Intracranial malignant meningioma with abdominal metastases associated with hypoglycemic shock: a case report

A thirty-year-old male with an intracranial malignant meningioma, first diagnosed 9 years ago, with three recurrences was admitted with a hypoglycemic shock. The blood glucose level was 17 mg/dl, requiring treatment with high doses of intravenous and oral dextrose for improvement. A large metastatic tumor in the liver was noted. All hormones and peptides influencing blood glucose levels were in their normal levels. Chemo-embolization and injection of anti-cancer drugs was employed in the management of the metastatic tumor. Positron emission tomography was performed to measure the glucose metabolism of the abdominal tumor and it indicated that glucose consumption within the tumor was much elevated than the surrounding abdominal organs. Hypoglycemia secondary to primary hepatoma or islet-cell cancer has been frequently described, but a complication of metastatic meningioma is an exceedingly rare event. Elevated glucose consumption within the tumor might be addressed as one of the reasons for hypoglycemia, not due to the elevated serum levels of insulin or IGF, but due to the closely related blood glucose level.

Sequential mRNA expression for immediate early genes, cytokines, and neurotrophins in spinal cord injury

In this communication, we demonstrate the sequential expression of endogenous molecules, including immediate early genes (IEGs), cytokines, neurotrophins, and neurotrophin receptors in the injured spinal cord. In the acute phase, expression of IEGs and cytokines mRNAs were rapidly upregulated within 1 h in nonneuronal cells in the lesioned sites and the surrounding spinal white and gray matter. Maximal expression was observed at 1 h for c-fos and TNF-alpha mRNAs, at 3 h for c-jun and IL-6 mRNAs, and at 6 h for IL-1 beta mRNA, and these signals were virtually nondetectable after 6-12 h from the onset of the injury. Some of these genes products may promote the degeneration of damaged cells and tissues, while others may be involved in the subsequent repair processes. In the subacute phase, expression of NGF, BDNF, NT-3, p75LNGFR and Trk B mRNAs began to increase in the nonneuronal cells and neuronal cells from 6 h, and peaked at 24-72 h in the area where expression of mRNAs for IEGs and cytokines overlapped. Signals for IL-6 mRNA were also observed in motoneurons at 24-72 h after the injury, with the suggestion that these molecules may be involved in promoting axonal sprouting in the injured spinal cord. Of further interest was the finding that this upregulation of IL-1 beta, BDNF, and NT-3 mRNAs in injured spinal cord was attenuated by treatment with high dose glucocorticoids, with the suggestion that the downregulation of BDNF and NT-3 might be disadvantageous to survival and axonal sprouting of spinal neurons.

Topological analysis of p21WAF1/CIP1 expression in esophageal squamous dysplasia

In the normal stratified squamous epithelium of the esophagus, only the third to the fifth layers of cells express the cyclin-dependent kinase inhibitor p21WAF1/CIP1 (p21). Using immunohistochemical staining, we examined the topological distribution of cells expressing p21, p53, Ki67, and cytokeratin 10 (CK10), a differentiation marker of esophageal squamous cell carcinoma (SCC), in 25 superficial SCCs and 72 dysplastic lesions of the esophagus. Image analysis of p21, p53, and Ki67 expression was also performed in 48 dysplastic lesions. In superficial SCCs, although Ki67- and p53-expressing cells were mainly distributed in the deep layers of tumors despite tumor differentiation, the distribution of p21 correlated with tumor differentiation. In dysplastic lesions, p53- and Ki67-coexpressing cells tended to locate in the same layers and expand in the lower layers of epithelium with the progression of dysplasia. p21-expressing cells shifted to the upper layers of the epithelium with the progression of dysplasia. However, this change was heterogeneous; in some lesions, p21-expressing cells were confined to the superficial layers of atypical cells (confined type), whereas in others, p21-overexpressing cells were scattered among atypical cells (scattered type). CK10 expression was observed in 25% of dysplastic lesions, and the frequency of CK10 expression was significantly higher in the scattered than in the confined type. Our results suggest that esophageal squamous dysplasia represents the earliest pathological process in esophageal squamous carcinogenesis. Our results also suggest that differentiation of esophageal SCC is determined at the stage of dysplasia, and that p21 plays a critical role in the differentiation process.

