Flow cytometric DNA analysis using cytokeratin labeling for identification of tumor cells in carcinomas of the breast and the female genital tract

Flow cytometric assessment of DNA-ploidy and S-phase fraction in malignant tumors is compromised by the heterogeneity of cell subpopulations derived from the malignant and surrounding connective tissue, e.g., tumor, stromal and inflammatory cells. To evaluate the effect on quality of DNA cell cycle analysis and determination of DNA ploidy, cytokeratin labeling of epithelial cells was used for tumor cell enrichment in breast, ovarian, cervical and endometrial cancer prior to DNA analysis. In a prospective study, tumor cell subpopulations of 620 malignant tumors were labeled by a FITC-conjugated cytokeratin antibody (CK 5, 6, CK18 and CK 5, 6, 8 and CK 17, respectively) prior to flow cytometric cell cycle analysis. Compared to total cell analysis, detection rate of DNA-aneuploid tumors following cytokeratin labeling was increased from 62% to 76.5% in breast cancer, from 68% to 77% in ovarian cancer, from 60% to 80% in cervical cancer and from 30% to 53% in endometrial cancer. Predominantly in DNA-diploid tumors, a significantly improved detection of S-phase fraction of the tumor cells was shown due to the elimination of contaminating nonproliferating "normal cells". S-phase fraction following tumor cell enrichment was increased by 10% (mean) following cytokeratin staining in ovarian and endometrial cancer, by 30% in breast cancer and even by 70% in cervical cancer compared to total cell analysis. Thus, diagnostic accuracy of DNA-analysis was enhanced by cytokeratin labeling of tumor cells for all tumor entities investigated.

Obstetric risks and vertical transmission of hepatitis C virus infection in pregnancy

BACKGROUND

Reports of obstetric complications of mothers infected with hepatitis C virus (HCV) are limited and the risk of mother-to-infant transmission varies widely. We assessed the course of pregnancy in HCV-infected women and the rate of vertical transmission.

METHODS

Between October 1992 and December 1996, 3712 pregnant patients of the university hospital Grosshadern Munich, Germany, were screened for anti-HCV and analyzed for HCV-RNA by polymerase chain reaction. Clinical and biochemical parameters were monitored. Children born to HCV-positive women were followed up at 6, 12 and 18 month intervals and screened for anti-HCV and HCV-RNA.

RESULTS

Thirteen (42%) of 31 anti-HCV positive patients had a cesarean section which was twice the rate of that in the HCV-negative group (p=0.004). None of the cesarean deliveries was due to complications directly caused by HCV infection. Nine (29%) of 31 anti-HCV positive women had preterm delivery compared to 19% in the anti-HCV negative patients, the difference being statistically not significant. Fetal outcome parameters such as APGAR score, umbilical pH and birth weight of HCV infected pregnancies were not impaired. All 29 babies tested for anti-HCV were seropositive after birth. Between 12 and 18 months of age, 10% of the infants still were anti-HCV positive, whereas only one baby was HCV-RNA positive beyond 12 months yielding a vertical transmission rate of 5% among HCV-RNA positive mothers.

CONCLUSION

Anti-HCV positive pregnancies have an increased risk of cesarean delivery, probably due to the high-risk collective of anti-HCV positive mothers. The mother-to-child transmission rate is low and linked to maternal HCV-RNA positivity.

Assessment of 5-aminolevulinic acid-induced porphyrin fluorescence in patients with peritoneal endometriosis

OBJECTIVE

The purpose of this study was to examine the diagnostic potential for patients with endometriosis of porphyrin fluorescence after oral administration of 5-aminolevulinic acid.

STUDY DESIGN

Fifteen women referred for laparoscopy because of suspected endometriosis received 1 or 10 mg/kg 5-aminolevulinic acid orally. After 1.5 to 6 hours endoscopic fluorescence spectral analysis and video inspection were performed.

