application of carbon nanotube (CN) probes for atomic force microscopy studies. Topographic and phase images were collected from Plasmodium falciparum malaria-infected erythrocytes using both TappingMode Etched Silicon Probes (TESP probe) and CN probes. We estimate that the lateral resolution of a CN probe-generated topographic image is at least four-fold higher than that of the TESP probe. Carbon nanotube probe-generated phase images of P. falciparum-induced knobs on the surface of erythrocytes also show a markedly higher lateral resolution than comparable TESP probe-generate phase images of the same area. We conclude that CN probes are useful for cell biological atomic force microscopy studies and should play an increasingly important role in the future of this evolving discipline.

Phase imaging by atomic force microscopy: analysis of living homoiothermic vertebrate cells

Atomic force microscope-based phase imaging in air is capable of elucidating variations in material properties such as adhesion, friction, and viscoelasticity. However, the interpretation of phase images of specimens in a fluid environment requires clarification. In this report, we systematically analyzed atomic force microscope-derived phase images of mica, glass, and collagen under the same conditions as used for living cells at various tapping forces; the resulting data provide critical information for the interpretation of phase images of living cells. The peripheral regions of COS-1 cells consistently show a more negative phase shift than the glass substrate in phase images at set-point amplitude: free amplitude (Asp/A0) = 0.6-0.8. In addition, at all Asp/A0 values suitable for phase imaging, tapping frequency appears to be high enough to ensure that phase shifts are governed primarily by stiffness. Consequently, phase imaging is capable of high resolution studies of the cellular surface by detecting localized variations in stiffness. We demonstrate that phase imaging of a bifurcating fiber in COS-1 cell cytoplasm is readily capable of a lateral resolution of approximately 30 nm.

Kinetic analysis of the mitotic cycle of living vertebrate cells by atomic force microscopy

The atomic force microscope (AFM) is becoming an important tool for qualitative and quantitative analyses of biological material. However, the difficulties involved in maintaining long-term, steady-state physiologic conditions and the problems associated with analyzing force curves generated from highly viscoelastic biological structures impede the use of the AFM for studies of kinetic processes in living vertebrate cells. In this report, we describe a simple method to track reproducibly kinetic changes in the localized stiffness of vertebrate cells. We tested our method on a study of vertebrate cells in mitosis and found a marked but transient decrease in stiffness occurs in the mitotic spindle region during anaphase. We propose that physical-chemical changes in the mitotic apparatus, most probably, changes in the state of polymerization of interzonal spindle fibers which also have been reported to undergo a marked reduction in birefringence during anaphase, are responsible for the observed decrease in stiffness. Our methodology affords a new approach to studying mitotic events and should be applicable to studies of a variety of viscoelastic properties of living cells.

An integrated approach to the study of living cells by atomic force microscopy

We describe a technique for studying living cells with the atomic force microscope (AFM) in tapping mode using a thermostated, controlled-environment culture system. We also describe the integration of the AFM with bright field, epifluorescence and surface interference microscopy, achieving the highest level of integration for the AFM thus far described. We succeeded in the continuous, longterm imaging of relatively flat but very fragile cytoplasmic regions of COS cells at a lateral resolution of about 70 nm and a vertical resolution of about 3 nm. In addition, we demonstrate the applicability of our technology for continuous force volume imaging of cultured vertebrate cells. The hybrid instrument we describe can be used to collect simultaneously a diverse variety of physical, chemical and morphological data on living vertebrate cells. The integration of light microscopy with AFM and steady-state culture methods for vertebrate cells represents a new approach for studies in cell biology and physiology.

[The authentication of modern Japanese acupuncture]

The Meiji government that modernized Japan decided the direction which adopted western medicine positively and eliminated Oriental medicine, and carried out the policy to inhibit acupuncture (1874). However, there was no concrete system until 1885, when the Ministry of Home Affairs issued a report to entrust the permission and superintendance of acupuncture to each prefecture. On the other hand, modern education for the blind was begun in various parts of the country in 1878, and acupuncture was adopted as a vocational course. The Rakuzenkai Blind School began Anma and acupuncture in 1881, but in 1885 acupuncture was removed from the curriculum and put under the direct control of the Ministry of Education. The principal of the school, Ryokichi Yatabe, had doubts about this and sent a question to Tokyo Imperial University. The answer to it (1887) was to recognize acupuncture, and this recognition became an admission of the revival of acupuncture in the course of blind education and the basis of the thought in legislation for modern Japanese acupuncture. There is a high possibilty that the reply to Yatabe was influenced by the article of Sansaku Okumura (1864-1912), a blind man in Kanazawa City, which appeared in the 157th issue of "Iji Shimbun" (1885).

Structural and functional studies on biliverdin-associated cyanoprotein from the bean bug, Riptortus clavatus

Structural and functional analysis were performed on biliverdin-associated cyanoprotein (CP) from the hemolymph (CP-1 to CP-4) and eggs (CPegg, identical to CP-1) of the bean bug, Riptortus clavatus. Isoelectric focusing analysis of purified CPegg and CP-4 revealed that they are composed of a single alpha subunit and a more acidic beta subunit respectively. N-terminal amino acid sequencing revealed that there are six different amino acid residues between the two subunits up to the 29 cycles determined, indicating that they are encoded by different genes. Appreciable sequence similarities in N-terminal region are found between the CP subunits and several insect hexamers. By chemical cross-linking analysis these CPs were demonstrated to have hexameric structures. Two dimensional peptide mapping revealed that alpha and beta subunits share common structures in part and that CP-2 and CP-3 are hybrid molecules bearing both alpha and beta subunits. From these results the molecular structure of CPs was established as follows: CP-1 (CPegg) = alpha 6; CP-2 = alpha 4 beta 2; CP-3 = alpha 2 beta 4; CP-4 = beta 6. In addition, using 125I-labeled CPegg and CP-4, in vivo incorporation into several tissues was examined during the nymphal-adult development. During the late phase of the 5th instar, CP-4 was sequestered preferentially over CPegg by the fat body, while after emergence both proteins were suggested to be incorporated into the newly-formed cuticle. CPegg was sequestered massively by the developing ovaries whereas no appreciable incorporation of CP-4 was observed.