Occupational lifting is associated with hip osteoarthritis: a Japanese case-control study

OBJECTIVE

Hip osteoarthritis (OA) is a frequent cause of pain and disability in Western countries, but the disorder is less common in Japan. A case-control study in Britain found obesity, hip injury, and occupational lifting to be associated with hip OA among men and women. However, there are few epidemiological studies concerning factors associated with hip OA in Japan. We performed a comparable case-control study of the disorder in Japan, and contrasted the findings with those from Britain.

METHODS

The study was carried out in 2 health districts in Wakayama Prefecture, Japan. Cases were men and women aged > or = 45 years listed for total hip arthroplasty due to OA over one year, and who did not have an established cause of secondary OA (e.g., rheumatoid arthritis, ankylosing spondylitis). For each case, a control was selected randomly from the general population and was individually matched to the case for age, sex, and district of residence. Cases and controls were interviewed with a structured questionnaire about medical history, physical activity, socioeconomic factors, and occupation. Measurements were made of height and weight.

RESULTS

One hundred fourteen cases (103 women, 11 men) were compared with 114 controls. We found no relationship between obesity and hip OA (OR = 1.0, 95% CI 0.5-1.9; highest vs lowest thirds of distribution of body mass index). There was, however, a statistically significant association between occupational lifting and hip OA, such that regular lifting of 25 kg in the individual's first job (OR = 3.6, 95% CI 1.3-9.7) or of 50 kg in their main job (OR = 4.0, 95% CI 1.1-14.2) was associated with increased risk of hip OA. These associations remained after adjustment for potential confounding variables. In contrast, those subjects who spent > 2 h each day sitting during their first job were significantly less likely to have the disorder (crude OR = 0.5, 95% CI 0.3-0.9). This association also remained statistically significant after adjustment for potential risk factors.

CONCLUSION

Our findings support the hypothesis that occupational physical activity, particularly the lifting of very heavy loads in the workplace at regular intervals, predisposes to hip OA in both Britain and Japan. The lack of association between obesity or hand involvement and hip OA in Japan suggests that the contribution of constitutional and mechanical risk factors to this disorder might differ in different populations. However, attention to manual handling in the workplace would appear an important aspect of preventive strategies against hip OA in Western and Oriental populations.

[An ultrasonic study of the relationship between extracranial carotid atherosclerosis and intracerebral hemorrhage]

We have evaluated the relationship between carotid atherosclerotic change and intracerebral hemorrhage patients. Forty-eight patients with intracerebral hemorrhage treated at our institution were included in this study. Their ages ranged from 38 to 86 years old (average: 61.5 years). There were 28 cases of putaminal hemorrhage and 20 cases of thalamic hemorrhage. Evacuation of hematoma or ventricle drainage was performed in 18 cases within 3 days after the onset of symptoms. The outcome in these cases was that 40 patients survived and 8 patients died. Carotid atherosclerosis was evaluated by B mode-ultrasonography. The severity of carotid atherosclerosis was assessed by using two indicators; incidence of carotid atherosclerosis and maximum percentage diameter of the stenosis. Carotid atherosclerosis on B mode-ultrasonography was detected more frequently in patients with thalamic hemorrhage (84.2%) than in those with putaminal hemorrhage (51.7%). Maximum percentage stenosis of thalamic hemorrhage (17.2 +/- 15.2%) was higher than maximum percentage stenosis of putaminal hemorrhage (6.4 +/- 9.7%). In conclusion, carotid atherosclerosis was an effective indicator of not only ischemical cerebrovascular disease but also of intracerebral hemorrhage.

