Age-related decrease of nerve growth factor-like immunoreactivity in the basal forebrain of senescence-accelerated mice

The senescence-accelerated mouse P10 (SAMP10) is a murine model of accelerated senescence characterized by the deterioration of learning and memory with advancing age. In the present study, we examined the distribution of nerve growth factor (NGF) immunohistochemically in SAMP10 mice and its control strain, SAMR1. In both strains, NGF-like immunoreactivity (NGF-IR) was observed in neurons throughout the entire forebrain and in glial cells in a particular location. In aged SAMP10 mice, each layer of the cerebral cortex retained its NGF-IR, although the thickness of the cortical mantle was markedly decreased in comparison with younger animals. There was an age-related decline in NGF-IR in the substantia innominata of SAMP10 mice at the age of 10 months, when compared to 2-month-old SAMP10. These results indicate age-related decrease of NGF in the basal forebrain in SAMP10 mice.

Regulation of ion transport by endothelins in rat colonic mucosa: effects of an ETA antagonist (FR139317) and an ETB agonist (IRL1620)

Rat colonic mucosa contains ETA and ETB receptors with Kd values for endothelin (ET)-1 of 32 and 11 pM and maximal binding capacities of 277 and 181 fmol/mg protein, respectively. In muscle-stripped rat colon without tonic nerve activity in Ussing chambers, the serosal addition of ET-1, ET-3 and IRL1620 inhibited amiloride-sensitive noncoupled Na+ entry and enhanced diphenylamine-2-carboxylate-sensitive Cl- secretion, producing a sustained decrease and a transient increase in the short-circuit current (Isc) and the transepithelial conductance, respectively. EC50 values of ET-1, ET-3 and IRL1620 and the maximal changes in Isc were 2.0, 10.2 and 10.9 nM and -12.7, -7.0 and -7.1 muA/cm2, respectively for the Na+ entry; these values were 50, 220 and 225 nM and +57.3, +47.3 and +21.3 muA/cm2, respectively, for the Cl- secretion. FR139317 (100 nM) inhibited ET-1-induced Na+ and Cl- movements, shifting the concentration-response curves to the right (EC50 = 25 nM and 1 microM, respectively), and inhibited ET-3 (> 100 nM)-induced Cl- movement, decreasing the maximal response to 35%, but it did not inhibit either ET-3-induced Na+ movement nor IRL1620-induced Na+ and Cl- movements. The removal of serosal Ca++ reduced 100 nM ET-1- and IRL1620-evoked changes in Isc by 50% and 70% for the Na+ entry and by 80% and 100% for the Cl- secretion, respectively. Indomethacin (1 microM) also reduced changes in Isc by 30% and 70% for the Cl- secretion but did not affect the Na+ entry. Our results show that ETA and ETB receptors regulate Na+ and Cl- transport by different mechanisms.

Adjuvant chemoimmunotherapy for hepatocellular carcinoma patients. Adriamycin, interleukin-2, and lymphokine-activated killer cells versus adriamycin alone

To determine improved postresection survival in patients with hepatocellular carcinoma, two postoperative protocols were compared: adoptive chemoimmunotherapy versus chemotherapy. Following resection, 24 patients were allocated at random to receive (1) arterial infusion of Adriamycin, recombinant interleukin-2 and lymphokine-activated killer cells or (2) arterial infusion of Adriamycin alone. The spleen was removed at operation and used to prepare lymphokine-activated killer cells. Each group had 12 patients. They were followed until signs of recurrence appeared. The overall survival rates of the patients were 91.7%, 82.9%, and 72.5% at 1, 2, and 3 years, respectively, and slightly higher than would be expected with surgery alone. No statistically significant difference was found between the two groups either in the survival rate (generalized Wilcoxon test, P = .936) or in the cumulative disease free rate (P = .182). However, when patients who had had hepatic resection with negative margin (> or = 1 cm) were separated, the 2-year cumulative disease-free rate in the adoptive chemoimmunotherapy was higher (83.3%, n = 6) than that in chemotherapy (37.5%, n = 8). Toxicity to adoptive chemoimmunotherapy was moderate; no severe side effects were observed. Totally no statistical difference between the two groups was found. Although only one of six patients in adoptive chemoimmunotherapy experienced recurrence after hepatic resection with negative margin, it was not feasible to determine the role of interleukin-2 and lymphokine-activated killer cells. We conclude that the adoptive chemoimmunotherapy in this study is not an ideal adjuvant protocol after hepatic resection.

