Changes in hepatic lobe volume in biliary tract cancer patients after right portal vein embolization

Changes in lobar volume of the liver and in total hepatic function were studied in 19 patients with biliary tract cancer who underwent right portal vein embolization as preoperative management for extensive liver resection. Computed tomography (CT) was performed to estimate liver volume before and approximately 11 days after embolization. An indocyanine green (ICG) test was performed before and 11 to 13 days after embolization. The calculated volume of the right lobe decreased from 761 +/- 181 cm3 to 625 +/- 110 cm3 11 days after embolization (P < .0001), whereas the volume of the left lobe increased from 420 +/- 94 cm3 to 555 +/- 110 cm3 (P < .0001). Thus, portal embolization produced a gain in left lobe volume of 136 +/- 62 cm3 and an almost equivalent loss in right lobe volume. The hypertrophy ratio of the left lobe, expressed as percentage of postembolization volume of the left lobe to preembolization size, of the 5 patients with diabetes mellitus (DM) was lower than that of the 14 patients without diabetes (116.7 +/- 6.3% vs. 140.4 +/- 18.4%; P < .005). The ICG disappearance rate in 16 patients improved from 0.163 +/- 0.034 to 0.177 +/- 0.027 (P < .05). The improvement was especially evident in 9 of 14 post-jaundice patients, although the rate decreased slightly in 2 patients without jaundice. We conclude that right portal vein embolization can produce a compensatory hypertrophy of the left lobe within 11 days without seriously affecting hepatic function. In diabetic patients, however, a longer interval between embolization and operation may be needed to achieve sufficient hypertrophy of the left lobe.

Thoracoscopic sympathectomy for Buerger's disease: a report on the successful treatment of four patients

We describe herein the successful treatment of four patients with ischemic ulcers or gangrene of the fingers due to Buerger's disease by thoracoscopic sympathectomy, a new method of surgery which eliminates the difficulties associated with the traditional "open" approaches to the thoracic sympathetic chain, such as poor exposure, risk of damage to the adjacent structures, and postoperative pain. After the patients were placed in the lateral decubitus position with unilateral pulmonary ventilation, the thoracic sympathetic ganglia (T) from the lower third of T1 to T3 were resected endoscopically. The operative results were excellent, with improvement or complete resolution of the ulcer being achieved in all four patients. All of the patients were satisfied with the results in terms of ulcer healing, postoperative pain, and cosmetic appearance. Although a postoperative air leakage developed in one patient with a history of pulmonary tuberculosis, it was successfully treated with an adhesive agent. None of the patients developed Horner's syndrome. Thus, because thoracoscopic sympathectomy is easier to perform with a lower risk of complications than conventional thoracic sympathectomy, we recommend this operative approach as the procedure of choice for surgical thoracic sympathectomy.

A hypothesis for cyanide-induced tonic seizures with supporting evidence

A possible relationship among cyanide-induced convulsions, calmodulin, nitric oxide and protein kinase C was investigated in mice. The ED50 value of cyanide as measured by induction of tonic seizures was significantly increased in a dose-dependent manner when mercuric chloride (0.5 or 5.0 nmol/body), gangliosides (GGS) (90 nmol/body), a protein kinase C inhibitor or trifluoperazine (TFP) (45 or 90 nmol/body), a calmodulin inhibitor were preinjected intracerebroventricularly (i.v.t.) and NG-nitro-L-arginine (NNA) (300 mg/kg), a nitric oxide (NO) synthase inhibitor was preinjected intraperitoneally (i.p.) in mice. These results suggest that protein kinase C, calmodulin, and NO dependent cyclic guanosine monophosphate (GMP) dependent enzymes may contribute to the induction of convulsions. In contrast, 2,4-dinitrophenol (DNP) (50 nmol/body, intracerebroventricularly (i.v.t.), an uncoupler of oxidative phosphorylation significantly decreased the ED50 value of cyanide. In addition, DNP (100 nmol/body, i.v.t.) produced a severe tonic seizure in all of the treated mice. These indicate that adenosine triphosphate (ATP) depletion may also contribute in part to the development of cyanide-induced convulsions.