Serum levels of tissue inhibitor of metalloproteinases 2 in patients with systemic sclerosis

BACKGROUND

The serum tissue inhibitor of metalloproteinases 1 (TIMP-1) level was reported to be a useful indicator of disease activity, especially of lung fibrosis in patients with systemic sclerosis. TIMP-2 is also an important inhibitor of matrix metalloproteinases (MMPs), such as interstitial collagenase, gelatinase, and stromelysin, which control the metabolism of the extracellular matrix. However, serum levels of TIMP-2 in patients with systemic sclerosis (SSc) have not been investigated.

OBJECTIVE

We sought to determine the clinical significance of serum levels of TIMP-2 and MMP-2 in patients with SSc.

METHODS

Serum samples were obtained from 128 patients with SSc (68 with limited cutaneous SSc and 60 with diffuse cutaneous SSc). Twenty-seven serum samples from healthy age- and sex-matched individuals were also examined as controls. The TIMP-2 and MMP-2 levels were determined by means of sandwich enzyme-linked immunosorbent assays.

RESULTS

The serum TIMP-2 levels were elevated in 29 (22.7%) of the 128 patients with SSc and were significantly higher than those of the healthy control subjects. The serum TIMP-2 levels were significantly correlated with the extent of skin sclerosis in the patients with SSc. The incidence of decreased percentage of the diffusing capacity of lung for carbon monoxide (DLCO ) and that of an elevated erythrocyte sedimentation rate were significantly greater in the patients with elevated TIMP-2 levels compared with the patients with normal TIMP-2 levels (P <.05). When these patients were classified into 2 groups by disease activity, TIMP-2 levels were significantly more elevated in the high active group than in those low active group (P <.001). The serum MMP-2 levels of the patients with SSc were not significantly higher than those of the healthy control subjects.

CONCLUSION

These findings suggest that the serum TIMP-2 level is a useful marker of the extent of skin sclerosis and disease activity in patients with SSc. The balance of TIMP-2 and MMP-2 may play an important role in patients with SSc. Furthermore, TIMP-2 may be thought to contribute to the development of disease in patients with SSc.

Effect of endothelin-1(1-31) on intracellular free calcium in cultured human mesangial cells

We found that human chymase selectively produces 31-amino-acid length endothelins (1-31) (ETs(1-31)). We investigated the effect of synthetic ET-1(1-31) on intracellular free Ca2+ concentration ([Ca2+]i) in cultured human mesangial cells. ET-1(1-31) increased [Ca2+]i in a concentration-dependent manner to a similar extent as ET-1. The ET-1 (1-31)-induced [Ca2+]i increase was not influenced by removal of extracellular Ca2+ but was inhibited by thapsigargin. ET-1(1-31)-induced [Ca2+]i increase was not affected by phosphoramidon. It was inhibited by BQ123, but not by BQ788. These results suggest that ET-1(1-31) by itself exhibits bioactive properties probably through endothelin ET(A) or ET(A)-like receptors. Since human chymase has been reported to exist in the kidney, ET-1(1-31) may be a candidate substance for mesangium-relevant diseases.

Stimulatory effect of enkephalins on calcium efflux from bovine adrenal chromaffin cells in culture

The effects of leucine- and methionine-enkephalin, opiate peptides, on Ca2+ efflux from cultured bovine adrenal chromaffin cells were examined. These enkephalins stimulated the efflux of 45Ca2+ from cells in a concentration-dependent manner (10(-8) M-10(-6) M). Leucine-enkephalin did not increase the intracellular free Ca2+ level, 45Ca2+ uptake, catecholamine secretion, cAMP level or cGMP level. The peptide-stimulated 45Ca2+ efflux was not inhibited by incubation in Ca2+-free medium, but was inhibited by incubation in Na+-free medium. These results indicate that enkephalins stimulate extracellular Na+-dependent 45Ca2+ efflux from cultured bovine adrenal chromaffin cells, probably by stimulating membrane Na+/Ca2+ exchange.

mRNA expression of interleukins, phospholipase A2, and nitric oxide synthase in the nerve root and dorsal root ganglion induced by autologous nucleus pulposus in the rat

