TNF-alpha up-regulates renal MIF expression in rat crescentic glomerulonephritis

BACKGROUND

Macrophage migration inhibitory factor (MIF) is a potent proinflammatory mediator that participates in the pathogenesis of endotoxemia and experimental crescentic glomerulonephritis. However, very little is known about how MIF production is regulated in disease. We therefore examined whether tumor necrosis factor alpha (TNF-alpha), a known inducer of MIF expression by macrophages in vitro, up-regulates local and systemic MIF expression in a macrophage-mediated rat model of crescentic glomerulonephritis.

MATERIALS AND METHODS

Anti-glomerular basement membrane (GBM) glomerulonephritis was induced in groups of six primed rats. Animals were treated with 1 mg/kg soluble TNF-alpha receptor (TNFbp) or saline from the time of disease induction until they were killed on Days 1, 7, or 14. Renal MIF expression was assessed by in situ hybridization, immunohistochemistry, and ELISA, and compared with macrophage accumulation and indices of renal damage.

RESULTS

Although TNFbp treatment on Day 1 of the disease had only a partial effect upon the up-regulation of glomerular MIF expression, on Days 7 to 14 it almost completely abrogated the increase in glomerular and interstitial MIF mRNA and protein expression. In addition, TNFbp treatment significantly inhibited MIF secretion by cultured glomeruli and reduced serum MIF levels. The inhibition of renal MIF expression was paralleled by a significant inhibition of glomerular and interstitial macrophage infiltration (p < 0.001 versus saline treated), a significant suppression of renal injury (proteinuria and serum creatinine), and a marked reduction in histologic damage (glomerular hypercellularity, crescent formation, and interstitial fibrosis; all p < 0.01 versus saline treated).

CONCLUSIONS

This study demonstrates for the first time that TNF-alpha up-regulates local MIF expression by both infiltrating macrophages and resident kidney cells in rat crescentic glomerulonephritis. In addition, TNF-alpha regulates systemic MIF production. Thus, TNF-alpha, together with MIF, may play a pathological role in immunologically induced renal disease.

Resistance of actin to cleavage during apoptosis

A small number of cellular proteins present in the nucleus, cytosol, and membrane fraction are specifically cleaved by the interleukin-1beta-converting enzyme (ICE)-like family of proteases during apoptosis. Previous results have demonstrated that one of these, the cytoskeletal protein actin, is degraded in rat PC12 pheochromocytoma cells upon serum withdrawal. Extracts from etoposide-treated U937 cells are also capable of cleaving actin. It was assumed that cleavage of actin represented a general phenomenon, and a mechanism coordinating proteolytic, endonucleolytic, and morphological aspects of apoptosis was proposed. We demonstrate here that actin is resistant to degradation in several different human cells induced to undergo apoptosis in response to a variety of stimuli, including Fas ligation, serum withdrawal, cytotoxic T-cell killing, and DNA damage. On the other hand, cell-free extracts from these cells and the ICE-like protease CPP32 were capable of cleaving actin in vitro. We conclude that while actin contains cleavage sites for ICE-like proteases, it is not degraded in vivo in human cells either because of lack of access of these proteases to actin or due to the presence of other factors that prevent degradation.

Heteronuclear ribonucleoproteins C1 and C2, components of the spliceosome, are specific targets of interleukin 1beta-converting enzyme-like proteases in apoptosis

Apoptosis induced by a variety of agents results in the proteolytic cleavage of a number of cellular substrates by enzymes related to interleukin 1beta-converting enzyme (ICE). A small number of substrates for these enzymes have been identified to date, including enzymes involved in DNA repair processes: poly(ADP-ribose) polymerase and DNA-dependent protein kinase. We describe here for the first time the specific cleavage of the heteronuclear ribonucleoproteins (hnRNPs) C1 and C2 in apoptotic cells induced to undergo apoptosis by a variety of stimuli, including ionizing radiation, etoposide, and ceramide. No cleavage was observed in cells that are resistant to apoptosis induced by ionizing radiation. Protease inhibitor data implicate the involvement of an ICE-like protease in the cleavage of hnRNP C. Using recombinant ICE-like proteases and purified hnRNP C proteins in vitro, we show that the C proteins are cleaved by Mch3alpha and CPP32 and, to a lesser extent, by Mch2alpha, but not by ICE, Nedd2, Tx, or the cytotoxic T-cell protease granzyme B. The results described here demonstrate that the hnRNP C proteins, abundant nuclear proteins thought to be involved in RNA splicing, belong to a critical set of protein substrates that are cleaved by ICE-like proteases during apoptosis.