Formation of hair follicles from a single-cell suspension of embryonic rat skin by a two-step procedure in vitro

A technique for culturing skin was devised whereby hair follicles in a normal state were generated from a single-cell suspension of embryonic rat skin. Dissociated cells obtained by trypsinization of the day-15 embryonic lip were cultured by a two-step procedure in vitro. Reorganization of hair-follicle rudiments was accompanied by reaggregation of the cells during a 24-hour initial culture with rotation, and the rudiments differentiated into hair follicles within a week during subsequent subculture of the cell aggregates by floatation. The light-microscopic features and the size of the follicles were similar to those of day-18 vibrissa follicles during normal development in vivo. Furthermore, the stratification of cells, including subcellular differentiation, and the ultrastructure of the hair follicles generated in vitro were similar to those of normal hair follicles with well-keratinized hair shafts. The present system appears to be a useful model for analytical studies in vitro on the formation of hair follicles and for studies designed to facilitate the transplantation of human hair.

Further characterization of locust low density lipophorin induced by adipokinetic hormone

This study was designed to resolve basic questions concerning the nature of low density lipophorin (LDLp) which is induced by adipokinetic hormone (AKH). For this purpose, lipophorin was fractionated by density gradient ultracentrifugation and each fraction containing lipophorin was analyzed for diacylglycerol and associated apolipophorin-III (apoLp-III). The diacylglycerol content of LDLp fractions increased significantly as the density of the fraction decreased (116 micrograms/100 micrograms protein at a high density to 209 micrograms/100 micrograms protein at a lower density). On the other hand, the content of diacylglycerol in each fraction of HDLp remained almost constant (33 micrograms/100 micrograms protein). It was also found that the number of apoLp-III molecules associated with LDLp increased as the density decreased (from 6.9 mol/mol LDLp to 13.2 mol/mol LDLp). However, electron microscopic observation showed that LDLp particles in each of the fractions were extremely heterogeneous in size with diameters of 29.4 +/- 6.8 nm, 27.1 +/- 5.5 nm, and 26.3 +/- 5.7 nm for low, medium, and high density fraction, respectively. HDLp particles were very homogeneous in size irrespective of the fraction (15.9 +/- 1.5 nm, 15.6 +/- 1.5 nm, and 15.6 +/- 1.3 nm for the respective fractions). A theoretical analysis based on all the experimental data strongly supports the hypothesis that the heterogeneity in the size of LDLp particles does not reflect different densities, but rather, heterogeneity is the result of intermolecular fusion between LDLp particles of the same density.

Ontogenetic transition of wound healing pattern in rat skin occurring at the fetal stage

Full-thickness excisional wounds were made in the dorsal skin of rat fetuses at day 16 and day 18 of gestation. A small patch of skin surrounding the open wound was cut out, mounted on a plastic ring and incubated in an organ culture system. In the presence of serum, the open wound in the day-16 fetal skin closed within three days of culture. During the wound-closure process, no new structures were formed in the wound space, and no conspicuous changes were noted in the histological architecture of the surrounding skin during culture, indicating that the wound closure may result from a centripetal movement of the surrounding skin only. In contrast, the size of the open wound in the day-18 fetal skin remained almost unchanged for one week, but a thin acellular network spread over the wound space within one day of culture. The predominant component of the network was cross-linked fibrin, as disclosed by scanning electron microscopy and sodium dodecylsulfate-polyacrylamide gel electrophoresis followed by immunoblotting. The network served as a scaffold for the ingrowth of fibroblast-like cells. These stage-dependent differences in fetal wound healing were consistent with an in vivo study showing that the day-16 wound was covered with the surrounding skin itself, whereas the day-18 wound was covered with newly formed epidermis and invaded by inflammatory cells. The present investigation strongly indicates the prenatal occurrence of a fetal-to-adult transition in the wound-healing pattern of rat skin.

Structural study of the asparagine-linked oligosaccharides of lipophorin in locusts

The complete structure of oligosaccharides from locust lipophorin was studied. The asparagine-linked oligosaccharides were first liberated from the protein moiety of lipophorin by digestion with almond glycopeptidase (N-oligosaccharide glycopeptidase, EC 3.5.1.52). Two major oligosaccharides (E and F), separated by subsequent thin-layer chromatography, were analyzed by methylation analysis and 1H-NMR. Based on the experimental data, the whole structure of oligosaccharide E was identified as Man alpha 1----2Man alpha 1----6(Man alpha 1----2Man alpha 1----3) Man alpha 1----6(Man alpha 1----2Man alpha 1----2Man alpha 1----3)Man beta 1----4GlcNAc beta 1----4GlcNAc. The data also revealed that oligosaccharide F is identical with oligosaccharide E in the structure, except for one glucose residue that is linked to the nonreducing terminal Man alpha 1----2 residue.