The purpose of this study was to examine whether mRNA of interleukin-A2, interleukin-6, phospholipase A2, and nitric oxide synthase was expressed in the nerve root and dorsal root ganglion of an animal model in which exposure to the nucleus pulposus induced mechanical hyperalgesia, a pain-related behavior. Autologous nucleus pulposus obtained from coccygeal discs was relocated on the L4 and L5 lumbar nerve roots after partial laminectomy. The reflex response to noxious mechanical stimuli to the hindpaw was measured preoperatively and to 4 weeks postoperatively. With a reverse transcription-polymerase chain reaction technique, expression of interleukin-1beta, interleukin-6, phospholipase A2, and inducible nitric oxide synthase genes in the nerve root and dorsal root ganglion was observed at 1, 2, and 4 weeks postoperatively. Mechanical hyperalgesia was observed from 3 days to 2 weeks postoperatively. The expression of interleukin-1beta, phospholipase A2, and inducible nitric oxide synthase mRNAs increased after only 1 week. This increase was related to mechanical hyperalgesia. Expression of interleukin-6 was detected in the neural tissue over time. It is possible that interleukin-1beta, phospholipase A2, and inducible nitric oxide in the nerve root or dorsal root ganglion, or in both, produce sciatic pain in the early stage of herniation of the lumbar disc.

Changes of plasma fibronectin in patients treated with cryofiltration for an extended period

The purpose of this study was to evaluate correlations between extra domain A fibronectin (EDA[+]FN) in plasma and the clinical course in cryofiltration for an extended period. Two patients with systemic lupus erythematosus (SLE), 1 with aortitis syndrome, 1 with ankylosis spondylitis, 1 with polymyositis, 1 with rheumatoid arthritis, and 1 with chronic rejection of a kidney graft, were regularly treated with cryofiltration for more than 3 years. The average level of EDA(+)FN in each year did not show significant change in clinically stable patients with aortitis syndrome, polymyositis, and SLE. In the patient with ankylosis spondylitis, the average level of EDA(+)FN in each year elevated, so cryofiltration was performed frequently. On the other hand, cryofiltration could not attenuate the progression in the juvenile rheumatoid arthritis patient. In the patient with chronic rejection of a kidney graft, kidney function without hemodialysis could be prolonged for 33 months by cryofiltration. The average level of EDA(+)FN elevated as the graft function got worse. Changes of average level of EDA(+)FN in plasma corresponded with changes in the clinical courses of patients with autoimmune disease and chronic rejection of a kidney graft. The EDA(+)FN level might give prognostic information and determine the interval of cryofiltration.

Comparison of the effects of endothelin-1, -2 and -3 (1-31) on changes in [Ca2+]i in human coronary artery smooth muscle cells

We have previously found that human chymase selectively cleaves big endothelins (ETs) at the Tyr31-Gly32 bond to produce 31-amino-acid endothelins, ETs (1-31). In the present study, we investigated the effects of ETs (1-31) on changes in intracellular free Ca2+ ([Ca2+]i) in cultured human coronary artery smooth muscle cells (HCASMCs) using confocal laser microscopy. ETs (1-31) increased [Ca2+]i in a concentration-dependent manner. Phosphoramidon did not inhibit the increases in [Ca2+]i caused by ETs (1-31). The [Ca2+]i increases induced by ETs (1-31) were compared to those of ETs (1-21) and big ETs. ET-1 (1-21) was about 10-times more potent than big ET-1 or ET-1 (1-31), whereas big ET-2 was 10-times less potent than ET-2 (1-21) or ET-2 (1-31). ETs (1-31) may induce [Ca2+]i increase through ET(A)-type or ET(A)-type-like receptors. The 10(-12) M ET (1-31)-induced increases in [Ca2+]i were not affected by removal of extracellular Ca2+, but were inhibited by thapsigargin. These results suggested that ET-1, -2 and -3 (1-31) showed similar potencies in increasing [Ca2+]i and mechanisms of ET (1-31)-induced increases in [Ca2+]i may be similar among the three ETs (1-31).

