Current management of incidental gallbladder cancer: A review

Early-stage gallbladder cancer (GBC) is mostly discovered incidentally by the pathologist after cholecystectomy for a presumed benign disease. It is the most common malignancy of the biliary tract with a variable incidence rate all over the World. The majority of patients with GBC remain asymptomatic for a long time and diagnosis is usually late when the disease is at an advanced stage. Radical surgery consisting in resection of the gallbladder liver bed and regional lymph nodes seems to be the best treatment option for incidental GBC. However, recurrence rates after salvage surgery are still high and the addition of neoadjuvant/adjuvant chemotherapy may improve outcomes. The aim of the present review is to evaluate current literature for advances in management of incidental GBC, with particular focus on staging techniques and surgical options.

Perianal mucinous adenocarcinoma with dysplastic polyps of the colon: A case report

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Mucinous adenocarcinoma of the perianal region is extremely rare (6.9% of anal neoplasms and 2–3% of all gastrointestinal malignancies).

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Given the low incidence of this tumor, it is often missed at initial evaluation.

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Association with chronic perianal fistula are common and inflammatory symptoms can be misleading with delay in diagnosis.

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The paucity of publications leads to a lack of consensus on both diagnostic and therapeutic approaches.

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The understanding of the etiopathogenic mechanisms may lead to the development of novel diagnostic and therapeutic protocols.

Introduction

Perianal mucinous adenocarcinoma is rarely encountered in the setting of anal neoplasms. The rarity of the disease and the paucity of publications on this topic are responsible for a lack of diagnostic and therapeutic guidelines.

Presentation of case

An 80-year-old man with mucinous adenocarcinoma of the anal canal associated with dysplastic polyps of the colon was treated by multiple endoscopic polypectomies and abdomino-perineal resection of the rectum. We discuss the management of this rare case from the diagnosis up to one-year follow-up.

Discussion

Perianal mucinous adenocarcinoma is a very rare entity frequently combined with chronic fistulas. Inflammatory symptoms may mislead its diagnosis, which is often delayed. The unique association between perianal mucinous adenocarcinoma and dysplastic polyps of the colon, that we have reported, may suggest a secondary etiology. High clinical suspicion is important for early and correct diagnosis, which should be based on endoanal ultrasound and/or magnetic resonance imaging followed by deep tissue biopsies.

Conclusion

We stress the importance of accumulating such cases in the literature. The understanding of the etiopathogenic mechanisms may lead to the development of novel diagnostic and therapeutic protocols.

Mastectomy patterns, but not rates, are changing in the treatment of early breast cancer. Experience of a single European institution on 2315 consecutive patients

BACKGROUND

Recent literature reports that rates of mastectomy are increasing in early breast cancer. However, data from European institutions are limited and revealed conflicting results. We report on 15-year trends of mastectomy, mastectomy plus immediate reconstruction and contralateral prophylactic mastectomy (CPM) at an academic institution.

METHODS

We identified women diagnosed with unilateral early breast cancer at stage 0-IIa, with tumour size ≤ 4 cm, between 2002 and 2016. Trends were assessed using the Cochrane-Armitage test. Multivariable logistic regression was used to identify factors associated with receipt of mastectomy plus immediate reconstruction.

RESULTS

A total of 2315 patients were identified. Of them, 65.7% underwent breast conserving surgery (BCS), while 34.3% underwent mastectomy as upfront surgery. Two point four per cent also received CPM. Immediate reconstruction was performed in 36.0% of patients receiving mastectomy. There was no change in trends of mastectomy over the 15 years studied (p = 0.69), as well as in trends of patients undergoing CPM (p = 0.44). In contrast, rates of immediate reconstruction rose significantly over the study period (from 12.2% in 2002 to 62.7% in 2016, p < 0.0001). Women were more likely to receive mastectomy plus immediate reconstruction if they were aged 50 years or younger, or had tumours larger than 2 cm, or had non-invasive carcinoma.

CONCLUSIONS

Our study suggests that rates of both mastectomy and CPM in early breast cancer are not increasing, while use of immediate reconstruction is on the rise.

Cost and morbidity analysis of chest port insertion in adults: Outpatient clinic versus operating room placement

Background

Totally implantable venous access devices (TIVADs) represent a convenient way for the administration of medications or nutrients. Traditionally, chest ports have been positioned by surgeons in the operating room, however there has been a transition over the years to port insertion by interventional radiologists in the radiology suite. The optimal method for chest port placement is still under debate.

Materials and methods

Data on all adult patients undergoing isolated chest port placement at our institution in a 12-year period were retrospectively reviewed. The aim of this cohort study was to compare cost and morbidity for chest port insertion in two different settings: outpatient clinic and operating room.

Results

Between 2003 and 2015 a total of 527 chest ports were placed in adult patients. Of them, 262 procedures were performed in the operating room and 265 procedures were undertaken in the outpatient clinic. Patient characteristics were similar and there was no significant difference in early (<30 days, p = 0.54) and late complications (30–120 days, p = 0.53). The average charge for placement of a chest port was 1270 Euros in the operating room versus 620 Euros in the outpatient clinic.

Conclusion

Our results suggest that chest ports can be safely placed in most patients under local anesthesia in the office setting without fluoroscopy or ultrasound guidance. Future randomized controlled studies may evaluate if surgeons or interventional radiologists should routinely perform these procedures in a dedicated office setting and reserve more sophisticated facilities only for patients at high risk of technical failure.

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Chest ports can be safely placed under local anesthesia in the office setting.

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Fluoroscopy and ultrasound guidance are not necessary in the majority of cases.

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Port placement in the outpatient clinic is cost-effective.

Molecular identification of Mycobacterium avium subspecies paratuberculosis in oral biopsies of Crohn's disease patients

Oral lesions may be found in patients with Crohn’s disease (CD), in a percentage up to 20%. The aim of this study was to investigate a possible relationship between Mycobacterium avium subsp. paratuberculosis (MAP) and oral lesions in CD patients. 23 oral biopsies were examined performing IS900 Nested PCR; 9 of them were positive: 8 from CD patients and 1 from a control. Our purpose is to go on with this study, amplifying the number of subjects examined and testing subjects with oral lesions related to diseases other than CD to verify the specific association between MAP and oral lesions in CD patients.

