A novel V beta 2-specific endogenous mouse mammary tumor virus which is capable of producing a milk-borne exogenous virus

We have previously reported new Mtv loci, Mtv-48 and -51, in the Japanese laboratory mouse strains CS and NC. Here we show by backcross analysis that both Mtv-48 and -51 cosegregate with very slow deletion of T cells bearing V beta 2. The nucleotide sequences of the open reading frames in the 3' long terminal repeats of Mtv-48 and -51 were very similar to those of Mtv-DDO, mouse mammary tumor virus C4 [MMTV(C4)], and MMTV(BALB/cV), which encode V beta 2-specific superantigens. Furthermore, backcross female mice carrying Mtv-48 but not Mtv-51 were found to be able to produce milk-borne MMTV(CS), which can vigorously stimulate V beta 2-expressing T cells after local injection in vivo in an I-E-dependent manner. On the other hand, mice carrying Mtv-51 but not Mtv-48 could not produce such an MMTV in milk. The nucleotide sequences of MMTV(CS) open reading frame were completely matched with those of Mtv-48. These results indicate that the provirus Mtv-48 but not Mtv-51 is capable of producing a milk-borne virus of which the superantigen stimulates V beta 2-expressing T cells.

Circulating concentrations and physiologic role of atrial natriuretic peptide during endotoxic shock in the rat

OBJECTIVES

To determine if there are changes in circulating concentrations of endogenous atrial natriuretic peptide and the physiologic role of this peptide in endotoxic shock.

DESIGN

A prospective, randomized, controlled animal trial.

SETTING

University research laboratory.

SUBJECTS

Anesthetized male Wistar rats, weighing 250 to 350 g.

INTERVENTIONS

Six rats received 1.5 mg/kg body weight of lipopolysaccharide alone. Five rats received 1.5 mg/kg of lipopolysaccharide and 200 microL/100 g body weight of rabbit anti-atrial natriuretic peptide serum. Another five rats received 1.5 mg/kg of lipopolysaccharide and normal rabbit serum in the same volume as the antiserum.

MEASUREMENTS AND MAIN RESULTS

Plasma concentrations of atrial natriuretic peptide, arginine vasopressin, and aldosterone were measured, and changes in hemodynamic parameters and renal function were monitored in rats with endotoxic shock after catheterization of the right jugular vein. Urine volume, urine sodium excretion, urinary potassium excretion, and urine 3', 5'-cyclic guanosine monophosphate (cGMP) excretion were measured at 12-hr intervals. The plasma atrial natriuretic peptide concentration was slightly but significantly lower 30 mins after the lipopolysaccharide injection (114.8 +/- 9.0 pg/mL at 0 hr, 75.6 +/- 6.2 pg/mL at 30 mins, p < .01) and then began to increase, peaking at 6 hrs (752.8 +/- 104.5 pg/mL, p < .01 vs. 0 time) and remaining at higher concentrations than before the preinjection value, up to 24 hrs. In contrast, acute spike-like increases of arginine vasopressin and aldosterone concentrations were observed 30 mins after the lipopolysaccharide injection, preceding the increase of the plasma atrial natriuretic peptide concentration. Measurements of urine volume and urine sodium excretion showed oliguria during the initial 12 hrs after the lipopolysaccharide injection, followed by diuresis and natriuresis during the subsequent 12 hrs. In addition, injection with anti-atrial natriuretic peptide serum in the diuretic phase 12 hrs after the lipopolysaccharide injection significantly inhibited the diuresis, natriuresis, and urine cGMP excretion in this model. Furthermore, the plasma aldosterone concentration 24 hrs after the lipopolysaccharide injection was significantly increased by the administration of the antisera.

CONCLUSIONS

These findings suggest that endogenous atrial natriuretic peptide increases in the acute phase of endotoxic shock and plays an important role in water and electrolyte balance by regulating diuresis.

Type VI collagen in mouse masseter tendon, from osseous attachment to myotendinous junction

BACKGROUND AND METHODS

The association of masseter tendon type VI collagen with other extracellular matrix (ECM) components was examined from osseous attachment to myotendinous junction by immunohistochemistry and transmission electron microscopy with ATP treatment and enzyme digestion.

