Meta-analysis of the effects of smoking and smoking cessation on triglyceride levels

Smoking increases lipid levels, including triglycerides, leading to increased cardiovascular disease risk. We performed a meta-analysis to quantify the effects of smoking and smoking cessation on triglyceride levels. The PubMed and Scopus databases were searched to identify studies reporting either triglyceride levels in smokers and non-smokers or the effects of smoking cessation on triglyceride levels. Fixed- and random-effects models were used to perform the analyses when three or more studies/comparisons were available. We identified 169 and 21 studies evaluating the effects of smoking and smoking cessation, respectively, on triglyceride levels. Triglyceride levels were 0.50 mmol/L (95% confidence interval: 0.49-0.50 mmol/L) higher in smokers than non-smokers, but the effect differed widely across studies. No statistically significant effect was observed on triglyceride levels between baseline and 6 weeks (mean difference [MD] = 0.02 [-0.09, 0.12] mmol/L), 2 months (MD = 0.03 [-0.21, 0.27] mmol/L), 3 months (MD = 0.08 [-0.03, 0.21] mmol/L), or 1 year (MD = 0.04 [-0.06, 0.14] mmol/L) after quitting. However, a slightly significant decrease in triglyceride levels was observed at 1 month after cessation (MD = -0.15 [-0.15, -0.01] mmol/L). The results of this meta-analysis provide a basis for understanding the effects of smoking and smoking cessation on triglyceride levels, which could have important implications for public health.

Effect of switching from cigarette smoking to the use of the tobacco heating system on periodontitis treatment outcome: Periodontal parameter results from a multicenter Japanese study

Objectives

We conducted a 6-month randomized clinical study to evaluate the impact of exposure to the aerosol of the Tobacco Heating System (THS), a smoke-free alternative to cigarettes, on changes in periodontal parameters after scaling and root planing (SRP) for periodontitis in subjects who were either continuing to smoke cigarettes or had switched to THS.

Material and methods

Smokers with generalized periodontitis were randomized to continue smoking cigarettes or switch to THS use. They underwent SRP for up to 8 weeks, with dental assessments conducted at baseline and at 3 and 6 months after the first treatment.

Results

After SRP treatment, all groups showed improvements in the mean full-mouth probing depth (PD), full-mouth clinical attachment level (CAL), gingival inflammation score, plaque control record (PCR), and bleeding on probing (BoP). There were no statistically significant intergroup differences. However, as compared to smokers, THS users showed a trend toward more favorable outcomes in BoP, PCR, and PD improvement at sites with higher initial PD (≥7 mm).

Conclusions

Our results indicate that SRP improves the course of periodontitis similarly in cigarette smokers and THS users. The beneficial effects of this treatment might mask the favorable changes that may occur upon modifying one of the several periodontitis risk factors, such as cigarette smoking.

Clinical trial registration

ClinicalTrials.gov, identifer: NCT03364751.

Ischemic Heart Disease and Chronic Obstructive Pulmonary Disease Hospitalizations in Japan Before and After the Introduction of a Heated Tobacco Product

To substantiate the beneficial effects of switching from cigarette smoking to heated tobacco products (HTP), this study conducted a time-trend analysis using data from the Japanese Medical Data Center (JMDC) database. Specifically, we assessed hospitalization numbers for chronic obstructive pulmonary disease (COPD) exacerbations and acute ischemic heart disease (IHD) before and after the introduction of HTPs in the Japanese market. This study replicated a previous study using a different Japanese real-world data source (Medical Data Vision). We retrieved the number of hospitalizations associated with the International Classification of Diseases-10 codes for COPD and IHD from 2010 to 2019−5 years before to 4 years after introducing HTPs in the Japanese market—from the JMDC database. Then, we used interrupted time-series analyses to test the hypothesis that the introduction of HTPs is associated with a reduction in hospitalizations for COPD (all codes), COPD exacerbation, COPD exacerbation plus lower respiratory tract infections (LRTI), and IHD, adjusting for age, sex, seasonality, and flu vaccination rates. Analysis of all available data from the JMDC database revealed a significant reduction in the number of hospitalizations for COPD (all codes; P = 0.0001) and IHD using Diagnosis Procedure Combination data on causative disease flags (P < 0.00001). We also observed a non-significant reduction in hospitalizations for COPD plus LRTI as well as IHD after HTP introduction in Japan. This study confirmed the findings of our previous study where a decrease in hospitalizations due to COPD exacerbation after the introduction of HTPs in Japan was also shown. Nevertheless, these findings warrant further research to evaluate the impact of HTPs on the health of populations in other countries where these products have been introduced.

