A case in which stent insertion is considered to have triggered contrast medium-induced coronary vasospasm

A Gianturco-Roubin II (GR-II) stent was inserted in a 75-year-old man who developed restenosis of the right coronary artery (RCA) after percutaneous transluminal coronary angioplasty (PTCA). Although the vessel became partially occluded after 7 months, it was redilated by PTCA. Follow-up angiography of the RCA and left coronary artery (LCA) was performed 3 months later. Chest pain with bradycardia and hypotension occurred immediately after this examination, and ST elevation appeared in ECG leads II, III, and aVF. Repeat angiography of the RCA confirmed complete occlusion due to a spasm at a site proximal to the GR-II stent. The spasm was resolved by intracoronary infusion of isosorbide dinitrate (ISDN), and PTCA was carried out for extensive recurrent restenosis of the RCA; however, vascular dissection developed at the distal end of the GR-II stent. Therefore, a Palmaz-Schatz (P-S) stent was placed such that its proximal end overlapped the distal end of the GR-II stent. Follow-up angiography 3 months later showed no restenosis, but an episode of vasospasm similar to the previous one occurred immediately after left ventriculography. The RCA was completely occluded proximal to the GR-II stent because of spasm. Although this spasm was gradually relieved by intracoronary infusion of ISDN, marked spasm was also observed distal to the P-S stent; complete relief was achieved by infusion of additional ISDN.

Characterization of free alpha- and beta-chains of recombinant macrophage-stimulating protein

Human serum macrophage-stimulating protein (MSP) induces motile activity of murine resident peritoneal macrophages and is a growth and motility factor for epithelial cells. It belongs to the plasminogen-related family of kringle proteins, and is secreted as a single-chain, 78-kDa, biologically inactive pro-MSP. Proteolytic cleavage of pro-MSP at a single site yields active MSP, a disulfide-linked alphabeta-chain heterodimer. However cleavage of recombinant pro-MSP yielded not only the disulfide-linked heterodimer, but also free alpha- and beta-chains, indicating that some of the recombinant molecules lacked an alphabeta-chain disulfide. We purified the free chains for characterization. The beta-chain of MSP has three extra cysteines, Cys527, Cys562, and Cys672, which are not found in the plasminogen beta-chain. Disulfide bond analysis showed a Cys527-Cys562, but also a Cys588-Cys672. Coopting Cys588 by Cys672 prevented the expected formation of a disulfide between alpha-chain Cys468 and beta-chain Cys588. Concomitant studies determined structures of oligosaccharides at the three Asn-linked glycosylation sites of MSP. The oligosaccharides at the three Asn loci are heterogeneous; 11 different sugars were identified, all being sialylated fucosyl biantennary structures. We also located the pro-MSP signal peptide cleavage site at Gly18-Gln19 and the scissile bond for formation of mature MSP at Arg483-Val484.

A diary form quality of life questionnaire for Japanese patients with lung cancer and summarization techniques for longitudinal assessment

The aim of this study was to confirm the validity and reliability of a new diary-type quality of life (QOL) self-rating questionnaire tailored for use by Japanese inpatients with lung cancer receiving chemotherapy. Two kinds of summary statistics were tested in QOL analysis. The questionnaire has a four-scale structure; physical, psychological, daily activity and global scales. Fifty-three patients were enrolled to test the reliability and validity. Summary statistics were assessed using indices of the area under the curve (AUC) and the maximum fluctuations of QOL scores (Dif max) in patients receiving cisplatin or carboplatin. The questionnaire had satisfactory reliability and validity. The physical, psychological and global scales scores changed to the worst levels after treatment, continuing for 1 week in the cisplatin group, whereas those of the carboplatin group began to worsen from day 3, but returned to prechemotherapy levels by day 9. The cisplatin group showed significant decrease of QOL compared with the carboplatin group in the AUC of psychological and two global scales, in the Dif max of psychological and linear analogue global scales. These results suggested that this questionnaire reflects differences in the influence of chemotherapy, and that AUC and Dif max may be useful indices for the analysis of QOL as measures to assess multidimensional QOL.