RESULTS

With 10 mg/kg 5-aminolevulinic acid and application intervals of >3 hours we observed a significantly higher porphyrin fluorescence in active peritoneal endometriosis than in adjacent normal peritoneum. Pigmented and nodular endometriosis showed weak to negative fluorescence. A strong fluorescence of the fimbrial mucosa was seen. A 1-mg/kg dose of 5-aminolevulinic acid was insufficient for fluorescence diagnosis. No side effects were recorded.

CONCLUSION

Porphyrin fluorescence after oral administration of 5-aminolevulinic acid may be beneficial in diagnosis of peritoneal endometriosis. The strong fluorescence of fimbrial mucosa may limit the applicability of this technique in young women, however, because phototoxic damage cannot be excluded at present.

[LEEP versus cold knife conization for treatment of cervical intraepithelial neoplasias]

OBJECTIVE

This study was performed to evaluate the effectiveness and side effects of loop electrosurgical excision procedure (LEEP) in comparison to cold knife conization for the treatment of cervical intraepithelial neoplasia (CIN).

MATERIAL AND METHODS

Between January 1996 and July 1998, 177 patients underwent conization. In a matched-pair setting, 50 cases with LEEP were compared with 100 classical conization cases. LEEP was performed with ectocervical and endocervical excision.

RESULTS

Perioperative complications were less in the LEEP group (6% vs. 11%). The mean volume of LEEP specimens (1.6 cm3) was significantly smaller than the volume of cone specimens (2.6 cm3). Thermal artifacts were negligible. There were no significant differences in the proportion of margin involvement (20% vs. 19%) and residual/recurrent CIN. The endocervical excision contained dysplastic tissue in 38% of the cases; more important, a positive endocervical excision was found in 14/21 CIN 3 cases (67%). The success rate, was similar in both groups (96% vs. 97%). Hospitalization time was less for the LEEP group.

CONCLUSIONS

LEEP conization is a safe and cost effective procedure with a lower complication rate providing a significantly smaller specimen compared to cold knife conization. Therefore, LEEP conization may substitute cold knife conization. However, we do recommend to perform LEEP conization with an endocervical excision to reduce residual CIN.

Photodetection of cervical intraepithelial neoplasia using 5-aminolevulinic acid-induced porphyrin fluorescence

BACKGROUND

Screening for cervical carcinoma and its precursors is based on cervical cytology and diagnostic colposcopy. Despite the decrease in the incidence of cervical carcinoma in countries with a good screening program, this rate of decline is leveling off. Known problems are false-negative rates of cytology and low specificity of colposcopy. This clinical study examined the diagnostic potential of porphyrin fluorescence in patients with cervical intraepithelial neoplasia Grade 1-3 (CIN 1-3).

METHODS

Sixty-eight women attending our colposcopy clinic underwent a gynecologic examination, including cytology, human papillomavirus (HPV) testing, and colposcopy. They received 10 mL 0.5% or 1.0% 5-aminolevulinic acid (5-ALA) topically. After 30-360 minutes, real-time image analysis was performed, and spectra were obtained from 685 sites.

RESULTS

Due to rapid photobleaching, 0.5% 5-ALA proved ineffective for fluorescence assessment. Using 1% 5-ALA, the authors found that fluorescence intensities correlated with incubation time; however, fluorescence contrast showed a maximum at 60-90 minutes (ratio 11:1). HPV DNA positive lesions showed significantly higher fluorescence. Fluorescence imaging after 60-90 minutes achieved similar sensitivity and specificity compared with colposcopy in detecting CIN with 94% and 51% versus 95% and 50%, respectively. However, the specificity was markedly improved by fluorescence spectroscopy, achieving 75%. The evaluation of spectral measurements revealed significantly higher values for CIN compared with normal tissue and for CIN 2/3 compared with CIN 1 (P < 0.001).

