An immunohistochemical study of glucagonoma conducted on the metastatic lymph nodes from a patient with recurrent metastatic glucagonoma: Report of a case

In this report, we briefly present the case of a 67-year-old woman who developed recurrent glucagonoma with lymph node metastasis. An immunohistochemical study of the metastatic tumor revealed immunoreactivity of glucagon and protein kinase C (PKC)-, -, and - in the tumor cells, two types of which were seen by electron microscopy. One type had abundant secretory granules and mitochondria, while the other had few granules and mitochondria. Some granules were similar to typical A cell granules and others were atypical. An immunoelectron microscopic demonstration revealed PKC-, -, and - immunostaining in the cytoplasm of all the tumor cells, while some secretory granules had PKC immunostaining, and others had no immunostaining. Thus, it appears that metastatic glucagonoma and its associated granules are composed of two types of mature and immature cells or granules. As immunoreactivity of PKC- and - was found in the tumor cells, but not in the normal A cells of the islets of Langerhans, the PKC subspecies and , which are not present in normal pancreatic A cells, may exist in human glucagonoma cells.     

Preliminary experience with intracorporeal laparoscopic ultrasonography using a sector scanning probe

Laparoscopic ultrasonography is a novel technique which may be useful in screening for choledocholithiasis during laparoscopic cholecystectomy. Following concerns regarding the learning curve and accuracy associated with the adoption of this user-dependent technology, we have prospectively evaluated a commercially available 90° sector scanning laparoscopic ultrasound probe during elective laparoscopic cholecystectomy. Laparoscopic ultrasonography was performed in 60 patients and identified common duct stones in nine patients (one false positive and one false negative), and previously unsuspected duct stones were defined in three out of four patients. The gallbladder and portal vein were constantly defined anatomical landmarks throughout the study, whereas the suprapancreatic bile duct, intrapancreatic bile duct, and pancreatic duct were identified in 100%, 80%, and 85% of patients in the third consecutive group of 20 patients examined. Laparoscopic ultrasonography has the potential to accurately identify common duct stones during laparoscopic cholecystectomy and thereby implement a policy of superselective operative cholangiography. However, adequate training for surgeons unfamiliar with this technology is recommended.Presented at the annual meeting of the Society of American Gastrointestinal Endoscopic Surgeons (SAGES), Nashville, Tennessee, USA, 18–19 April 1994     

Comparison of adrenoceptor subtype expression in porcine and human bladder and prostate

We have quantified and characterized ₁-, ₂-and -adrenoceptor subtypes in porcine bladder detrusor and bladder neck, human bladder detrusor, and porcine and human prostate. ₁-, ₂- and -adrenoceptor were identified in radioligand binding studies using [³H]prazosin, [³H]RX 821002 and [¹²⁵I]iodocyanopindolol, respectively, as the radioligands. In porcine male and female detrusor and bladder neck and male prostate, adrenoceptors were detected in the order of abundance > _{2 1} (not detectable), with no major differences between the sexes or between detrusor and bladder neck. In human detrusor and prostate the order of abundance was > _{2 1} (not detectable) and ₁ > ₂. respectively. The ₂-adrenoceptors in all tissues were homogeneously of the _2A-subtype as evidenced by competition binding studies with yohimbine, prazosin, ARC 239 and oxymetazoline. The -adrenoceptors represented a mixed population with a dominance of the ₂-subtype in all tissues as demonstrated by competition binding with ICI 118,551 and CGP 20,712A. We conclude that pigs may be a suitable model for studies of detrusor function with respect to adrenoceptor expression. They may be less suitable for studies of bladder neck or prostate function.     

Noninvasive assessment of left ventricular pressure–area relationship using transesophageal echocardiography and tonometry during cardiac and abdominal aortic surgery

