Urinary excretion of albumin and retinol-binding protein in lithium-treated patients: a longitudinal study

The urinary excretion of albumin and retinol-binding protein was determined by means of sensitive immunochemical methods in a 2-year longitudinal study of 22 lithium-treated patients. During lithium treatment, there were no significant changes in the median albumin:creatinine ratios or retinol-binding protein:creatinine ratios. However, the median albumin:creatinine ratios were significantly higher in lithium-treated patients than in 22 normal subjects, which indicates that glomerular permeability is increased; no correlation with serum lithium level or duration of lithium treatment could be shown. In patients treated with slow-release tablets, the urinary excretion of albumin was significantly higher after 2 years than in patients given lithium carbonate. The median retinol-binding protein:creatinine ratios did not differ significantly between lithium-treated patients and normal subjects, suggesting that lithium does not affect the catabolism of low-molecular-weight proteins in the proximal tubules. In conclusion, the study supports the hypothesis that lithium treatment produces a small but significant and nonprogressive elevation of the urinary excretion of albumin.

Conversion of an apparent 100 kDa folate binding protein from human milk, choroid plexus and semen to a 25 kDa molecular species by phosphatidylinositol-specific phospholipase C

Gel filtration studies in the presence of Triton X-100 showed that treatment with phosphatidylinositol-specific phospholipase C reduced the apparent molecular size of the 100 kDa folate binding protein from human milk, choroid plexus and semen to 25 kDa. Cleavage of a hydrophobic glycosyl phosphatidylinositol domain (a membrane anchor) inserting the protein into Triton X-100 micelles could account for this phenomenon.

EDTA treatment of intermittent claudication--a double-blind, placebo-controlled study

A double-blind, randomized multicentre study was undertaken to evaluate the possible effect of chelation treatment with ethylenediamine-tetraacetic acid (EDTA) in patients with severe intermittent claudication. A total of 153 patients received 20 intravenous infusions of either 3 g Na2EDTA or placebo during a period of 5-9 weeks. Vitamin, mineral and trace element supplements were administered orally. The changes observed in the pain-free and maximal walking distances, measured on a treadmill, were similar in the two groups. During the 3-month (n = 149) and 6-month (n = 123) follow-up period, no long-term therapeutic effect of EDTA could be demonstrated. The ankle-brachial blood pressure index remained unchanged throughout the study period. This study failed to demonstrate any effect of EDTA chelation treatment in intermittent claudication.

Bioavailability of starch in various wheat-based bread products: evaluation of metabolic responses in healthy subjects and rate and extent of in vitro starch digestion

Glucose and insulin responses to bread products were evaluated in healthy subjects. Also studied were the rate of in vitro starch digestion and the content of in vitro resistant starch (RS). Three white-wheat-bread (WWB) products varying in crust-crumb ratio and monoglyceride addition, three bread products with a high soluble fiber content (HSFB), and two coarse-wheat breads (CB) were included. The metabolic responses to WWBs were in general higher than those to CB and HSFB products. The most prominent reduction in metabolic responses was noted with the CBs with intact kernels and the HSFBs with oat bran. The starch in these products was also more slowly released from a dialysis tubing after enzyme incubation of chewed samples. The RS content ranged from 0 to 1.7 g/100 g starch. HSFBs and the CB with intact kernels showed a higher satiety score than did the WWBs immediately after the test meal.

T lymphocytes in human atherosclerotic plaques are memory cells expressing CD45RO and the integrin VLA-1

The cellular composition of human atherosclerotic plaques has been analyzed in several immunohistochemical studies in recent years. These studies have shown that the main cell types of the plaque are macrophages, smooth muscle cells, and T lymphocytes. To further characterize the T-lymphocyte population in atherosclerotic plaques, human plaque tissue was digested enzymatically and the released cells were labeled with fluorescent antibodies and analyzed by flow cytometry. Fifteen patients undergoing carotid endarterectomy were studied. Sixty-four percent of plaque T cells expressed the low-molecular-weight form (CD45RO) of the leukocyte common antigen (CD45). Many of these cells expressed the integrin very late activation antigen-1 (VLA-1), which suggests that they are in a state of late activation. In contrast, only 1% of peripheral blood T cells from the same patients expressed VLA-1. Other markers of T cell activation, such as Ta1 (CD26) and HLA-DR, were also increased on plaque T cells. The interleukin-2 receptor (CD25), which is transiently expressed after activation, was present on only a small proportion of the cells. Taken together, this analysis of plaque lymphocytes shows that the majority of plaque T cells are memory cells, many of which are in a state of late or chronic activation. This T-cell phenotype may be the result of a preferential recruitment and/or retention of activated peripheral blood T cells or local antigenic stimulation of resting T cells.