Interaction between Mycobacterium tuberculosis, Mycobacterium bovis, Mycobacterium avium subspecies paratuberculosis with the enteric glia and microglial cells

Background

We investigated the interaction of Mycobacterium avium subspecies paratuberculosis, M. bovis and M. tuberculosis and different glial cells (enteric glial and microglial cells) in order to evaluate the infecting ability of these microorganisms and the effects produced on these cells, such as the evaluation of cytokines expression.

Results

Our experiments demonstrated the adhesion of M. paratuberculosis to the enteroglial cells and the induction of IL-1A and IL-6 expression; M. tuberculosis and M. bovis showed a good adhesive capability to the enteric cell line with the expression of the following cytokines: IL-1A and IL-1B, TNF-α, G-CSF and GM-CSF; M. bovis induced the expression of IL-6 too.

The experiment performed with the microglial cells confirmed the results obtained with the enteroglial cells after the infection with M. tuberculosis and M. bovis, whereas M. paratuberculosis stimulated the production of IL-1A and IL-1B.

Conclusion

Enteroglial and microglial cells, could be the target of pathogenic mycobacteria and, even if present in different locations (Enteric Nervous System and Central Nervous System), show to have similar mechanism of immunomodulation.

A rare variant of gallstone ileus: Bouveret's syndrome

INTRODUCTION

Bouveret's syndrome (gastric outlet obstruction due to impaction of a stone) is a rare variant of gallstone ileus. A recently observed case led us to review the literature, with the aim to discuss the recent advances in the management of this rare syndrome.

DISCUSSION

A 69-year-old woman was admitted with symptoms of high intestinal obstruction. Computed tomography scan of the abdomen showed a large gallstone impacted in the duodenum. One-stage surgery, consisting in enterolithotomy, cholecystectomy, and fistula repair, was carried out. Although several surgical and nonoperative procedures have been used, the optimal treatment of Bouveret's syndrome remains controversial. Surgery still maintains a prominent position, even though nonoperative procedures have an increasing role especially in high risk patients with important comorbidities. The decision should be taken on an individual basis, after evaluating patient's general condition and age, stone size, comorbidities influencing the operative risk, and expertise of surgical and endoscopic teams. One-stage surgery may offer definitive management in selected patients.

A rare variant of gallstone ileus: Bouveret's syndrome

INTRODUCTION

Bouveret's syndrome (gastric outlet obstruction due to impaction of a stone) is a rare variant of gallstone ileus. A recently observed case led us to review the literature, with the aim to discuss the recent advances in the management of this rare syndrome.

DISCUSSION

A 69-year-old woman was admitted with symptoms of high intestinal obstruction. Computed tomography scan of the abdomen showed a large gallstone impacted in the duodenum. One-stage surgery, consisting in enterolithotomy, cholecystectomy, and fistula repair, was carried out. Although several surgical and nonoperative procedures have been used, the optimal treatment of Bouveret's syndrome remains controversial. Surgery still maintains a prominent position, even though nonoperative procedures have an increasing role especially in high risk patients with important comorbidities. The decision should be taken on an individual basis, after evaluating patient's general condition and age, stone size, comorbidities influencing the operative risk, and expertise of surgical and endoscopic teams. One-stage surgery may offer definitive management in selected patients.

Contrast-enhanced ultrasonographic evaluation of inflammatory activity in Crohn's disease

BACKGROUND & AIMS

We sought to test the diagnostic accuracy of ultrasound (US), color Doppler US (CD-US), and contrast-enhanced US (CE-US) in the evaluation of inflammatory activity in patients with Crohn's disease (CD), and to correlate the findings of these sonographic studies with inflammatory activity, as scored by the CD activity index (CDAI).

METHODS

Patients with CD were enrolled in the study. Radiologists performing the scans were blinded to clinical status. Baseline US, CD-US, and CE-US examinations were conducted with high-frequency probes (8-14 and 5-7 MHz) before and after injection of sulfur hexafluoride-filled microbubbles. The diagnostic accuracy of baseline US, CD-US, and CE-US were calculated by using the endoscopic and histologic findings as reference standards and correlated with the CDAIs by using the Pearson linear correlation coefficient.

RESULTS

Forty-seven patients (20 men; 27 women; mean age +/- SD, 38 +/- 14 years) with a CDAI > 150 (n = 30) or < 150 (n = 17), were recruited. CE-US showed the highest performance, with 93.5% sensitivity, 93.7% specificity, and 93.6% overall accuracy. CE-US revealed 3 bowel wall perfusion patterns after microbubble injection: submucosal enhancement and inward and outward transparietal enhancement. The linear correlation coefficient for CE-US versus CDAI was 0.74 (P < .0001); for baseline US (assessing thickness, length, and multilayer appearance of the diseased bowel) versus the CDAI, the coefficients were 0.68 (P < .0001), 0.47 (P = .0009), and 0.60 (P < .0001), respectively; and for CD-US versus CDAI the coefficient was 0.73 (P < .0001).

CONCLUSIONS

CE-US has a high sensitivity and specificity in detecting inflammatory activity and a strong correlation with the CDAI.