Coordinating two degrees of freedom during human arm movement: load and speed invariance of relative joint torques

1. Eight subjects performed three series of pointing tasks with the unconstrained arm. Series one and two required subjects to move between two fixed targets as quickly as possible with different weights attached to the wrist. By specifying initial and final positions of the finger tip, the first series was performed by flexion of both shoulder and elbow and the second by shoulder flexion and elbow extension. The third series required flexion at both joints, and subjects were instructed to vary movement speed. We examined how variations in load or intended speed were associated with changes in the amount and timing of the electromyographic (EMG) activity and the net muscle torque production. 2. EMG and torque patterns at the individual joints varied with load and speed according to most of the same rules we have described for single-joint movements. 1) Movements were produced by biphasic torque pulses and biphasic or triphasic EMG bursts at both joints. 2) The accelerating impulse was proportional to the load when the subject moved "as fast and accurately as possible" or to speed if that was intentionally varied. 3) The area of the EMG bursts of agonist muscles varied with the impulse. 4) The rates of rise of the net muscle torques and of the EMG bursts were proportional to intended speed and insensitive to inertial load. 5) The areas of the antagonist muscle EMG bursts were proportional to intended movement speed but showed less dependence on load, which is unlike what is observed during single-joint movements. 3. Comparisons across joints showed that the impulse produced at the shoulder was proportional to that produced at the elbow as both varied together with load and speed. The torques at the two joints varied in close synchrony, achieving maxima and going through zero almost simultaneously. 4. We hypothesize that "coordination" of the elbow and shoulder is by the planning and generation of synchronized, biphasic muscle torque pulses that remain in near linear proportionality to each other throughout most of the movement. This linear synergy produces movements with the commonly observed kinematic properties and that are preserved over changes in speed and load.

Modulators of crescentic glomerulonephritis

Glomerular crescent formation is a prominent feature of aggressive forms of glomerulonephritis and is associated with a poor prognosis. An understanding of the mechanisms involved in crescent formation is crucial for the development of new therapies for this disease. This article reviews current ideas on the pathogenesis of glomerular crescent formation and describes methods for modulation of this process. Emphasis is given to the role of the proinflammatory cytokines interleukin-1 and tumor necrosis factor-alpha in crescent development and its modulation by cytokine blockade.

High level of circulating human tissue kallikrein induces hypotension in a transgenic mouse model

We established a unique transgenic mouse model in liver-targeted expression of human tissue kallikrein using a mouse albumin enhancer and promoter. Northern blot analysis and ELISA showed that human tissue kallikrein was predominantly expressed in the liver of transgenic mice and secreted into the circulation at a high level. The transcript was also detected in the kidney, pancreas, salivary gland and heart at a low level by reverse transcription-polymerase chain reaction followed by Southern blot analysis. Systolic blood pressures were measured by the tail-cuff method, all three independent transgenic mouse lines are hypotensive (84.6 +/- 1.0 mmHg, n = 17; 84.5 +/- 1.5 mmHg, n = 9; 83.1 +/- 0.8 mmHg, n = 13, P < 0.01) compared with the control mice (100.9 +/- 0.9 mmHg, n = 17). Administration of aprotinin, a potent tissue kallikrein inhibitor or Hoe 140, a bradykinin receptor antagonist, restored the blood pressure of transgenic mice but had no significant effect on control littermates. These studies show that over-production of tissue kallikrein in the circulation plays a role in blood pressure regulation.