CONCLUSIONS

Using a time interval of 60-90 minutes after topical application of 1% 5-ALA, the authors observed specific porphyrin fluorescence of CIN. Fluorescence spectroscopy promises to become a valuable tool for the diagnosis of CIN.

Photodynamic therapy of vulvar intraepithelial neoplasia using 5-aminolevulinic acid

Photodynamic (PDT) therapy is a relatively new technique with unique properties that make it attractive for the local treatment of superficial epithelial disorders. The objective of this study was to investigate the clinical response of PDT with the photosensitizing agent 5-aminolevulinic acid (5-ALA) in patients with vulvar intraepithelial neoplasia (VIN) grades 1 to 3. Twenty-five patients with 111 lesions of VIN 1-3 were topically sensitized with 10 ml of a 20% solution of 5-ALA and treated with 57 cycles of laser light at 635 nm (100 J/cm(2)). Seventy (64%) of the 111 VIN lesions regressed after various PDT cycles. A complete response was achieved in 13 patients (52%) with 27 lesions. All patients with VIN 1 and mono- and bifocal VIN 2-3 showed complete clearance. However, a complete response could be achieved in only 4 (27%) of 15 women with multifocal VIN 2-3, whereas a partial response was noted in 9 of these patients with a total of 70 lesions, out of which 44 (63%) lesions disappeared. No response was seen in 2 patients with multifocal VIN 3. Histological assessment of the fluorescence-directed biopsies revealed that increased pigmentation and hyperkeratosis of the lesions were associated with low response rates. PDT using 5-ALA represents an alternative treatment modality for VIN which is easy to perform and has the advantage of minimal tissue destruction, low side effects and excellent cosmetic results. However, multifocal VIN disease with pigmented and hyperkeratinic lesions remains difficult to treat.

Screening for cervical neoplasia by self-assessment for human papillomavirus DNA

We evaluated self-collected vaginal human papillomavirus tests for cervical cancer screening and compared it with the specimens taken directly from the cervix in 247 patients at high-risk for cervical disease. The sample taken by the patient showed human papillomavirus DNA in a higher percentage than the sample taken by a doctor. Sensitivity of high-risk human papillomavirus types for high-grade cervical precursors (CIN 2/3) and invasive cervical cancers were 93% for both methods.

Photodynamic therapy in women with cervical intraepithelial neoplasia using topically applied 5-aminolevulinic acid

Photodynamic therapy (PDT) is a novel treatment modality that produces local tissue necrosis with laser light after prior administration of a photosensitizing agent. We performed a study of topically applied 5-aminolevulinic acid (5-ALA) in the photodynamic treatment of women with high-grade cervical intraepithelial neoplasia (CIN) using fixed 5-ALA doses and application protocols derived from previous in vitro and in vivo results. Three to 5 hr prior to PDT, 10 ml of a 20% solution of 5-ALA was topically applied using a cervical cap. PDT was performed with irradiation of 100 J/cm2 at an irradiance of 100-150 mW/cm2 with an argon-ion-pumped dye laser at 635 nm. For the endocervix, a specifically designed cylindrical applicator was used. Ten treatment cycles of PDT using 5-ALA were performed in 7 patients with high-grade CIN. Non-thermal laser treatment with 100-150 mW/cm2 was well tolerated. Local toxicity was minor as several patients reported burning sensations and vaginal discharge, but no necrosis, sloughing or scarring occurred. After 3 months, a significant reduction in the size of the ectocervical CIN lesions was noted in only 3 patients, who underwent a second PDT cycle. However, no significant improvement in CIN lesions was noted since cold knife conization revealed persistent CIN in all 7 cases. Therefore, PDT after topical application of 5-ALA using an irradiation of 100 J/cm2 produces only minimal side effects. However, it does not appear to be effective in treating CIN.

Photodynamic therapy of vulvar lichen sclerosus with 5-aminolevulinic acid

OBJECTIVE

To evaluate the therapeutic effect of photodynamic therapy on vulvar lichen sclerosus.

