Scanning electron microscopic study of the capillary loops in the dermal papillae. Skin of the hand of the Japanese monkey (Macaca fuscata)

The microvasculature of the skin of the hand of Japanese monkeys was examined by means of scanning electron microscopy of corrosion casts. The vasculature of all areas of the skin of the hand was examined and divided into three structures excluding the nail bed: (1) In the ball of the finger, the typical structure of the capillary loops was studied. Capillary loops were formed out of not just one capillary vessel, but two or three vessels. Each capillary vessel arose and divided into several branches at the papilla, and they became descending limbs. After the loop passed a hairpin turn, the descending limbs were 1.5 times larger than the ascending limbs in the intrapapillary portion, and they became extrapapillary venules. The descending limbs connected with the postcapillary venules in the postpapillary portion and with the horizontal network. The postcapillary venules fused with each other (1-5 loops) to form the primary and secondary venous arcades. (2) In the thenar eminence, the capillary loops were a little lower, and their grooves were wider than in the ball of the finger. The characteristic structure in this area was the interpapillar capillary network. (3) In the lateral side of the finger, the number of capillary loops formed by the arterial capillary network of the subepidermal layer was smaller. The capillary loops here had the lowest height and a simple structure.     

Activation of TIMP-2/progelatinase A complex by stromelysin.

Progelatinase A was purified as a complex with TIMP-2 from the conditioned medium of a human glioblastoma cell line. The TIMP-2/progelatinase complex was resistant to the activation by p-aminophenylmercuric acetic acid (APMA), and showed less than 10% of the activity of the TIMP-2-free active enzyme. When the complex was incubated with stromelysin in the presence of APMA, the 64-kDa progelatinase was effectively converted to the 57-kDa mature enzyme, increasing its gelatinolytic activity about 8-fold. These results suggest that stromelysin is a natural activator of TIMP-2-bound progelatinase A.     

The combined effect of lymphokine activated killer cell and radiation therapy on rat brain tumorin vitro

Thein vitro effect of a combined treatment with lymphokine activated killer (LAK) cell and radiation therapy on rat brain tumor was examined using⁵¹Cr release assay. The tumor cell-line used in this experiment was 9L rat brain tumor derived from a Fischer 344 rat. LAK cells were obtained by culturing rat lymphocytes with recombinant human interleukin 2 for at least 3 days. The cytotoxic activity of the LAK cells was examined by⁵¹Cr release assay. Irradiation was done by exposing the microtiter plate in which the¹⁵Cr labeled 9L cells and LAK cells were cultured to a¹³⁷Cs gamma cell unit. Without irradiation, there was 18% cytotoxicity in the 1:100 tumor-to-LAK cell ratio specimen after 24 hrs cocultivation. However, if 5 Gy of irradiation was given, followed by 12 hrs incubation, the cytotoxicity was enhanced significantly at the same cell ratio (30%). This enhancement effect was the most prominent when the cell ratio was 1:100 and the irradiation dose was 5 Gy. To generate the enhancement effect, an incubation time of over 8 hrs both before and after irradiation was required. The supernatant of the LAK cells showed 19.8% and 11.4% cytotoxicity with and without irradiation, respectively. This result indicates the participation of a cytotoxic factor released from LAK cells.This work is supported in part by grant from Univeristy of Tsukuba Project Research.     

Acute reversible cataract due to nitrocompounds in Japanese quail (Coturnix coturnix japonica)

The present study was designed to examine the usefulness of the Japanese quail as an experimental model of cataractogenic activity. Chemicals, 2, 6-dibromo-4-nitro-phenol (2, 6-D), 2, 4-dinitroanisole (2, 4-DA), and 2, 4-dinitrophenol (2, 4-D; for the positive control), were administered singly through an oral route to 2-week old male Japanese quails to investigate the reversibility of cataracts. A single administration of 2, 4-D (36 and 43 mg/kg) produced reversible cataract in 14 of 16 animals (87.5%). This cataract was seen 1 or 2 hours after treatment and continued for 1 to 12 hours. Treatment with 2, 6-D (20 and 25 mg/kg) and 2, 4-DA (120 and 150 mg/kg) caused cataracts in 7 of 11 (63.6%) and 8 of 8 surviving animals (100%), respectively. Cataracts produced by 2, 6-D and 2, 4-DA, which were observed from 1 and 2 to 4 hours after the treatment, continued for 6 to 15 and 1 to 13 hours, respectively. Mortalities in the 25 mg/kg group of 2, 6-D, 120 mg/kg and 150 mg/kg group of 2, 4-DA were found in 2 of 5 animals, 1 of 5 animals and 5 of 9 animals, respectively. These results indicate that the Japanese quail is useful as an animal model to evaluate toxicity to the eye and cataractogenesis.     