Role of protein kinase activity in apoptosis

The transmission of signals from the plasma membrane to the nucleus involves a number of different pathways all of which have in common protein modification. The modification is primarily in the form of phosphorylation which leads to the activation of a series of protein kinases. It is now evident that these pathways are common to stimuli that lead to mitogenic and apoptotic responses. Even the same stimuli under different physiological conditions can cause either cell proliferation or apoptosis. Activation of specific protein kinases can in some circumstances protect against cell death, while in others it protects the cell against apoptosis. Some of the pathways involved lead to activation of transcription factors and the subsequent induction of genes involved in the process of cell death or proliferation. In other cases, such as for the tumour suppressor gene product p53, activation may be initiated both at the level of gene expression or through pre-existing proteins. Yet in others, while the initial steps in the pathway are ill-defined, it is clear that downstream activation of a series of cystein proteases is instrumental in pushing the cell towards apoptosis. In this report we review the involvement of protein kinases at several different levels in the control of cell behaviour.

Expression and cellular localization of tissue kallikrein-kinin system in human adrenal gland

The tissue kallikrein-kinin system has been implicated in regulating blood pressure and electrolyte homeostasis. To understand the function of this system, we identified the expression and cellular localization of its components including tissue kallikrein, kallistatin, kininogen, and bradykinin B1 and B2 receptors in human adrenal gland. Reverse transcription-polymerase chain reaction followed by Southern blot analysis showed that these five components of this system were all expressed in human adrenal gland. In situ hybridization histochemistry with respective digoxigenin-labeled antisense riboprobes revealed localization of kallikrein transcript throughout the adrenal cortex and medulla except the zona glomerulosa, whereas kallistatin mRNA was only localized in the zona fasciculata. Low-molecular-weight kininogen and B2 receptor mRNAs were colocalized in the zona glomerulosa and zona fasciculata and also in the zona reticularis and chromaffin cells but to a lesser degree. The B1 receptor mRNA was stained in the zona fasciculata and medulla. These results show the expression and differential colocalization of the components of the tissue kallikrein-kinin system and reveal the potential action sites of this system in the adrenal gland.

Induction of p53 and increased sensitivity to cisplatin in ataxia-telangiectasia cells

Several reports have demonstrated a defective p53 response to ionizing radiation exposure in ataxia-telangiectasia (A-T) cells. On the other hand, p53 induction was normal after u.v. irradiation, an agent to which A-T cells are not hypersensitive. We show here that A-T cells are more sensitive than normal lymphoblastoid cells to cisplatin treatment but the rate of induction of p53 by cisplatin is similar in both cell types. In addition, the half-life of p53, both in the induced and uninduced forms, is the same in A-T and normal lymphoblastoid cells. The use of a reporter assay to determine the functional status of p53 confirmed the results obtained in the induction experiments with cisplatin. These results demonstrate that p53 induction status in A-T cells does not correlate with sensitivity to the inducting agent and there is no inherent defect in the turn-over of p53 in the induced or uninduced states in A-T.

Interleukin-1 beta-converting enzyme-like protease cleaves DNA-dependent protein kinase in cytotoxic T cell killing

Cytotoxic T cells (CTL) represent the major defense mechanism against the spread of virus infection. It is believed that the pore-forming protein, perforin, facilitates the entry of a series of serine proteases (particularly granzyme B) into the target cell which ultimately leads to DNA fragmentation and apoptosis. We demonstrate here that during CTL-mediated cytolysis the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs), an enzyme implicated in the repair of double strand breaks in DNA, is specifically cleaved by an interleukin (IL)-1 beta-converting enzyme (ICE)-like protease. A serine protease inhibitor, 3,4-dichloroisocoumarin (DCl), which is known to block granzyme B activity, inhibited CTL-induced apoptosis and prevented the degradation of DNA-PKcs in cells but failed to prevent the degradation of purified DNA-PKcs by CTL extracts. However, Tyr-Val-Ala-Asp-CH2Cl (YVAD-CMK) and other cysteine protease inhibitors prevented the degradation of purified DNA-PKcs by CTL extracts. Furthermore, incubation of DNA-PKcs with granzyme B did not produce the same cleavage pattern observed in cells undergoing apoptosis and when this substrate was incubated with either CTL extracts or the ICE-like protease, CPP32. Sequence analysis revealed that the cleavage site in DNA-PKcs during CTL killing was the same as that when this substrate was exposed to CPP32. This study demonstrates for the first time that the cleavage of DNA-PKcs in this intact cell system is exclusively due to an ICE-like protease.