A sensitive and specific ELISA for plasma pentosidine

BACKGROUND

Advanced glycation end products are formed by non-enzymatic glycation and oxidation reaction. Pentosidine is a well-known and characterized structure among them, and has been implicated in the pathogenesis of complications associated with chronic renal failure and long-term dialysis, such as dialysis-related amyloidosis and atherosclerosis.

METHODS

We established a highly sensitive and specific competitive enzyme-linked immunosorbent assay (ELISA) for plasma pentosidine and applied it to large numbers of plasma samples including haemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) patients. We compared their plasma pentosidine levels determined by the competitive ELISA with those determined by high-performance liquid chromatographic (HPLC) assay currently used.

RESULTS

The plasma pentosidine levels determined by the ELISA were correlated well with those determined by sophisticated instrumental HPLC assay, both in non-diabetic and diabetic dialysis patients. Both analyses yielded comparable results, with over 8-fold higher plasma pentosidine levels in HD and CAPD patients, irrespective of the presence or absence of diabetes, as compared to normal subjects and non-uraemic diabetic patients.

CONCLUSIONS

The competitive ELISA will provide a rapid and convenient determination of plasma pentosidine content and thus be useful to assess the carbonyl stress in uraemic patients.

Clinical outcome in three patients with myelodysplastic syndrome showing polyclonal hematopoiesis

The clinical outcome of 3 myelodysplastic syndrome (MDS) patients with polyclonal hematopoiesis is reported. All patients were heterozygous for the phosphoglycerate kinase (PGK) gene. The presence of polyclonal hematopoiesis was determined by the X-chromosome-linked restriction fragment length polymorphism-methylation method using the PGK gene as a marker. The patients were initially diagnosed as having refractory anemia (RA), RA with ring sideroblasts (RARS), and RA with an excess of blasts (RAEB), respectively. Their pancytopenia persisted during the follow-up period of 11.4 years for the RA patient, 19.5 years for the RARS patient and 0.8 years for the RAEB patient. Although the RARS patient continues to be in good health, leukemic transformation occurred in the other 2 patients. A karyotype change from 46,XX to 45,XX,t(3;21),-7 was observed at the time of disease progression in the RA patient. The coexistence of a monoclonal MDS clone and normal bone marrow cells is thought to be the most probable reason for the polyclonal hematopoiesis of these patients.

Prognostic significance of beta-microseminoprotein mRNA expression in prostate cancer

BACKGROUND

Human beta-microseminoprotein (beta-MSP or PSP94) is a small protein secreted by prostatic epithelial cells. We recently reported the presence of low levels of beta-MSP mRNA expression and protein in most prostate cancer tissues.

METHODS

Beta-MSP and mRNA expression was examined by in situ hybridization in biopsy specimens obtained from 92 patients with prostate cancer. All tissue specimens were obtained by needle biopsies prior to treatment. All patients subsequently received endocrine therapy. To estimate the influence of beta-MSP mRNA expression and three possible prognostic factors, i.e., patient age, clinical stage, and Gleason score, on time to progression under endocrine therapy, univariate and multivariate analyses were performed using Cox's proportional hazards regression model.

RESULTS

Multivariate survival analysis showed that clinical stage was the strongest prognostic factor (P = 0.006) and that beta-MSP mRNA expression was the second strongest factor (P = 0.038) in 92 patients with stage B-D disease. Analysis of only 51 patients with stage D disease showed that beta-MSP mRNA expression was the only significant prognostic indicator for progression under endocrine therapy (P = 0.003).

CONCLUSIONS

The presence of cells that express the beta-MSP transcript may be a novel indicator of potentially aggressive prostate cancer.