Preoperative assessment of the risk for cardiac death following thrombo-embolectomy for acute lower limb ischaemia

Cardiac monitoring and the selective use of initial non-operative management is reported to reduce the high mortality rate in patients with acute lower limb ischaemia. Early estimation, prior to selection of initial therapy, of the risk for intraoperative or postoperative cardiac death following thrombo-embolectomy is therefore important. The aim of this prospective multi-centre study was to develop a simple and clinically useful index for assessment of the risk of post-operative cardiac death. Patients judged to need thrombo-embolectomy for acute lower limb ischaemia were evaluated on admission for routine clinical, cardiac and limb ischaemia parameters that could be related to cardiac function and these parameters compared to postoperative cardiac outcome. Sixteen per cent of the 117 patients died from intraoperative or postoperative cardiac complications. Analysis revealed five admission parameters that significantly and independently predicted a high risk for cardiac death: mean arterial blood pressure below 90 mmHg, clinical sign(s) of cardiac decompensation, ischaemia affecting the thigh, haemoglobin concentration exceeding 140 gl-1, and a history of a myocardial infarction in the previous 4 weeks. Definition of risk points for each risk factor allowed a simple classification of each patient into one of three significantly different cardiac risk classes with cardiac death rates of 6 +/- 3%, 27 +/- 8% and 75 +/- 16%, respectively. More than two thirds of the patients belonged to the low risk group. The described risk index provides a tool for preoperative assessment of the cardiac death risk associated with early thrombo-embolectomy in patients with acute lower limb ischaemia.

A high-affinity folate binding protein in proximal tubule cells of human kidney

High-affinity 3H-folate binding in solubilized brush border membranes of human kidney cortex display characteristics such as apparent positive cooperativity typical of specific folate binding. The folate binding activity and the activity of the brush border membrane-marker enzyme, gamma-glutamyltransferase, were eightfold higher in brush border membranes compared to crude kidney homogenate. Ultrogel AcA 44 chromatography revealed a major (Mr approximately 100 kDa) and a minor (Mr approximately 25 kDa) folate binding protein in brush border membranes. The large molecular size form may represent a membrane-derived hydrophobic folate binding protein inserted in Triton X-100 micelles. This notion was supported by the identical molecular weights of the 100 kDa and 25 kDa folate binding peaks determined by sodium dodecylsulfate polyacrylamide gel electrophoresis and immunoblotting. The folate binding protein in renal brush border membranes cross reacted with rabbit antibodies against 25 kDa human milk folate binding protein, and showed immunoprecipitation in the presence of these antibodies. Paraffin embedded sections of kidney cortex showed immunostaining of cells in the convoluted proximal tubules after exposure to rabbit antiserum (1:8000 dilution). Glomeruli and distal tubules showed no immunostaining.

T lymphocytes inhibit the vascular response to injury

The proliferation of vascular smooth muscle cells is controlled by specific growth factors and cytokines acting in paracrine networks. Macrophage products such as the platelet-derived growth factor and interleukin 1 promote smooth muscle proliferation and are released in the arterial wall during atherosclerosis and repair processes. T lymphocytes are also present in vascular tissue, but their role in vascular growth control in vivo has been unclear. We now demonstrate that rats in which T lymphocytes have been eliminated by a monoclonal antibody develop larger proliferative arterial lesions after balloon-catheter injury. Larger lesions also develop in athymic rnu/rnu rats that lack T lymphocytes, when compared with rnu/+ littermates with normal T-cell levels. Finally, injection of the lymphokine interferon gamma inhibits smooth muscle proliferation and results in smaller lesions compared with controls injected with buffer alone. These results indicate that T lymphocytes modulate smooth muscle proliferation during vascular repair. We propose that T lymphocytes may play an important, immunologically nonspecific role in tissue repair processes.

High-affinity folate binding in human choroid plexus. Characterization of radioligand binding, immunoreactivity, molecular heterogeneity and hydrophobic domain of the binding protein