Mycobacterium avium subspecies paratuberculosis infection in cases of irritable bowel syndrome and comparison with Crohn's disease and Johne's disease: common neural and immune pathogenicities

Mycobacterium avium subsp. paratuberculosis causes Johne's disease, a systemic infection and chronic inflammation of the intestine that affects many species, including primates. Infection is widespread in livestock, and human populations are exposed. Johne's disease is associated with immune dysregulation, with involvement of the enteric nervous system overlapping with features of irritable bowel syndrome in humans. The present study was designed to look for an association between Mycobacterium avium subsp. paratuberculosis infection and irritable bowel syndrome. Mucosal biopsy specimens from the ileum and the ascending and descending colon were obtained from patients with irritable bowel syndrome attending the University of Sassari, Sassari, Sardinia, Italy. Crohn's disease and healthy control groups were also included. Mycobacterium avium subsp. paratuberculosis was detected by IS900 PCR with amplicon sequencing. Data on the potential risk factors for human exposure to these pathogens and on isolates from Sardinian dairy sheep were also obtained. Mycobacterium avium subsp. paratuberculosis was detected in 15 of 20 (75%) patients with irritable bowel syndrome, 3 of 20 (15%) healthy controls, and 20 of 23 (87%) people with Crohn's disease (P = 0.0003 for irritable bowel syndrome patients versus healthy controls and P = 0.0000 for Crohn's disease patients versus healthy controls). One subject in each group had a conserved single-nucleotide polymorphism at position 247 of IS900 that was also found in isolates from seven of eight dairy sheep. There was a significant association (P = 0.0018) between Mycobacterium avium subsp. paratuberculosis infection and the consumption of hand-made cheese. Mycobacterium avium subsp. paratuberculosis is a candidate pathogen in the causation of a proportion of cases of irritable bowel syndrome as well as in Crohn's disease.

Effective management of intrathoracic anastomotic leak with covered self-expandable metal stents. Report on three cases

Intrathoracic anastomotic leakage is one of the major complications of esophageal surgery that can lead to high mortality rate. Depending on the clinical presentation, therapeutic options include surgical reintervention and conservative management with or without external drainage or stenting. In this paper, we report a series of three patients, two men and one woman, mean age of 55.6 years (range 34-68 years), having intrathoracic anastomotic leak after esophagogastrectomy treated by insertion of four covered self-expandable metal stents performed exclusively under fluoroscopic view. Complete resolution of the leakage was obtained in all patients. Despite the limited number of patients, conservative management of intrathoracic anastomotic leaks with covered self-expandable metal stents performed under fluoroscopic guidance has proved to be rapid, safe, and effective in all cases of this series.

Mycobacterium avium subsp. paratuberculosis, genetic susceptibility to Crohn's disease, and Sardinians: the way ahead

The present study was performed to determine what proportion of people in Sardinia with or without Crohn's disease were infected with Mycobacterium avium subspecies paratuberculosis and had a preponderance of allelic variants of Nod 2, an intracellular protein involved in Crohn's disease susceptibility. Genetic analysis of the alleles of the NOD 2/CARD 15 gene (ins C 3020, G 908 R, and R 702 W alleles), linked to susceptibility or genetic predisposition to Crohn's disease in humans, was carried out on specimens from 37 Crohn's disease patients and 34 patients without Crohn's disease. Our results show that more than 70 percent of people in Sardinia with Crohn's disease carry at least one of the susceptibility-associated NOD 2/CARD 15 alleles and were infected with Mycobacterium avium subspecies paratuberculosis.

Detection and Isolation of Mycobacterium avium subspecies paratuberculosis from intestinal mucosal biopsies of patients with and without Crohn's disease in Sardinia

OBJECTIVES

Sardinia is an island community of 1.6 million people. There are also about 3.5 million sheep and one hundred thousand cattle in which Johne's disease and Mycobacterium avium subspecies paratuberculosis infection are endemic. The present study was designed to determine what proportion of people in Sardinia attending for ileocolonoscopy with or without Crohn's disease were infected with this pathogen.

METHODS

Mycobacterium avium subspecies paratuberculosis was detected by IS900 PCR on DNA extracts of fresh intestinal mucosal biopsies as well as by isolation in culture using supplemented MGIT media followed by PCR with amplicon sequencing.

RESULTS

Twenty five patients (83.3%) with Crohn's disease and 3 control patients (10.3%) were IS900 PCR positive (p = 0.000001; Odds ratio 43.3). Mycobacterium avium subspecies paratuberculosis grew in cultures from 19 Crohn's patients (63.3%) and from 3 control patients (10.3%) (p = 0.00001; Odds ratio 14.9). All patients positive by culture had previously been positive by PCR. Mycobacterium avium subspecies paratuberculosis first appeared in the liquid cultures in a Ziehl Neelsen (ZN) staining negative form and partially reverted through a rhodamine-auramine positive staining form to the classical ZN positive form. This resulted in a stable mixed culture of all 3 forms illustrating the phenotypic versatility of these complex chronic enteric pathogens.

CONCLUSIONS

Mycobacterium avium subspecies paratuberculosis was detected in the majority of Sardinian Crohn's disease patients. The finding of the organism colonizing a proportion of people without Crohn's disease is consistent with what occurs in other conditions caused by a primary bacterial pathogen in susceptible hosts.

Spontaneous regression of hepatocellular carcinoma: report of a case

The widespread use of ultrasound in screening programmes for chronic liver disease has led to early diagnosis of hepatocellular carcinoma (HCC), and to the observation of some cases of tumour spontaneous regression. This is a rare event whose underlying mechanism is still unclear. We present here a case of spontaneous regression of HCC in a 71-year-old woman with chronic hepatitis and discuss possible aetiologies. None of the causative mechanisms proposed for spontaneous regression of HCC is completely satisfactory, so further studies are necessary to improve understanding of this unusual biological event. Therefore, we stress the importance of accumulating all such cases in the literature, because the clarification of aetio-pathogenic mechanisms may lead to the development of new treatment strategies for HCC.