New technique of leukocytapheresis by the use of nonwoven polyester fiber filter for inflammatory bowel disease

Leukocytapheresis (LCAP) is widely used for the treatment of immunological diseases. We studied a new treatment of LCAP using a nonwoven polyester fiber filter. In a basic study, 30-70% of leukocytes were removed. Also, 30-68% of the leukocyte subsets were removed. Sixteen inflammatory bowel disease (IBD) patients, mainly with ulcerative colitis (UC), were treated by this method. Their cytokine activity was normalized in the filter and in the peripheral blood. Eleven of 12 patients with UC were induced to remission. Four patients with Crohn's disease (CD) exhibited improvement. The LCAP using a nonwoven polyester fiber filter was very efficient for treating the patients with IBD. Also, it will be a very useful treatment for immunological diseases and extracorporeal immunomodulation.

Ligamentum flavum hematoma in the lumbar spine

A patient who presented with symptoms suggestive of nerve root compression secondary to an extradural mass was found to have a hematoma in the ligamentum flavum. Pathological examination of surgical specimens revealed an old hemorrhage, and hemosiderin deposits around organized granulation tissue within the ligamentum flavum. Vessels within the ligamentum flavum had, presumably, ruptured during minor trauma when the patient stood up.

Hypolipidemic effect of NK-104, a potent HMG-CoA reductase inhibitor, in guinea pigs

The hypolipidemic effect of NK-104 and its mechanisms of action (effects on hepatic sterol synthesis, low density lipoprotein (LDL)-receptor expression and very low density lipoprotein (VLDL) secretion) were studied in guinea pigs using simvastatin as a reference substance. There was a dose-dependent and significant reduction of both plasma total cholesterol (17.4, 24.5 and 45.3% at 0.3, 1 and 3 mg/kg, respectively) and triglycerides (21.1 and 32.2% at 1 and 3 mg/kg, respectively) after 14-day administration of NK-104. Simvastatin at 30 mg/kg lowered plasma total cholesterol (25.0%) but not triglyceride levels. NK-104 (3 mg/kg) and simvastatin (30 mg/kg) inhibited hepatic sterol synthesis by approximately 80%, 3 h after dosing, and enhanced LDL receptor binding-capacity of liver membranes 1.5-fold after 14-day dosing. The former group accelerated LDL clearance somewhat more markedly than the latter, and increased fractional catabolic rate 1.8-fold (vs. 1.4-fold). Furthermore, only the NK-104 (3 mg/kg) suppressed VLDL secretion into the liver perfusate (triglyceride. 19.9%; apoB, 24.2%) with extensive reduction of hepatic sterol synthesis caused by prolonged action. These results indicate that NK-104 and simvastatin at 10 times the dosage of the former, similarly enhances hepatic LDL receptor; however, only NK-104 with prolonged action suppresses VLDL secretion to show higher cholesterol-lowering potency and triglyceride-reducing effect.

Kienböck's disease in women

We examined 133 patients with Kienbock's disease, five of whom had bilateral disease. There were 47 women and 86 men. The mean age of patients was 42.7 years (range, 14-80 years). The frequencies of involvement of the right and left sides were approximately equal for women, but male patients tended to have right wrist joint involvement. The side of the affected wrist in the female group differed significantly from that in the male group. The age at onset for women was significantly higher than that for men. The percentage of manual workers was significantly lower among women than among men. The characteristics of Kienböck's disease in women differed from those in men and those previously reported for this disease. These findings suggest that the pathogenesis of Kienböck's disease in women differs from that in men.

[Study on the safety of rapid infusion and the efficacy of incadronate against bone metastasis of breast cancer]

To assess the safety of rapid infusion of incadronate and its efficacy against bone metastasis of breast cancer, we conducted a trial using incadronate therapy for breast cancer patients with bone metastasis. Of the 12 patients, 6 had undergone pamidronate or alendronate therapy. Rapid infusion of incadronate consisted of administration of 10 mg incadronate diluted in 100 ml saline in 30 minutes, and was repeated every two weeks. Each patient underwent 2 to 20 incadronate administrations. With the incadronate therapy, no patients showed hypocalcemia, but 3 patients showed asymptomatic hypophosphoremia. Of the 11 patients with bone pain, 5 patients (45%) experienced pain relief. A decrease in tumor marker levels in serum was found in 5 (56%) of the 9 patients with elevated marker levels. The side effects of incadronate administration were general fatigue (25%), pyrexia (17%) and transient pain increase (17%), but no renal dysfunction was found. In conclusion, rapid infusion of incadronate was a safe treatment and the incadronate therapy was effective against bone metastasis of breast cancer.

