Matrix metalloporoteinases (MMPs), which are dominantly regulated by tissue inhibitors of metalloproteinase (TIMPs), play important roles in extracellular matrix (ECM) degradation and are involved in the progression of kidney diseases. In glomeruli and tubulointerstitum of hereditary nephrotic (ICR-derived glomerulonephritis: ICGN) mouse kidneys, hyper-accumulation of ECM components occurred, and MMP activity decreased. In the present study, because lower levels of MMP activity may contribute to the progression of renal fibrosis in ICGN mice, Western blotting analysis and immunohistochemical staining for MMPs and TIMPs were performed to verify the expression levels of these proteins. Levels of MMP-2, MMP-9, MT1-MMP, TIMP-1 and TIMP-2 in the kidneys were decreased in ICGN mice in comparison with normal ICR mice. These results indicate that small amounts and low levels of activity of MMPs cause the progression of renal fibrosis in ICGN mice.
Musculature and glands of the esophagus in various wild birds and mammals were examined histologically. Cervical and thoracic esophagi of all birds used (mallard, spot-billed duck, Ural owl and Hodgson's hawk-eagle) were comprised of smooth muscle fibers only. In contrast, esophagi of the nutria, Japanese raccoon dog, common raccoon and Japanese marten consisted largely of striated muscle fibers. In the masked palm civet, Japanese macaque and bottlenose dolphin, esophageal muscle layers consisted of both striated and smooth muscle fibers. Esophageal glands were observed except for the nutria and masked palm civet. These results show a wide variety of the structural composition in the esophagus of wild animals, particularly mammals, examined in this study.
The major organs and tissues of 24 broiler chickens (70 or 71 days old) suspected of spindle-cell proliferative disease (SPD) because of showing the tumorous lesions distributed throughout the body at meat inspection were collected for histopathological and immunohistochemical examination. Macroscopically, liver, spleen and cecal tonsil showed severe enlargement and white nodules or plaques were observed in the liver, spleen, kidney, intestine and bone marrow of the femur. All chickens were diagnosed with SPD based on the histopathological examination. The lesions of SPD were observed in the liver, spleen, kidney, heart, lung, pancreas, proventriculus, gizzard, duodenum, jejunum, ileum, rectum, cecal tonsil, bursa of Fabricius, bone marrow of the femur and skin. Hemangioma was observed in the lung of 1 bird. Eight 1-day-old specific pathogen-free chicks were inoculated intraperitoneally with 0.25 ml of a 20% homogenate of the affected spleens of three naturally occurring cases. One inoculated bird, necropsied at 10 weeks of age, macroscopically had a white nodule in the kidney and histopathologically had spindle-cell proliferative lesions, a pattern similar to that seen in the naturally occurring cases, in the liver, spleen, kidney, heart, lung, pancreas, proventriculus, duodenum, cecal tonsil and bone marrow of the femur, and was diagnosed with SPD. Immunohistochemically, significant positive reactions with a rabbit antiserum against avian leukosis virus antigens were detected in all spindle cells in the proliferative lesions of all examined SPD cases and in tumor cells of the hemangioma of a field case.
Bioactive recombinant chicken interferon-α (ChIFN-α) was expressed in a baculovirus system. For easy purification, it was expressed as ChIFN-α bearing histidine hexamer (His-tag) at C-terminal, designated ChIFN-αHis. The expressed proteins were detected by SDS-PAGE analysis with Coomassie brilliant blue staining as around 23 and 19 kDa bands thought to be immature and matured ChIFN-αHis respectively. The purified ChIFN-αHis with a nickel chelated column showed anti-viral activity in vitro.
The activity of Clostridium septicum alpha-toxin was determined in erythrocytes of various animals, with sensitivities observed in the order of mouse, rat, canine, equine, rabbit, chicken, bovine, swine and ovine. Temperature and protease treatment affected the sensitivity of erythrocytes to alpha-toxin. Proteinase K treatment decreased the sensitivity of murine, canine, equine and bovine erythrocytes, but ovine erythrocytes did not change the sensitivity to alpha-toxin activity. On the other hand, the activity of alpha-toxin on swine erythrocytes increased after treatment with proteinase K, trypsin, chymotrypsin or lysyl endopeptidase. Toxin overlay assay showed that alpha-toxin bound to erythrocyte membrane proteins with a molecular mass of 30 to 45-kDa in mouse, equine, bovine, swine and chicken, whereas in rat erythrocyte membranes the toxin reacted with 100-kDa protein. The treatment of murine and swine erythrocyte membranes with phosphatidylinositol-specific phospholipase C resulted in liberation of the toxin-binding protein from the individual membranes in a native state. These results show that alpha-toxin associates with specific erythrocyte membrane proteins in any animal species, and are subsets of glycosylphosphatidylinositol-anchored proteins in various animal species. These results may reflect distinct characteristics of the hemolytic activity of alpha-toxin in response to various erythrocytes.