211Real-World Data Assessment Plan for a Heat-Not-Burn Tobacco Product: Proof of Concept

Focus of Presentation

Real-world data (RWD) is readily available in Japan through multiple sources. Considering the crucial need to substantiate the beneficial effects of switching from cigarette smoking to heat-not-burn (HNB) products, both at the individual and population levels, the use of RWD seems a viable option.

For instance, ecological studies using RWD have assessed the impact of population-level interventions such as smoking bans and their effects on smoking-related diseases and their endpoints

As a proof of concept, ecological analyses were performed to assess the rates of chronic obstructive pulmonary disease (COPD) exacerbations and acute Ischemic Heart Disease (IHD) hospitalizations before and after the introduction of and HNB product in the Japanese market.

Findings

Hospital admissions associated with ICD codes for COPD and IHD from 2008 to 2019—5 years before and 4 years after the introduction of the target HNB product in the Japanese market—were retrieved from the MDV database. Referrals were below those predicted from pre-launch trends.

Conclusions

The use of RWD in assessment of HNB products is viable for ecological studies with the well-known caveats. Their use in exposure-specific studies will become feasible once the systematic collection of exposure to tobacco products and use history is guaranteed. This will greatly increase the range and robustness of the evidence base.

Key messages

The use of RWD is a practical way of assessing the impact of HNB products in the population as a whole.

Impact of switching to a heat-not-burn tobacco product on CYP1A2 activity

Background

Cigarette smoking induces cytochrome P450 1A2 (CYP1A2) expression and activity, while smoking cessation normalizes the levels of this enzyme. The aim of this publication is to summarize the data on CYP1A2 gene expression and activity in preclinical and clinical studies on the Tobacco Heating System (THS), currently marketed as IQOS® with HEETs®, and to summarize the potential effects on CYP1A2 to be expected upon switching to reduced-risk products (RRPs).

Methods

We summarized PMI’s preclinical and clinical data on the effects of switching from cigarette smoking to THS.

Results

Data from four preclinical mouse and rat studies showed that, upon either cessation of cigarette smoke exposure or switching to THS exposure, the upregulation of CYP1A2 observed with exposure to cigarette smoke reverted close to fresh-air levels. Data from four clinical studies yielded similar results on CYP1A2 activity within a time frame of five days. Furthermore, the effects of switching to THS were similar to those seen after smoking cessation.

Conclusions

Because smoking cessation and switching to either electronic cigarettes or THS seem to have similar effects on CYP1A2 activity, the same measures taken for patients treated with narrow therapeutic index drugs that are metabolized by CYP1A2 and who quit smoking should be recommended for those switching to RRPs.

Ventricular outflow tract obstruction secondary to leiomyosarcoma of the right ventricle

Primary leiomyosarcomas of the heart, particularly those affecting the right ventricle, are uncommon. We report the case of a 70-year-old Belgian woman presenting with the symptoms of progressive exertional dyspnea and left-sided pleuritic pain. A leiomyosarcoma which originated from the right lateral ventricle wall, causing pulmonary outflow obstruction, was diagnosed. Pathology revealed a neoplasm with a myxoid stroma, high mitotic activity and nuclei expressing atypia. Immunohistochemical staining was positive for vimentine and desmin. Seven months after complete surgical resection the tumor relapsed. This case demonstrates the poor outcome, the high relapse rate and inefficiency of treatment associated with primary cardiac leiomyosarcomas. The current literature regarding the incidence, diagnostic techniques, treatment strategies and survival rates of this rare but terminal disease is reviewed.

Itraconazole in the treatment of onychomycosis: a double-blind comparison with miconazole

BACKGROUND

In recent years, itraconazole pulse therapy for onychomycosis has been developed [three 1-week pulses with itraconazole 400 (2 x 200) mg daily every month]. This has proved an effective and safe regimen which requires only 50% of the medication used for continuous dosing schedules. Parallel to the development of the new dosage schedule, additional studies were conducted to further document the safety and efficacy of itraconazole 200 mg once daily for 3 months to treat onychomycosis.

OBJECTIVE

To compare the safety of itraconazole 200 mg once daily for 3 months, with or without itraconazole 200 mg once weekly for a further 3 months, with that of miconazole cream twice daily for 6 months, in the treatment of onychomycosis. Treatment efficacy was compared as a secondary objective.