Purpose The purpose of this study was to noninvasively evaluate intraoperative left ventricular (LV) performance by an online pressure–area relationship using transesophageal echocardiography (TEE) and tonometry.Methods In study 1, LV pressure with a micromanometer catheter, LV cross-sectional area with TEE, direct radial pressure, and tonometric arterial pressure were simultaneously recorded in 5 patients (10 measurements) undergoing cardiac surgery. End-systolic elastance (Ees) was determined from pressure–area loops during inferior vena caval (IVC) occlusion. In study 2, in 16 patients undergoing repair of abdominal aortic aneurysm, LV performance (Ees; effective arterial load, Ea, and LV end-diastolic area, LV-EDA) was examined by noninvasive assessment of pressure–area loops using TEE and tonometry at aortic cross-clamping and unclamping.Results Ees by tonometric arterial pressure closely correlated with Ees by LV pressure (r = 0.92) in study 1. Ees at aortic clamping were not significantly different from those at unclamping. The clamping increased LV-EDA and Ea by approximately 13% and 44%, and the unclamping significantly decreased by 9% and 22%, respectively.Conclusion Our results demonstrated that online tonometric arterial pressure and LV area measured by automated border detection (ABD) of TEE might be used to calculate Ees to estimate LV contractility and allow the estimation of LV performance during aortic clamping and unclamping.     

The dynamic pressure response to rapid dilatation of the resting urethra in healthy women: an in vivo evaluation of visco-elastic properties

Summary The urethral pressure response to a sudden forced dilatation was studied at the bladder neck, in the high-pressure zone and in the distal urethra in ten healthy female volunteers. The pressure response was fitted with a duoble exponential function of the form P _t = P _equ + P e^–t / + P e^–t /, where P _equ, P and P are constants, and and are time constants; this equation has previously been demonstrated to describe the pressure decay following dilatation. On the basis of a theoretical model the elastic and viscous constants for the urethral tissues were computed. The results showed significant differences along the urethra, with the high-pressure zone showing the highest maximum and equilibrium pressures, fastest pressure decay and highest elastic coefficient. The pressure response represents an integrated stress response from the surrounding structures, which reflects the viscoelastic properties of the tissues involved. The findings seem therefore to correlate well with the anatomical findings, which have shown a high fibre density of the horseshoe-shaped rhabdosphincter in the mid-portion of the urethra. The method permits a detailed assessment of static and dynamic urethral responses to dilatation which can be applied as an experimental simulation of urine ingression, and is therefore presumed to be of value in the evaluation of normal and pathological urethral sphincter function.     

Comparison between the Klemetti index and heel DXA BMD measurements in the diagnosis of reduced skeletal bone mineral density in the elderly

Osteopenia/osteoporosis affect many elderly people and might not be detected until symptoms of fractures occur. Early detection of osteopenia/osteoporosis is important and would allow preventive measures and treatment. Access to screening for osteopenia/osteoporosis is often limited, whereas panoramic radiography is commonly used in dentistry. The aim of this study was to determine the validity of the Klemetti index (KI), measured on panoramic radiographs, in the diagnosis of osteopenia/osteoporosis as defined by a bone mineral density (BMD) measurement below –1.5 standard deviations (SDs) of a community based sample. In total, 211 consecutive participants (102 men and 109 women) 60–96 years in the SNAC–Blekinge study (Swedish National Study on Ageing and Care) underwent bone densitometry [by dual-energy X-ray absorptiometry (DXA)] of both heels. A panoramic radiograph was taken of each participant, and mandibular cortex on a panoramic radiograph was classified as 0 or normal (even and sharp endosteal margin), 1, moderately eroded (evidence of lacunar resorption or endosteal cortical residues), or 2, severely eroded (unequivocal porosity). From logistic regression, the odds ratio of having a BMD measurement below –1.5 SD was 8.04 (95% CI 2.39 to 27.12, P<0.001) in the osteopenic (KI category 2), compared with the normal group (KI categories 0 and 1). Receiver operating characteristic (ROC) curve analysis was used to measure the validity of the KI indicating osteopenia (KI category 2) in predicting reduced BMD. This point provided a sensitivity of 50% and a specificity of 89%. Positive and negative predictive values were 21% and 97%, respectively. There were 87% correctly classified subjects. The area under the ROC curve was 0.64. The present study demonstrated that a negative finding (KI category <2) is highly predictive of the absence of osteopenia/osteoporosis as defined by the DXA measurements.     