A total of 27 clinical isolates of Mannheimia haemolytica from cattle in Japan from 2001 to 2002 were examined for antimicrobial susceptibility to 25 antimicrobial agents. The minimum inhibitory concentrations of 25 different antimicrobials were determined by an agar dilution method according to the guidelines of the National Committee for Clinical Laboratory Standards. Of the 27 isolates, seven isolates (26.9%) were resistant to at least one of the 25 drugs and resistance rates ranged from 3.7 to 18.5%. Resistance rates to dihydrostreptomycin (18.5%), oxytetracycline (11.1%), and doxycycline (11.1%) were relatively high and those to the remaining drugs were less than 10%.
Staphylococcus intermedius isolates from diseased and healthy dogs were examined for production of extracellular enzymes and toxins, and phage patterns. There were no significant differences between the two groups of isolates in the production rates of DNase, protease, lipase, gelatinase, hyaluronidase, hemolysins, protein A, and TSST-1, or in phage patterns. But the production rate of enterotoxins in isolates from diseased dogs was significantly higher than that in isolates from healthy dogs. PFGE analysis was performed with isolates from different body sites in individual dogs. In 3 of 6 healthy dogs, identical PFGE patterns were seen in isolates from the nares, external auditory meatus or skin. The remaining 3 dogs yielded isolates of different patterns. In 4 of 6 diseased dogs, identical patterns were seen in isolates from lesions as well as from the other normal sites.
In the cytosol of cow mammary gland, several proteins are phosphorylated in the presence of the protein kinase C (PKC) cofactors 1-oleoyl-2-acetyl-sn-glycerol (OAG), phosphatidylserine (PS) and Ca2+. Of the substrates, the 21-kDa protein is inferred to be a 20-kDa regulatory myosin light chain (MLC20) from smooth muscle because of its molecular mass, its distribution in the cytosol, its association with melittin and sphingosine (the PKC modulators), and phosphorylation by PKC as well as by Ca2+/calmodulin-dependent myosin light chain kinase (MLCK). The present study was undertaken to examine whether the 21-kDa protein could be identified as MLC20, by adding cow uterine MLC20 to the reaction mixture containing cytosol with or without the PKC cofactors and/or calmodulin. In the absence of MLC20, the 21-kDa protein was phosphorylated when the PKC cofactors and calmodulin were added to the reaction mixture. Phosphorylation of the 21-kDa protein was inhibited by melittin or sphingosine, and the inhibition was reversed by PS, but not by calmodulin. When MLC20 was included in the reaction mixture, it was phosphorylated in the presence of the PKC cofactors, and the phosphorylated MLC20 band overlapped that of the 21-kDa protein. The indistinguishably overlapped band of the two proteins was inhibited by melittin and by sphingosine, and their inhibition was reversed by PS, not by calmodulin. It is suggested that the 21-kDa protein is the smooth muscle MLC20 and also that the 21-kDa MLC20 is phosphorylated by PKC, but not by MLCK.
Polypoid cystitis is a rare disease of the urinary bladder in dogs characterized by chronic inflammation, epithelial proliferation, and development of a polypoid mass or masses without histopathologic evidence of neoplasia. The ultrasonographic appearances of eight dogs with polypoid cystitis are described. Ultrasonography confirmed the presence of a bladder mass or masses in all patients. Ultrasonographic findings are mucosal projections and a polypoid to pedunculated mass of variable size and shape. Although a polypoid mass tends to be located in the cranioventral bladder mucosa, the polyps also could arise in the craniodorsal bladder mucosa. Ultrasonographic images are well correlated with contrast radiographic studies and gross morphological appearance. Ultrasound is a non-invasive, very useful diagnostic tool for detecting bladder polyps, but histopathology is required for definitive diagnosis.