Femoral peak bone mass and osteoclast number in an animal model of age-related spontaneous osteopenia

BACKGROUND

SAMP6 was developed as a murine model of age-related spontaneous osteopenia characterized by low peak bone mass. A morphometric study of the growing femur in SAMP6 and sex-matched SAMP2 at 10 days to 4 months of age was done to examine the pathogenic process related to osteopenia.

METHODS

Age-related changes in cortical bone thickness, femur score, trabecular bone volume, thickness of epiphyseal growth plate, number of osteoclasts, and osteoclast surface were measured with a computerized image analyzer. Osteoclasts were examined cytomorphometrically after TRAP (tartrate resistant acid phosphatase) staining of the femoral sections.

RESULTS

Cortical bone thickness and femur score increased significantly with age, while trabecular bone volume decreased significantly. Comparing mean values of cortical bone thickness, femur score and trabecular bone volume, we noted significantly lower mean values in SAMP6 than in SAMP2 mice. These significant inter-stain differences first became evident in 20-40-day-old mice, but there was no significant difference in thickness of the epiphyseal growth plate between the two strains. The mean values of the number of osteoclasts per unit bone surface length and of the osteoclast surface in SAMP6 were significantly greater than in age- and sex-matched SAMP2. Histograms of distribution of size of osteoclasts of 40-day-old male mice revealed that larger ones were more frequently seen in SAMP6. Furthermore, the ratio of osteoclasts/TRAP positive cells free in the bone marrow cavity was significantly higher in SAMP6 than in SAMP2.

CONCLUSION

Activated bone resorption may play a role in the osteopenia seen in SAMP6.

Combined V figure-shaped scapular osteocutaneous and latissimus dorsi myocutaneous flap for composite mandibular reconstruction

BACKGROUND

As early as 1981, the scapular crest was reported as a versatile donor site of vascularized bone flap. In our institute, much attention has been paid to applying a compound flap based on the subscapular vascular system for composite mandibular reconstruction.

METHODS

The combined V figure-shaped scapular osteocutaneous and latissimus dorsi myocutaneous flap has been used for primary or secondary reconstruction of the mandible, intraoral mucosa and/or external skin following major ablation of the malignant tumors in seven patients.

RESULTS

There was one total flap failure. Satisfactory results were obtained in the remaining patients.

CONCLUSIONS

The V figure-shaped scapular bone flap supplied by the angular branch provides a long rotation arc of vascular pedicle, a long bony segment of more than 14 cm, and a good contour of mental protuberance. The combination of the scapular osteocutaneous flap with latissimus dorsi myocutaneous flap allows reliable reconstruction of massive and three-dimensional composite mandibular defects.

Mesenteric flap in free jejunal transfers: a versatile technique for head and neck reconstruction

BACKGROUND

The technique of free jejunal transfers has been widely used for pharyngoesophageal reconstruction. However, secondary infectious and fistulous complications may develop in extensive and preoperatively high-dose irradiated cases.

METHODS

A generous jejunomesenteric composite graft was harvested and the mesenterium was effectively applied for head and neck reconstruction.

RESULTS

The mesenteric flap connected with the revascularized jejunum was used as means for obliterating dead space in the head and neck region, as a cover for the cover for the cervical vessels, as a vascularized bolstering for the vascular and enteral anastomoses, or as a vascularized bed for skin grafting when the skin flaps are deficient. Only one small fistula occurred in 10 patients who underwent the mesenteric flap.

CONCLUSIONS

This versatile technique is expected to reduce the incidence of postoperative complications in pharyngoesophageal reconstruction using free jejunal transfers.