High-affinity [3H]folate binding in solubilized human choroid plexus homogenate displayed characteristics, e.g. apparent positive co-operativity, which are typical of specific folate binding. The highest folate-binding activity per g of protein was associated with the 27000 g membrane pellet where the membrane-marker enzyme gamma-glutamyltransferase had its main localization. Ultrogel AcA 44 chromatography revealed two major folate-binding proteins (molecular masses greater than 110 kDa and approx. 100 kDa) and one minor one (molecular mass approx. 25 kDa) and approx. 100 kDa) and one minor one (molecular mass approx. 25 kDa) in the Triton X-100-solubilized membrane pellet. After exposure of the membrane pellet to phosphatidylinositol-specific phospholipase C there was only one large 25 kDa peak of folate binding. This could suggest that the folate-binding protein is anchored to the membrane by a glycosylphosphatidylinositol moiety, which can be inserted into Triton X-100 micelles and thus can give rise to forms of large molecular size on gel filtration. This notion was supported by the identical molecular masses of the greater than 110 kDa and 25 kDa folate-binding peaks determined by SDS/PAGE and immunoblotting. The folate-binding protein in choroid plexus cross-reacted with rabbit antibodies against the 25 kDa human milk folate-binding protein, and paraffin-embedded sections of choroid plexus showed immunostaining after exposure to rabbit anti-(human milk folate-binding protein) serum (1:8000 dilution).

Chronic lower limb ischaemia. A prospective randomised controlled study comparing the 1-year results of vascular surgery and percutaneous transluminal angioplasty (PTA)

In a prospective randomised study, performed over a 6-year period, 102 patients with severe lower limb ischaemia or claudication resistant to exercise training were randomised either to percutaneous transluminal angioplasty (PTA) or vascular surgery. Only patients who could be treated by both methods were included, constituting only 5% of the total number of patients treated during this period. The two groups were similar regarding age, severity of symptoms and diabetes. The immediate and 1-year results showed similar success and complication rates. There was, however, a significantly shorter hospital stay for patients treated with PTA. Due to early complications and initial failures PTA should, however, only be used in institutions where vascular surgical facilities are available since PTA demands access to such treatment.

A high-affinity folate binding protein in human semen

The presence of a folate binding protein of high-affinity type (affinity constant 3.10(10) M-1, maximum folate binding 1.4 nM) in human semen was demonstrated in equilibrium dialysis experiments (37 degrees C, pH 7.4) with the radioligand 3H-folate. Radioligand dissociation from the binding protein was slow at pH 7.4, but rapid at pH 3.5. By use of rabbit antibodies against 25 kDa human milk folate binding protein we determined the concentration of folate binding protein in 16 specimens of human semen in an enzyme-linked immunosorbent assay. The concentration of immunoreactive folate binding protein was independent of the number of spermatozoa in individual specimens. Gel filtration showed that immunoreactive and radioligand bound folate binding protein coeluted in two peaks: a major one of 100 kDa and a minor one of 25 kDa.

Induction of tenascin in rat arterial injury. Relationship to altered smooth muscle cell phenotype

Arterial smooth muscle cells produce large amounts of extracellular matrix molecules during repair processes and in primary culture. This occurs after a transition of the cells from a contractile to a synthetic phenotype and together with the acquisition of proliferative capacity. Here, the deposition of the glycoprotein tenascin in the extracellular matrix of rat arterial smooth muscle cells in vivo and in vitro was studied by immunofluorescence microscopy and immunoblotting. Tenascin was found in the intimal layer of the adult rat aorta and carotid artery, but not in the media. Tenascin also appeared in the neointima formed by proliferating smooth muscle cells 2 weeks after balloon catheter injury of the carotid artery. To determine if the deposition of tenascin in the neointima after arterial injury was related to changes in smooth muscle function, freshly isolated rat aortic smooth muscle cells were seeded on a substrate of plasma fibronectin and allowed to modulate from a contractile to a synthetic state in a serum-free medium. In these quiescent cultures, a tenascin-containing extracellular matrix was formed after 3 to 4 days. Taken together, the results show that tenascin production is induced concomitantly with changes in smooth muscle phenotype both in vivo and in vitro.

Interferon-gamma inhibits arterial stenosis after injury

BACKGROUND

Arterial injury initiates a proliferative response among the smooth muscle cells of the artery. This leads to the formation of a thickened intima that may reduce the diameter of the arterial lumen. Such intimal lesions often develop after vascular surgery and angioplastic procedures. Previous cell culture studies have shown that the lymphokine, interferon-gamma (gIFN), inhibits smooth muscle cell proliferation.

METHODS AND RESULTS

We therefore tested whether administration of exogenous gIFN could inhibit the development of intimal lesions. Rat carotid arteries were denuded with a balloon catheter, resulting in the formation of a standardized intimal lesion. The animals were then treated with recombinant rat gIFN at 200,000 units (approximately 400,000 units or 100 micrograms/kg body wt) administered parenterally once daily for 7 days. Autoradiographic analysis of 3H-thymidine incorporation revealed that gIFN reduced the early smooth muscle replication by approximately 75%. gIFN treatment for 1 week resulted in a 50% reduction of intimal cross-section area at 2 weeks after injury when compared to control rats injected with buffer alone. The difference in lesion development persisted in rats analyzed 10 weeks after injury, suggesting that proliferative events during the first week determine the long-term development of the intima. Inhibition of lesion development was accompanied by expression of the class II histocompatibility (Ia) gene, RT1B, suggesting that both were directly related to the administration of gIFN.