Synergetic activation of outwardly rectifying Cl- currents by hypotonic stress and external Ca2+ in murine osteoclasts

1. An outwardly rectifying Cl- (ORCl) current of murine osteoclasts was activated by hypotonic stimulation. The current was characterized by rapid activation, little inactivation, strong outward rectification, blockage by DIDS and permeability to organic acids (pyruvate and glutamate). 2. The hypotonically activated ORCl current was inhibited by intracellular dialysis with an ATP-free pipette solution, but not by replacement of ATP with a poorly hydrolysable ATP analogue adenosine 5'-O-(3-thiotriphosphate). The current amplitude was reduced when intracellular alkalinity increased over the pH range 6.6-8.0. 3. Intracellular application of cytochalasin D occasionally activated the ORCl current without hypotonic stress, but inhibited activation of the ORCl current by hypotonic stimulation. The hypotonically activated ORCl current was unaffected by a non-actin-depolymerizing cytochalasin, chaetoglobosin C, but partially inhibited by deoxyribonuclease I. 4. Removal of extracellular Ca2+ inhibited activation of the ORCl current by hypotonic shock, but did not reduce the current once activated. The hypotonically activated ORCl current was partially decreased by intracellular dialysis with 20 mM EGTA. 5. With 10 mM Ca2+ in the extracellular medium, the ORCl current was activated in response to more minor decreases in osmolarity than with 1 mM Ca2+. The increased sensitivity to hypotonicity was mimicked by increasing the intracellular Ca2+ level (pCa 6.5). 6. These results suggest that hypotonic stimulation and a rise in the extracellular Ca2+ level synergistically activate the ORCl channel of murine osteoclasts, and that the activating process is modified by multiple intracellular factors (pH, ATP and actin cytoskeletal organization).

Enhanced shear-induced platelet aggregation in acute myocardial infarction

BACKGROUND

Experiments under controlled flow conditions indicate that the binding of von Willebrand factor (vWF) to platelet glycoprotein (GP) Ibalpha and integrin alphaIIbbeta3 (GP IIb/IIIa complex) is crucial for aggregation at elevated shear rates. We have tested how the plasma of patients with acute myocardial infarction affects this process.

METHODS AND RESULTS

Citrated plasma was obtained from 18 patients with acute myocardial infarction within 6 hours from the onset of symptoms and from 26 control subjects with chest pain syndrome without evidence of ischemia. Aggregation of normal platelets at high shear rates was significantly greater in the presence of patient than control plasma and was inhibited by both anti-GP Ibalpha and anti-alphaIIbbeta3 monoclonal antibodies. The observed values (mean+/-SD) were 47.6+/-17.8% versus 30.1+/-9.9% at 10 800 s-1 (P<0.01) and 32.9+/-14.1% versus 17.5+/-9.5% at 7200 s-1 (P<0.01), respectively, and were positively correlated with plasma vWF antigen levels and ristocetin cofactor activities. In contrast, at the lower shear rate of 1200 s-1, aggregation was similar in the presence of control or patient plasma and was not inhibited by the anti-GP Ibalpha antibody. Both vWF antigen and platelet aggregation decreased 2 weeks after the onset of myocardial infarction.

CONCLUSIONS

Shear-induced platelet aggregation is enhanced in plasma in the presence of acute myocardial infarction, apparently as a result of increased vWF concentration. This may contribute to the onset of acute coronary artery thrombosis and early reocclusion after reperfusion treatment.

Induction of B-cell lymphoma in BALB/c nude mice with an ecotropic, B-tropic helper virus present in the murine AIDS virus stock

The pathogenicities of the murine AIDS (MAIDS) virus complex (LP-BM5) and ecotropic helper virus (BM5eco) isolated from the complex to BALB/c nude mice were studied to elucidate the possible role of replication-competent helper virus in inducing the monoclonal outgrowth of lymphoid cells. Neither LP-BM5 nor BM5eco was pathogenic in adult BALB/c nude mice. However, B-cell lymphoma developed with a very high frequency when either virus was inoculated into newborn BALB/c nude (nu/nu) mice. The cells from the B-cell lymphoma were easily transplanted into nude mice. These results suggested that ecotropic helper virus in the MAIDS virus complex plays an important role in inducing the monoclonal outgrowth of lymphoid cells under immunodeficient conditions caused by defective virus.