Molecular species of phospholipids of interleukin-2-dependent murine cytotoxic T lymphocytes

We reported that phospholipids of interleukin-2 (IL-2)-dependent murine cytotoxic T lymphocytes (CTL) contained high amounts of ether lipids (Biochem. Mol. Biol. Int., 33, 137-146, 1994). In this study, the molecular species of fatty acids at the sn-1 and sn-2 positions were determined. First, phosphatidylcholine mainly consisted of the 1,2-diacyl subclass (78%) in which the major molecular species was 16:0/18:1 (24%). It should be noted that arachidonic acid was abundant in both 1-O-alkyl-2-acyl subclasses in the form of 18:0/20:4 (21%) even though the content of the subclass was low (8%). Second, phosphatidylethanolamine mainly consisted of ether subclasses (93%) and contained a large amount of arachidonic acid in the forms of either 18:0/20:4 (19%) or 16:0/20:4 (10%). Third, phosphatidylinositol, a putative phospholipid involved in transmembrane signal transduction, had a significant amount of arachidonic acid at the sn-2 positions of 1,2-diacyl and 1-O-alkyl-2-acyl subclasses. Fourth, phosphatidylserine, consisting of mostly the 1-O-alkyl-2-acyl subclass (86%), contained arachidonic acid dominantly in the form of 18:0/20:4 (33%). Considering these results, it appears that CTL have the potential to mediate its signal transduction mediated by the bioactive lipids, i.e. arachidonic acid metabolites and the ether lipids.

Development of autoreactivity and changes of T cell repertoire in different strains of aging mice

Physiological changes with increasing age are generally accompanied by disorders of immunity, including autoaggression which can be seen in some syngeneic host-versus-graft reactions provoked when responder and stimulator cells are of different ages. The magnitude of the response, however, varies with the strain of mice. Footpad injection of irradiated spleen cells from 1-year-old, but not from 2-month-old, BALB/c mice (H-2d) into syngeneic young mice evoked popliteal lymph node-swelling, but this was not the case in DBA/2 (H-2d) mice. Therefore, the generation of autoreactivity was thought to be closely related to the change of T cell repertoire with age in the former strain of mice. At around 1 year of age, when only a small reduction in T cell number was observed and when a slight increase in CD8+ T cells in the periphery caused the CD4/CD8 ratio to be lower than in young mice, the proportion of V beta 8+ cells in BALB/c mice started to increase, increasing from 16% in the young to 27% in 2-year-old mice (P < 0.01). On the other hand, V beta 6+ T cells remained at the same level as in young mice throughout life. The increasing fraction of V beta 8+ T cells was characterized by a low density of T cell receptors (TcR) and it was more conspicuous in the spleen than in the peripheral blood in mice more than 1 year of age. A shift to a TcR-low population in V beta 8+, T cells was followed in a few months by a shift in V beta 6+ T cells. Although both the change of T cell repertoire and development of autoaggression may be parameters of aging, no direct correlation was demonstrated between them in experiments with cross-hybrids and recombinant inbred strains of BALB/c and DBA/2 mice. Probably, the two parameters are genetically and independently controlled. All the data taken together indicate that T cells undergo V beta-TcR-restricted changes during their life history, depending on their genetic background.

Localization of an isoform of carboxylesterase in rat brain differs from that in human brain

Liver carboxylesterase (CE) is an enzyme capable of metabolizing drugs, and may also function as a regulator of lipid metabolism. We examined two isoforms of CE (RH1 and RL1) by immunohistochemistry in rat brain. The anti-RL1 antibody did not stain any brain structures. The anti-RH1 antibody, however, stained oligodendrocytes in all brain tissues and tanycytes, as well as some neurons in the deep cingulate gyrus, various hypothalamic nuclei and the spinal trigeminal nucleus. In the central nervous system, rat CE may function as a protective factor against foreign chemicals in these glial and neuronal cells. The distribution differed from that of the homologous human isoform which has been previously found only in endothelial cells in human brain. A possible relation between RH1 positive neurons and the medial pain system is discussed.