METHODS

In this multicenter, double-blind study, patients were randomized to receive itraconazole 200 mg once daily for 3 months followed by either itraconazole 200 mg once weekly for 3 months (ITR-ITR group, n = 599) or oral placebo once weekly for 3 months (ITR-PLAC group, n = 613), or to receive miconazole cream twice daily for 6 months (MIC-MIC group, n = 396). The primary variable was elevation of alanine amino-transferase (ALT) concentration above 50 U/I.

RESULTS

Overall incidence of elevation of ALT concentration above 50 U/I, adverse events and rate of withdrawal because of adverse events were low and similar in the three treatment groups. Efficacy was significantly greater in the ITR groups than the MIC-MIC group.

CONCLUSION

Itraconazole and miconazole were well tolerated and had no significant effect on liver function, but itraconazole was significantly more effective.

Efficacy and safety of short-term itraconazole in tinea pedis: a double-blind, randomized, placebo-controlled trial

BACKGROUND

Treatment of plantar or moccasin-type tinea pedis with conventional oral antifungal agents produces poor response rates. Itraconazole is a synthetic, broad-spectrum, orally active antifungal agent with pronounced antimycotic activity.

OBJECTIVE

To confirm the efficacy and safety of short-term treatment with itraconazole for plantar or moccasin-type tinea pedis.

METHODS

The study was a double-blind, randomized, placebo-controlled, multicenter trial. Seventy-two patients with tinea pedis (plantar or moccasin-type) were treated with itraconazole (200 mg twice daily) or placebo for 1 week with an 8-week treatment-free follow-up period.

RESULTS

Thirty-six patients were randomized to each treatment group. The overall success rate (mycological cure and clinical response) at the end-point of follow-up was significantly higher in the itraconazole group than in the placebo group (53 vs. 3%; p <0. 001). Mycological cure (56 vs. 8%; p <0.001) and clinical response rates (75 vs. 11%; p <0.001) were significantly higher after itraconazole treatment compared with placebo treatment. During treatment, adverse events were recorded in 7 patients in the itraconazole group and 2 patients in the placebo group. Adverse events were noted in 3 patients in the placebo group during follow-up. No serious adverse events were reported in either group.

CONCLUSIONS

Short-term treatment with itraconazole was significantly more effective than placebo in tinea pedis. The safety and tolerability profile or itraconazole was comparable with placebo.

Itraconazole pulse therapy for onychomycosis and dermatomycoses: an overview

BACKGROUND

Itraconazole is a broad-spectrum antifungal agent that has been used to treat dermatomycosis and onychomycosis using continuous therapy. More recently the drug has been used as pulse dosing.

OBJECTIVE

Our purpose was to review the studies in which itraconazole pulse therapy (PT) has been administered in the management of dermatomycoses.

RESULTS

For tinea pedis and manuum, the recommended dosage is itraconazole 200 mg twice daily for 1 week (n = 220). A clinical response and mycologic cure rate of 90% +/- 4% and 76% +/- 6%, respectively, has been obtained. For tinea corporis/cruris, itraconazole 200 mg/day for 1 week (n = 354) resulted in a clinical response and mycologic cure rate of 90% +/- 4% and 77% +/- 6%, respectively. When three pulses of itraconazole are used to treat toenail onychomycosis (n = 1389), the clinical cure rate, clinical response, and mycologic cure rate at follow-up 12 months after the start of therapy were 58% +/- 10%, 82% +/- 3%, and 77% +/- 5%, respectively. With two pulses for onychomycosis of the fingernails, the clinical cure rate, clinical response, and mycologic cure rate at follow-up, 9 months after the start of therapy, were 78% +/- 10%, 89% +/- 6%, and 87% +/- 8%, respectively.

CONCLUSION

Itraconazole PT is effective and safe in the treatment of tinea pedis/manuum, tinea corporis/cruris, and onychomycosis.

Effect of ketoconazole-medicated shampoos on squamometry and Malassezia ovalis load in pityriasis capitis

Pityriasis capitis is improved by the use of antifungal shampoos. A double-blind randomized, placebo-controlled study was conducted to compare the efficacy of ketoconazole 0.5 percent and 1 percent formulation shampoos. Evaluations were made in seventy-eight volunteers before and after a two-week duration of daily shampooing. Grading the Malassezia ovalis load in dandruff and values of squamometry were used as noninvasive methods to evaluate efficacy.