[Breast cancer with osteoblastic bone metastasis treated successfully with bisphosphonate: a case report]

A 52-year-old woman with painful osteoblastic bone metastasis received pamidronate therapy which resulted in marked pain relief with a normalization of elevated tumor marker levels. However, the patient complained of increased pain after the 26th pamidronate infusion. Although a change from pamidronate to alendronate therapy did not relieve bone pain, a second change from alendronate to incadronate therapy resulted in pain relief with a decrease in re-elevated tumor marker levels. These findings suggest that bisphosphonate therapy is effective against osteoblastic bone metastasis in breast cancer, and that sequential therapy with bisphosphonates may be effective against bone metastasis in some cases.

Experimental spinal fusion using sintered bovine bone coated with type I collagen and recombinant human bone morphogenetic protein-2

STUDY DESIGN

Posterolateral lumbar transverse process fusion using recombinant human bone morphogenetic protein (rhBMP)-2 carried by sintered bovine bone and Type I collagen complex was compared with fusion achieved using autogeneous bone graft or sintered bovine bone alone.

OBJECTIVES

This study examined the efficacy of sintered bovine bone coated with Type I collagen as a carrier of rhBMP-2 for lumbar intertransverse process arthrodesis.

SUMMARY OF BACKGROUND DATA

Posterolateral intertransverse process arthrodesis using osteoinductive growth factors is performed experimentally in the lumbar spine. The previous studies revealed the efficacy of osteoinductive factors applied to carriers having no bony structures, such as collagen sheet or polylactic acid polymer, for the spinal fusion. However, in their studies, a large amount of osteoinductive proteins have been applied for the spinal fusion. We used the sintered bovine bone "True Bone Ceramics" (TBC; Koken Co., Tokyo, Japan) coated with type I collagen as the carrier. True Bone Ceramics is the only biomaterial possessing a natural trabecular structure and an organized crystal of bone minerals.

METHODS

Twenty-two adult rabbits underwent bilateral lumbar intertransverse process arthrodesis at L4-L5. The animals were divided into four groups and had materials implanted as follows: autologous bone group, grafted autologous corticocancellous bone harvested from the posterior iliac crest; implanted TBC group; TBC collagen group, implanted TBC coated with Type I collagen infiltrating into the porous space; and BMP group, implanted sintered bovine bone coated with Type I collagen infiltrated with 100 micrograms of rhBMP-2. Spinal fusion was evaluated by radiographic analysis, manual palpation, biomechanical testing, and histologic examination 6 weeks after surgery.

RESULTS

Two rabbits were killed because of infection and lumbar plexus palsy. Radiographs of the BMP group showed a homogeneous fusion mass at the intertransverse area, and stability was confirmed by dynamic radiographs at 3 and 6 weeks after surgery. In the BMP group, a bony mass in the intertransverse area was more prominent than in the other groups. The BMP group had a higher fusion rate based on manual palpation than the-other groups, and BMP fusions showed significantly higher tensile strength and stiffer fusion. The histologic findings in the BMP group demonstrated membranous bone and endochondral bone formations between the transverse process and the fusion mass. In the other groups, continuous trabecular bone formation was observed in the area surrounding the transverse process, but gaps between grafted fragments and less mature bone formation were present in the intertransverse area.

CONCLUSIONS

Sintered bovine bone coated with Type I collagen and rhBMP-2 resulted in a higher fusion rate than the autograft and can be used as a carrier for rhBMP-2 in spinal fusion.