[Primary aortoenteric fistula. Report of a case]

Primary aortoenteric fistulas (PAEF) are rare entities associated with a high mortality. Although several causes have been reported, their occurrence is usually due to erosion of an abdominal aortic aneurysm into the intestinal tract. The most common sites for the fistula are the third and fourth portions of duodenum. The classical triad of gastrointestinal hemorrhage, abdominal mass and abdominal or back pain, though highly suggestive for PAEF, is uncommon. The typical bleeding pattern associated with PAEF is characteristically intermittent, starting with a brief "herald bleeding" followed eventually by major gastrointestinal hemorrhage, often with fatal outcome. The pre-operative examinations are often not helpful and can lead to delayed diagnosis and surgery. In a patient with risk factors for atherosclerosis and significant upper gastrointestinal bleeding in the absence of an evident source, PAEF should be suspected. A high index of suspicion of this condition allows correct diagnosis and definitive treatment to be carried out. If PAEF is suspected and the patient is unstable the surgeon should be prepared to skip the preoperative investigations in favour of early surgical exploration. Definitive treatment includes primary duodenal repair and aortic aneurismal resection with graft "in situ" replacement. The authors present a successfully treated case and stress the importance of clinical suspicion in order to achieve correct diagnosis and treatment.

Correction of congenital chordee penis by 'ventral separation and outward rotation of corpora'

BACKGROUND/PURPOSE

The formation of congenital chordee penis in patients with or without hypospadias is multifactorial and not completely clear. In most cases, after release of all known causes of chordee, "residual" penile curvature can persist. The authors discuss the etiopathogenetic mechanisms of congenital chordee penis and describe their experience in surgical correction of "residual" penile curvature by "ventral separation and outward rotation of corpora."

METHODS

In 22 patients with congenital chordee penis with or without hypospadias, "residual" penile curvature was corrected by "ventral separation and outward rotation of corpora."

RESULTS

Ventral separation and outward rotation of corpora resulted in satisfactory correction of penile curvature. In only 2 cases of chordee penis without hypospadias was further intervention necessary: a Nesbit's plication was carried out in one and a neourethra placed in the other. At follow-up no residual penile curvature was observed.

CONCLUSIONS

An arrest of development of the penis caused by failure of outward ventral rotation of the corpora, may contribute to the formation of chordee penis. When "residual" penile curvature persists, "ventral separation and outward rotation of corpora" can be used to correct this complex malformation.

Stimulation of interleukin-8 production in human THP-1 macrophages by apolipoprotein(a). Evidence for a critical involvement of elements in its C-terminal domain

In the vessel wall, macrophages are among the cells that upon activation contribute to the atherosclerotic process. Low density lipoproteins (LDL) can mediate this activation but only after enzymatic or oxidative modification. Lipoprotein(a) (Lp(a)) is an LDL variant that has been shown to have an atherogenic potential by no clearly established mechanisms. In the present study we examined whether native Lp(a) can activate macrophages and, if so, identify the structural elements involved in this action. For this purpose, we utilized human THP-1 macrophages, prepared by treating THP-1 monocytes with phorbol ester, and we exposed them to Lp(a) and its two derivatives, apo(a)-free LDL (Lp(a-)) and free apo(a). We also studied apo(a) fragments, F1 (N terminus) and F2 (C terminus) and subfragments thereof, obtained by leukocyte elastase digestion. By Northern blot analyses, Lp(a), but not Lp(a-), caused up to a 12-fold increase in interleukin 8 (IL-8) mRNA as compared with untreated cells. Free apo(a) also induced the production of IL-8 mRNA; however, the effect was 3-4-fold higher than that of Lp(a). The increase in mRNA was associated with the accumulation of IL-8 protein in the culture medium. F1 had only a minimal effect, whereas F2 was 1.5-2-fold more potent than apo(a), an activity mostly contained in the Kringle V-protease region. A monoclonal antibody specific for Kringle V inhibited the apo(a)-mediated effect on IL-8. We conclude that Lp(a) via elements contained in the C-terminal domain of apo(a) causes in THP-1 macrophages an increased production of IL-8, a chemokine with pro-inflammatory properties, an event that may be relevant to the process of atherosclerosis.

99mTc-Tetrofosmin pinhole-SPECT (P-SPECT) and radioguided sentinel node (SN) biopsy and in breast cancer axillary lymph node staging

We compared 99mTc-Tetrofosmin P-SPECT with radioguided SN biopsy in 101 T1/T2 BC pts to predict axillary lymph node status. The day before surgery all pts underwent lymphoscintigraphy (LS) to mark the SN, following subdermal injection of 99mTc-colloidal sulphur surrounding the breast lesion. LS was combined with pre and intraoperative gamma probe. Previously, all pts had also undergone P-SPECT. ALND was performed in all cases. The SN(s) was detected in 97/101 cases (96%) by LS and gamma probe; in the 4 missed cases P-SPECT predicted lymph node status. In the 97 comparable cases, radioguided SN biopsy showed a slightly higher accuracy than P-SPECT (94.8% vs 93.8%), but a higher false-negative rate (14.3% vs 8.6%); P-SPECT had a higher NPV (95.2% vs 92.5%). The two procedures when combined achieved 100% accuracy. Radioguided SN biopsy alone had 100% accuracy only in pts with BC < 15 mm. P-SPECT had 3 false negative cases, 2 of which were micrometastatic SNs, and 3 false positives. P-SPECT identified 81.2% of cases with a single node, determined the exact number of nodes in 82.6% of cases with 1 to 3 node and correctly classified 93.7% of pts as having < or = 3 or > 3 metastatic nodes. Radioguided SN biopsy seems indicated in selected, early stage, small BC pts, while P-SPECT shows a high sensitivity independent of primary tumor size, giving additional important preoperative prognostic information. The two procedures combined provided a better axillary lymph node status prediction in T1/T2 carcinomas, and could thus improve ALND pt selection.