Antifungal pulse therapy for onychomycosis. A pharmacokinetic and pharmacodynamic investigation of monthly cycles of 1-week pulse therapy with itraconazole

BACKGROUND AND DESIGN

In the treatment of onychomycosis, oral therapies have generally been given as a continuous-dosing regimen. For example, the suggested dose of itraconazole for the treatment of onychomycosis has thus far been 200 mg/d for 3 months. Based on the advances in our understanding of the pharmacokinetics of itraconazole, we investigated the efficacy and nail kinetics of intermittent pulse-dosing therapy with oral itraconazole in patients who were suffering from onychomycosis. Fifty patients with confirmed onychomycosis of the toenails, predominantly Trichophyton rubrum, were recruited and randomly assigned to three (n = 25) or four (n = 25) pulses of 1-week itraconazole therapy (200 mg twice daily for each month). Clinical and mycological evaluation of the infected toenails, and determination of the drug levels in the distal nail ends of the fingernails and toenails, were performed at the end of each month up to month 6 and then every 2 months up to 1 year.

RESULTS

In the three-pulse treatment group, the mean concentration of itraconazole in the distal ends of the toenails ranged from 67 (month 1) to 471 (month 6) ng/g, and in the distal ends of the fingernails, it ranged from 103 (month 1) to 424 (month 6) ng/g. At month 11, the drug was still present in the distal ends of the toenails at an average concentration of 186 ng/g. The highest individual concentrations of 1064 and 1166 ng/g were reached at month 6 for toenails and fingernails, respectively. At end-point follow-up, toenails in 84% of the patients were clinically cured with a negative potassium hydroxide preparation and culture in 72% and 80% of the patients, respectively. In the four-pulse treatment group, the mean concentration of itraconazole in the distal ends of the toenails ranged from 32 (month 1) to 623 (month 8) ng/g, and in the distal ends of the fingernails, it ranged from 42 (month 1) to 380 (month 6) ng/g. The highest individual concentrations of 1549 and 946 ng/g were reached at month 7 for toenails and at month 9 for fingernails, respectively. At month 12, the drug was still present in the distal ends of the toenails at an average concentration of 196 ng/g. At end-point follow-up, toenails in 76% of the patients were clinically cured with a negative potassium hydroxide preparation and culture in 72% and 80% of the patients, respectively. There were no significant intergroup differences between the three- and four-pulse treatment groups for the primary efficacy parameters. The drug was well tolerated with no significant side effects in either patient group.

CONCLUSIONS

Following pulse therapy with itraconazole (400 mg/d given for 1 week each month for 3 to 4 months), the drug has been detected in the distal ends of nails after the first pulse, and it has reached therapeutic concentrations with further therapy. After stopping the last pulse, the drug remains in the nail plate at levels above 300 ng/g for several months. Clinical cure rates between 76% and 84% and negative mycological examination findings between 72% and 80%, respectively, were observed in toenail onychomycosis. The data suggest that pulse therapy with itraconazole is an effective and safe treatment option for onychomycosis.

Topical R-85355, a potent and selective 5-lipoxygenase inhibitor, fails to improve psoriasis

Inhibitors of 5-lipoxygenase have been studied with respect to antipsoriatic efficacy. Of these compounds, R-68151 is of particular interest as it proved to inhibit 5-lipoxygenase without inhibiting 12-lipoxygenase, cyclooxygenase and thromboxane-A2 synthetase. R-68151 has been shown to have a mild-to-moderate therapeutic effect in psoriasis. In the present study a new 5-lipoxygenase, R-85355, was investigated with respect to its efficacy in psoriasis. R-85355 is 3 times more potent compared to R-68151 with respect to inhibition of in vitro A-23187-stimulated leukotriene-B4 production by polymorphonuclear leukocytes. In a left-right double-blind comparative study, the compound was studied at saturation with respect to its antipsoriatic efficacy in 11 patients with chronic stable plaque psoriasis. In addition, various markers for epidermal proliferation, keratinization and inflammation were assessed. In no single patient was a left-right difference observed in favour of R-85355 compared to placebo with respect to clinical severity scores or the cell-biological markers. The present study indicates that a selective and highly potent 5-lipoxygenase inhibitor was not effective in the topical treatment of chronic plaque psoriasis.

alpha-Amylase, a flour additive: an important cause of protein contact dermatitis in bakers

BACKGROUND

alpha-Amylase, an enzyme commonly used in flour additives, has been reported to be an important cause of rhinitis and asthma in bakers.