Enhanced effect of epidermal growth factor on pulmonary metastasis and in vitro invasion of rat mammary carcinoma cells

We examined the effects of epidermal growth factor (EGF) on metastatic and in vitro invasive capacity of weakly malignant ER-1 cells derived from a rat mammary carcinoma cell line, c-SST-2. EGF enhanced the metastatic capacity and in vitro invasiveness to reconstituted basement membrane, Matrigel, of ER-1 cells in a dose-dependent fashion. EGF-stimulated invasiveness was inhibited by anti-EGF antibody, which is able to neutralize the binding of EGF to EGF receptor, in the invasion assay system. EGF stimulated chemotactic migration toward fibronectin, laminin or newborn rat fibroblast-conditioned medium which was used as a chemoattractant in the in vitro invasion assay, but showed neither adhesion to Matrigel nor production of gelatinase and plasminogen activators. These results suggested that the increased metastatic and invasive capacity of ER-1 cells by EGF might be due to the increase in cell motility.

A possible role of 92 kDa type IV collagenase in the extramedullary tumor formation in leukemia

Production of metalloproteinases such as collagenases has been reported to be involved in the metastasis of cancer cells. Granulocytic sarcoma in extramedullary sites can be formed by similar steps to other cancers. In this study, we have examined the secretion of type IV collagenases and a tissue inhibitor of metalloproteinase-1 (TIMP-1) in several human leukemia cell lines, including a granulocytic sarcoma-derived cell line established from a patient with granulocytic sarcomas in dermal tissues. We have also examined the invasive capacity of these leukemia cell lines into reconstituted basement membrane, Matrigel, which was used for in vitro invasion assay. Among the human leukemia cell lines used in this study, only the granulocytic sarcoma cell line was found to secrete type IV collagenase constitutively. Other myeloid leukemia cell lines such as HL-60 and U-937 produced type IV collagenase only after treatment with 12-O-tetradecanoylphorbol-13-acetate. All the cell lines secreted similar amounts of the tissue inhibitor of metalloproteinases. In vitro invasion assay revealed that the granulocytic sarcoma cell line showed higher invasive capacity than the other cell lines. These results suggest that the secretion of 92 kDa type IV collagenase plays a role in the leukemia cells' invasion of extramedullary tissues.

[Clinical evaluation of endoscopic ultrasonography (EUS) in the diagnosis of superficial esophageal carcinoma]

Pre-operative diagnosis of the depth of invasion is important to decide the treatment of superficial esophageal carcinoma. The ability of EUS to diagnose the depth of invasion was examined in 40 lesions with superficial esophageal carcinoma between January 1993 and April 1994. The depth of invasion was classified as m1 or m2, m3 or sm1, and sm2 or more. Mucosal carcinoma could be detected clearly by using the 20MHz miniature probe. The diagnostic accuracy was 82.5% in all 40 lesions, and 77.8% in mucosal carcinoma (included with sm1). The reasons for incorrect diagnosis were broadness of the lesion, microinvasion, and artifact of endoscopic biopsy. EUS is considered to be useful even for superficial esophageal carcinoma as one of the preoperative diagnostic imagings.

[Mucosal carcinoma of the esophagus--the pathological point of view by subclassification of depth of invasion]

We studied 58 cases of mucosal carcinoma of the esophagus and 21 cases of submucosal carcinoma to evaluate the macroscopic features and histological risk factors (lymphatic and venous permeations and lymph node metastasis) by subclassification of depth of invasion (m1, m2, m3, sm1, sm2, sm3). Carcinoma of m1 and m2 invasion revealed neither venous permeation nor lymph node metastasis. One case of m2 carcinoma (5%) showed lymphatic permeation, 2 cases of m3 carcinomas (20%) showed lymphatic permeation and 3 cases (27%) had lymph node metastasis. Otherwise "sm" carcinoma revealed a high percentage of lymphatic permeation and lymph node metastasis. Also venous permeation were seen in some cases of "sm" carcinoma. The macroscopic appearance of all mucosal carcinomas was 0-II type and most of the 0-iib type carcinomas were "m1" carcinoma. Clinicopathologically it is useful to subclassify mucosal carcinoma as m1, m2, m3, and "m1" and "m2" carcinomas are indications for endoscopic mucosal resection.