Expression and cellular localization of the kallikrein-kinin system in human ocular tissues

Tissue kallikrein is a serine proteinase which processes kininogens to release bioactive kinins. Kinins mediate a variety of biological processes through the interaction with kinin receptors. Kinins are involved in the regulation of blood pressure and local blood flow, vasodilation, smooth muscle contraction and relaxation, production of pain and inflammation, and stimulation of cell proliferation. The tissue kallikrein-kinin system has been implicated in a number of pathophysiological processes such as hypertension, allergy and diabetes mellitus. In the present study, we have identified the expression and localization of components of the kallikrein-kinin system in the human eye by reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot analyses, and in situ hybridization histochemistry. RT-PCR and Southern blot analyses have detected mRNAs of the key components of the system including tissue kallikrein, low molecular weight kininogen, and bradykinin B1 and B2 receptors at high levels in human retina, choroid and ciliary body, and relatively low levels in the optic nerve. In situ hybridization has identified cellular localization of these four mRNAs in ocular tissues. They are expressed in retinal neuronal cells including the outer nuclear layer, inner nuclear layer and ganglion cell layer. These mRNAs were also identified in endothelial cells of ocular blood vessels, ciliary muscle and lens epithelial cells. The sense riboprobes showed negative staining, which indicates the specificity of the antisense riboprobes. These results suggest that the tissue kallikrein-kinin system is produced endogenously in human ocular tissues. Similar expression patterns of kallikrein, kininogen and kinin receptors indicate that the kallikrein-kinin system may function in an autocrine or paracrine fashion in the eye.

Expression of p53, bcl-2, bax, bcl-x2 and c-myc in radiation-induced apoptosis in Burkitt's lymphoma cells

Apoptosis, a form of physiological cell death, is a genetically determined program essential for normal development and maintenance of tissues, which has been linked to a variety of gene products. We have examined the susceptibility to radiation-induced apoptosis of cell lines derived from the human B cell tumour, Burkitt's lymphoma (BL), displaying a variety of phenotypic characteristics and expressing genes implicated in apoptosis at different levels. The susceptibility to apoptosis following gamma radiation varied significantly amongst the lines. Cell lines with wild type p53 were susceptible to radiation-induced apoptosis but two of five BL lines with only mutant p53 allele also displayed similar susceptibility. Some BL cell lines that expressed bcl-2 at levels comparable with Epstein-Barr virus (EBV) transformed normal B cells were highly susceptible to gamma radiation-induced apoptosis, whereas others expressing low levels were resistant. When these lines were analysed for bax and bcl-X(L) expression again no correlation was observed with susceptibility or resistance to apoptosis. Two BL cell lines having deregulated expression of c-myc were resistant to the induction of apoptosis while two others which had regulated c-myc expression were susceptible. Thus the status of p53, c-myc, bcl-2, bcl-X(L) and bax is not sufficiently informative in BL lines to predict susceptibility to radiation-induced apoptosis.

DNA-dependent protein kinase catalytic subunit: a target for an ICE-like protease in apoptosis

Radiosensitive cell lines derived from X-ray cross complementing group 5 (XRCC5), SCID mice and a human glioma cell line lack components of the DNA-dependent protein kinase, DNA-PK, suggesting that DNA-PK plays an important role in DNA double-strand break repair. Another enzyme implicated in DNA repair, poly(ADP-ribose) polymerase, is cleaved and inactivated during apoptosis, suggesting that some DNA repair proteins may be selectively targeted for destruction during apoptosis. Here we demonstrate that DNA-PKcs, the catalytic subunit of DNA-PK, is preferentially degraded after the exposure of different cell types to a variety of agents known to cause apoptosis. However, Ku, the DNA-binding component of the enzyme, remains intact. Degradation of DNA-PKcs was accompanied by loss of DNA-PK activity. One cell line resistant to etoposide-induced apoptosis failed to show degradation of DNA-PKcs. Protease inhibitor data implicated an ICE-like protease in the cleavage of DNA-PKcs, and it was subsequently shown that the cysteine protease CPP32, but not Mch2alpha, ICE or TX, cleaved purified DNA-PKcs into three fragments of comparable size with those observed in cells undergoing apoptosis. Cleavage sites in DNA-PKcs, determined by antibody mapping and microsequencing, were shown to be the same for CPP32 cleavage and for cleavage catalyzed by extracts from cells undergoing apoptosis. These observations suggest that DNA-PKcs is a critical target for proteolysis by an ICE-like protease during apoptosis.