RESULTS

In the tendon proper, fibrocytes extended their processes among bundles of striated collagen fibrils and associated with adjacent cells through amorphous materials, thus forming a three-dimensional network. The amorphous or filamentous material was observed around the fibrocyte cell body and along the cell processes, where the localization of type VI collagen was confirmed by immunohistochemistry using anti-type VI collagen antibody. After treatment with 20 mM adenosine 5'-triphosphate (ATP), 100 nm periodic fibrils, an aggregated form of type VI collagen, were formed in the place where amorphous or filamentous material was present before the treatment. In myotendinous junction, the ATP-aggregated periodic fibrils were observed to associate with the external lamina of the muscle cells as well as among junctional tendon collagen fibrils. In the tendon-bone boundary, ATP-aggregated periodic fibrils were observed around fibrocartilage-like cells in the uncalcifying area but not in the calcification front. Prolonged ATP treatment or hyaluronidase predigestion caused the formation of type VI collagen periodic fibrils in the area near the calcified matrix.

CONCLUSIONS

The distribution of type VI collagen in mouse masseter tendon is different in different anatomical position. This may reflect the different functional demand for this collagen.

In vivo effect of TGF- beta 1. Enhanced intimal thickening by administration of TGF- beta 1 in rabbit arteries injured with a balloon catheter

The in vivo effect of transforming growth factor-beta 1 (TGF-beta 1) was studied in a model system in which arterial intimal thickening was induced by injury of rabbit arteries with a balloon catheter (BCI). Intimal area and its ratio to medial area in carotid arteries after BCI were significantly higher in rabbits treated with 10 micrograms/kg TGF-beta 1 and 10 mg/kg aspirin i.v. QD (TGF-beta 1 group) than in those treated with 10 mg/kg aspirin i.v. QD only (control group). Intimal cell numbers in the TGF-beta 1 and control groups were not significantly different from each other, but matrix volume in the intimal layer was significantly higher in the TGF-beta 1 group. By immunohistochemical and Northern blot analyses, the fibronectin content in carotid intimal and medial layers was greater in the TGF-beta 1 group compared with that in the control group. Thus, in intimal thickenings induced by BCI. TGF-beta 1 mainly enhanced the formation of matrix containing fibronectin. Moreover, the mRNAs of TGF-beta 1 and type II receptors were detected in carotid arteries 7 and 14 days after, but not before, BCI. Thus, TGF-beta 1 influences the process of intimal thickening induced by BCI through a receptor-mediated mechanism in vivo. The significance of this fact is discussed in relation to the development of atherosclerosis.

Enhancing effect of platelets on staphylokinase-mediated clot lysis and plasminogen activation

The effects of platelets on clot lysis and plasminogen activation by staphylokinase (SAK) were investigated. At concentrations ranging from 2 x 10(-7) to 1 x 10(-5)g/ml of SAK, the lysis time of platelet-rich plasma clots (PRP-clots) was shorter than that of platelet-poor plasma clots (PPP-clots). This reduction of clot lysis time was observed in a dose-dependent manner on platelet count in PRP. The activation rate of plasminogen by SAK measured by the amidolytic method using S-2251 was enhanced by the addition of washed platelets. These enhancing effects of platelets on clot lysis and plasminogen activation were not altered by pretreatment of platelets with indomethacin and theophylline, but were diminished by platelet disruption. Thus, we concluded that platelets enhance fibrinolytic activity of SAK, and this effect is not due to the release reaction or intracellular contents of platelets, but to the existence of platelet surface in the intact shape as a catalytic site for fibrinolysis.

Effect of endogenous and exogenous EGF on the growth of EGF receptor-hyperproducing human squamous cell carcinoma implanted in nude mice