Massive pericardial effusion in a patient with Hashimoto's thyroiditis: histological examination of underlying cardiomyopathy

An unusual case of a hypothyroid patient with huge pericardial effusion due to Hashimoto's thyroiditis is reported. Cardiac tamponade occurred during admission. Eight hundred milliliters of pericardial effusion was withdrawn by pericardiocentesis. Even after successful replacement of thyroid hormone, she had recurrent effusion two years later. Refractory pericardial effusion is a rare complication in treated hypothyroid patients. Underlying cardiomyopathy was presented with hemodynamic and histological examinations.

Interferon-gamma (IFN-gamma) production by human T lymphocytes upon Legionella pneumophila stimulation in vitro

In vitro immune responses to Legionella pneumophila were investigated. When human peripheral blood lymphocytes (PBL) from healthy volunteers were stimulated with formalin-killed L. pneumophila for 7 days in vitro, strong proliferative responses were observed. The responding cells were shown to be a CD4 T cell subset. It was also found that the CD4 T cells secreted significant amounts of IFN-gamma into the PBL culture supernatant. The production of IFN-gamma and IL-4 by PBL was measured semiquantitatively by reverse transcriptase-assisted polymerase chain reaction (RT-PCR) methods. Formalin-killed or live L. pneumophila-stimulated PBL expressed the mRNA for IFN-gamma but not the mRNA for IL-4. The results suggest that the whole bacterium, as opposed to the supernatant, predominantly stimulates Th1 type helper T cells. The cloned T cells specific for L. pneumophila expressed the mRNA for IFN-gamma but not for IL-4. In contrast to formalin-killed or live L. pneumophila stimulation, when PBL were stimulated with the bacterial culture supernatant, the proliferating T cells produced the mRNA for IL-4 as well as for IFN-gamma. A significant correlation between the proliferative response to formalin-killed L. pneumophila and IFN-gamma release in culture was observed (r = 0.6932, P < 0.001) in PBL from 30 healthy volunteers. From these in vitro studies, it is suggested that the whole L. pneumophila bacterium and their soluble antigens stimulate T cells in a manner which results in a different pattern of cytokine production.

Expression of matrix metalloproteinase matrilysin (MMP-7) was induced by activated Ki-ras via AP-1 activation in SW1417 colon cancer cells

The matrix metalloproteinase matrilysin (MMP-7) is a member of the matrix metalloproteinase gene family, which is believed to play an important role in tumor invasion and metastasis. We have previously found that matrilysin mRNA is specifically expressed in colorectal cancers and adenomas and that its message is localized in the tumor cells themselves. We examined the effects of activated Ki-ras oncogene on the expression of matrilysin in colon cancer cells. We showed that both mRNA and the enzymatic activity of matrilysin were induced by the introduction of activated Ki-ras into SW1417 colon cancer cells. To understand the mechanisms regulating this induction, we analyzed alterations of AP-1 activity induced by activated Ki-ras, using the chloramphenicol acetyltransferase assay. AP-1 activity in SW1417 cells expressing activated Ki-ras was higher than that in control cells. The gel-shift assay also showed higher levels of AP-1 binding protein in SW1417 cells expressing activated Ki-ras than those in control cells. Our results suggest that activated Ki-ras may play a role in inducing expression of matrilysin through an AP-1-dependent pathway in colon cancer cells.