The Dependence of the Apparent Contact Angles on Gravity

We have studied theoretically the effect of gravity on the rough solid-liquid interface and have shown that its tension is enhanced by gravity when gas is adsorbed at it. As a result, the apparent contact angle on rough surfaces, which has been considered not to be influenced by gravity so far, can be raised by gravity. The calculated dependence of contact angles on gravity under the ordinary conditions of the sessile drop method is large enough to detect by experiment. The observed asymmetrical deviations from Wenzel's contact angle caused by the gas adsorption at the solid-liquid interface and by the liquid adsorption at the solid-gas interface are explained in terms of this gravitational effect. Copyright 1999 Academic Press.

Microvascular responses to hemodilution with Hb vesicles as red blood cell substitutes: influence of O2 affinity

Phospholipid vesicles encapsulating purified hemoglobin (HbV) were developed to provide O2-carrying capacity to plasma expanders. Microvascular perfusion was determined for HbV with different O2 affinity (P50 = 9, 16, and 30 mmHg) prepared by coencapsulating pyridoxal 5'-phosphate (PLP) at the molar ratios of [PLP]/[Hb] = 0, 0.5, and 3, respectively (cf. hamster blood, P50: 28 mmHg), and suspended in 8 g/dl human serum albumin (HSA). Eighty percent of the red blood cell (RBC) mass of conscious Syrian golden hamsters fitted with dorsal skinfold windows was substituted with either of the HbV-HSA suspensions, washed hamster RBC suspended in HSA (RBC-HSA), and HSA alone. All three HbV-HSA groups and RBC-HSA groups showed stable blood pressure and heart rate, which could not be sustained with HSA alone. Only the HbV (P50 = 9)-HSA group showed an increase in arterial O2 tension (89.8 +/- 14.7 mmHg, baseline 58.4 +/- 4.0 mmHg) because of hyperventilation, and microvascular perfusion was decreased, indicating that facilitated O2 unloading of HbV by decreasing the O2 affinity (increasing P50) with PLP as an allosteric effector is important. Microvascular perfusion and microvascular and interstitial O2 tensions in the HbV (P50 = 16 and 30)-HSA groups were significantly higher than those in the HSA group. The O2 release rate from the HbV was 18-32 s-1 vs. 4.4 s-1 for RBC. Functional capillary density was improved from 17 to 41% on average by decreasing P50 from 30 to 16 mmHg, which appears to be an optimal value for the P50 in this system.

Changes in resistance vessels during hemorrhagic shock and resuscitation in conscious hamster model

The unanesthetized hamster dorsal skinfold preparation was used to monitor diameters and blood flow rates in resistance arteries (small arteries, A0: diameter, 156 +/- 23 micrometers) and capacitance vessels (small veins, V0: 365 +/- 64 micrometers), during 45 min of hemorrhagic shock at 40 mmHg mean arterial pressure (MAP) and resuscitation. A0 and V0 vessels constricted significantly to 52 and 70% of the basal values, respectively, whereas precapillary arterioles (A1-A4, 8-60 micrometers) and collecting venules (VC-VL, 26-80 micrometers) did not change or tended to dilate. Blood flow rates in the microvessels declined to <20% of the basal values. Resuscitation with shed autologous blood (SAB) showed incomplete recovery of A0 and V0 diameters even 2 h after resuscitation (71 +/- 14% and 81 +/- 18%, respectively, of basal value), whereas other vessels did not change significantly. The behavior of A0 diameter coincided with the incomplete recovery of blood flow rates in all the vessels (ca. 50%) according to Poiseuille's law, and the incomplete recovery of functional capillary density (ca. 75%). Resuscitation with 8% human serum albumin in saline (HSA) tended to show higher levels of A0 constriction and A4 dilation and lowered blood flow rates. Resuscitation with SAB restored tissue PO2 27 +/- 10 mmHg after 2 h, which was near control levels (28 +/- 5 mmHg), whereas resuscitation with HSA caused tissue PO2 to remain significantly depressed (6 +/- 2 mmHg), and flow rates were significantly lower than resuscitation with SAB. These results indicate that response of the A0 vessels is the crucial determinant of blood flow in the observed area. The constriction of A0 may help sustain MAP, and constriction of V0 may enhance blood redistribution from the skin to the vital organs under the hypotensive condition.