Rabbit syphilis was experimentally transmitted from clinical cases to healthy rabbits. The purpose was to evaluate changes in RPR titers during the course of infection and to detect the pathogenic organism. Two of three littermate rabbits were inoculated topically. One rabbit became symptomatic, with typical clinical signs on its genitalia about 8 weeks after inoculation and a marked rise in RPR titers, another remained asymptomatic with a moderate rise in titers, and the control rabbit remained negative. These results supported the specific relationship between clinical signs and RPR titers. Histopathological examination of the skin lesion from the symptomatic rabbit revealed spirochetes.
VP2 gene of a canine parvovirus (CPV) isolate from the feces of a puppy which was diagnosed to be CPV infection was analysed. The result indicated that this clinical isolate was phylogenetically close to the isolate of wild-type CPV (strain CPV-T37) prevailing in Taiwan rather than isolates from Japan.
In clinical medicine improved diagnostic methods for the detection of infection are needed. A good infectious animal model is very important for the development of a new diagnostic method or drug. The purpose of this study was to establish a good animal model with soft tissue infection. Twenty-four SD rats were divided into four groups (6 in each group). Various bacilli including Staphylococcus aureus (S. aureus), Streptococcus pneumoniae (S. pneumoniae), and Escherichia coli (E. coli) were injected intramuscularly into the left caudal thighs of three groups of rats to create soft tissue infection. In addition, normal saline was injected into the left caudal thighs of ten rats which were used as controls. Before and 48 hr after inoculation of the bacilli, a blood sample (0.5 ml) was taken from each rat and analyzed to determine the white blood cell count and differentiated cell count. In addition, 48 hr after the inoculation, 0.2 mCi of gallium-67 was injected via the tail vein. Gallium scan was performed at 24 hr and 48 hr after administration of the radiotracer. The dorsal view of both hind legs was imaged and analyzed by computers to calculate the lesion-to-normal (L/N) ratio. After imaging, all rats were sacrificed and specimens from portions of the infected thigh muscle were sent for histopathologic investigation to confirm the infection. The increase in both the WBC counts and the segmented polymorphonuclear leukocytes (PMNs) were most significant in the S. aureus group, followed by the S. pneumoniae group, E. coli group and normal control groups. The rats with S. aureus infection had significant gallium uptake at the site of infection and the highest L/N ratio of 2.14 on the 24-hr image and 2.0 on the 48-hr image. The rats with S. pneumoniae had the second highest L/N ratio (1.41 at 24 hr, and 1.48 at 48 hr). The L/N ratio for the E. coli group was 1.27 at 24 hr and 1.35 at 48 hr. No obviously abnormal gallium uptake was demonstrated in the normal controls. We conclude that all three bacilli induced a soft tissue infection in SD rats. S. aureus resulted in the most significant infectious signs.
The effects of topical administration of polysaccharides isolated from fungus, Phellinus gilvus (PG) on the healing of rat dermal wounds were assessed. In 10 Sprague-Dawley (SD) rats, six 6 mm diameter defects were made with a punch biopsy appliance. After 24 hr, test substances were applied to the defects twice a day: 0.025, 0.25, and 2.5% polysaccharides from PG (PG0.025, 0.25, and 2.5 groups), Madecassol® ointment (MC group), aqueous gel (AG group) and no treatment (control group). Six days postoperatively, the contraction and reepithelialization of the wound surface were assessed. Wound diameter was significantly reduced in all PG groups (P<0.05). Complete epithelialization and macrophages were noted in the PG0.25 group, as compared to the control group. We conclude that polysaccharides isolated from PG have significant dermal wound healing effects, and this investigation suggests the potential clinical application of PG as a wound healing agent.
A high prevalence of larval Echinococcus multilocularis (Em) infection was found in zoo primates in Hokkaido, Japan. In October 1997, a Japanese monkey (Macaca fuscata) died and histopathologically diagnosed as alveolar hydatidosis. Serum samples were collected from the remaining Japanese monkeys and examined for antibodies against Em by enzyme-linked immunosorbent assay and western blotting. Serological tests showed 12 more animals of the remaining 57 monkeys were possibly infected. Ultrasonography revealed that nine of these 12 animals had a cystic lesion in the liver. The band patterns of western blotting in the monkeys were very similar to those in human.
Diffuse global granulomatous glomerulonephritis with unique morphological characters was detected in a pig. The structure of the basement membrane of glomerular tufts was destroyed in almost all glomeruli. Various inflammatory cells consisted mainly of macrophages infiltrated severely into the glomerular tuft and the Bowman's space of and extended to the periglomerular interstitium. Periarteritis with fibrinoid necrosis was occasionally seen in the arterioles and small arteries running through the renal parenchyma and pelvis. In the present case, the results of either the immunohistochemical reactions to the antigens against PRRSV or PCV-2 or Ziel-Neelsen staining for acid-fast bacilli were negative and no pathogenic bacteria were cultured.