Cloning and functional expression of a Na(+)-dependent phosphate co-transporter from human kidney: cDNA cloning and functional expression

A cDNA clone encoding a protein 69% identical in amino acid sequence with that of the Na/P(i) co-transporter NaP(i)-1 was isolated from a human kidney cDNA library. The DNA sequence was identical with that of NPT-1 cDNA published by Chong, Kristjansson, Zoghbi and Hughe (1993) (Genomics, 18, 355-359). In the present study, we have characterized the function of the encoded protein and the tissue distribution of its mRNA. Injection of RNA transcribed from NPT-1 into Xenopus oocytes resulted in expression of Na/P(i) co-transport activity showing a high affinity for P(i) transport (Km 0.29 mM). Kinetic characterization ([P(i)], [Na+]) demonstrated that the expressed transport activity has properties similar to those displayed by oocytes injected with human kidney poly(A)+ RNA. Northern blotting demonstrated that NPT-1 mRNA is expressed in renal cortex, liver and brain but not in other tissues. Hybrid depletion with antisense oligonucleotides to NaP(i)-3 and NPT-1 completely inhibited poly(A)+ RNA-induced Na(+)-dependent P(i) uptake in oocytes. These findings indicate that two high-affinity Na/P(i) cotransporters (NaP(i)-3 and NPT-1) are present in human kidney cortex.

Is CIS of the ureter responsible for skipped lymph node metastasis? A case report

A case of skipped lesion of lymph node metastasis of left ureteral tumour with concurrent carcinoma in situ in the affected ureter is presented. Postoperatively, lymph node metastasis was de novo detected in the left retrocrural and renal hilar regions on CT scan, although only the obturator lymph node was histologically metastatic among the regional lymph nodes completely dissected. The possible explanations of this rare metastatic mode are discussed.

Aldosterone biosynthesis and action in vascular cells

In view of the hypothetical possibility that the vascular renin-angiotensin system (RAS) might include aldosterone biosynthesis and action in the vasculature, we have undertaken a study to identify aldosterone released into the perfusion circuit from the rat mesenteric artery, and to investigate the effects of an angiotensin converting enzyme inhibition (ACEI) on aldosterone production from the vasculature. After 30 min equilibration, 240 mL of perfusate was collected and subjected to reverse-phase HPLC and subsequent mass spectrometry. Mass spectra corresponding to authentic corticosterone and aldosterone were obtained from the samples of mesenteric artery perfusate. Production of aldosterone in the mesenteric artery was not changed by adrenalectomy, although it was reduced in the arterial perfusate from rats pretreated with ACEI. By RT-PCR the expression of CYP 11B2 and mineralocorticoid receptor genes were demonstrated in both vascular endothelial and smooth muscle cells. These studies constitute indirect evidence supporting our hypothesis that locally produced aldosterone in the vascular tissue acts on vascular tone and remodeling via a paracrine or autocrine manner.

Sigma ligands indirectly modulate the NMDA receptor-ion channel complex on intact neuronal cells via sigma 1 site

To investigate the modulatory effects of sigma ligands on the N-methyl-D-aspartate (NMDA) receptor-ion channel complex in vivo, we examined the intact cell binding of 3H-N-[1-(2-thienyl)cyclohexyl]piperidine (3H-TCP) to cultured neuronal cells prepared from fetal rat telencephalon. The 3H-TCP binding was saturable, reversible, and inhibited by a selective NMDA receptor antagonist, D-amino-5-phosphonovaleric acid. MII-limolar Mg2+ inhibited 3H-TCP binding both in the absence and presence of L-glutamate. 5-Methyl-10,11-dihydro-5H-dibenzo [a,d]cyclohepten-5,10-imine maleate (MK801) inhibited 3H-TCP intact cell binding in a competitive manner, while haloperidol inhibited it in a noncompetitive manner. The effect of the test drugs to inhibit 3H-TCP intact cell binding was in the order of dextromethorphan, haloperidol > (+/-)MK 801 > (+)pentazocine > (-)pentazocine > DTG > PCP > (+)-N-allylnormetazocine [(+)SKF 10047] > (+)3-(3-hydroxyphenyl)-N- (1-propyl)piperidine [(+)3-PPP] > (-)SKF 10047 > (-)3-PPP. The IC50 values of the six sigma ligands for 3H-TCP binding were closely correlated with the Ki values of the corresponding drugs for DTG site 1 in the guinea pig brain reported by Rothman et al. (1991). These findings suggest that the sigma ligand indirectly modulates the NMDA receptor ion channel complex, presumably through sigma 1 sites in vivo as well as in vitro.