Growth potential of loose bodies: an immunohistochemical examination of primary and secondary synovial osteochondromatosis

Histologic and immunohistochemical studies of growth potential were performed on 53 surgically removed loose bodies representing 10 cases of primary synovial osteochondromatosis, 37 bodies representing 12 cases of secondary synovial osteochondromatosis, and five bodies representing five cases of osteochondral fracture. Loose bodies in primary synovial osteochondromatosis were nodular, showing plump chondrocytes and irregular calcification, and all contained proliferative cell nuclear antigen-positive chondrocytes (labeling index: 42.5%; range: 36.0-52.0%). Other markers stained less frequently. Loose bodies in secondary synovial osteochondromatosis showed uniform chondrocytes and annular calcification surrounding core tissue. Eighteen of 37 loose bodies showed proliferative cell nuclear antigen-positive chondrocytes, mostly peripherally. Chondrocyte labeling indices were less than 5% for proliferative cell nuclear antigen and other markers, although some connective tissue cells in the outer layer were stained. Loose bodies from osteochondral fractures were composed of articular cartilage, subchondral bone, and connective tissue; cartilage was negative for markers, whereas connective tissue contained positive cells. One specimen showed cartilaginous metaplasia of connective tissue. These results suggest that loose bodies have the potential for slow growth by proliferation of chondrocytes in primary synovial osteochondromatosis and by metaplasia following proliferation of surrounding connective tissue in secondary synovial osteochondromatosis.

Proliferative potential of canine oral epulides and malignant neoplasms assessed by bromodeoxyuridine labeling

The proliferative potential of canine oral lesions, including epulides, squamous cell carcinomas, a malignant melanoma, and a fibrosarcoma, was examined using a monoclonal antibody to bromodeoxyuridine (BrdU). Twenty-three dogs with oral masses were administered BrdU intravenously at a dose of 8 mg/kg 1 hour before surgery, and the BrdU labeling index (LI) of each lesion was determined immunohistochemically. The average BrdU LIs for the main proliferating elements in the fibromatous epulis (4 cases), ossifying epulis (2 cases), and acanthomatous epulis (10 cases) were 4.9, 3.0, and 8.8%, respectively. The squamous cell carcinomas (5 cases) had an average LI of 15.9%, and the LIs of the malignant melanoma and fibrosarcoma were 7.5 and 10.3%, respectively. All cases of acanthomatous epulides and squamous cell carcinoma treated with simple marginal surgical resection recurred within a short time. The higher LIs in the acanthomatous epulides, squamous cell carcinomas, and fibrosarcoma correlate well with their poor prognoses, reflected by rapid growth and frequent recurrence. Acanthomatous epulis is clearly distinguished from other epulides by its aggressive clinical behavior and high proliferative potential, which is equivalent to that of malignant tumors, despite a lack of cell atypia. The BrdU LI is a useful marker for evaluating the proliferative potential and prognosis of canine oral tumors.