Age-related cochlear degeneration in senescence-accelerated mouse

Age-related hair cell loss and strial atrophy were investigated in an accelerated senescence-prone strain, SAMP1 mice, and an accelerated senescence-resistant strain, SAMR1 mice. The loss of inner and outer hair cells in SAMP1 progressed more rapidly than that in SAMR1 with age. In both strains, areas of the loss of inner and outer hair cells were located mainly in the apex and base. Atrophy of the stria vascularis was observed in both strains, but in SAMP1 it appeared to increase earlier than in SAMR1. These results reveal that age-related hair cell loss and atrophy of the stria vascularis comparable to that in the human cochlea occur earlier and progress more rapidly in SAMP1 than in SAMR1. Hearing impairment in SAM may be due to a combination of sensory and strial presbycusis as well as to neural presbycusis, as reported previously. The morphological changes in the cochlea observed in SAMP1 and SAMR1 make these strains suitable for the study of the mechanisms of presbycusis.

[Histological effect and prognosis after preoperative chemotherapy in esophageal cancer]

Preoperative chemotherapy for esophageal cancer was performed and the toxic effects, post-operative complications, histological effects and survival time were evaluated. Toxic effects and post-operative complications were rare. The histological effect was evaluated according to the Guidelines for Clinical and pathologic studies on carcinoma of the esophagus by the Japanese Society for Esophageal Disease. A histological effect of more than Grade II was seen from 25 to 42.1%. A significant difference was seen in the Kaplan-Meier survival curves between the response group and the no response group (p < 0.05). If we perform preoperative chemotherapy for esophageal cancer only to responsive cases determined by chemosensitivity tests, the prognosis of advanced esophageal cancer may be improved.

Dietary alpha-linolenate/linoleate balance influences learning and memory in the senescence-accelerated mouse (SAM)

The senescence-accelerated mouse (SAMP8) is a model of age-related deterioration of memory and learning ability. A semipurified diet supplemented either with safflower oil (rich in linoleate) or with perilla oil (rich in alpha-linolenate) was fed to SAMP8 mouse dams and their pups. The offspring (males from several mothers) at 28 weeks of age were used for behavioral tests. The proportions of n-3 and n-6 highly unsaturated fatty acids in brain phospholipids reflected the n-3/n-6 balance of the diets. The learning and memory abilities of the two dietary groups were tested with the Sidman active avoidance task and the light and dark discrimination learning test. The group given perilla oil showed much greater improvement in learning in the Sidman active avoidance task than did the group fed safflower oil. In the light and dark discrimination learning test, the total number of responses to positive and negative stimuli was lower in those fed perilla oil, and their responses to positive stimuli were higher than to negative stimuli after the 10th session. Consequently, the correct response ratios of discrimination were higher in the perilla oil group than in the safflower oil group. In the open field test, the total amount of locomotor activity during 5 min was lower in the perilla oil group at 7 months of age than in the group fed safflower oil.(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of pulmonary metastases and tumor cell invasion in experimental tumors by sodium D-glucaro-delta-lactam (ND2001)

Sodium D-glucaro-delta-lactam (ND2001) inhibited spontaneous pulmonary metastases of the highly metastatic B16 melanoma variant with a maximal inhibition rate of 99.5%, and 6 of 7 animals remained metastasis-free. Likewise, ND2001 inhibited the spontaneous pulmonary metastases of both Lewis lung carcinoma (3LL) with a rate of 98.0% (3 of 5 animals remaining metastasis-free) and rat KDH-8 liver carcinoma with a rate of 82.5% (3 of 7 animals remaining metastasis-free), although it was unable to inhibit the metastases of mouse BMT-11 fibrosarcoma and rat SST-2 breast carcinoma. Pretreatment with ND2001 in vitro inhibited the pulmonary metastases of the B16 variant and 3LL cells, which indicates direct action upon the cancer cells. When the invasive activity of cancer cells was measured by the Boyden chamber method, the number of invading B16 variant or 3LL cells was reduced with maximal inhibition rates of 93.0% or 89.9%, respectively, but pretreatment with ND2001 failed to reduce the invasive activity of BMT-11 or SST-2 cells. ND2001 showed neither cytocidal nor antitumor activity. These results suggest that ND2001 inhibited pulmonary metastases at the invasive step into the basement membrane by directly changing some property of the tumor cells.