NE-100, a novel sigma ligand: effects on [3H]TCP binding to intact primary cultured neuronal cells

N,N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]-ethylamine monohydrochloride (NE-100), a potent and highly selective sigma ligand, haloperidol, (+)pentazocine, 1-(cyclopropyl-methyl)-4-(2'-(4"-fluorophenyl)-2'-oxoethyl) piperidine HBr (DuP 734) and 4-(2'-(4"-cyanophenyl)-2'-oxoethyl) 1-(cyclopropylmethyl)piperidine (XJ 448) inhibited carbachol-induced inositol 1,4,5-triphosphate (IP3) formation in a dose-dependent manner. The rank order of potency of the tested drugs for inhibition was: haloperidol > or = (+)pentazocine = NE-100 > DuP 734 = XJ 448. In addition, the effects of NE-100, DuP 734 and XJ 448 upon [3H]TCP binding were examined using primary cultured neuronal cells derived from the fetal rat telencephalon. These drugs inhibited [3H]TCP binding to intact cells. The ability of the test drugs to inhibit [3H]TCP binding to primary cultured neuronal cells was in the order: NE-100 > DuP 734 > XJ 448. These observations suggest that NE-100 indirectly modulates the N-methyl-D-aspartate (NMDA)/phencyclidine (PCP) receptor ion channel complex (NMDA receptor-ion channel), presumably through sigma-1 sites.

Hepatic collagen synthesis and degradation during liver regeneration after partial hepatectomy

To elucidate hepatic collagen metabolism during liver regeneration after partial hepatectomy, we measured collagen content, collagen synthesis, and collagen-degrading enzyme activity in the remnant livers of rats 3, 5, 7, and 14 days after a partial hepatectomy of 68%. Hepatic collagen synthesis was significantly higher 3, 5, and 7 days after partial hepatectomy than it was in sham-operated control rats, but there was no such difference 14 days after surgery, the maximal hepatic collagen synthesis being observed 5 days after surgery. Although the collagen concentration in the remnant liver was similar to that in the control liver, the total collagen content of the remnant liver increased rapidly with liver regeneration until 7 days after partial hepatectomy. Hepatic collagenase activity was similar to the control; however, hepatic cathepsin B and cathepsin L activity and the intracellular degradation of newly synthesized collagen were markedly decreased 3, 5, and 7 days after partial hepatectomy compared with the controls. Hepatic collagen synthesis was significantly and inversely correlated with cathepsin L activity and with the intracellular degradation of newly synthesized collagen. These findings suggest that a combination of increased collagen synthesis and decreased intracellular collagen degradation contributes to the rapid supply of collagen that is observed during the early phase of liver regeneration.

[Free rectus abdominis muscle perforating artery flaps for reconstruction of the head and neck defects]

During the past eight years, tissue defects of the head and neck region in a total of 45 patients were repaired with free rectus abdominis muscle perforating artery flaps. These flaps are subclassified into (1) reduced musculocutaneous flaps, (2) thin reduced musculocutaneous flaps, (3) paraumbilical perforator-based flaps, and (4) thin paraumbilical perforator-based flaps. The advantages of these flaps are as follows. Since the flaps involve no or only a small portion of the rectus abdominis muscle, (1) the muscle can be left intact on the abdominal wall, and (2) a thin flap can be easily created by simple defatting of the flap. These flaps overcome the major disadvantages of the conventional rectus abdominis musculocutaneous flap, i.e., bulkiness of the flap and frequent postoperative abdominal herniation. The territory of the thin flaps is within 10 cm around the perforator. These flaps are suitable for defects in the head and neck region, because simultaneous flap elevation is possible at the time of tumor resection. Paraumbilical perforator-based flaps are suitable for young females and elderly patients.