Expression and characterization of rat UDP-N-acetylglucosamine: alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I in Saccharomyces cerevisiae

The yeast Saccharomyces cerevisiae is a useful host for the production of heterologous proteins through the secretory pathway. However, because of the potential antigenicity of mannan-type sugar chains in humans, yeast cannot be used as a host for the production of glycoprotein therapeutics. To overcome this problem, we are trying to breed a yeast which can produce hybrid- or complex-type carbohydrates. UDP- N- acetylglucosamine:alpha-3-d-mannoside beta-1, 2- N- acetylglucosaminyltransferase I (GnT-I) is essential for the conversion of high mannose-type N- glycans to hybrid- and complex-type ones. As yeast lacks this enzyme, we have introduced the rat GnT-I cDNA into yeast cells. The transformed yeast cells expressed GnT-I activity in vitro. The expressed GnT-I was localized in all organella, including the endoplasmic reticulum (ER), Golgi apparatus, and vacuole, suggesting that the mammalian Golgi retention signal of GnT-I did not function in yeast cells. Analysis of the GnT-I gene product with a c-Myc epitope tag at the C-terminus elucidates that the N - terminal region of GnT-I, including the mammalian Golgi retention signal, should be removed in the yeast ER.

cDNA, genomic cloning, and gene expression analysis of mouse PSP94 (prostate secretory protein of 94 amino acids)

The potential use of prostate secretory protein of 94 amino acids (PSP94) as a diagnostic biomarker or a therapeutic agent for prostate cancer has been reported. In order to establish an animal model to further elucidate on its biological role, we cloned the mouse PSP94 cDNA (approximately 500 bp) by reverse transcriptase-polymerase chain reaction (RT-PCR) and disclosed its genomic structure. The whole mouse PSP94 gene (approximately 23 kb) was amplified by long and accurate-PCR and also cloned by screening of a mouse embryo stem-cell genomic library. Computational and statistical analyses have demonstrated several highly conserved characteristics of PSP94 among different species. Comparison of PSP94 from human, two primates, pig, and rodents revealed that the most significant feature is that PSP94 is rich in cysteines (10% of the total sequence) and their positions are highly conserved. The three intron-four exon structure of the human PSP94 gene and the consensus sequence (....GT-intron-AG...) for mRNA splicing are also strongly conserved. A high divergence in cDNA sequence in the protein-coding region and also in the genomic sequence of PSP94 was also observed among these species. Comparing with alpha-globin, a typical evolutionally conserved gene, with the PSP94 gene, the rate of nonsynonymous changes per site per year (kN) is 2 to 6 times higher, indicating that PSP94 gene has been under far fewer evolutionary constraints than other genes and has a potential role as a species barrier in reproductive biology. In order to test this hypothesis, we investigated the gene expression of PSP94 and its tissue distribution in various rodent tissues by RT-PCR and in situ hybridization (ISH). Gene expression was found only in the prostate, suggesting that PSP94 is probably more tissue specific in the prostate of rodents than in mammals. The ISH analysis also revealed a prostate lobe-specific expression of the PSP94 gene in both mice and rats. It was strongly expressed in the lateral prostate, but the findings were negative in the dorsal and ventral lobe. Therefore, it is hypothesized that one of the primary functions of rodent PSP94, as a major prostate secretory protein, is related to reproductive biology.

Urticarial vasculitis in systemic lupus erythematosus: fair response to prednisolone/dapsone and persistent hypocomplementemia

Two cases of urticarial vasculitis (UV) accompanying systemic lupus erythematosus (SLE) are reported. Both patients developed characteristic wheal and purpuric lesions of UV followed by pigmentation, and histological examination revealed leucocytoclastic vasculitis. Although oral prednisolone was beneficial for the systemic symptoms and various serological abnormalities, one patient needed dapsone and the other needed dapsone and cyclophosphamide to control the UV. In both patients, hypocomplementemia with no evidence of congenital complement deficiency or complement consumption persisted even after all other laboratory data and symptoms improved.