METHODS

Twelve women with lichen sclerosus were enrolled in a prospective, single-arm pilot study. Four to 5 hours before photodynamic therapy, 10 mL of a 20% solution of 5-aminolevulinic acid was applied topically to the vulva. Photodynamic therapy was administered with an irradiation of 80 J/cm2 at an irradiance of 40-70 mW/cm2. Light with a wavelength of 635 nm was delivered by an argon ion-pumped dye laser. The degree of pruritus was evaluated using a horizontal visual analog scale before and after 6-8 weeks, and patients were followed tri-monthly after photodynamic therapy.

RESULTS

Two women underwent two cycles of photodynamic therapy, one underwent three cycles, and the remaining nine women underwent one cycle each. Treatment was tolerated moderately well, with eight patients not requiring any analgesia; three treated with opioids intravenously during the procedure, due to burning sensations; and one undergoing separation of adhesions under general anesthesia. Minimal local toxicity included vulvar erythema but no necrosis, sloughing, or scarring. No generalized cutaneous photosensitivity was present. Six to 8 weeks after photodynamic therapy, pruritus significantly improved in ten of the 12 women. A prolonged effect of photodynamic therapy was reported, with a mean of 6.1 months.

CONCLUSION

Photodynamic therapy after topical application of 5-aminolevulinic acid produced statistically significant relief of symptoms of vulvar lichen sclerosus for an average of 6.1 months with minimal side effects.

Pharmacokinetics and selectivity of aminolevulinic acid-induced porphyrin synthesis in patients with cervical intra-epithelial neoplasia

Photodynamic therapy (PDT), due to its tumor selectivity, represents an alternative approach to diagnose and treat cervical intra-epithelial neoplasia (CIN) without altering normal surrounding tissue. Our aim was to investigate the pharmacokinetics and the selectivity of 5-aminolevulinic acid (5-ALA)-induced porphyrin fluorescence after topical administration, to obtain basic clinical data for future diagnostic fluorescence imaging and PDT protocols for CIN. Twenty-eight non-pregnant women with a cytological diagnosis of low-grade or high-grade squamous intra-epithelial lesions were included. An aqueous solution containing 3% 5-ALA was topically applied 1 to 6 hrs prior to conization using a cervical cap. After excision, porphyrin-induced fluorescence was quantified in dysplastic (n = 14) and normal epithelium (n = 28) by means of quantitative fluorescence microscopy. High values of porphyrin fluorescence were found in squamous epithelium between 150 and 450 min, with a maximum at 300 min following administration of 5-ALA. Ratios of porphyrin fluorescence of dysplastic vs. surrounding normal epithelium were 1.3 and 1.21 for CIN 1 (n = 3) and CIN 2 (n = 3), respectively. In CIN 3 patients (n = 8), this ratio was 2.35; the best selectivity of 5-ALA-induced porphyrin fluorescence in CIN 3 lesions (ratio 3) was observed with a topical administration time of between 150 and 250 min. Our results demonstrate that patients with CIN 3 show higher 5-ALA-induced fluorescence compared with normal epithelium. The optimal administration time of topically applied 5-ALA was between 3 and 4 hr. Our data suggest that topical ALA-PDT and photodynamic diagnosis might be suitable for detecting CIN.

[Epidemiology and diagnosis of cervical intraepithelial neoplasia--is the present concept of screening and diagnosis still current?]

Infection with human papillomavirus (HPV) is the major factor in the genesis of cervical intraepithelial (CIN) and invasive neoplasia. However, screening is still based upon cytology and further diagnostic investigation relies on colposcopy with punch biopsy. In this review, recent studies are evaluated with regard to consequences for optimal screening and management strategies of CIN. In summary, exfoliative cytology is still widely considered as the method of choice for population screening. Primary HPV DNA screening proves equivalent or superior to cytology only in populations with a low prevalence of HPV infections. Preliminary data from serological HPV tests are less promising. Cytological diagnosis of HPV infection may be verified by HPV testing. Recognizing high oncogenic risk viruses in CIN 1 may help to reduce the control period from 24 to 12 months and may lead to immediate therapy for CIN 2 lesions. However, further prospective studies evaluating the cost-effectiveness of HPV DNA tests in German-speaking countries are necessary.