[Diltiazem abolishes the effect of ryanodine in St. Thomas' Hospital cardioplegic solution on the post-ischemic functional recovery]

Calcium-induced calcium release (CICR) from sarcoplasmic reticulum (SR) may contribute to calcium depletion of SR during the infusion of cardioplegic solution, which may protect the intracellular calcium overload observed during myocardial reperfusion. We have, therefore, investigated (1) the ability of ryanodine-containing cardioplegic solution to enhance myocardial protection and (2) the influence of diltiazem, L-type calcium channel blocker, on the ryanodine-enhanced cardioprotective effect in the isolated working rat heart. Hearts (n = 6-8/group) from male Wistar rats were aerobically (37 degrees C) perfused (20 min) with bicarbonate buffer (Ca2+ = 2.4 mM). This was followed by a 3 min infusion of St. Thomas' Hospital cardioplegic solution containing (1) 0 nmol/L of ryanodine or (2) 1.75 nmol/L of ryanodine combined with various concentrations of diltiazem (0, 0.13, 0.25 and 0.50 mumol/L). Hearts were then subjected to 40 min of normothermic (37 degrees C) global ischemia and 35 min of reperfusion (15 min Langendorff, 20 min working). (1) The recovery of aortic flow (%AF) was 52.2 +/- 3.5% in the ryanodine-free group. (2) %AF was 72.0 +/- 1.4%, 50.0 +/- 2.6*, 61.7 +/- 3.2* and 58.3 +/- 2.8*% in the 0, 0.13, 0.25 and 0.50 mumol/L diltiazem groups, respectively (*p < 0.05 vs the 0 mumol/L diltiazem group). Creatine kinase (CK) leakage during Langendorff reperfusion was less in the 0 mumol/L diltizaem (plus 1.75 nmol/L ryanodine) group than the ryanodine-free group.(ABSTRACT TRUNCATED AT 250 WORDS)

[Shortening of hospitalization period for patients with pulmonary tuberculosis]

The development of specific chemotherapeutic agents revolutionally improved the prognosis of tuberculosis and markedly shortened the duration of the treatment. Evidence of successful treatment with short-course regimens for pulmonary tuberculosis has been accumulated. But, the duration of hospitalization tends to be determined empirically and varys among hospitals and clinicians. Generally speaking, the duration of hospitalization is longer in Japan than in the United States and Europian countries. We investigated retrospectively the duration of hospitalization, treatment period, and recurrence rate of the disease for patients with pulmonary tuberculosis who admitted to the Tokyo Metropolitan Fuchu Hospital in the years 1984, 1988, and 1991. Patients who had been previously treated for more than 2 weeks and/or, had severe complications, such as malignancy and miliary tuberculosis were excluded from the study. Cases who died during the hospitalization and discharged without permission were also excluded. Numbers of subjects in each year were 114, 114, and 115 in 1984, 1988, and 1991, respectively. A total of 343 patients (M: 254, F: 89) were enrolled to the study and their average age was 49.4 yr old. A number of patients with both smear and culture positive in sputum bacteriology was 210 (61.2%), and 42 cases (12.2%) were smear negative and culture positive. The results are as follows: (1) Mean duration of hospitalization in the years 1984, 1988, and 1991 were 141, 102, and 72 days, respectively. That is, a mean hospitalization period was shortened to about half during these seven years. (2) According to the chest x-ray classification (Group A: I, II3, B: II1, II2, III3, C: III1, III2), mean durations of hospitalization were 186 days for group A, 143 days for group B, and 108 days for group C in 1984, and 96 days, 76 days, and 59 days in 1991, respectively. (3) According to sputum bacteriology, mean durations of hospitalization were 169 days for (S+/C+) cases, 105 days for (S-/C+) cases, and 90 days for (S-/C-) cases in 1984, and 83 days, 67 days, and 41 days in 1991, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Transformation of type 1 astrocytes with N-ethyl-N-nitrosourea: establishment of an in vitro system and the role of the p53 gene