The effect of epidermal growth factor (EGF) on the biological behaviour of human tumours in vivo is still controversial. We investigated the effect of EGF on the growth of an EGF receptor-hyperproducing human epidermoid carcinoma, A431 tumour, and on a human small-cell lung carcinoma, H69 tumour, without detectable EGF receptor by using sialoadenectomised (sialex) mice as an endogenous EGF-suppressed animal model. The plasma EGF concentration in the sialex athymic mice was significantly lower than that in the sham-operated mice (P < 0.05). After exogenous EGF replacement with an implanted minipump, the plasma EGF concentration was significantly increased in both groups (P < 0.05). There was no significant difference between the body weight growth curves of sialex and sham-operated mice with and without EGF treatment. The tumour weight of A431, both estimated and measured in sialex mice, was significantly lower than that in sham-operated control mice (P < 0.05), and the growth of A431 tumour was significantly increased by exogenous EGF treatment (P < 0.05). Mitotic activity of these tumours detected by immunohistochemical staining for incorporated bromodeoxyuridine indicated a mitosis-stimulatory effect of endogenous and exogenous EGF on A431 tumours. In contrast to these findings on A431 tumours, a growth-stimulatory effect of endogenous and exogenous EGF was not observed in the H69 tumour. These results suggest a growth-promoting effect of physiological levels of endogenous EGF on EGF receptor-hyperproducing human tumours in vivo.

Integrin alpha 6 is a differentiation antigen of human granulosa cells

We previously reported a new murine monoclonal antibody (mAb), OG-1, raised against human granulosa cells (GC) and showed that the OG-1 antigen is a cell surface differentiation-related molecule expressed on GC of follicles and on large luteal cells in the early to midluteal phase. In this study, we further characterized the OG-1 antigen. An immunohistochemical study showed that the OG-1 antigen was also expressed on endometrial glandular and stromal cells and on first trimester and term placental trophoblasts. The antigen purified from endometrium, chorionic villi, or placenta by immunoaffinity chromatography using the mAb OG-1 consisted of a 120-kilodalton (kDa) protein. Partial amino acid sequencing of the 120-kDa protein purified from placenta revealed that the 16 amino acids from the N-terminus were identical to those of the heavy chain of human integrin alpha 6, the molecular mass of which is reportedly 118-126 kDa. We examined the tissue distribution of integrins alpha 6, beta 1, and beta 4, because integrin alpha 6 forms heterodimers with integrins beta 1 or beta 4. Indirect immunofluorescence staining of various follicles and corpora lutea using two known antiintegrin alpha 6 monoclonal antibodies (450-30A1 and GoH3) showed that integrin alpha 6 was expressed on granulosa and large luteal cells in a profile similar to that of the OG-1 antigen. Integrin beta 1 was expressed on granulosa and large luteal cells, but integrin beta 4 was undetectable. Integrin beta 1 was also expressed on thecal and stromal cells. In term placentas, the OG-1 antigen and integrins alpha 6 and beta 4 were expressed on trophoblasts, whereas integrin beta 1 was expressed on villous capillary endothelia. These results indicate that the mAb OG-1 recognizes integrin alpha 6, and that integrin alpha 6 is a differentiation-related antigen of human GC, suggesting the involvement of integrins in human folliculogenesis and luteal formation.

[Clinical characteristics of pancreatitis after cardiovascular surgery]

Increases in pancreatic enzyme levels after cardiovascular surgery were studied, and their clinical characteristics evaluated. The subjects were 128 patients who had undergone cardiovascular surgery (65 patients after valve replacement, 32 after coronary bypass surgery and 31 after aortic artificial graft replacement). The pancreatic enzyme (serum amylase and lypase) levels were monitored serially before and after operation, and amylase fractions were measured at their peaks. The relationships of the peak lypase level with underlying cardiac diseases, background factors, factors related to surgery, factors related to the extracorporeal circulation, presence or absence of symptoms, and treatments were examined. The amylase level exhibited biphasic changes consisting of a peak in which salivary glands amylase (S type) was dominant and a peak in which pancreatic amylase (P type) was dominant. The second peak coincided with the peak lypase and occurred mostly 3 to 10 days after operation. The peak lypase level exceeded the normal range in 78% of all the patients. It exceeded 564 U/l, 4 times the normal value in 28% of the patients, many of whom were symptomatic. So, we recommended that these cases should be treated as "postoperative pancreatitis". A high peak lypase level showed a significant correlation with the history of gallbladder and pancreatic diseases and diabetes mellitus among the background factors and emergency operation and the use of IABP among the surgery-related factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Cyclin D and retinoblastoma gene product expression in actinic keratosis and cutaneous squamous cell carcinoma in relation to p53 expression