[Effective alendronate therapy against a bone metastasis occurring during docetaxel therapy for breast cancer--a case report]

A 65-year-old woman underwent radical operation for breast cancer in December, 1992. Between September, 1994 and January, 1997, she developed local recurrences four times as well as a supraclavicular lymph node recurrence. Each recurrence was treated with surgery and various types of chemoendocrine therapy, including anthracycline-containing chemotherapy. In April, 1997, she had developed a liver metastasis, which showed a partial response to docetaxel therapy. However, she developed a bone metastasis in January, 1998 (9 months after the initiation of docetaxel therapy). In addition to the docetaxel therapy, she was treated with a potent bisphosphonate, alendronate, 10 mg of which was infused every two weeks. Eight alendronate infusions resulted in a marked improvement in the bone metastasis, and the liver metastasis has been in regression for 13 months in response to the docetaxel therapy. In conclusion, alendronate is a promising agent against bone metastases which occur during docetaxel therapy for breast cancer.

Nitric oxide-forming reactions of the water-soluble nitric oxide spin-trapping agent, MGD

The objective of this study was to elucidate the nitric oxide-forming reactions of the iron-N-methyl-D-glucamine dithiocarbamate (Fe-MGD) complex from the nitrogen-containing compound hydroxyurea. The Fe2+(MGD)2 complex is commonly used in electron paramagnetic resonance (EPR) spectroscopic detection of NO both in vivo and in vitro. The reaction of Fe2+(MGD)2 with NO yields the resultant NO-Fe2+(DETC)2 complex, which has a characteristic triplet EPR signal. It is widely believed that only NO reacts with Fe2+(MGD)2 to form the NO-Fe2+(MGD)2 complex. In this report, the mechanism leading to the formation of NO-Fe2+(MGD)2 was investigated using oxygen-uptake studies in conjunction with the EPR spin-trapping technique. We found that the air oxidation of Fe2+(MGD)2 complex results in the formation of the Fe3+(MGD)3 complex, presumably concomitantly with superoxide (O3*-). Dismutation of superoxide forms hydrogen peroxide, which can subsequently reduce Fe3+(MGD)3 back to Fe2+(MGD)2. The addition of NO to the Fe3+(MGD)3 complex resulted in the formation of the NO-Fe2+(MGD)2 complex. Hydroxyurea is not considered to be a spontaneous NO donor, but has to be oxidized in order to form NO. We present data showing that in the presence of oxygen, Fe2+(MGD)2 can oxidize hydroxyurea to yield the stable NO-Fe2+(MGD)2 complex. These results imply that hydroxyurea can be oxidized by reactive oxygen species that are formed from the air oxidation of the Fe2+(MGD)2 complex. Formation of the NO-Fe2+(MGD)2 complex in this case could erroneously be interpreted as spontaneous formation of NO from hydroxyurea. The chemistry of the Fe2+(MGD)2 complexes in aerobic conditions must be taken into account in order to avoid erroneous conclusions. In addition, the use of these complexes may contribute to the overall oxidative stress of the system under investigation.

Impaired recoloration of a discordant liver xenograft in the guinea pig-to-rat combination: physiological insults or immunological responses

BACKGROUND

The aim of this study was to clarify, using guinea pig (GP) syngeneic and xenogeneic liver graft models, the mechanisms of impaired recoloration caused by immunological responses or physiological insults; and to examine the effect of an anti-complement agent, FC43 emulsion, on xenograft rejection.

METHODS AND RESULTS

GP syngeneic and xenogeneic liver grafts flushed with 4 degrees C lactated Ringer's solution were poorly perfused around the porta hepatis, whereas those flushed with 15 degrees C solution were immediately recolored, and the portal venography confirmed homogeneous perfusion throughout the GP livers. Impaired recoloration of GP xenografts was also ameliorated by reduction of ischemic time. Pretreatments with FC43 emulsion significantly extended xenograft survivals. Rejected GP liver xenografts showed C3 deposits on sinusoids and central veins and IgM deposits faintly stained only on some small vessels, but there were no detectable deposits of IgG.

CONCLUSIONS

The impaired recoloration in this model may be caused by physiological insults during the initial stage of revascularization, and the immunological responses that probably followed.