Epitheliocystis in the carp of a pet fish market were investigated by our diagnostic work and collecting information from department of laboratory animal medicine and fish & shellfish laboratory. The epitheliocystis was identified by using histopathological examination. Epitheliocystis was confirmed as inflammation, epithelial hyperplasia, and lamellar fusion of the gill tissue. Electron microscopic observation showed that the inclusions were filled with Chlamydia-like organism.
A male 8-year-old Yorkshire Terrier dog with unilateral cryptorchism was presented for investigation of reduced appetite and multifocal alopecia. Abdominal sonography and radiography demonstrated abnormal enlargement of left testicle in abdominal cavity. Both of the retroperitoneal cryptorchid testicle and the other contralateral testicle were removed surgically. The concentrations of testosterone and estradiol in blood collected from the jugular vein and the two spermatic veins were evaluated and the results revealed high estradiol concentration. The retroperitoneal cryptorchid testicle was enlarged, firm, bulging sphere mass. The cut surface revealed homogeneous white color and lobulation by septa. The contralateral testicle in scrotum showed atrophic testicle and enlarged epididymis. Histopathologically, the retroperitoneal cryptorchid testicle was diagnosed as seminoma. We thought that hyperesterogenemia and alopecia in this case was probably related with his seminoma, although high correlations between Sertoli cell tumor and alopecia have been reported. To our knowledge, this report may be a rare case of seminoma with hyperesterogenemia and alopecia.
A total of 307 brains of purebred sows obtained from an abattoir were retrospectively examined. These sows were culled with reasons of reproductive failure, urogenital infections, or locomotor problems. The most common macroscopic lesions were cavitations or lacunae in the basal nuclei (9.1%, 28/307) and coarse and thickened leptomeninges with marked vessels (3.9%, 12/307). The most frequent microscopic lesion was polyarteritis nodosa (21.2%, 65/307), which was found in all 40 brains with the above-mentioned gross lesions and in all 25 brains with microscopic cerebral infarcts or cavitations. The affected arteries of polyarteritis nodosa were distributed primarily in the cerebral leptomeninges, basal nuclei, and internal and external capsules. Histopathologically, a characteristic change of the affected arteries was transmural fibrinoid necrosis with severe infiltration of mixed inflammatory cells; narrowing or occlusion of the lumen. The inflammatory cells were chiefly composed of lymphocytes, macrophages, and plasma cells, with a few eosinophils and occasional multinucleated giant cells. Polyarteritis nodosa was found at a high percentage in the brains from culled sows. It may result in cerebral ischemia, infarcts, and hemorrhage, and possibly play a role in the necessity for culling due to locomotor problems.
Equine carbonic anhydrase isozymes (CA-I and CA-II) were purified from erythrocytes by several column chromatography. Polyclonal anti-CA-I and anti-CA-II sera were produced in rabbits. Sensitive competitive enzyme-linked immunosorbent assays (ELISA) were established to determine the developmental changes in CA-I and CA-II levels in equine erythrocytes. Concentrations of CA-I and CA-II in erythrocytes from 150 clinically normal thoroughbreds (123 racehorses and 27 riding horses) were determined by ELISA. Mean (± SD) concentrations of CA-I and CA-II in racehorses were 1.70 ± 0.48 and 0.94 ± 0.13 mg/g hemoglobin (Hb), respectively. Mean concentrations of CA-I and CA-II in riding horses were 2.34 ± 0.52 and 0.76 ± 0.08 mg/g Hb, respectively. When the CA levels in racehorses and riding horses were compared, the CA-I level in riding horses was higher than that in racehorses (p=0.01). The CA-II level in racehorses was higher than that in riding horses (p=0.02). These data suggest that the levels of CA isozymes in erythrocytes of racehorses were influenced by chronic physical stress. The CA-I concentration in erythrocytes of 2-month-old horses was approximately 0.25 mg/g Hb. The CA-I level noticeably increased during the first year of life and approached normal adult levels by 2 years. The CA-II level decreased slightly with age, indicating different regulation of CA-I and CA-II expression during development.