Abnormality of the molecules regulating the cell cycle has been shown to lead cells to transformation. Recently, overexpression of cyclin D protein, one of the G1 cyclins, and the abnormality of the retinoblastoma gene have been found in various human cancers. We analyzed the expression of cyclin D, retinoblastoma gene product (pRB) and p53 in actinic keratoses (AKs) and cutaneous squamous cell carcinomas (SCCs) by immunohistochemistry to elucidate the role of these molecules in keratinocyte carcinogenesis. In the normal epidermis, a few cyclin D positive cells were seen mainly at the basal layer. In 11 seborrheic keratoses, no overexpression of cyclin D was observed. Twelve of 26 AKs (46%) and 27 of 45 SCCs (60%) showed cyclin D overexpression. A few pRB positive cells were seen in the basal layer and in the suprabasal spinous layer of the normal epidermis. An abnormality of pRB, loss of expression, was seen in 2 of 26 AKs (8%) and 7 of 45 SCCs (16%). p53 protein was positive in 12 of 26 AKs (46%) and 24 of 45 SCCs (53%). Forty-five SCCs examined were divided into 22 ultraviolet (UV)-related SCCs and 23 UV-unrelated SCCs. Though UV-related SCCs showed a significantly higher incidence of p53 positivity, as previously reported by us, no significant difference in cyclin D overexpression and loss of the pRB expression was observed between UV-related and UV-unrelated SCCs. These results suggest that cyclin D overexpression is frequently involved in keratinocyte carcinogenesis and that this is an early event, as well as p53 abnormality. In addition, abnormality of the retinoblastoma gene is also related to epidermal cell carcinogenesis, though the frequency is relatively low.

[Suppressed increase of C3 receptors on polymorphonuclear leukocytes by stimulation with C5a in diabetes mellitus]

This study was undertaken to clarify the susceptibility to infection of patients with diabetes mellitus. The complement system is activated through the classical and/or the alternative pathways to produce many kinds of anaphylatoxins in the inflammatory process. One of the anaphylatoxins, C5a, possesses both the strong biological activity of a chemotactic factor and the increasing effect of CR1 and CR3 expression on polymorphonuclear leukocytes (PMNs). It is well known that the complement receptors, CR1 and CR3, on PMNs play important roles in the phagocytosis. We studied the changes of the expression of these receptors on PMNs in non-insulin dependent diabetes mellitus after the stimulation with recombinant human C5a. PMNs from 11 patients with non-insulin dependent diabetes mellitus and 11 normal controls were tested. There was no significant difference of CR1 and CR3 expression on PMNs after the addition of 10 ng/ml C5a between patients with diabetes mellitus and normal controls. However, by the stimulation with 50 ng/ml C5a, the increase of the CR3 expression on PMNs of patients with diabetes mellitus was significantly smaller than normal controls (p < 0.02). The increase of the expression of CR1 on PMNs was not significantly different the two groups. It is suggested that the small increase of the CR3 expression on PMNs by the stimulation with C5a is one of the factors of the susceptibility to infection in patients with diabetes mellitus.

Correlation of the clinical manifestations and gene mutations of Japanese xeroderma pigmentosum group A patients

The gene responsible for xeroderma pigmentosum (XP) group A has recently been cloned and designated XPA gene. Previous studies have shown that most Japanese XPA patients have homozygous mutations for the splicing site of intron 3 of the XPA gene, which was recognized by restriction endonuclease (RE) AlwNI (AlwNI mutation). Other mutations found to date have been the nonsense mutation at codon 228 in exon 6, recognized by RE HphI (HphI mutation), and at codon 116 in exon 3, recognized by RE MseI (MseI mutation). Using polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis, we examined the point mutations of the XPA gene in 16 XPA patients, their parents, and their four asymptomatic siblings. We found that eight patients were homozygous for the AlwNI mutation, two were compound heterozygotes for the AlwNI mutation and the HphI mutation, one was a compound heterozygote for the AlwNI mutation and the MseI mutation, three were compound heterozygotes for the AlwNI mutation and an unidentified mutation, and two were compound heterozygotes for the HphI mutation and an unidentified mutation. Investigation of their clinical features suggested that the four patients who were heterozygous for the HphI mutation and the AlwNI or an unidentified mutation had milder clinical manifestations such as later development of skin cancers and milder neurological deterioration, than those patients who were either homozygous for the AlwNI mutation or heterozygous for the AlwNI mutation and MseI mutation.(ABSTRACT TRUNCATED AT 250 WORDS)