Cellular localization of low-molecular-weight kininogen and bradykinin B2 receptor mRNAs in human kidney

Kininogen is the precursor of the kinin peptide, which binds to kinin receptors and mediates a broad spectrum of physiological effects. To understand the function of kinin in the kidney, we have identified the cellular localization of the human low-molecular-weight (LMW) kininogen and bradykinin B2 receptor mRNAs in the human kidney by in situ hybridization histochemistry. Kininogen mRNA was found in the juxtaglomerular cells, mesangial areas, epithelium of parietal and visceral (podocytes) layers of Bowman's capsule, proximal and distal tubules, thin and thick segments of Henle's loop, collecting ducts, and the endothelial cells of the blood vessels. B2 receptor mRNA was colocalized with kininogen mRNA in the kidney except the podocytes. The most intense signals were observed in the distal tubules and collecting ducts for both kininogen and B2 receptor mRNAs. No signals were observed in the interstitial cells and macula densa. Control sections did not stain with either the kininogen or B2 receptor sense riboprobe. A Northern blot showed that the expression of LMW kininogen is in the liver and the kidney. Reverse transcription-polymerase chain reaction Southern blot showed expression of B2 receptor mRNA in the endothelial cells, renal proximal tubular cells, and kidney. Our results show the sites of action of kinin in the human kidney and provide further insight into the physiological role of the kallikrein-kinin system on renal function.

High level expression of human tissue kallikrein in the circulation induces hypotension in transgenic mice

In order to create an animal model expressing a high level of tissue kallikrein in the circulation, the human tissue kallikrein gene was placed under the control of a mouse albumin enhancer and promoter to target its expression to liver. Three lines of transgenic mice carrying the human tissue kallikrein gene were established. The major site of human tissue kallikrein synthesis was identified in the liver of transgenic mice, and a high level of human tissue kallikrein was secreted into the mouse circulation. The systolic blood pressures of these transgenic mice are about 15-20 mmHg lower than that of the control mice. Administration of aprotinin, a potent tissue kallikrein inhibitor, restored normal blood pressure in these animals. These studies show that a high level of foreign tissue kallikrein in the circulation plays a role in blood pressure regulation.

Reorientations in the bacteriorhodopsin photoscycle are pH dependent

Chromophore reorientations during the bacteriorhodopsin photocycle in the purple membrane of Halobacterium salinarium have been detected by time-resolved linear dichroism measurements of the optical anisotropy over the pH range from 4 to 10 and at ionic strengths from 10 mM to 1 M. The results show that reorientations in the L and M states of bacteriorhodopsin are pH dependent, reaching their largest amplitude when the membrane is at pH 6-8. Reorientations on the millisecond time scale of unexcited spectator proteins in the native purple membrane also depend on pH, consistent with the suggestion that spectator reorientations are triggered by reorientation of the photoexcited protein. The results imply that a group with a PK(a) of 5 to 6 enables reorientations, and that the deprotonation of a site at pH values above 9 restricts reorientational motion. This suggests that reorientations in M may be correlated with proton release.