Motility as an intestinal colonization factor for Campylobacter jejuni

The colonization of the intestinal tract of suckling mice by Campylobacter jejuni was examined by orally challenging the mice with a wild-type strain and several nonmotile mutant strains which were isolated after treating the wild-type strain with mutagens. The wild-type strain had colonized the lower portion of the small intestine, the caecum and the colon 2 d after inoculation. Two nonmotile strains, one of which (M8) had lost all the flagellar structure including the filament, the hook and the basal structure, and the other (M1) which had lost only the filament region, were both cleared from the intestinal tract 2 d after challenge. Another nonmotile strain (M14), which had a complete flagellar structure like that of the wild-type strain, did not colonize and was cleared from the intestinal tract like the other nonmotile and nonflagellated strains. One atypically motile strain (M5), which had a shorter flagellar filament than that of the wild-type strain, colonized the intestinal tract only when mice were challenged with a large inoculum. None of the mice challenged with either the wild-type or any of the mutant strains showed signs of illness. We concluded that motility is an important factor in the colonization of the intestinal tract of suckling mice by C. jejuni.     

Visual interneurons in the lobula complex of the fleshfly,Boettcherisca peregrina

Summary The physiology and morphology of visual interneurons in the lobula complex of the fleshfly,Boettcherisca peregrina, were studied using intracellular recordings and intracellular cobalt stainings, respectively. Using responses to movements of a spot of light and on-off stimuli at single positions, we classified the interneurons into five physiological groups ON, OFF, ON-OFF, nondirectional motion sensitive (NDM) and directional motion sensitive (DM) neurons. They could be further divided into four morphological types, depending on the location and extent of their dendrites and terminal branches.     

Analysis of cloned mRNA sequences encoding subfragment 2 and part of subfragment 1 of alpha- and beta-myosin heavy chains of rabbit heart

Two cardiac myosin heavy chain cDNA clones, pMHC alpha 252 and pMHC beta 174, were constructed using rabbit ventricular mRNA isolated from adult thyrotoxic and normal hearts, respectively. The complete DNA sequences of the 2.2- and 1.4-kilobase inserts of pMHC beta 174 and pMHC alpha 252, respectively, were obtained. The 736 amino acids specified by pMHC beta 174 begin 439 (1.3 kilobases) residues from the heavy chain NH2 terminus and include a 400-amino acid segment of subfragment 1 and the entire subfragment 2 region. Clone pMHC alpha 252 encodes 465 amino acids encompassing all of subfragment 2 and a portion of light meromyosin. Comparison of these two clones revealed extensive sequence overlap which included 1107 nucleotides specifying a 369-amino acid segment corresponding to subfragment 2. Within this region 78 (7%) base and 32 (8.7%) amino acid mismatches were noted. These differences were clustered within discrete regions, with the subfragment 1/subfragment 2 junctional region being particularly divergent. Structural differences between pMHC alpha 252 and pMHC beta 174 indicate that these two clones represent two similar but distinct myosin heavy chain genes whose expression is responsible for ventricular myosin heavy chain isoforms alpha and beta, respectively. The derived amino acid sequences of both clones exhibit extensive homology (greater than 81%) with sequences obtained by direct analysis of adult rabbit skeletal muscle myosin heavy chain protein. The sequences corresponding to the subfragment 2 region are consistent with an alpha-helical conformation with a characteristic 7-residue periodicity in the linear distribution of nonpolar amino acids. Conversely, subfragment 1 sequences specified by pMHC beta 174 suggest a folded highly irregular structure.