Type VI collagen periodic fibrils in the synovium of the mouse temporomandibular joint

Immunohistochemical staining with anti-type VI collagen antibody was strongly positive in the intimal layer and moderately positive in the subsynovium. After treatment with 20 mM ATP, numerous structures with a periodicity of 100 +/- 10 nm (type VI collagen fibrils) appeared around the synovial cells. As the periodic dark bands were stained by ruthenium red, proteoglycan(s) or glycosaminoglycan(s) were probably associated with the type VI collagen fibrils. When the tissue was digested with testicular hyaluronidase before ATP treatment, the periodic fibrils were not found, and only a filamentous network of 100-nm interval was seen around the cells. Thus, type VI collagen is abundant in the synovium of the mouse mandibular joint and is associated with proteoglycans or glycosaminoglycans, which might have a role in its formation.

Single-step purification of prostatic acid phosphatase: immunoaffinity chromatography with a monoclonal antibody

BACKGROUND

Prostatic acid phosphatase (PAP) is an important protein which should be studied further as a tumor marker or as a biologically functional molecule. The purpose of the study was to establish a simple and reliable method to obtain highly pure PAP.

METHODS

Spleen cells from mice immunized with prostatic epithelial cells prepared from benign prostatic hyperplasia tissue were fused with myeloma cells X63Ag8-653. Hybrid cells of interest were selected using the indirect immunofluorescence method with unfixed frozen tissue sections. One clone of the hybrid cell lines was established which secreted the monoclonal antibody specifically reactive to prostatic acid phosphatase. Using this monoclonal antibody, we purified the antigen from human prostatic tissue by means of single-step immunoaffinity chromatography.

RESULTS

SDS-PAGE profiling under reducing conditions indicated that the protein recognized by this antibody consisted of several components of molecular weight 41,000-45,000. Partial amino acid sequence analysis of this protein indicated that these components involved a heterogeneously modified single polypeptide, and that this antigen is identical to human prostatic acid phosphatase.

CONCLUSIONS

This single-step method saves the time needed to purify prostatic acid phosphatase and requires only half a day for the whole procedure. Moreover, the purity of the isolated protein was extremely high. This method seems to be useful not only for purifying prostatic acid phosphatase but also for purifying other proteins from the prostate gland and for analysis of antigenic macromolecules.

[A study on cathepsin B-like substance in cancer of the urinary tract]

Cathepsin B, a cysteine proteinase, has been shown to be increased in tumor tissue and to be responsible for the process of invasion and metastasis. To study the biochemical characteristics of cathepsin B-like substance in the tissue of a non-cancerous kidney and some urologic cancer tissues, we extracted cathepsin B-like substances from a non-cancerous human kidney tissue, human renal tumor, human renal pelvic tumor and human bladder tumor. The cathepsin B-like substance extracted from the non-neoplastic human kidney has a molecular weight of approximately 28,000. On the result of western blotting with anti-human liver cathepsin B antibody, two types of protein were observed in the fraction extracted from urologic cancer tissues. The molecular weights of them were 28,000 and 35,000, respectively. Both types of cathepsin B-like substances had the same activities for benzyloxy-carbonyl-L-arginine-L-arginine-4-methyl-7-coumarylamide, and both activities were inhibited by (L-3-transcarboxyoxiran-2-carbonyl)-L-leucyl-agmatin. These findings suggest that both cancer cells of the renal parenchyma and urothelium secrete cathepsin B-like protease which express not only a normal cathepsin B but also a higher molecular weight of cathepsin B-like protease and that a higher one plays an important role in a process of invasion.