Antibodies directed at mouse IL-2-R α and β chains act in synergy to abolish T-cell proliferation in vitro and delayed type hypersensitivity reaction in vivo

The anti-mouse IL-2-R chain mAb TM-1 which, by itself, does not affect IL-2-dependent proliferation throught the high affinity mouse IL-2 receptor, was shown to cooperate in a synergistic way with a set of anti-IL-2-R chain mAbs both in vitro and in vivo. In vitro, when associated at equimolar concentrations, the TM-1/anti- mAb association was four to ten times more efficient at inhibiting the proliferation of the CTL-L2 cell line than was a similar concentration of anti- mAb alone. In addition, a bispecific antibody in which a Fab' fragment of TM-1 was covalently linked to a Fab' fragment of one of the anti- mAb (5A2) was shown to be as efficient as the TM-1/5A2 association. The association of TM-1 with 5A2 was also tested in vivo in a sheep red blood cell-induced delayed type hypersensitivity (DTH) model. TM-1 which, by itself, had no effect on DTH, induced a two- to threefold decrease in the doses of 5A2 required to suppress this cell-mediated immune reaction.     

The Normal and Malignant Mammary Gland: A Fresh Look with ERβ Onboard

Estrogens are important for the development and function of the normal mammary gland as well as for development of mammary cancer. The frontline therapy for treatment of estrogen receptor (ER)⁴ positive breast cancer is antiestrogens. A second estrogen receptor (ER) is also expressed in the breast but it has not been measured because it is not detected by the immunoassays used to detect ER. In many cell systems ER has actions which are opposite to those of ER and this finding has raised questions about the role of ER in the development and treatment of breast cancer.     

Previous synovectomy or epiphyseal stapling and the influence on knee replacement in juvenile chronic arthritis

Seventy-seven anatomically graduated components (AGC) total knee arthroplasties (TKA) were performed on 52 patients with juvenile chronic arthritis. According to the nature of previous surgery on the knee, the patients were subdivided into three groups. The mean age at onset of disease in 23 patients with previous synovectomy of the knee was 11 (1.5–16) years, the mean age at the time of synovectomy was 20 (4–42) and the mean age when arthroplasty was performed was 31 (18–45) years. In nine patients with previous epiphyseal stapling, the mean age at disease onset was 4 (1.5–8) years, at stapling 8 (4–16) years, and at arthroplasty 23 (18–30) years. In patients with no previous surgery, the mean age at disease onset in this group was 7 (1.5–16) years and the mean age at arthroplasty 34 (16–64) years. Patients with need for epiphyseal arrest had an early disease onset and knee replacement in early adulthood. The mean age at knee replacements was highest in the group with no prior surgery.

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Résumé 77 arthroplasties totales du genou total (TKA) de type AGC ont été exécutées sur 52 malades avec arthrite chronique juvénile. Daprès la nature de la chirurgie précédente sur le genou les malades ont été divisés en trois groupes. Lâge moyen du début de la maladie chez les 23 malades avec synovectomie était de 11 (1,5–16) années, lâge moyen au temps de la synovectomie était de 20 (4–42) ans et lâge moyen quand larthroplastie a été exécuté était de 31 (18–45) ans. Pour 9 malades avec agrafage epiphysaire, lâge moyen au début de la maladie était de 4 (1,5–8) ans, avec 8 (4–16) ans à lagrafage et 23 (18–30) à larthroplastie. Pour les malades sans chirurgie précédente, lâge moyen au début de la maladie était de 7 (1,5–16) ans et lâge moyen à larthroplastie de 34 (16–64) ans. Les malades ayant eu besoin dun blocage épiphysaire avaient un début de la maladie précoce et un remplacement précoce du genou à lâge adulte . Lâge moyen au remplacement du genou était plus élevé dans le groupe sans chirurgie précédente.

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Study conducted at Rheumatism Foundation Hospital, Heinola, Finland.     

Distribution of sodium channels during nerve elongation in rat peripheral nerve

A number of studies have investigated electrophysiological and morphological changes of peripheral nerves during gradual elongation. There has been, however, no report on the distribution of sodium channels at Ranviers nodes during peripheral nerve elongation. We investigated peripheral nerve injury after the gradual elongation of rat sciatic nerves. Indirect nerve elongation was induced by leg lengthening at a rate of 3mm/day by 15 or 30mm. At 7 days after the leg lengthening, the electrophysiological properties of sciatic nerves, the ultrastructures of the Ranviers nodes and axons, and the distribution of voltage-dependent sodium channels were examined. In the control nerves, most sodium channels were localized at Ranviers nodes in myelinated axons, providing the physiological basis of saltatory conduction. In the elongated nerves, both the amplitude and conduction velocity of compound nerve action potential decreased following leg lengthening. The elongated nerves also showed paranodal demyelination in Ranviers nodes longer than those in the control group. In addition, the distribution of sodium channels became diffuse or disappeared at Ranviers nodes of elongated nerves. The diffuse distribution and/or disappearance of sodium channels may underlie the electrophysiological changes in compound nerve action potential induced by nerve elongation.     