"Boomerang" rectus abdominis musculocutaneous free flap in head and neck reconstruction

Immediate head and neck reconstruction after cancer resection using the "boomerang" rectus abdominis musculocutaneous (RAM) free flap was performed in 13 patients over the past 2 years. The skin paddle of the flap is designed as a boomerang shape based on the anatomical construction of the dominant perforators from the inferior epigastric vascular system. A versatile technique of the boomerang RAM flap provides effective use for reconstruction of the complex defects at the skull base, orbital, nasal cavity, paranasal sinuses, oropharynx, palate, buccal mucosa, tongue, floor of mouth, and neck. It also allows a reconstructive surgical team to elevate the flap simultaneously with a head and neck surgical team before the size and location of the defect are exactly determined and greatly reduces operating time. This flap will be a routine technique for immediate head and neck reconstruction after cancer resection.

Accumulation of blood-borne horseradish peroxidase in medial portions of the mouse hippocampus

The intracerebral distribution of intravenously injected horseradish peroxidase (HRP) in young adult DDD mice was examined. HRP-tetramethylbenzidine reaction products were observed in the medial portions of the hippocampus, particularly the medial CA1 region and medial dentate gyrus. Reaction products were observed in the subfornical organ in mice decapitated 5 min after HRP injection, and then also progressively more caudally in the medial portions of the hippocampus as postinjection survival time increased. These findings suggest that blood-borne macromolecules have ready access to the medial portions of the hippocampus, particularly the medial CA1 region and medial dentate gyrus.

Human CYP2A6 activation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK): mutational specificity in the gpt gene of AS52 cells

The tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1- butanone (NNK) is a potential human carcinogen that is known to be metabolized to DNA-reactive intermediates by the cytochromes P450. We have examined the nature of NNK's DNA damaging effects in a mammalian cell system expressing a specific human cytochrome P450 (2A6) and containing a target gene for mutagenesis. Human CYP2A6, which is known to activate NNK to a mutagen, was lipofected via a retroviral vector into the Chinese hamster ovary AS52 cell line, which contains the bacterial gpt gene and can be mutated to 6-thioguanine resistance. AS52 cells expressed negligible CYP2A6-specific coumarin 7-hydroxylase activity (0.7 pmol/mg protein/min), while a CYP2A6 transfected clone (AS52-E8) expressed 30 pmol/mg protein/min. Both cell lines were equally sensitive to the cytotoxic and mutagenic effects of the direct-acting mutagen ethylmethanesulfonate; however, only the AS52-E8 cells exhibited a dose-dependent increase in cytotoxicity and mutant frequency upon treatment with NNK. At the highest NNK dose (1200 micrograms/ml), the mutant frequency in AS52-E8 cells was 14-fold (339 x 10(-6)) greater than the spontaneous frequency of 24 x 10(-6). Ninty-eight mutant clones were isolated following NNK treatment. Based on PCR analysis, 21 clones contained deletions/rearrangements and 77 were putative point mutants. Sequencing potential point mutants showed that 81% contained G:C to A:T transitions. Four of six G:C to A:T hotspots were at the second G of the GGT motif, which is the motif and major mutation found in codon 12 of Ki-ras from NNK-induced lung tumors in strain A mice. Since NNK may be metabolized via different pathways to pyridyloxobutylate or methylate DNA, the data suggest that methylation damage causes the major mutagenic events in AS52-E8 cells when NNK is activated by human CYP2A6.

Establishment of a retrodifferentiated cell line from a single differentiated rat myelomonocytic leukemia cell: possible roles of retrodifferentiation in relapses of leukemia after differentiation-inducing therapy

In order to demonstrate possible roles of retrodifferentiation in relapses after differentiation therapies, we have established a retrodifferentiated cell line (RD-1) from a single rat myelomonocytic leukemia cell which differentiated into a macrophage-like cell by treatment with lipopolysaccharide (LPS). The established RD-1 cells showed microscopic features slightly maturer than their parent cells. The RD-1 cells had the ability to differentiate into macrophage-like cells by treatment with fewer doses of LPS than those for parent cells. All rats inoculated with the parent cells (more than 10(2)/rat) died within 50 days. Rats inoculated with 10(4) RD-1 cells survived for more than 120 days, whereas two out of four rats inoculated with 10(5) cells and all the rats inoculated with 5 x 10(5) cells died of leukemia. These results suggest that RD-1 cells are retrodifferentiated cells from a single rat myelomonocytic leukemia cell which differentiated into a macrophage-like cell; they have similar phenotypes and lower tumorigenicity than the parent cells and they also suggest that the appearance of retrodifferentiated leukemia cells may be responsible for relapse after differentiation therapy for leukemia in some cases.