Tissue-specific activation of tumor marker glutathione transferase P transgenes in transgenic rats

By means of transgenic rats, we have recently shown that the GPEI enhancer of the glutathione transferase P (GST-P) gene, which has two one-base-missmatched AP-1 sites locating palindromically with three-base spacing in between, is sufficient for conferring tumor-specific activation of the gene in vivo. It is noted that there is another consensus AP-1 site near the promoter of this gene. By using seven independent transgenic rats, bearing distinct areas of the GST-P gene that are connected to the chloramphenicol acetyltransferase (CAT) coding sequence, we analyzed CAT expression in various tissues (brain, lung, liver, kidney, spleen) in these transgenic rats. We found that the ECAT gene, which has sufficient of the upstream regulatory region (approx. 2.9 kb) of the gene containing GPEI, is trans-activated in the kidney and lung of transgenic rats in a similar manner to endogenous GST-P. When either the GPEI core sequence or the AP-1 site near the promoter is deleted, CAT expression decreases to almost background level. Substitution of the GPEI core or the AP-1 site near the promoter to this silent construct (5CATGPEIcore) reconstituted CAT expression in the transgenic rats. In these rats, CAT was expressed in the brain and lung rather than in the kidney, showing a somewhat different pattern from the endogenous GST-P. In the brain tissue of the 5CATGPEIcore transgenic rat, CAT was demonstrated in the glia cells, which is consistent with endogenous GST-P expression. These results suggest that a relatively long upstream region (approx. 2.9 kb) is required for tissue-specific expression of the GST-P gene and that GST-P expression in the brain may be regulated differently from its expression in other organs.

Visual findings and histologic diagnosis of pelvic endometriosis under laparoscopy and laparotomy

OBJECTIVE

To assess the diagnostic value of visual findings in the diagnosis of endometriosis from the histological point of view.

STUDY DESIGN

212 specimens from 107 patients with benign (74.8%) or malignant (25.2%) disease were obtained by biopsy or resection under laparoscopy (65 patients) or laparotomy (42 patients). Ages ranged from 19 to 62 (mean age 36.4). Visual findings were classified according to the criteria established by the Endometriosis Committee of the Japan Society of Obstetrics and Gynecology in 1993. Specimens were stained with hematoxylin-eosin, and 15 cases with periodic acid-Schiff stain or silver impregnation stain.

RESULTS

Among pigmented lesions, endometriosis was found in 73.0% of specimens from the pelvic peritoneum and in 56.4% of those from the ovaries. Blueberry spots in the pelvic peritoneum as well as ovarian chocolate cysts showed the highest positive rate. In the presence of multiple or complex pigmented lesions of the pelvic area, the rate was still higher (88.6%). Those rates were due to our inclusion of inaccurate and incomplete biopsy specimens. Endometriosis of nonpigmented lesions was found in only 11 patients (12.0%) who also had pigmented lesions and/or adenomyosis.

CONCLUSION

The laparoscopic diagnosis of endometriosis can be made only when multiple complex pigmented lesions are observed, but, otherwise, histopathological confirmation is necessary.

A proposal of FK506 optimal dosing in living related liver transplantations

We analyzed the relation between FK506 trough levels (ELISA: patients 1-41, IMx: patients 42-70) and rejection and/or viral infection episodes, retrospectively, in the first 70 consecutive cases of living related liver transplantation. Twenty patients (28.6%) had rejection episodes. Of the 13 patients who had evidence of rejection during the first 3 months, 6 patients without infection and 7 patients with viral infection showed low concentrations of FK506 (< 5 ng/ml). Twelve patients were treated and improved with high dose steroid administration and an increase in the FK506 dosage. One patient died of refractory rejection. Nine patients had evidence of rejection after the first 3 months. In 3 patients, weaning from FK506 initiated the rejection episodes. Five patients repeated rejection and 4 patients required a third immunosuppressant (azathioprine). Viral infection included CMV (11 cases), EBV (13 cases), HZV (3 cases), and HSV (1 case). Excess immunosuppression might have been the cause, but no clear correlation was found. We propose that the optimal dosage of FK506 obtained by monitoring the trough levels using the IMx method should maintain a 10-20 ng/ml level during the first month, and a 5-10 ng/ml level at the second and third months.

Idiopathic colonic phlebitis with massive ascites

We describe a 35-year-old woman with colonic phlebitis of unknown origin accompanied by effusion of serum protein into the peritoneal cavity. Abdominal ultrasonography and computed tomography showed massive ascites and edematous wall thickness of the colon. Laboratory examination of the peritoneal fluid showed a high concentration of protein, probably due to nonselective efflux of serum protein. The main histopathological finding was extensive edema of the submucosa with vasculitis in the colon. This kind of phlebitis with massive ascites, but without systemic involvement, and with the ascitic fluid almost identical to the serum protein level, has not been reported previously.