(99)mTc-tetrofosmin SPET in the detection of both primary breast cancer and axillary lymph node metastasis

The aim of this study was to evaluate the usefulness of (99m)Tc-tetrofosmin single-photon emission tomography (SPET) in the detection of both primary breast cancer and axillary lymph node metastasis. We studied 192 consecutive patients in whom primary breast cancer was suspected on the basis of mammography and/or physical examination. After intravenous injection of 740 MBq (99m)Tc-tetrofosmin, both planar and SPET scintimammography was performed in all patients using a rectangular dual-head gamma camera equipped with low-energy, high-resolution, parallel-hole collimators. In 175 patients with breast cancer at histology, the per-lesion overall sensitivity of SPET and planar imaging for the detection of breast cancer was 95.8% and 75.9% (P<0.0005), respectively. The sensitivity of SPET and planar imaging was, respectively, 96.5% and 79.5% in palpable (P<0.0005) and 90% and 45% in non-palpable lesions (P<0.01). With regard to lesion size, the sensitivity of SPET and planar imaging was, respectively, 90.5% and 45.2% in lesions < or =10 mm ( P<0.0005), 95.3% and 81.4% in lesions of 11-20 mm (P<0.005), 100% and 84.6% in lesions of 21-30 mm (P<0.05) and 100% and 95.8% in lesions >30 mm (P>0.05). In the remaining 17 patients with benign mammary lesions at histology, per-lesion overall specificity of SPET and planar imaging was 76.2% and 85.7% (P>0.05), respectively. Neither SPET nor planar imaging showed false-positive results in non-palpable lesions or in those < or =10 mm. In 173 breast cancer patients submitted to axillary lymph node dissection (ALND), per-axilla overall sensitivity of SPET and planar imaging in the detection of axillary lymph node metastasis was 93% and 52.3% ( P<0.0005), respectively. The sensitivity of SPET and planar imaging was, respectively, 100% and 82.6% in palpable nodes (P>0.05), 90.5% and 41.3% in non-palpable nodes (P<0.0005), 92.8% and 35.7% in the presence of < or =3 nodes ( P<0.0005) and 93.2% and 68.2% in the presence of >3 nodes (P<0.005). The specificity of SPET and planar imaging was 91% and 100% (P<0.05), respectively. (99m)Tc-tetrofosmin SPET appears to be a reliable method for the detection of both primary BC and axillary lymph node metastasis, and its diagnostic accuracy exceeds that of (99m)Tc-tetrofosmin planar scintimammography. The use of SPET is particularly important in the identification of small non-palpable primary carcinomas and metastatic axillae with < or =3 non-palpable lymph nodes. More extensive use of SPET appears warranted in the management of breast cancer patients.

Domains of apolipoprotein E involved in the binding to the protein core of biglycan of the vascular extracellular matrix: potential relationship between retention and anti-atherogenic properties of this apolipoprotein

We recently identified elements in the C-terminal domain of apolipoprotein E that are critical for the binding of this protein to the protein core of biglycan, a proteoglycan of the vascular extracellular matrix. This binding, ionic in nature, requiring no participation by glycosaminoglycans, suggests that protein-protein interactions may play an important role in the binding of apolipoprotein E to the extracellular matrix. These interactions may represent a potential mechanism for the anti-atherogenic potential of this apolipoprotein by preventing further anchoring to the vascular matrix of pro-atherogenic factors.

Oxidative events cause degradation of apoB-100 but not of apo[a] and facilitate enzymatic cleavage of both proteins

Lipoprotein [a] (Lp[a]) contains equimolar amounts of apoB-100 and apolipoprotein [a] (apo[a]). Both proteins are amenable to degradation in vivo by mechanisms yet to be clearly defined. In this study, we examined the in vitro susceptibility of LDL and Lp[a], obtained from the same donor, to oxidation by either Cu(2)+ or the combined Crotalus adamanteus phospholipase A2 and soybean lipoxygenase system, monitoring the course of the reaction by the generation of conjugated dienes and fatty acids. In some experiments, treatment with leukocyte elastase (LE) or matrix metalloproteinase 12 (MMP-12) was administered before and after the oxidative step. In the case of Lp[a] we found that with both oxidizing systems, conditions that caused the breakdown of apoB-100 did not degrade apo[a] although oxidation-mediated changes were detected in the latter by intrinsic tryptophan fluorescence spectroscopy. Similar results were obtained with a reassembled Lp[a] obtained by incubating free apo[a] with LDL. Both apo[a] and apoB-100 were cleaved by LE and MMP-12 but the enzymatic cleavage was more marked when the preoxidized proteins were used as a substrate. Taken together, our in vitro studies indicate that apo[a] but not apoB-100 resists oxidative fragmentation, whereas both proteins are cleaved by enzymes of the serine and metalloproteinase families. We speculate that the fragments of apo[a] observed in vivo may be preferentially generated by proteolytic rather than oxidative events, whereas apoB-100 can be degraded by both mechanisms.

The role of lipoprotein(a) in the pathogenesis of atherosclerotic cardiovascular disease and its utility as predictor of coronary heart disease events

Lipoprotein(a), is a highly heterogeneous lipoprotein, due to variations in the size of apolipoprotein(a), and the density of the apoB100-containing particles to which apo(a) is linked. Although high plasma levels of Lp(a) have been associated with an increased risk for atherosclerotic cardiovascular disease, the mechanism underlying this association is still largely undetermined, as is the potential role played by the particle's heterogeneity. Lp(a) pathogenicity may also be influenced by the action of environmental factors and post-translational events relating to oxidative processes, and the action of lipolytic and proteolytic enzymes. Complicating the study of Lp(a) are the competing methods for its quantification due to its complex structure, and the lack of standardized methodologies. The recognition that Lp(a) particles may not all be alike in atherogenic potential should encourage studies to identify genetic and nongenetic factors underlying its heterogeneity, in order to reach a better understanding of its actual impact on atherosclerotic cardiovascular disease.