OBJECTIVE

Our purpose was to determine whether this enzyme could also cause dermatitis. We tested it routinely in bakers with hand eczema.

METHODS

Patch tests were administered with the International Contact Dermatitis Research Group standard series and a bakery series and scratch-chamber or prick tests were performed with the bakers' own material and with alpha-amylase powder.

RESULTS

Of 32 bakers tested, seven had an immediate wheal-and-flare reaction and two also had a delayed eczematous reaction. High dilutions of the alpha-amylase powder still gave strong reactions.

CONCLUSION

alpha-Amylase is an important cause of skin reactions in bakers and should be tested routinely if a contact allergy is suspected.

Measurement of lung density by means of quantitative CT scanning. A study of correlations with pulmonary function tests

In recent years, much attention has been given to the role of CT in detecting and quantitating pulmonary emphysema. We measured CT lung density in 45 patients undergoing a diagnostic work-up and compared this with pulmonary function tests. The CT lung densities measured with the sector method and with the whole lung method were very highly correlated with each other (r = 0.96, p less than 0.001), and measurements at TLC systematically gave a lower density than those at FRC (p less than 0.001). Also, CT density measurements at TLC and even more so at FRC correlated well with pulmonary function indices of airway obstruction and of hyperinflation, but not with indices that are considered more specific for emphysema (single breath DCO, static lung compliance) We conclude that CT lung-density gives a good reflection of the degree of hyperinflation, ie, enlargement of distal airways, but is not sensitive to detect whether or not this is associated with emphysema.

The core protein of the matrix-associated heparan sulfate proteoglycan binds to fibronectin

The extracellular matrix of cultured human lung fibroblasts contains one major heparan sulfate proteoglycan. This proteoglycan contains a 400-kDa core protein and is structurally and immunochemically identical or closely related to the heparan sulfate proteoglycans that occur in basement membranes. Because heparitinase does not release the core protein from the matrix of cultured cells, we investigated the binding interactions of this heparan sulfate proteoglycan with other components of the fibroblast extracellular matrix. Both the intact proteoglycan and the heparitinase-resistant core protein were found to bind to fibronectin. The binding of 125I-labeled core protein to immobilized fibronectin was inhibited by soluble fibronectin and by soluble cold core protein but not by albumin or gelatin. A Scatchard plot indicates a Kd of about 2 x 10(-9) M. Binding of the core protein was also inhibited by high concentrations of heparin, heparan sulfate, or chrondroitin sulfate and was sensitive to high salt concentrations. Thermolysin fragmentation of the 125I-labeled proteoglycan yielded glycosamino-glycan-free core protein fragments of approximately 110 and 62 kDa which bound to both fibronectin and heparin columns. The core protein-binding capacity of fibronectin was very sensitive to proteolysis. Analysis of thermolytic and alpha-chymotryptic fragments of fibronectin showed binding of the intact proteoglycan and of its isolated core protein to a protease-sensitive fragment of 56 kDa which carried the gelatin-binding domain of fibronectin and to a protease-sensitive heparin-binding fragment of 140 kDa. Based on the NH2-terminal amino acid sequence analyses of the 56- and 140-kDa fragments, the core protein-binding domain in fibronectin was tentatively mapped in the area of overlap of the two fragments, carboxyl-terminally from the gelatin-binding domain, possibly in the second type III repeat of fibronectin. These data document a specific and high affinity interaction between fibronectin and the core protein of the matrix heparan sulfate proteoglycan which may anchor the proteoglycan in the matrix.

Matrix-associated heparan sulfate proteoglycan: core protein-specific monoclonal antibodies decorate the pericellular matrix of connective tissue cells and the stromal side of basement membranes

Cultured human lung fibroblasts produce a large, nonhydrophobic heparan sulfate proteoglycan that accumulates in the extracellular matrix of the monolayer (Heremans, A., J. J. Cassiman, H. Van den Berghe, and G. David. 1988. J. Biol. Chem. 263: 4731-4739). A panel of four monoclonal antibodies, specific for four distinct epitopes on the 400-kD core protein of this extracellular matrix heparan sulfate proteoglycan, detects similar proteoglycans in human epithelial cell cultures. Immunohistochemistry of human tissues with the monoclonal antibodies reveals that these proteoglycans are concentrated at cell-matrix interfaces. Immunogold labeling of ultracryosections of human skin indicates that the proteoglycan epitopes are nonhomogeneously distributed over the width of the basement membrane. Immunochemical investigations and amino acid sequence analysis indicate that the proteoglycan from the fibroblast matrix shares several structural features with the large, low density heparan sulfate proteoglycan isolated from the Engelbreth-Holm-Swarm sarcoma. Thus, both epithelial cell sheets and individual mesenchymal cells accumulate a large heparan sulfate proteoglycan(s) at the interface with the interstitial matrix, where the proteoglycan may adopt a specific topological orientation with respect to this matrix.