Cloacal swabs were sampled from 100 duck farms in Taiwan between March 2000 and January 2001 for isolation and standard cultivation of Salmonella spp. and thermophilic Campylobacter spp. Salmonella spp. were isolated from 4.6% (91/2000) of ducks from 20% (20/100) of duck farms. Ten serotypes of Salmonella enterica were identified: S. Potsdam (31.9% of isolates), S. Dusseldorf (18.7%), S. Indiana (14.3%), S. Typhimurium (7.7%), S. Hadar (5.5%), S. Newport (4.4%), S. Derby (4.4%), S. Montevideo (2.2%), S. Schwarzengrund (2.2%), and S. Asinnine (1.1%). Isolation of S. Asinnine or S. Indiana from poultry had not hitherto been described in Taiwan. The salmonella isolation rate in ducklings under two weeks of age was significantly higher than the other age groups (P<0.05). Campylobacter spp. were isolated from 43.5% (1045/2400) of ducks from 92% (92/100) of duck farms. Among them, 991 isolates (94.8%) were identified as C. jejuni and 54 isolates (5.2%) as C. coli. The campylobacter isolation rate in ducklings under two weeks of age was significantly lower than other age groups (P<0.05). Antimicrobial susceptibility testing was conducted by the disk diffusion and E- test methods. The results indicated that Salmonella isolates were 100% susceptible to amikacin, amoxicillin/clavulanic acid, ceftraxone, cephalothin, ciprofloxacin, norfloxacin, ofloxacin, and polymyxin B. A markedly higher antimicrobial resistance to amoxicillin, florfenicol, flumequine, josamicin/trimethoprim, nalidixic acid, nitrofurantoin, norfloxacin, ofloxacin, polymyxin B, sulfamethoxazole/trimethoprim and tetracycline was found in campylobacter isolates.
From November 2000 to July 2002, 112 fecal samples from pet reptiles, including 18 turtles, 71 lizards and 23 snakes, sold at a pet shop were examined for the prevalence of Salmonella spp. in Japan. Salmonella spp. were isolated from 83 (74.1%) of 112 samples, and a total of 112 Salmonella isolates were identified as subspecies I to IV. The majority of isolates (62.5%) belonged to subspecies I and 54 isolates could be identified as any of 28 serovars. The predominant serovars were found to be S. Bardo, S. Newport and S. Panama, which cause human salmonellosis. These results indicate that pet reptiles may be a potential infectious source of human salmonellosis in Japan.
Two isolates of mecA-positive methicillin-resistant Staphylococcus aureus (MRSA) from retail raw chicken meat were characterized by phenotypic and genotypic methods. One isolate showed the human biovar, coagulase type III, phage group I · III, the lack of production of enterotoxins and TSST-1, and resistance to PCG/ABPC/EM/GM/KM. The other isolate showed the human biovar, coagulase type III, phage group III, production of enterotoxin C and TSST-1, and resistance to PCG/ABPC/CEZ. The biotyping results indicate that the two isolates showed characteristics of human S. aureus. They also harbored SCCmec type IV, which has prevalently been found in community-acquired MRSA isolates. This paper is the first publication regarding MRSA isolates from raw chicken meat in Japan.
In order to analyze the detailed mechanisms responsible for macrophage activation by chitin derivatives, resident peritoneal macrophages were prepared and stimulated with chitin, chitosan and low-molecular weight chitosan. Our findings were as follows: (i) chitosan induced apoptosis of peritoneal macrophages, but this did not occur when chitin or water soluble low-molecular weight chitosan were used; (ii) chitosan treatment induced activation markers, such as the major histocompatibility complex (MHC) class I, class II, Fc receptors, transferrin receptor, mannose receptor, Fas, and macrophage inflammatory protein (MIP)-2, whereas chitin and low molecular weight soluble chitosan induced only the expression of MHC class I and II molecules; (iii) apoptosis induced by chitosan was mediated by the Fas signaling pathway, in response to phagocytosis via the mannose receptor. We conclude that since chitosan activates macrophages, this may be the mechanism by which it accelerates wound healing.
The aims of this study were to investigate whether upper airway sounds of dogs with laryngeal paralysis and tracheal collapse have distinct sound characteristics, compared with unaffected dogs. The sounds of 5 dogs with laryngeal paralysis and 5 dogs with tracheal collapse were recorded. Honking sound appeared as predominant clinical signs in dogs with tracheal collapse. Laryngeal stridors appeared as predominant clinical signs in dogs with experimentally produced laryngeal paralysis by resection of laryngeal nerve, in which two types of stridor, I and II, were recorded. All these sounds were analyzed using sound spectrogam analysis. There were significant differences in duration (sec), intensity (dB), pitch (Hz), first formant (Hz), second formant (Hz), third formant (Hz), fourth formant (Hz) of sounds between the normal bark and two types of stridor or honking sound, indicating that the sound analysis might be a useful diagnostic modality for dogs with tracheal collapse and laryngeal paralysis.