Acute response of the lung mechanics of the rabbit to hypoxia

We measured the change in total lung resistance (RL) and that in total lung elastance (EL) induced by hypoxia (n = 7) and compared the results with those by intravenous histamine bolus (n = 5) at three different positive end-expiratory pressure (PEEP) levels (2, 5, and 8 hPa) in open-chest and vagotomized rabbits. The percent increase ratio of RL (PIRR) and EL (PIRE) was defined as the change in RL and EL, respectively, induced by hypoxia compared with that in the normoxic condition, expressed as a percentage. PIR values for the change in RL and EL induced by bolus injection of histamine were also calculated. The PIRR and PIRE induced by hypoxia and by histamine were positive by a statistically significant amount at every PEEP level, except for the PIRE value at 8-hPa PEEP in the hypoxic challenge. The PIRE-to-PIRR ratio values in the hypoxic challenge at 2-hPa PEEP were significantly larger than those in the histamine challenge (hypoxia: 0.91 +/- 0.23%; histamine: 0.37 +/- 0. 065%, P < 0.05). The increase in EL induced by histamine in the acute phase has been reported to be mainly derived from tissue distortion secondary to bronchial constriction. Thus our results suggest that a part of the increase in EL by hypoxia was originated in different parenchymal responses from histamine and imply that this hypoxic response of lung parenchyma is sensitive to the increase in parenchymal tethering at high PEEP levels.

Follow-up study on urinary type IV collagen in patients with early stage diabetic nephropathy

Type IV collagen is a major component released from the glomerular and tubular basement membranes. To investigate the alteration of renal type IV collagen turnover in early stage diabetic nephropathy, urinary type IV collagen was measured by a highly sensitive one-step sandwich enzyme immunoassay (EIA). Urinary samples were obtained from 94 diabetic patients without overt proteinuria. Among those patients, 61 were normoalbuminuric and 33 patients were in the microalbuminuric group. Levels of urinary type IV collagen were serially examined at the start of this study and again one year later. The levels of urinary type IV collagen in patients in the microalbuminuric group were significantly higher than those in the normoalbuminuric group (P < 0.01). There was a significant correlation between the concentration of urinary albumin and urinary type IV collagen in both groups (P < 0.05). Twenty-eight patients (45.3%) in the normoalbuminuric group who showed an abnormal elevation of urinary type IV collagen in comparison to the reference range of normal healthy adults (normal range; less than 3.5 microg/g x Cr). Seven (25%) out of these 28 normoalbuminuric patients with increased urinary type IV collagen progressed to the microalbuminuric group one year later. The levels of urinary type IV collagen in such patients were significantly increased. In the 21 patients who stayed within the normoalbuminuric group, the urinary type IV collagen levels were significantly decreased one year later. It appears that the levels of urinary type IV collagen might reflect ongoing alteration of the extracellular matrix (ECM) turnover and might define more specifically the early stage diabetic nephropathy than the detection of microalbuminuria. It is concluded that the serial measurement of urinary type IV collagen can be a useful marker for detecting renal injury in diabetes.

Unregulated exposure of the ribosomal M-site caused by NAC depletion results in delivery of non-secretory polypeptides to the Sec61 complex

Nascent polypeptide associated complex (NAC) interacts with nascent polypeptides emerging from ribosomes. Both signal recognition particle (SRP) and NAC work together to ensure specificity in co-translational targeting by competing for binding to the ribosomal membrane attachment site. While SRP selects signal-containing ribosomes for targeting, NAC prevents targeting of signal peptide-less nascent chains to the endoplasmic reticulum membrane. Here we show that the ribosome binding that occurs in NAC's absence delivers signalless nascent chains to the Sec61 complex, underscoring the danger of unregulated exposure of the ribosomal M-site. Recently, the idea that NAC prevents ribosome binding has been challenged. By carefully examining the physiologic NAC concentration in a variety of tissues from different species we here demonstrate that the discrepancy resulted from subphysiologic NAC concentrations.