[Prevalence and follow-up of hepatitis C virus infection in pregnancy]

Hepatitis C shows an increasing distribution in countries of western Europe. The aim of our study was to assess the prevalence of antibodies to hepatitis C (anti-HCV) in pregnancy, to evaluate the risk factors for anti-HCV positive women and the course of hepatitis C during pregnancy. 3712 pregnant patients of the university hospital Grosshadern, Munich, were analyzed for anti-HCV, anti-HIV and hepatitis B surface antigen. Anti-HCV seropositive women were further tested with western blot and polymerase chain reaction for HCV-RNA. Thirty-five (0.94%) of the 3712 pregnant women were found anti-HCV positive. 20% of them had present or previous injection drug abuse, hereof one patient had an associated seropositivity for HIV. Parenteral transmission through blood transfusion was likely in 11%. However, no parenteral exposure was recognized in 57% of the anti-HCV positive patients. The presence of serum HCV-RNA was detected in 16 (57%) of the 28 patients tested. In 17% (6/35) of the anti-HCV positive pregnancies elevated liver enzymes were noted, which did not show any significant change during the course of pregnancy. In conclusion, the prevalence of hepatitis C in pregnancy is relatively high with nearly 1%-comparable to chronic hepatitis B infection. Selected pregnancy screening based on perceived high-risk groups alone fail to detect about 60% of HCV antibody-positive women. Pregnancy did not influence the course of hepatitis C.

Prevalence of anal human papillomavirus infection and anal cytologic abnormalities in HIV-seropositive women

OBJECTIVE

To determine the prevalence of anal human papillomavirus (HPV) infections and anal cytologic abnormalities in HIV-seropositive and HIV-seronegative women.

DESIGN

This cross-sectional study of a cohort of women with known HIV serostatus involved a standardized interview and a gynecologic examination, including a cytologic evaluation of the cervix and anus. Anal swabs were tested for HPV DNA using the Hybrid Capture assay.

SETTING

Two HIV/AIDS clinics, a sexually transmitted disease clinic, a methadone clinic and women enrolled in a study of HIV heterosexual transmission in the greater New York City metropolitan area.

PATIENTS

One hundred and two HIV-seropositive and 96 HIV-seronegative women were selected from an ongoing study of the gynecologic manifestations of HIV infection.

MAIN OUTCOME MEASURES

Detection of anal HPV DNA and anal cytologic abnormalities.

RESULTS

Anal cytologic abnormalities were detected in 27 (26%) of the 102 HIV-seropositive women and in six (7%) of 96 HIV-seronegative women. Five (5%) of the anal smears from the HIV-seropositive women and one (1%) from the HIV-seronegative women had low-grade anal intra-epithelial neoplasia. The remainder of the anal cytologic abnormalities were classified as mild squamous cytologic atypia. HPV DNA was detected in 30 (29%) of 102 HIV-seropositive and two (2%) of 96 HIV-seronegative women. Of the 33 patients with anal cytologic abnormalities, 19 (58%) had anal HPV DNA detected as compared to 13 (8%) of 160 women without cytologic abnormalities (P < 0.001). In a multivariate logistic regression analysis, HIV-seropositivity was found to be an independent risk factor for both anal HPV infection and anal cytologic abnormalities and the strength of the association was greater in women with lower CD4+ T-lymphocyte counts.

CONCLUSION

The prevalence of both anal cytologic abnormalities and anal HPV infection are significantly increased in HIV-seropositive women.