Comparative study of intravenous administration of Ringer’s lactate,Ringer’s acetate and 5% glucose containing these Ringer’s solutions in human being

The effects of the administration of Ringers lactate (L) and Ringers acetate (A) solution on blood biochemistry in human subjects operated for tympanoplasty under general anesthesia were investigated. And the feasibilities of the clinical use of Ringers lactate (LD) and Ringers acetate (AD) solution containing 5% glucose were also assessed. In all cases the rate of infusion was 500ml for initial 20min, and then 5ml·hr^–1·kg^–1 B.W. for 3hr and 10min.There were significant increases in blood L- and D-lactate, pyruvate, and L-lactate/pyruvate ratio in L group. A significant increase in blood acetate but not lactate was found in A group. These metabolic changes were minimal and considered as clinically not significant. The urinary excretion of lactate, pyruvate, acetate and glucose were also negligible. In both LD and AD group, the higher blood concentrations of lactate, pyruvate, acetate and glucose were found than in L and A group. Urinary excretions of these metabolites were much higher in LD and AD group than in L and A group. So glucose containing Ringers lactate or acetate solutions should be administered in appropriate amounts and rate not to induce clinically significant metabolic alterations.(Kuze S, Naruse T, Ito Y et al.: Comparative study of intravenous administration of Ringers lactate, Ringers acetate and 5% glucose containing these Ringers solutions in human being. J Anesth 4: 155–161, 1990)     

Nihilism: A Benign Denial

Nihilism is the belief that all possible knowledge on a given topic has been amassed and codified. Ranging from benign denial to deliberate attempts at excommunication, nihilism is often encountered in the history of medicine. Eustachius, Columbus, and Sylvius strongly criticized Vesalius and defended the authority of Galen. Riolan fervently rejected Harveys monumental work on the circulation of blood. Gross stated that no honest and sensible surgeon would ever sanction thyroidectomy. Sandstroms discovery of the parathyroids was met with silence. Transplantation of parathyroids by Mandl was not appreciated when announced. Aristotles dictum that the heart cannot withstand serious injury led to Pagets statement that cardiac surgery had reached the limits set by nature, which no new techniques could overcome. The first Billroth I operation was welcomed as, Hopefully, also the last. Pancreatic surgery was opposed because the organ was of no clinical interest and was impossible for surgeons to reach. Pancreatic transplantation was rejected for many years, despite good results. When Blundell used blood transfusion for postpartum hemorrhage, critics averred that his next exploit would be radical removal of the spleen. Bassini stated that it could be risky to publish more about radical treatment of inguinal hernias. Carcinomas of the lower sigmoid and upper rectum were deemed untreatable because of their inaccessibility. Colostomy during pediatric surgery was rejected many times. Although it is difficult for the human mind to move from a familiar point of view, this propensity should not infect science, thereby impeding advancement.     

Computer assisted quantification of vasospasm on angiograms

Summary We describe a new computer-based, automated method for the assessment of in vivo cerebral vasospasm. Arterial diameter measurements were performed on post-processed digital substraction angiographic images, using pixel as the unit. Vasospasm which was difficult to detect by visual inspection could be measured by the stenosis quantification program. A computer-assisted method such as we describe might decrease the risk of subjective errors.     

Tierexperimentelle Untersuchungen über die Wundheilung unter dem Einfluß von Phenothiazinderivaten

Zusammenfassung Zur Klärung der Frage, ob der Künstliche Winterschlaf in irgendeiner Form Wundheilungsvorgänge beeinflußt, wird die primäre und sekundäre Wundheilung am Meerschweinchen untersucht, die durch Gagen von täglich je 10 mg N-(2-Dimethylaminopropyl)-Phenothiazin (A) und N-(3-Dimethylaminopropyl)-3chlor-Phenothiazin (M) und 20 mg Methylphenylpiperidincarbonyläthylhydrochlorid (D) je Kilogramm bis zu 6 Tagen in den sog. künstlichen Winterschlaf versetzt werden. Die Tiere werden 2,4 und 6 Tage nach den Eingriffen getötet. Das Wundgebiet wird histologisch untersucht und das Ergebnis mit dem an Kontrolltieren gewonnenen verglichen.Die Versuche zeigen, daß in den genannten Zeiträumen bei den Winterschlaftieren gegenüber den Kontrolltieren keinerlei Unterschiede in der Wundheilung auftreten.Während die histologische Untersuchung der Nieren keinen pathologischen Befund ergibt, zeigt der histologische Befund der Leber bei einer großen Zahl der Winterschlaftiere kleinfleckige Massennekrosen im SinneRössles, die bei keinem der Kontrolltiere zu finden sind und deren Genese erörtert wird.     