Membrane-associated chondroitin sulfate proteoglycans of human lung fibroblasts

Cultured human fetal lung fibroblasts produce some chondroitin sulfate proteoglycans that are extracted as an aggregate in chaotropic buffers containing 4 M guanidinium chloride. The aggregated proteoglycans are excluded from Sepharose CL4B and 2B, but become included, eluting with a Kav value of 0.53 from Sepharose CL4B, when Triton X-100 is included in the buffer. Conversely, some of the detergent-extractable chondroitin sulfate proteoglycans can be incorporated into liposomes, suggesting the existence of a hydrophobic membrane-intercalated chondroitin sulfate proteoglycan fraction. Purified preparations of hydrophobic chondroitin sulfate proteoglycans contain two major core protein forms of 90 and 52 kD. A monoclonal antibody (F58-7D8) obtained from the fusion of myeloma cells with spleen cells of BALB/c mice that were immunized with hydrophobic proteoglycans recognized the 90- but not the 52-kD core protein. The epitope that is recognized by the antibody is exposed at the surface of cultured human lung fibroblasts and at the surface of several stromal cells in vivo, but also at the surface of Kupffer cells and of epidermal cells. The core proteins of these small membrane-associated chondroitin sulfate proteoglycans are probably distinct from those previously identified in human fibroblasts by biochemical, immunological, and molecular biological approaches.

Carcinosarcoma of the lung. Report of two cases and review of the literature

Two cases of carcinosarcoma of the lung are presented. Until now, 76 cases have been recorded in the literature. The lesion contains an epithelial and a mesenchymal component, both with cytologic features of malignancy. A central endobronchial and a peripheral invasive type have been described. Fiberoptic biopsies usually show no tumour at all or contain only one of the two components. Treatment consists of lobectomy or pneumonectomy. Prognosis is not better for this tumour than for non-small cell bronchogenic carcinoma, and may even be worse.

Heparan sulfate proteoglycan from the extracellular matrix of human lung fibroblasts. Isolation, purification, and core protein characterization

Confluent cultured human lung fibroblasts were labeled with 35SO4(2-). After 48 h of labeling, the pericellular matrix was prepared by Triton X-100 and deoxycholate extraction of the monolayers. Heparan sulfate proteoglycan (HSPG) accounted for nearly 80% of the total matrix [35S]proteoglycans. After solubilization in 6 M guanidinium HCl and cesium chloride density gradient centrifugation, the majority (78%) of these [35S] HSPG equilibrated at an average buoyant density of 1.35 g/ml. This major HSPG fraction was purified by ion-exchange chromatography on Mono Q and by gel filtration on Sepharose CL-4B, and further characterized by gel electrophoresis and immunoblotting. Intact [35S]HSPG eluted with Kav 0.1 from Sepharose CL-4B, whereas the protein-free [35S]heparan sulfate chains, obtained by alkaline borohydride treatment of the proteoglycan fractions, eluted with Kav 0.45 (Mr approximately 72,000). When analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography, core (protein) preparations, obtained by heparitinase digestion of 125I-labeled HSPG fractions, yielded one major labeled band with apparent molecular mass of approximately 300 kDa. Reduction with beta-mercaptoethanol slightly increased the apparent Mr of the labeled band, suggesting a single polypeptide structure and the presence of intrachain disulfide bonds. Immunoadsorption experiments and immunostaining of electrophoretically separated heparitinase-digested core proteins with monoclonal antibodies raised against matrix and cell surface-associated HSPG suggested that the major matrix-associated HSPG of cultured human lung fibroblasts is distinct from the HSPG that are anchored in the membranes of these cells. Binding studies suggested that this matrix HSPG interacts with several matrix components, both through its glycosaminoglycan chains and through its heparitinase-resistant core. Core (protein) interactions seem to be responsible for the association of the proteoglycan with the extracellular matrix.