[Emergency cesarean section--organization and decision-delivery time]

The German Society of Gynaecology and Obstetrics has published standards for obstetrical services concerning equipment, personnel and organisation. All obstetrical services must be able to perform an emergency Caesarean section with a 20 minutes interval from decision to delivery (D-D time). This study represents an analysis of the 75 emergency Caesarean sections performed at the University hospital Grosshadern of Munich during the interval from 1987 to 1994. This being a level III hospital, there is a 24 hour obstetrical, anaesthesia and neonatal service, and personnel is readily available. The operation can and has been done in each delivery room. 1. The incidence of emergency Caesarean sections was 0.6% compared to a total Caesarean rate of 21.5% in a high risk population having a preterm rate of 19% during the period of the study. 55% of the patients who had emergency Caesarean sections presented with a gestational age of less than 37 weeks and 35% of less than 32 weeks. 2. The mean time elapsed between decision and delivery (D-D time) was 12.8 minutes; however, the 90 percentile was 22 minutes and exceeded the recommended D-D time of 20 minutes. The mean decision to incision interval represented 9.1 minutes, and 3.6 minutes were needed between incision and delivery. 3. There was a significantly higher frequency of emergency Caesarean sections, performed during daytime and evening hours compared to early morning (0-8 a.m.). However, the D-D time intervals examined for these three time periods showed only minor, non-significant differences. In conclusion, an efficient emergency Caesarean delivery requires a coordinated team effort with excellent cooperation between obstetrics, anaesthesia and neonatology. Our study demonstrates that even in this optimal setting a decision to delivery time within the 20-minute interval can not always be achieved. Based upon our results and other studies, we recommend a D-D time of 30 minutes.

Rupture of splenic artery aneurysm in a pregnant patient with portal hypertension

The rupture of a splenic artery aneurysm in pregnancy is a rare emergency. As our case illustrates, immediate laparotomy often cannot prevent the fatal outcome. Pregnancies with portal hypertension are at increased risk, and therefore screening for splenic artery aneurysm is recommended, if possible, before conception.

Expression of cellular retinol- and cellular retinoic acid-binding proteins in the rat cervical epithelium is regulated by endocrine stimuli during normal squamous metaplasia

To determine the potential roles of retinoids in the growth and differentiation of the reproductive tract epithelium, we have studied the expression of the cellular retinol- and retinoic acid-binding proteins, CRBP I and CRABP I, in the reproductive tract of female rats. CRBP I and CRABP I gene expression have been examined in the oviduct, ovary, uterus, and particularly in the cervix, which normally undergoes a cyclical squamous metaplasia during the estrus cycle. CRBP I was expressed in all four tissues examined, whereas CRABP I was expressed predominantly in cervix and uterus. In the cervix, CRBP I was detected in all epithelial layers including the columnar epithelium but was greatly reduced in the superficial, cornified layers of the stratified squamous epithelium. CRABP I was localized to the basement membrane region of the epithelium with the strongest expression in the basal layer of epithelial cells. While the expression of CRBP I and CRABP I in the keratinizing exocervix changed during the estrus cycle, it remained constant in the incompletely keratinized endocervix. The highest levels of CRBP I were seen during anestrus and proestrus, and for CRABP I during proestrus. Both CRBP I and CRABP I levels fell to barely detectable levels during estrus and metestrus. Using estrogen repletion of ovariectomized rats, we found that CRABP I levels transiently increased during the early proliferative response to estrogen, whereas CRBP I levels gradually declined, becoming barely detectable by 24 to 48 hours. These results suggest that CRBP I and CRABP I play different roles in the cyclical squamous metaplasia normally occurring in this tissue and that hormonal control of CRBP I and CRABP I expression might modulate the retinoid responsiveness of the epithelium during this process.