Species differences in the induction of hepatic microsomal carboxylesterases caused by dietary exposure to di(2-ethylhexyl)phthalate, a peroxisome proliferator

The ability of di(2-ethylhexyl)phthalate (DEHP), a very widely used commercial plasticizer, to induce hepatic microsomal carboxylesterase isozymes in rats, mice (C5BL/6 and DBA/2 strains), and hamsters was studied by measuring hydrolase activities and by immunoblotting analysis using specific antibodies. Animals were given 2% (v/w) DEHP in the diet for 7 days. In rats, p-nitrophenyl acetate, isocarboxazid, and butanilicaine hydrolase activities and the contents of RL1, RL2, and RH1 in liver microsomes were all increased, but acetanilide hydrolase activity was not increased. In hamsters, the only significant change was a slight increase of butanilicaine hydrolase activity. In mice, butanilicaine hydrolase was strongly induced in both the C57BL/6 (7.35-fold) and DBA/2 (4.96-fold) strains. The anti-RL1 and RH1 antibody-reactive proteins in C57BL/6 mouse liver microsomes were increased, but the extent of induction was much less than that of butanilicaine hydrolase activity. The butanilicaine hydrolysis seems to be catalyzed by not only anti-RL1 reactive protein, but also some other carboxylesterase in C57BL/6 mouse. Anti-RL1 antibody inhibited the DEHP-induced butanilicaine hydrolase activity by > 50%. The results strongly suggest that multiple carboxylesterase isozymes were induced in mouse hepatic microsomes by dietary exposure to DEHP.

Protein alterations in age-related cataract associated with a persistent hyaloid vascular system in senescence-accelerated mouse (SAM)

The occurrence of age-related cataract associated with a persistent hyaloid vascular system is the most prominent feature in SAMP9, an inbred strain of Senescence-accelerated Mouse. To examine the cataractogenesis, we analysed protein changes in the process of cataract formation in the lens. The cataractous lenses showed a striking decrease in water-soluble protein content, in contrast to increases in the amount of water insoluble protein. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blots of water-soluble protein in the cataractous lenses showed additional high molecular weight beta-crystallin proteins of about 43 kDa, concomitant with decreased amounts of 29-kDa and 31-kDa beta-crystallins and 21-kDa gamma-crystallin, as compared with findings in normal lenses. Although there was no apparent difference between the patterns of SDS-PAGE of urea-soluble and urea-insoluble proteins isolated from cataractous and normal lenses, slightly increased reactivity of bands around 43 kDa against anti-beta-crystallin antibody was observed in cataractous lenses. The calcium content was elevated and activity of transglutaminase was increased in the cataractous lenses. While the molecular weight of beta-crystallin polymers cross-linked in vitro by exogenous transglutaminase was not completely compatible with those of high molecular weight beta-crystallins observed in the cataractous lenses, these findings do suggest the contribution of this enzyme to production of high molecular weight beta-crystallins and to insolubilization of these proteins in the cataractous lenses in SAMP9.

Immunohistochemistry with an antibody to human liver carboxylesterase in human brain tissues

Human liver carboxylesterase (CE) is an enzyme capable of metabolizing drugs, and may also function as a regulator of lipid metabolism. We examined one isoform of CE by immunohistochemistry in the brains of neurologically normal, Alzheimer disease (AD), amyotrophic lateral sclerosis (ALS) and cerebral infarction cases. In all but the infarcted brains, the anti-CE antibody stained only capillary endothelial cells in the brain and spinal cord tissues. In infarct brain areas, intense immunoreactivity of the macrophages was seen. In contrast, the macrophages in the ALS lateral columns and the reactive microglia located in the center of classical senile plaques in AD, as well as other reactive microglial cells in the grey matter, showed no immunoreactivity. In the central nervous system, CE may function as a protective factor against foreign chemicals in capillary endothelial cells, and the antibody to CE may serve as a marker for invading macrophages from the systemic circulation.