N-ethyl-N-nitrosourea (ENU)-induced gliomas, animal models of human gliomas, are most frequently oligodendrocytic, while human gliomas tend to be astrocytic. To facilitate a detailed study of human glial carcinogenesis, we developed an in vitro system using type 1 astrocyte transformation with ENU. Type 1 astrocytes from fetal Wistar rat brain were treated by a single dose of ENU. Transformed colonies appeared 50 days after exposure to single doses of ENU greater than 150 micrograms/mL. Cloned cells from these colonies retained the immunohistochemical characteristics of type 1 astrocytes. They showed rapid growth and high saturation densities, colony formation in low (2%) serum medium and gave rise to tumors when injected into nude mice. When p53 expression was studied at each passage, a single cell positive for mutant p53 protein emerged 40 days after ENU treatment. In the next 1-3 passages, the mutant p53 positive cell formed piled-up colonies and exhibited dominant growth. Northern blot analysis showed markedly increased accumulations of p53 mRNA in transformed cells. This in vitro transformation system of type 1 astrocytes provides a valuable tool for further investigations of astrocyte carcinogenesis.

[Percutaneous transluminal angioplasty of the ilio-femoro-popliteal arteries: initial and long-term results]

The initial and long-term results of percutaneous transluminal angioplasty (PTA) were assessed in 254 atherosclerotic lesions of the ilio-femoro-popliteal arteries in 130 patients. There were 122 men and 8 women, aged 36-85 years (average, 68 years). Follow-up periods ranged from 1 to 131 months, with a mean of 42 months. PTA was performed in 6 patients in Fontaine's stage I, 112 patients in stage II, and 12 patients in stage III-IV. We reported initial success rates of 92%, 58%, 83% and 74% for iliac stenosis, occlusion, femoro-popliteal stenosis and occlusion, respectively. Overall, the initial success rate was 82% (203/247). The 5-year patency rates according to Kaplan-Meier analysis were 70%, 69% and 63% for iliac stenosis, occlusion and femoro-popliteal stenosis, respectively. In femoro-popliteal occlusion, the 1-year patency rate was 42%, which was significantly worse than that for stenosis (P < 0.01). The longest patency periods obtained were 131 months in the iliac artery, and 106 months in the femoro-popliteal artery. The recurrence rate within 6 months was significantly higher in patients with diabetes. The recurrence rate between 6 and 12 months was significantly higher in patients with poor run-off, and those of advanced age.

Insulin response after treatment depends on fasting plasma glucose level in NIDDM

We investigated the relationship between the improvement in insulin secretion and glycemic control in non-insulin-dependent diabetes mellitus (NIDDM). Fifty-two patients were classified into three groups according to their pretreatment fasting plasma glucose (FPG) level: Group A, FPG < 7.8 mM, n = 20; Group B, 7.8 mM < or = FPG < 11.1 mM, n = 17; and Group C, 11.1 mM < or = FPG, n = 15. A 75-g oral glucose tolerance test (OGTT) and a glucagon loading test were performed to evaluate insulin secretion before and after treatment. Plasma glucose levels during a 75-g OGTT were decreased significantly after treatment in all groups (P < 0.01). In Group A, there was no significant change in insulin secretion before and after treatment (1466 +/- 213 pM to 1565 +/- 191 pM, P = 0.35). In contrast, in Groups B and C, insulin secretion was poor and suppressed initially, but increased significantly when good glycemic control was obtained after treatment (respectively, 587 +/- 70 pM to 863 +/- 79 pM, P < 0.01, and 621 +/- 94 pM to 1236 +/- 232 pM, P < 0.01). The degree of improvement in insulin secretion in 75-g OGTT correlated positively with the degree of improvement in FPG level after treatment (r = 0.5, P < 0.001). However, the C-peptide response to glucagon did not change before and after treatment. In conclusion, impaired insulin secretion recovered by the good glycemic control in NIDDM with FPG levels above 7.8 mM. Therefore, strict glycemic control (FPG below 7.8 mM) seems important for maintaining good insulin secretion.