Delayed surgical treatment for neglected or mal-reduced talar fractures

From 1993 to 2002, we treated nine patients for neglected or mal-reduced talar fractures. Average patient age was 39 (20–64) years and average follow-up 53 months. The time interval between injury and index operation ranged from 4 weeks to 4 years. Surgical procedures included open reduction with or without bone grafting in six cases, open reduction combined with ankle fusion in one case, talar neck osteotomy in one case, and talar neck osteotomy combined with subtalar fusion in one case. All cases had solid bone union. One patient developed avascular necrosis of the talus needing subsequent ankle arthrodesis. In six patients, adjacent hindfoot arthrosis occurred. The overall AOFAS ankle–hindfoot score was in average 77.4. We conclude that in neglected and mal-reduced talar fractures, surgical treatment can lead to a favourable outcome if the hindfoot joints are not arthritic.

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Résumé De 1993 à 2002, nous avons traité neuf malades pour fracture du talus négligée ou mal réduite. Lâge moyen des malades était de 39 ans (20–64) et la moyenne de suivi était 53 mois. Lintervalle de temps entre le traumatisme et lopération étudiée était de 4 semaines à 4 années. Les techniques chirurgicales ont inclus la réduction ouverte, avec ou sans greffe dos dans six cas; la réduction ouverte combiné avec larthrodèse de la cheville dans un cas; lostéotomie du col de talus dans un cas, et lostéotomie du col du talus combiné avec larthrodèse sous-talienne dans un cas. Tous les cas avaient une union osseuse solide. Un malade a développé une nécrose avasculaire du talus et a pour cela été arthrodésé. Chez six malades une arthrose de larrière-pied sest développée. Le score de cheville AOFAS était en moyenne de 77.4. Nous concluons que dans les fractures astragaliennes négligées et mal réduites, le traitement chirurgical peut mener à un résultat favorable si les articulations de larrière pied sont sans arthrose.

     

Cytokines in childhood hemolytic uremic syndrome and thrombotic thrombocytopenic purpura

Serum and urine cytokines were analyzed in children with hemolytic uremic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP). Interleukin-6 (IL-6) was elevated in the serum of 33 of 35 children with HUS (94%) and in 2 of 2 children with recurrent TTP. Serum IL-6 was higher in children with HUS who developed anuria, extrarenal manifestations during the acute phase of illness and/or chronic renal sequelae. Tumor necrosis factor- (TNF-) was detected in the serum of 7 patients with HUS (20%) and 1 patient with TTP. IL-6 and TNF- were elevated in the urine of 4 of 4 children with HUS and 2 of 2 children with TTP. Urinary levels were higher than serum levels, suggesting local production of cytokines in the urinary tract. Sequential serum and urine samples showed that IL-6 levels varied with disease activity. IL-6 and TNF- were not detected in the serum (n=25) and urine (n=15) of healthy children. We conclude that IL-6 in urine may be used to monitor disease activity in HUS and TTP.     

Prediction of chronic renal allograft dysfunction from evaluations of TGFΒ1 and the renin-angiotensin system