Detection of parvovirus B19 in fetal autopsies

In a 10-year retrospective study we examined the incidence of parvovirus B19 (B19)-related hydrops fetalis in fetal autopsies (n = 1,299) carried out between 1982 and 1991. Intrauterine death had occurred in 399 cases (30.7%); in 42 (10.5%) of these hydrops fetalis was diagnosed. Of these 42 hydropic fetuses, parvovirus B19 infection was identified in 6 (14.3%) cases by the presence of typical erythroblastic nuclear inclusions in hematoxylin-eosin stained tissue and the diagnosis was confirmed by in situ hybridization using a Digoxigenin-labelled B19 DNA probe. The study shows that the overall incidence of B19-associated intrauterine death associated with hydrops fetalis is low. However, B19 infection should be considered in all cases of hydrops fetalis.

Localization of cellular retinoid-binding proteins in human cervical intraepithelial neoplasia and invasive carcinoma

Cellular retinoic acid-binding protein (CRABP) and cellular retinol-binding protein (CRBP) were localized in biopsies of normal squamous epithelium, cervical intraepithelial neoplasia (CIN), and invasive squamous cell cancer of the cervix uteri by immunohistochemistry. In both the normal stratified squamous epithelium of the exocervix and low-grade CIN, CRABP I was present predominantly in the basal layer of the epithelium. The more superficial, differentiated cell layers lacked immunoreactive protein. In high-grade CIN (CIN2-3), the distribution of CRABP I was altered. Immunoreactive CRABP I was detected in all layers of high-grade CIN. In squamous cell carcinoma of the cervix, CRABP I was detected in cells throughout the tumor but was minimal in cells demonstrating squamous differentiation. In contrast to CRABP I, CRBP was diffusely present throughout the cervical epithelium irrespective of the state of differentiation or the presence of disease.

A beta 1-integrin receptor for fibronectin in human kidney glomeruli

The fibronectin receptor (FNR) is a transmembrane heterodimeric glycoprotein which shares a common beta 1-chain with several other members of the integrin family of adhesion receptors. The authors have prepared a membrane fraction of isolated human glomeruli, from which two proteins (apparent molecular weights 120 kd and 140 kd) bound to a fibronectin-column, and were selectively released by the synthetic peptide Arg-Gly-Asp-Ser. These molecules were labeled in immune overlays by an antibody raised against the FNR from human placenta that recognizes both the FNR-specific a-chain and the group-specific beta 1-integrin chain. In sections of normal human kidneys this antibody labeled predominately the mesangia and the peripheral capillary walls of glomeruli by an immunoperoxidase procedure. Quantitative immunoelectron microscopy, using an indirect immunogold procedure, revealed a preferential localization along the cell membranes of mesangial, epithelial, and endothelial cells that face the mesangial matrix or the glomerular basement membrane (GBM). In kidney biopsies from patients with various glomerular diseases (membranous and other forms of glomerulonephritis, minimal change disease) the distribution was similar to that in normal glomeruli. These findings indicate that a beta 1-integrin-related FNR is present in normal and diseased human glomeruli.

Identification of a 400-kd protein in the brush borders of human kidney tubules that is similar to gp330, the nephritogenic antigen of rat Heymann nephritis

The nephritogenic antigen of Heymann nephritis (HN)--a well-studied experimental rat model disease of human membranous glomerulonephritis (MGN)--was recently shown to be a 330-kd glycoprotein (gp330) which is present in the membranes of both the rat tubular brush borders and of podocytes. Because the pathogenic antigen(s) of MGN are unknown, the authors have searched for a gp330-like molecule in human kidney and for its role in MGN. The authors here report that a membrane protein (apparent molecular weight 400 kd) is present in human kidney which is immunologically cross-reactive with rat gp330. By immunoelectron microscopy (using rabbit anti-rat gp330 IgG or a monoclonal anti-400-kd IgG) this molecule is similarly localized in human proximal tubules, but it is absent from the podocytes of human glomeruli. The 400-kd molecule is not detected in the glomerular immune deposits of 30 biopsies of MGN. It is proposed that this is due to the lack of the 400-kd protein in human glomeruli which prevents the formation of initial 400-kd anti-400-kd IgG immune complexes in situ.