To induce luteal regression-related abortion/delivery and treat pyometra in dogs, various PGF2α-analogues (PGAs) are administered, but a PGA most appropriate for clinical application in dogs, with a low incidence of side effects, is being investigated. In this study, we compared the effects of etiproston tromethamine (PGA-E), which has not been investigated in dogs, with those of cloprostenol (PGA-C), which is routinely used in dogs. A single dose of PGA-E at 100, 200, 400 or 800 μg or PGA-C at 12.5, 25, 50 or 100 μg was administered to beagles (n=5 per group) 25 days after ovulation, when the corpus luteum was in the functional phase. We compared the state of luteal regression by measuring plasma progesterone levels. As side effects, the incidences of salivation, vomiting, tachypnea, diarrhea and the drop in body temperature were investigated. In the 400-μg and 800-μg groups treated with PGA-E, the mean intervals from administration until luteal regression were 18.6 days and 31.2 days, respectively. In the dogs treated with 50 μg or more of PGA-C, luteal regression was noted 2 days after administration. The above side effects were observed for 3 hr after administration of PGA-E/PGA-C. In the dogs treated with 800 μg of PGA-E, the mean body temperature was 36.7°C 4 hr after administration; hypothermia persisted. PGA-E may be less useful than PGA-C for promoting luteal regression in dogs in clinical application.
To elucidate the physiological role of insulin-like growth factor-I (IGF-I) during early pregnancy in mares, number of ovarian follicles was monitored ultrasonically during different stages of the first trimester of pregnancy in 36 thoroughbred mares. From 9 of 36 mares, blood samples were collected weekly from the mating day till the end of the first trimester of pregnancy and plasma IGF-I profiles were examined with other hormones, like follicle stimulating hormone (FSH), luteinizing hormone (LH), ir-inhibin, progesterone and estradiol-17β. Plasma IGF-I level fluctuated throughout the studied period with four peaks on the 7th, 28th, 49th and 84th days of pregnancy. Plasma IGF-I showed a positive correlation with plasma FSH (P<0.05), whereas no correlation was found with other hormones during the studied period. Plasma IGF-I had no correlation with the foetal size, but positive correlation with the number of large (> 30 mm) and medium (10-30 mm) follicles. These results suggested that IGF-I might produce from the medium and large follicles during early pregnancy and promote to develop their growth via pituitary FSH mediated effects in the mares.
The right testis and epididymis were excised from a Beagle dog that ejaculated high percentages of sperm with detached tails and with coiled tails. Cross sections of the organs were stamped on glass slides and histological examination of the organs was performed to find the portion where sperm with the abnormal tails appear. Many sperm with tails whose axoneme was exposed near the neck region were observed in the testis and they decreased in order from the caput, to the corpus, and the cauda epididymis. Sperm with detached tails and sperm with coiled tails gradually increased in the epididymis. These findings indicate that the tails of sperm with an exposed axoneme detached in the epididymis.
Green tea, one of the most popular beverages consumed in Asian countries, has been reported to possess anticarcinogenic and antimutagenic properties. The aim in this study is to test the radical scavenging effect of catechins and caffeine, which were major components of green tea, and if they really prevent oxygen radical-induced mutagenesis. We used TA102 strain of Salmonella typhimurium which is sensitive to hydroxyl radical in the Ames mutation assay. We found that caffeine did not show any effects on mutagenesis in this system, but catechin significantly reduced mutagenesis or genotoxicity caused by hydroxyl radical. This radical-scavenging action of catechins may indeed contribute to the anticarcinogenic activity of green tea as has been proposed.
We investigated the relationship between CD8+ T cell anti-feline immunodeficiency virus (FIV) activity and FIV proviral DNA load integrated in mononuclear cells. The anti-FIV activity and the proviral DNA load were correlated, and the number of proviral DNA copies was high in cats with decreased anti-FIV activity. Particularly, no anti-FIV activity was detected in the cats staged as having an acquired immunodeficiency syndrome (AIDS)-related complex or AIDS, and the number of proviral DNA copies was obviously increased compared to those in the cats in the asymptomatic stage. These results suggest that decreased anti-FIV activity destroys the control of in vivo FIV replication, which leads to an increased proviral DNA load with the progression of the clinical stage of disease.