Background. Growth factors, cytokines, and the renin-angiotensin system (RAS) are involved in chronic allograft dysfunction. However, it is unclear whether clinical evaluations of TGF1 and the RAS in longterm stable transplant patients can predict the development of chronic allograft dysfunction. Methods. Urinary TGF1 excretion and the response of plasma renin activity (PRA) to angiotensin I converting-enzyme inhibition (ACE-I) were prospectively examined in transplant patients who had had stable graft function (n = 16) for at least 1 year after renal transplantation. Four-year follow-up studies were undertaken to evaluate the impact of these parameters on the development of chronic allograft dysfunction. Results. Urinary TGF1 excretion and PRA response to ACE-I in renal transplant patients who developed chronic allograft nephropathy 4 years after the evaluations (n = 7) were significantly higher and greater, respectively, than these values in those who did not (n = 9; P 0.01). If the cutoff level for urinary TGF1 excretion was 250pg/min, the 4-year positive predictive value (PPV) with respect to the development of chronic allograft nephropathy was 83% and the negative predictive value (NPV) was 78% (sensitivity [sen.], 71%; specificity [sp.], 88%). If the cutoff level for PRA at 60min after ACE-I was 4.0ng/ml per h, the 4-year PPV was 71% and NPV was 75% (sen., 70%; sp., 75%). The stable transplant patients with high TGF1 excretion and exaggerated PRA response showed significantly higher rates of chronic allograft dysfunction than those with low TGF1 excretion and weak PRA response. Conclusions. This study demonstrates that some transplant patients with longterm stable graft function show increases in the activities of the TGF system and the RAS. Evaluations of urinary TGF1 excretion and PRA response to ACE-I present a possibility for predicting the development of chronic allograft dysfunction, with significant 4-year predictive values.     

Influence of intravesical administration of tumor necrosis factor α and systemic γ-interferon on murine bladder cancer: Lack of dose response

Summary The effect of intravesical administration of high dose recombinant tumor necrosis factor- (rTNF) and in combination with systemic recombinant -interferon (rIFN) on murine bladder cancer was studied. RTNF was given at 12.5 g/mouse on days 7, 11 and 15 after tumor instillation or at 2.5 g/mouse on days 7, 9, 11, 13 and 15. Some groups were also injected i.v., 24-h prior to each rTNF treatment with rIFN at a dose of 1.3 g/mouse. RTNF treatment suppressed tumor growth up to 48% of control, although the difference was not statistically significant. Combined administration of rIFN did not provide additional benefit.     

Effects of lead on osteoclast-like cell formation in mouse bone marrow cell cultures

To examine an effect of lead (Pb) on the process of osteoclast-like cell formation from its progenitors, we used a mouse bone marrow culture system in which osteoclast-like multinucleated cells (MNCs) were formed in response to bone-resorbing agents. In a 9-day culture period, Pb dose-dependently stimulated MNC formation over the concentration range 2–10 M, whereas at 40 M Pb, MNC formation declined. In an 11-day culture period, MNC formation reached a maximum at 5 M Pb and decreased with increasing concentration of Pb at 10–40 M. Pb-stimulated MNC formation was inhibited by both indomethacin and SC19220, an antagonist of prostaglandin E₂ (PGE₂) receptor. Pb stimulated the production of PGE₂ in marrow cell cultures, suggesting that Pb-stimulated MNC formation is dependent on the production of PGE₂. 3-Isobutyl-1-methylxanthine potentiated Pb-stimulated MNC formation and 2,5-dideoxyadenosine, an inhibitor of adenylate cyclase, inhibited it. A calcium ionophore A23187 increased Pb-induced MNC formation and verapamil, a calcium channel blocker, depressed it. It is possible that a PGE₂-induced increase in the levels of cyclic adenosine 3,5-monophosphate (cAMP) and calcium ions in marrow cells is involved in Pb-induced MNC formation. Pb and parathyroid hormone showed a synergistic stimulation on MNC formation. From these results, Pb is thought to induce osteoclast-like cell formation by a mechanism involving PGE₂ which increases the intracellular levels of cAMP and calcium ions.     

Collagen distribution in human membranous glomerulonephritis

In membranous glomerulonephritis (MGN), thickening of the glomerular basement membrane (GBM) is partly due to the accumulation of basement membrane material between and around immune deposits located on the epithelial aspect of the GBM. We investigated the distribution of type IV collagen chains (1/2, 3, 4, 5, 6) and of types I, III, V, and VI collagen in the glomeruli from 16 patients, by indirect immunofluorescence in 13 and the high-resolution immunogold technique in 6. No changes were detected in stage I MGN. The spiky projections of the GBM in stage II MGN and the basement membrane layers encircling immune deposits in stage III contained the 3, 4, and 5 chains of type IV collagen. In contrast, the 1/2 chains of type IV, as well as type VI collagen accumulated in the subendothelial aspect of the GBM. No significant staining for types I, III, and V collagens or for the 6 chain of type IV collagen was detected. The results show that, as in the normal glomeruli, the different chains of type IV collagen are not co-distributed in the glomerular extracellular matrix in MGN. They also indicate that type IV collagen chains and type VI collagen play an important role in the thickening of the GBM in human MGN.