Changes in plasma triglyceride levels shift lipoprotein(a) density in parallel with that of LDL independently of apolipoprotein(a) size

Lipoprotein(a) [Lp(a)] represents a class of low density lipoprotein (LDL) particles that have as a protein moiety apolipoprotein B-100-linked covalently to a single molecule of apolipoprotein(a) [apo(a)], a specific multikringle protein of the plasminogen family. Lp(a) is polymorphic in density because of either the density heterogeneity of constitutive LDL, apo(a) size, or both. Authentic LDL also represents a set of heterogeneous particles whose density is affected by metabolic events. Whether in vivo these events may also affect Lp(a) density is not clearly established. To this effect, we studied 75 subjects with plasma Lp(a) protein levels between 7 and 50 mg/dL and containing a single apo(a) size isoform. We used density gradient ultracentrifugation to simultaneously monitor the changes in the peak density of LDL and Lp(a) at entry and during the course of treatments directed at reducing plasma triglyceride levels. In each case, we found that at entry, Lp(a) peak density was correlated with LDL peak density (r=0.71, P<0.0001) and that during treatment, changes in plasma triglycerides were associated with shifts of Lp(a) peak density that paralleled those of LDL peak density. A high correlation (r=0.94, P<0.0001) was particularly evident in subjects with initial plasma triglycerides in the 300-mg/dL range. In vitro assembly studies showed that an apo(a) isoform containing 14 kringle IV type 2 repeats, exhibited, on incubation with LDL, a comparable degree of incorporation into LDL species varying in density between 1.035 and 1.057 g/mL Taken together, our results indicate that metabolically dependent changes in the peak density of Lp(a) can occur independently of apo(a) size. These changes may have to be taken into account in assessing the cardiovascular pathogenicity of this lipoprotein particle in hypertriglyceridemic subjects.

Three cases of cardiac hydatidosis: diagnosis, surgical treatment, and complications

Three cases of cardiac hydatid disease from among the many cases of hydatidosis (>300) in various organs observed by the authors are reported. The sites of the cysts and the complications that arose are described. The first case developed hydatid pulmonary embolism caused by rupture into the right ventricular cavity, the second suffered peripheral hydatid embolism caused by rupture into the left ventricular cavity, and the third, whose diagnosis was fortuitous, had no complications. The first patient died shortly after admission. The other two underwent radical pericystectomy and partial pericystectomy with cardiopulmonary bypass. The best result was obtained in the third case where rupture had not occurred. The second patient recovered but developed hemiparesis. The various diagnostic tools available are discussed, as well as some technical aspects of pericystectomy, which has a high mortality rate. The importance of early diagnosis and treatment of this rare localization of Echinococcus granulosus is emphasized, and echocardiography is recommended even for nonspecific cardiac symptoms in areas where the parasite is endemic.

Lipoprotein(a), Friedewald formula, and NCEP guidelines. National Cholesterol Education Program

The Friedewald low-density lipoprotein cholesterol formula, which is commonly used in clinical chemistry laboratories, comprises both low-density lipoprotein and lipoprotein(a) cholesterol. This confounder must be recognized and appropriately corrected when dealing with subjects with high plasma lipoprotein(a) levels.

Apolipoprotein(a): structure and biology

Apolipoprotein(a), apo(a), the distinctive glycoprotein constituent of lipoprotein(a), Lp(a), is synthesized in the liver, links covalently to apoB100-lipoprotein, and travels so linked in the plasma to tissue sites where removal mechanisms are yet undetermined. Depending on the redox status of the surrounding milieu, apo(a) may re-acquire its unbound state shown to have structural and functional properties different from those of the bound form. Apo(a) is potentially athero-thrombogenic, a property which may be influenced by its size, sequence polymorphism, type of lipoprotein it is linked to and the inflammatory state of the vessel wall. This set of variables must be taken into account when assessing the cardiovascular pathogenicity of free and bound apo(a).

Properties of human free apolipoprotein(a) and lipoprotein(a) after either freezing or lyophilization in the presence and absence of cryopreservatives

Apolipoprotein(a), apo(a), the specific multikringle glycoprotein constituent of lipoprotein(a), Lp(a), occurs in the plasma mostly bound to apoB100-containing lipoproteins but also in a free form. Often the properties of these products are determined after storage in the cold; yet limited information is available on their stability at low temperatures. To shed light on this subject, we examined the effect of two parameters, freezing and lyophilization, in either the absence or the presence of cryopreservatives. Lp(a)s each having a single apo(a) size isoform containing either 14 or 17 kringle (K) IVs were isolated from the plasma of healthy donors by combining density gradient ultracentrifugation and lysine-Sepharose column chromatography using solutions containing both antioxidants and proteolytic inhibitors. Apo(a) was obtained from parent Lp(a) by a mild limited reductive procedure. Either freezing at -20 degrees C or lyophilization in the presence of 5% sucrose did not change the electrophoretic, immunochemical, and lysine-binding properties of Lp(a) including its ability to generate free apo(a). Irrespective of source, apo(a) remained stable when either frozen at -20 and -80 degrees C or lyophilized in the presence of 125 mM trehalose. In all cases, the absence of cryopreservatives caused the samples to aggregate irreversibly. Thawed or reconstituted samples of both free and bound apo(a) kept at 4 degrees C under sterile conditions in the presence of antioxidants, proteolytic inhibitors, and cryopreservative exhibited no significant changes in properties within the time of observation. Both apo(a) isoforms gave comparable results. We conclude that apo(a), either free or bound, can be kept stable at low temperatures in the presence of appropriate cryopreservatives.

Use of a reference material proposed by the International Federation of Clinical Chemistry and Laboratory Medicine to evaluate analytical methods for the determination of plasma lipoprotein(a)

BACKGROUND

As part of the NIH/National Heart, Lung and Blood Institute Contract for the Standardization of Lipoprotein(a) [Lp(a)] Measurements, a study was performed in collaboration with the IFCC Working Group for the Standardization of Lp(a) Assays. The aims of the study, performed with the participation of 16 manufacturers and 6 research laboratories, were to evaluate the IFCC proposed reference material (PRM) for its ability to transfer an accuracy-based value to the immunoassay calibrators and to assess concordance in results among different methods.

METHODS

Two different purified Lp(a) preparations with protein mass concentrations determined by amino acid analysis were used to calibrate the reference method. A Lp(a) value of 107 nmol/L was assigned to PRM. After uniformity of calibration was demonstrated in the 22 evaluated systems, Lp(a) was measured on 30 fresh-frozen sera covering a wide range of Lp(a) values and apolipoprotein(a) [apo(a)] sizes.