Platelet activation is not involved in acceleration of the coagulation system in acute cardioembolic stroke with nonvalvular atrial fibrillation

BACKGROUND AND PURPOSE

It is generally accepted that the coagulation system is activated in ischemic stroke and that platelet activation is involved in the pathogenesis of this disease. However, little is known about how and to what extent platelet activity participates in coagulation system enhancement. We evaluated the hemostatic condition, especially with regard to platelet function and the coagulation system, within 3 days of onset of acute stroke. The study participants were limited to elderly patients with cardioembolic stroke due to nonvalvular atrial fibrillation.

METHODS

Seventeen elderly patients with acute cardioembolic stroke due to nonvalvular atrial fibrillation were investigated. Within 3 days of stroke onset, beta-thromboglobulin (BTG), platelet factor 4 (PF4), thrombin-antithrombin III complex (TAT), and D-dimer from arterial blood were carefully evaluated in these patients. Blood samples from 19 healthy age- and sex-matched control subjects were also examined.

RESULTS

The two studied markers of platelet activity did not change in the patients or the control subjects, and the between-group differences between the stroke and control groups were not statistically significant (BTG, 43.8 versus 31.9 ng/mL; PF4, 9.06 versus 5.78 ng/mL; respectively). In contrast, the two studied coagulation-system indicators were markedly elevated in the patients compared with the control subjects (TAT, 13.8 versus 3.5 ng/mL, P < .01; D-dimer, 366.3 versus 147.2 ng/mL, P < .01; respectively).

CONCLUSIONS

Platelet function was not enhanced in the acute stage of cardioembolic stroke with nonvalvular atrial fibrillation. This result indicates that enhancement of the coagulation system in cardioembolic stroke is not the result of platelet hyperfunction, ie, "platelet-fibrin" thrombi, but rather of "stasis-related" thrombi formation.

A porcine homolog of human integrin alpha 6 is a differentiation antigen of granulosa cells

To search for new molecules relating to the mechanism(s) of follicular differentiation, we raised a new monoclonal antibody (mAb), POG-2, which reacted with the surface of porcine ovarian granulosa cells. An immunohistological study revealed that the antigen appeared initially on the primary follicles. The antigen expression increased during follicular development, reached the highest level in small follicles 1-2 mm in diameter, and then decreased in the preovulatory follicles. The antigen was not detected on luteal cells in the CL. SDS-PAGE profiles of POG-2 antigen purified from isolated porcine granulosa cells by immunoaffinity chromatography indicated that it consisted of two proteins (120 and 130 kDa) and that the antigenic epitope of POG-2 was on the 120-kDa protein. We next purified a large amount of POG-2 antigen from the homogenate of porcine ovaries by immunoaffinity chromatography. Analysis of the partial amino acid sequence of the 120-kDa protein showed that 16 amino acids from the amino terminus were very similar to those of both human and murine mature integrin alpha 6, with 88% homology. SDS-PAGE profiles revealed that the 120-kDa protein was bound to a 28-30-kDa protein by a disulfide bond; this was compatible with the reported characteristics of human integrin alpha 6. We then examined the immunoreactive distribution of integrin alpha 6 using anti-integrin alpha 6 mAb GoH3. The staining profiles obtained with GoH3 were very similar to those obtained with POG-2. These findings showed that the molecule detected by POG-2 was a porcine homolog of human integrin alpha 6 and that integrin alpha 6 was a differentiation antigen of porcine granulosa cells, suggesting an involvement of integrins in follicular differentiation.

Loss of heterozygosity in chromosomes 1, 5, 7 and 13 in mouse hepatoma detected by systematic genome-wide scanning using RLGS genetic map

We have developed an RLGS-based scanning system to detect DNA alteration in tumor tissues, using 575 mapped spots/loci in a single gel. This system is very powerful for screening and identifying not only loss of heterozygosity (LOH) but also DNA methylation change. In this study, we applied this system to search for the LOH of hepatoma from an interspecific F1 hybrid between Mus spretus and C57BL/6 with SV40 early T antigen transgene connected to a mouse major urinary protein enhancer/promoter. Comparing the RLGS profiles of each tumor to that of the normal tissue showed significant LOH in chromosomes 1, 5, 7 and 13.