Coordinating movement at two joints: a principle of linear covariance

1. Six subjects performed fast, "single-joint" flexions at either the elbow or shoulder over three angular distances in a sagittal plane. Movement endpoints were located to require flexion of only a single, "focal" joint, without any external, mechanical constraint on the other, "nonfocal" joint. Three subjects performed another series of movements between two targets while moving along different paths and in which both joints were flexed. 2. We compared the torque patterns that were produced at the two joints. For single-joint movements, they were both biphasic pulses that accelerated and then decelerated the limb. 3. The torque at the nonfocal joint of a single joint movement was very close to linearly proportional to that at the focal joint throughout the movement. Elbow and shoulder torques differed by a linear scaling constant and went through extrema and zero crossings almost simultaneously. 4. In contrast, during movements in which subjects were explicitly instructed to use a hand path they would not naturally, use the linear interjoint torque scaling rule did not apply. This demonstrated that when we wish to move along a path between two targets that is not produced by linear torque covariation, we are able to modify that rule at will. 5. We speculate that linear, dynamic covariation of the torque patterns across two joints may be an important principle for reducing the number of degrees of freedom that the nervous system must independently control in performing unconstrained limb movements over naturally chosen paths.

Use of chimeric human immunodeficiency virus types 1 and 2 reverse transcriptases for structure-function analysis and for mapping susceptibility to nonnucleoside inhibitors

The human immunodeficiency virus type 1 and type 2 (HIV-1 and HIV-2) reverse transcriptases (RTs) are evolutionary related. To study the effect of homologous sequence replacements on polymerase function and to map the determinants of the lack of susceptibility of HIV-2 RT to nonnucleoside drugs, a series of chimeric HIV-1/HIV-2 RTs were constructed. Analysis of the chimeric RTs showed that wild-type levels of RNA-dependent DNA polymerase activity were retained when both finger and palm subdomains were exchanged as a unit between the two parental RTs. Analysis of enzymatically active chimeras for inhibition by the thiobenzimidazolone derivative TIBO R82150 showed that a segment of HIV-2 RT at 212-250, when placed in the HIV-1 RT context, conferred a 40-fold decrease in susceptibility to TIBO R82150. Site-directed mutagenesis of this segment found Tyr227 to be a key residue in this segment for the natural resistance of HIV-2 RT to TIBO R82150.

Enhanced fidelity of 3TC-selected mutant HIV-1 reverse transcriptase

Monotherapy with (-)2',3'-dideoxy-3'-thiacytidine (3TC) leads to the appearance of a drug-resistant variant of human immunodeficiency virus-type 1 (HIV-1) with the methionine-184 --> valine (M184V) substitution in the reverse transcriptase (RT). Despite resulting drug resistance, treatment for more than 48 weeks is associated with a lower plasma viral burden than that at baseline. Studies to investigate this apparent contradiction revealed the following. (i) Titers of HIV-neutralizing antibodies remained stable in 3TC-treated individuals in contrast to rapid declines in those treated with azidothymidine (AZT). (ii) Unlike wild-type HIV, growth of M184V HIV in cell culture in the presence of d4T, AZT, Nevirapine, Delavirdine, or Saquinavir did not select for variants displaying drug resistance. (iii) There was an increase in fidelity of nucleotide insertion by the M184V mutant compared with wild-type enzyme.

Protein phosphatase activity is required for prothoracicotropic hormone-stimulated ecdysteroidogenesis in the prothoracic glands of the tobacco hornworm, Manduca sexta

The multiple phosphorylation of ribosomal protein S6 appears to be required for prothoracicotropic hormone (PTTH)-stimulated protein synthesis and ecdysteroidogenesis by the prothoracic glands of Manduca sexta. The present study investigated the role of protein phosphatase in these phenomena by analyzing the effects of pretreatment of prothoracic glands with the phosphatase inhibitors okadaic acid and calyculin A in both basal and PTTH-stimulated glands. Okadaic acid or calyculin A treatment enhanced ribosomal S6 phosphorylation in control glands to a level similar to that observed with PTTH-stimulated glands. This treatment also prevented S6 dephosphorylation but had no apparent synergistic effect on S6 phosphorylation in PTTH-stimulated glands. Most importantly, okadaic acid or calyculin A treatment inhibited, rather than augmented, ecdysteroidogenesis in both PTTH-stimulated and non-stimulated glands. The composite data suggest that protein phosphatase activity sensitive to okadaic acid or calyculin A is required for PTTH-stimulated ecdysteroidogenesis.