RESULTS

The among-laboratory CVs for these samples (6-31%) were, in general, higher than those obtained for PRM (2.8%) and the quality-control samples (14%, 12%, and 9%, respectively), reflecting the broad range of apo(a) sizes in the 30 samples and the sensitivity of most methods to apo(a) size heterogeneity. Thus, although all of the assays were uniformly calibrated through the use of PRM, no uniformity in results was achieved for the isoform-sensitive methods.

CONCLUSIONS

Linear regression analyses indicated that to various degrees, apo(a) size heterogeneity affects the outcome of the immunochemical methods used to measure Lp(a). We have also shown that the inaccuracy of Lp(a) values determined by methods sensitive to apo(a) size significantly affects the assessment of individual risk status for coronary artery disease.

Apolipoprotein (a) fragments in relation to human carotid plaque instability

PURPOSE

An elevated plasma level of lipoprotein (a) is an independent risk factor for atherothrombotic cardiovascular disease by yet undefined mechanisms. We have previously reported that matrix metalloproteinases cleave apolipoprotein (a) into 2 main fragments, F1 and F2, the latter (the C-terminal domain) exhibiting in vitro a high-affinity binding to extracellular matrix components, including fibrin(ogen). We therefore tested the hypothesis that the lipoprotein (a) matrix metalloproteinase-derived F2 is localized in potentially or morphologically unstable human carotid plaque at regions of increased matrix metalloproteinase activity.

METHODS

Carotid plaques removed after endarterectomy (n = 18) were evaluated for structural features indicative of instability (thin fibrous cap, inflammation, and proximity of the necrotic core to the lumen); each plaque was classified as unstable (n = 10) or stable (n = 8). Western blot analysis was performed to quantitate apolipoprotein (a) and its fragments F1 and F2 in plaque extracts. Immunohistochemical staining was used to localize apolipoprotein (a) and its fragments within the atherosclerotic plaque. In situ zymography was used to determine regions of gelatinase (matrix metalloproteinase 2 and matrix metalloproteinase 9) activity.

RESULTS

Western blot analyses demonstrated a 2.5-fold higher density of F2 in unstable plaques than in stable plaques (3.07 +/- 1.9 vs 1.18 +/- 0.8; P <.05). In morphologically unstable plaques, there was preferential distribution of F2 within regions of fibrous cap inflammation and/or foam cell accumulation and within abluminal necrotic cores. In morphologically stable plaques, however, localization was predominantly found in the medial smooth muscle cells. Regions of enhanced matrix metalloproteinase 2 and matrix metalloproteinase 9 activity co-localized with the transmural distribution of F2 within the plaque.

CONCLUSIONS

These findings suggest that F2 in regions of increased matrix metalloproteinase activity is a potential mechanism for superimposed thrombotic events in morphologically unstable human carotid plaques. The relationship between plasma lipoprotein (a) levels and accumulation of F2 and the potential correlation of F2 to human plaque disruption and thrombosis warrant further study.

Structural determinants in the C-terminal domain of apolipoprotein E mediating binding to the protein core of human aortic biglycan

Apolipoprotein (apo) E-containing high density lipoprotein particles were reported to interact in vitro with the proteoglycan biglycan (Bg), but the direct participation of apoE in this binding was not defined. To this end, we examined the in vitro binding of apoE complexed with dimyristoylphosphatidylcholine (DMPC) to human aortic Bg before and after glycosaminoglycan (GAG) depletion. In a solid-phase assay, apoE.DMPC bound to Bg and GAG-depleted protein core in a similar manner, suggesting a protein-protein mode of interaction. The binding was decreased in the presence of 1 m NaCl and was partially inhibited by either positively (0.2 m lysine, arginine) or negatively charged (0.2 m aspartic, glutamic) amino acids. A recombinant apoE fragment representing the C-terminal 10-kDa domain, complexed with DMPC, bound as efficiently as full-length apoE, whereas the N-terminal 22-kDa domain was inactive. Similar results were obtained with a gel mobility shift assay. Competition studies using a series of recombinant truncated apoEs showed that the charged segment in the C-terminal domain between residues 223 and 230 was involved in the binding. Overall, our results demonstrate that the C-terminal domain contains elements critical for the binding of apoE to the Bg protein core and that this binding is ionic in nature and independent of GAGs.

[Unusual case of benign neoplasm of the breast mimicking a carcinoma: granular cell tumor. Case report]

Granular cell tumors are rare, usually benign neoplasms of soft tissues which most commonly occur in the tongue, skin and subcutaneous tissue. Although the histogenesis is still object of debate, recent immunohistochemical studies and ultrastructural findings support the origin of this neoplasm from the peripheral nervous tissue, most likely from Schwann's cells. Occurrence of this neoplasm in the breast, although uncommon, warrants special attention, since its clinical, mammographic and pathological appearances on frozen sections "may often closely resemble" hose of breast malignancy. The authors analyze and commenton, with special reference to clinical aspects and surgical treatment, a case of benign granular cell tumor of the breast occurring in a 42 year-old woman. The mammographic and clinical findings suggested a breast carcinoma. The correct diagnosis was established by definitive microscopic examination of the paraffin-embedded specimens and the treatment was a simple local excision of the tumour and a small rim of surrounding breast parenchyma. Although the granular cell tumor of the breast is a rare entity, surgeons and pathologists should be aware of its existence in order to avoid inappropriate radical surgery not justified by the benign behavior of the neoplasm.

Dominant role of the C-terminal domain in the binding of apolipoprotein(a) to the protein core of proteoglycans and other members of the vascular matrix

The C-terminal domain of apolipoprotein(a) binds in vitro to the protein core of proteoglycans as well as fibrinogen and fibronectin, suggesting that this domain plays a role in anchoring lipoprotein(a) or free apolipoprotein(a) to the vascular subendothelial matrix.