Myosin phosphorylation and Ca2+ sensitization in porcine coronary arterial smooth muscle stimulated with endothelin-1

We examined the mechanism of endothelin-1-induced contraction in the porcine coronary artery by assessing the changes in myosin light chain phosphorylation and cytosolic Ca2+ concentration ([Ca2+]i) determined by fura-2 and front-surface fluorometry. Endothelin-1 induced a rapid phosphorylation of myosin both in the presence and in the absence of extracellular Ca2+. During the later phase of contraction (5-30 min), the tension and [Ca2+]i were maintained, while the phosphorylated myosin decreased in the presence of extracellular Ca2+. At a similar extent of [Ca2+]i elevation, endothelin-1 induced a greater tension development than did 118 mM K(+)-depolarization and this was not attributed to a greater degree of phosphorylation of myosin. In the Ca(2+)-depleted strips, endothelin-1 induced a slow and transient contraction without an increase in either [Ca2+]i or myosin phosphorylation. Therefore, in addition to the activation of mechanisms of [Ca2+]i-myosin phosphorylation, endothelin-1 may activate additional calcium regulatory mechanisms which may thus increase the Ca2+ sensitivity of contractile elements while also enhance and prolong the contractions in the porcine coronary artery.

Allotransplantation of a spontaneous malignant fibrous histiocytoma in the ddY mouse

Malignant fibrous histiocytoma (MFH) developed spontaneously in the subcutaneous tissue of the hind leg of a 7-month-old female ddY mouse. Histologically, an original tumor was composed of an admixture of fibroblast-like and histiocyte-like cells arranged in predominantly storiform or cartwheel pattern. The tumor was serially transplanted into syngeneic mice up to the 70th generation. Moreover, the tumor was also consistently transplanted into allogeneic mice of several inbred strains. Allogeneic mice used in the present study were 7 strains having the different H-2 haplo-types. During succeeding passages, transplanted tumor pieces showed aberrant growth properties. Histopathological features of these tumors were basically similar to original tumors. As mentioned above, a spontaneous MFH in the ddY mouse was consistently transplantable into both syngeneic and allogeneic mice. The tumor was designated S-MFH-1T.

Generation of des-(1-3) insulin-like growth factor-I in serum by an acid protease

Des-(1-3) insulin-like growth factor-I (IGF-I), a more potent IGF-I variant, has been isolated from biological fluids and tissue extracts. The mechanisms involved in this posttranslational modification of IGF-I have not been elucidated. In this study we demonstrated the presence in rat serum of an acid protease activity that is capable of generating des-(1-3) IGF-I from intact IGF-I. An assay for measuring this enzyme activity using an immobilized synthetic substrate, biotin-G-P-E-T-L-C, that includes the site of cleavage of intact IGF-I was developed. Using this assay, the time, temperature, and pH dependency of the enzyme activity was investigated. Although some activity was observed under neutral conditions, the optimal pH was pH 5.5. Of a variety of commercially available proteases tested, only trypsin and cathepsin-D had activity. In contrast to the serum enzyme activity, trypsin was more active at pH 7.5 than at pH 5.5, and cathepsin-D resulted in extensive proteolysis of IGF-I. Soybean trypsin inhibitor, alpha 1-antitrypsin, and pepstatin-A were able to partially inhibit the serum enzyme activity. This enzymatic activity was partially purified from serum by acid-ethanol extraction (6-fold) and further purified by pepstatin-A affinity chromatography (200-fold). The partially purified enzyme had characteristics similar to those of the activity measured in serum. The enzymatic conversion of [125I]IGF-I to [125I]des-(1-3) IGF-I in serum was confirmed by immunoprecipitation using antibody to an N-terminal fragment of IGF-I (residues 1-9), which could recognize intact IGF-I, but not des-(1-3) IGF-I (< 3% cross-reactivity), and by size-exclusion HPLC analysis. When [125I]IGF-I was incubated with serum, only the 7.5-kilodalton free IGF-I fraction contained the des-(1-3) IGF-I variant. [125I]des-(1-3) IGF-I was not detected in the 150- to 200- or 50-kilodalton IGF-I-binding protein complexes. These findings demonstrate that des-(1-3) IGF-I can be generated in serum at neutral pH and that this process may be enhanced under the acidic conditions that occur in the pericellular environment.