Prospective studies on the relationship between the 50 g glucose challenge test and pregnant outcome

The 50 g oral glucose challenge test (50gGCT) was performed on 622 pregnant women, and 75 g oral glucose tolerance test (75gGTT) was further done on subjects with screening tests value of > or = 7.78 mmol/L. The results showed that there were 16.56% (103/622) women with screening value of > or = 7.78 mmol/L, among whom, 32 were identified as having gestational impaired glucose tolerance (GIGT) and 12, gestational diabetes mellitus (GDM) by confirmatory test of 75gGTT. The sensitivity of 50gGCT was 42.72%(44/103). The incidences of edema-proteinuria-hypertension syndrome (EPH-syndrome), premature rupture of membranes, fetal macrosomia, operative deliveries and perinatal morbidity were higher in women with GIGT/GDM than in women without GIGT/GDM. It suggests that 50gGCT is an ideal method of screening for GDM and should be performed on all pregnant women.

Does the common bile duct dilate after cholecystectomy? Sonographic evaluation in 234 patients

OBJECTIVE

The purpose of this study was to determine whether the common bile duct dilates after cholecystectomy.

SUBJECTS AND METHODS

All 234 patients who had cholecystectomy at our hospital between October 1985 and April 1994 were included in this study. The luminal diameter of the proximal segment of the common bile duct was measured on antero-posterior transverse sonograms 4-15 days before cholecystectomy. In all patients, the luminal diameter was measured again on sonograms obtained 7-2160 days after surgery (mean, 393 days; median, 180 days; mode, 360 days). A diameter of 6 mm or less was considered normal. This study contained 197 patients with a normal common bile duct (< or = 6 mm) and 37 patients with a dilated common bile duct (> 6 mm).

RESULTS

The mean diameter of the common bile duct measured on sonograms was 5.9 mm before cholecystectomy and 6.1 mm after cholecystectomy. This difference was statistically significant (p < .05). The diameter of the common bile duct increased in 110 patients, decreased in 61 patients, and stayed the same in 63 patients. Of the 234 patients, 197 (84%) had a normal preoperative diameter of the common bile duct, whereas 167 (71%) had a common bile duct with a normal diameter postoperatively.

CONCLUSION

The diameters of the common bile duct as measured on sonograms increase slightly after cholecystectomy. Most patients do not have significant compensatory dilatation of the duct after cholecystectomy.

Cellular localization of tissue kallikrein and kallistatin mRNAs in human kidney

The renal kallikrein-kinin system has been implicated in the regulation of blood pressure and sodium/water excretion. The activity of renal kallikrein is controlled by a number of factors in vivo. Kallistatin is a newly identified serine proteinase inhibitor (serpin) which binds to tissue kallikrein and inhibits its enzymatic activity in vitro. To understand the role of kallistatin in modulating tissue kallikrein's function in vivo, we examined the anatomical relationship between human tissue kallikrein and kallistatin in the kidney by in situ hybridization histochemistry. Tissue kallikrein and kallistatin gene transcripts were identified using digoxigenin-labeled riboprobes at the cellular level. Antisense and sense riboprobes corresponding to the 3' region of the human kallikrein and kallistatin mRNAs were synthesized by in vitro transcription and used for hybridization. Using an antisense kallikrein riboprobe, sites of kallikrein synthesis were localized in the distal tubules, collecting ducts and Henle's loops of the kidney. To a lesser degree, juxtaglomerular cells were also stained. Kallistatin mRNA was found at the same sites where kallikrein mRNA was localized. The most intense signals of both kallikrein and kallistatin were seen in the distal tubules and collecting ducts. Hybridization was specific for the target mRNA since sense kallikrein or kallistatin riboprobe did not bind to the sections. Immunoreactive human renal kallikrein and kallistatin levels were measured in the kidney and urine by immunoassays using specific antibodies. Co-localization of kallikrein and kallistatin mRNA in the kidney suggests a potential role of kallistatin in regulating tissue kallikrein's function.