CONCLUSIONS

These results show that gIFN is a potent inhibitor of the formation of arterial proliferative lesions in vivo. It is possible that gIFN could be useful in preventing arterial stenosis after surgery and angioplasty in man.

High-affinity folate binding in human liver membranes

High-affinity binding of 3H-folate in Triton X-100 solubilized membranes of human liver displayed characteristics, e.g. apparent positive cooperativity, which are typical of specific folate binding. Ultrogel AcA 44 chromatography of solubilized membranes saturated with 3H-folate revealed a major peak of 100 kDa and a minor peak of 25 kDa. The 100 kDa peak could represent a hydrophobic membrane associated molecular form of the protein. This notion was supported by the fact that the two peaks had identical molecular weights as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis with immunoblotting.

Spontaneous percutaneous delivery of a renal stone. Case report

A case with spontaneous percutaneous delivery of a renal stone is presented. The case is unique since the affected kidney became stone-free without any apparent loss of function.

Acute lower limb ischemia: failure of anticoagulant treatment to improve one-month results of arterial thromboembolectomy. A prospective randomized multi-center study

The value of short-term anticoagulant treatment in improving the early outcome in patients operated on for acute lower-limb ischemia has been debated and so far unproven. In this prospective randomized multi-center study, 188 such patients were randomized on admission, either to preoperative and postoperative anticoagulant medication (AC group, n = 94) or no anticoagulant treatment during the first month after surgery (O group, n = 94). Background factors were evenly distributed in the two groups, and 89% of the cases were considered as embolic. Analysis on an intention-to-treat basis showed no differences in outcome after 30 days. Good results, survivors who had amputation, and patients who died in the two groups are given respectively: AC group, 61%, 9%, 30%; O group, 65%, 11%, 24%. The results were similar in the two treatment groups also if only patients with a cardiac source of embolism were analyzed. Local bleeding complications were more common in the AC group (17% vs 2%, p less than 0.01). It is concluded that preoperative and early postoperative anticoagulant medication should not be routinely administered since such treatment is unlikely to improve the short-term results of lower-limb arterial thromboembolectomy while bleeding complications increase. The possible value of late (beyond 1 month) long-term anticoagulant treatment remains to be studied.

Atrial natriuretic peptide and renal adaptation to contralateral nephrectomy in healthy man

Atrial natriuretic peptide (ANP), angiotensin II (AII), aldosterone (Aldo) and arginine vasopressin (AVP) in plasma were determined in 12 healthy renal transplant donors before and 5, 12, 26, 54 days after uninephrectomy (Nx) in order to study the possible role of these hormones in functional adaptation to acute reduction in renal mass. Glomerular and tubular function was studied by measurements of the clearances of 51Cr-EDTA, lithium, sodium, potassium, and albumin. ANP was 7.4 +/- 3.1 pmol l-1 (mean +/- SD) before Nx and 8.7 +/- 6.1 pmol l-1 at 5 days after Nx and remained at this level through the observation period. Aldo showed a non-significant transient fall at 5 days after Nx. AII and AVP remained normal after Nx. At 5 days after Nx glomerular filtration rate (GFR) of the remaining kidney had risen from 45 +/- 7 ml min-1 before Nx to 57 +/- 8 ml min-1 (p less than 0.01), lithium clearance had risen from 13 +/- 2 ml min-1 before Nx to 20 +/- 7 ml min-1 (p less than 0.01), and sodium and water balance was normal. To conclude, plasma ANP, AII, Aldo and AVP do not appear to be responsible for the hyperfiltration and depression of fractional proximal sodium and water reabsorption observed in recently uninephrectomized man with normal sodium and water balance.

Leukocyte interferon in the treatment of chronic myelogenous leukemia in second chronic phase

Four patients with Philadelphia chromosome positive CML were treated with 18-42 x 10(6) IU of purified natural leukocyte IFN-alpha per week, after high-dose chemotherapy for blast phase and attainment of 2nd chronic phase. The second blast phase occurred within 3 months in 3 patients, but one patient is still in second chronic phase after 22 months of treatment. Treatment consisted of interferon only during the first year, and interferon in combination with hydroxyurea during the second year. During the second year suppression of the Philadelphia chromosome was seen in one patient, with 20% Philadelphia negative bone marrow metaphases. The toxicity of purified natural leukocyte IFN-alpha was similar to the toxicity of recombinant IFN-alpha. Antibodies to IFN-alpha were not detected in any patient.