Macrophage metalloelastase, MMP-12, cleaves human apolipoprotein(a) in the linker region between kringles IV-4 and IV-5. Potential relevance to lipoprotein(a) biology

In this study we found that macrophage metalloelastase, MMP-12 cleaves, in vitro, apolipoprotein(a) (apo(a)) in the Asn3518-Val3519 bond located in the linker region between kringles IV-4 and IV-5, a bond immediately upstream of the Ile3520-Leu3521 bond, shown previously to be the site of action by neutrophil elastase (NE). We have also shown that human apo(a) injected into the tail vein of control mice undergoes degradation as reflected by the appearance of immunoreactive fragments in the plasma and in the urine of these animals. To define whether either or both of these enzymes may be responsible for the in vivo apo(a) cleavage, we injected intravenously MMP-12(-/-), NE -/- mice and litter mates, all of the same strain, with either lipoprotein(a) (Lp(a)), full-length free apo(a), or its N-terminal fragment, F1, obtained by the in vitro cleavage of apo(a) by NE. In the plasma of Lp(a)/apo(a)-injected mice, F1 was detected in control and NE -/- mice but was virtually absent in the MMP-12(-/-) mice. Moreover, fragments of the F1 type were present in the urine of the animals except for the MMP-12(-/-) mice. These fragments were significantly smaller in size than those observed in the plasma. All of the animals injected with F1 exhibited small sized fragments in their urine. These observations provide evidence that, in the mouse strain used, MMP-12 plays an important role in the generation of F1 from injected human Lp(a)/apo(a) and that this fragment undergoes further cleavage during renal transit via a mechanism that is neither NE- nor MMP-12-dependent. Thus, factors influencing the expression of MMP-12 may have a modulating action on the biology of Lp(a).

Effect of phospholipase A2 digestion on the conformation and lysine/fibrinogen binding properties of human lipoprotein[a]

In vitro hydrolysis of human lipoprotein[a] (Lp[a]) by phospholipase A2 (PLA2) decreased the phosphatidylcholine (PC) content by 85%, but increased nonesterified fatty acids 3.2-fold and lysoPC 12.9-fold. PLA2-treated Lp[a] had a decreased molecular weight, increased density, and greater electronegativity on agarose gels. In solution, PLA2-Lp[a] was a monomer, and when assessed by sedimentation velocity it behaved like untreated Lp[a], in that it remained compact in NaCl solutions but assumed the extended form in the presence of 6-amino hexanoic acid, which was shown previously to have an affinity for the apo[a] lysine binding site II (LBS II) comprising kringles IV5-8. We interpreted our findings to indicate that PLA2 digestion had no effect on the reactivity of this site. This conclusion was supported by the results obtained from lysine Sepharose and fibrinogen binding experiments, in the presence and absence of Tween 20, showing that phospholipolysis had no effect on the reactivity of the LBS-II domain. A comparable binding behavior was also exhibited by the free apo[a] derived from each of the two forms of Lp[a]. We did observe a small increase in affinity of PLA2-Lp[a] to lysine Sepharose and attributed it to changes in reactivity of the LBS I domain (kringle IV10) induced by phospholipolysis. In conclusion, the extensive modification of Lp[a] caused by PLA2 digestion had no significant influence on the reactivity of LBS II, which is the domain involved in the binding of apo[a] to fibrinogen and apoB-100. These results also suggest that phospholipids do not play an important role in these interactions.

Recombinant kringle IV-10 modules of human apolipoprotein(a): structure, ligand binding modes, and biological relevance

The kringle modules of apolipoprotein(a) [apo(a)] of lipoprotein(a) [Lp(a)] are highly homologous with kringle 4 of plasminogen (75-94%) and like the latter are autonomous structural and functional units. Apo(a) contains 14-37 kringle 4 (KIV) repeats distributed into 10 classes (1-10). Lp(a) binds lysine-Sepharose via a lysine binding site (LBS) located in KIV-10 (88% homology with plasminogen K4). However, the W72R substitution that occurs in rhesus monkeys and occasionally in humans leads to impaired lysine binding capacity of KIV-10 and Lp(a). The foregoing has been investigated by determining the structures of KIV-10/M66 (M66 variant) in its unliganded and ligand [epsilon-aminocaproic acid (EACA)] bound modes and the structure of recombinant KIV-10/M66R72 (the W72R mutant). In addition, the EACA liganded structure of a sequence polymorph (M66T in about 42-50% of the human population) was reexamined (KIV-10/T66/EACA). The KIV-10/M66, KIV-10/M66/EACA, and KIV-10/T66/EACA molecular structures are highly isostructural, indicating that the LBS of the kringles is preformed anticipating ligand binding. A displacement of three water molecules from the EACA binding groove and a movement of R35 bringing the guanidinium group close to the carboxylate of EACA to assist R71 in stabilizing the anionic group of the ligand are the only changes accompanying ligand binding. Both EACA structures were in the embedded binding mode utilizing all three binding centers (anionic, hydrophobic, cationic) like plasminogen kringles 1 and 4. The KIV-10/T66/EACA structure determined in this work differs from one previously reported [Mikol, V., Lo Grasso, P. V. and, Boettcher, B. R. (1996) J. Mol. Biol. 256, 751-761], which crystallized in a different crystal system and displayed an unbound binding mode, where only the amino group of EACA interacted with the anionic center of the LBS. The remainder of the ligand extended into solvent perpendicular to the kringle surface, leaving the hydrophobic pocket and the cationic center of the LBS unoccupied. The structure of recombinant KIV-10/M66R72 shows that R72 extends along the ligand binding groove parallel to the expected position of EACA toward the anionic center (D55/D57) and makes a salt bridge with D57. Thus, the R72 side chain mimics ligand binding, and loss of binding ability is the result of steric blockage of the LBS by R72 physically occupying part of the site. The rhesus monkey lysine binding impairment is compared with that of chimpanzee where KIV-10 has been shown to have a D57N mutation instead.

Atherothrombogenicity of lipoprotein(a): the debate

Although lipoprotein(a) (Lp[a]) has been recognized as an atherothrombogenic factor, the underlying mechanisms for this pathogenicity have not been clearly defined. Plasma levels have received most of the attention in this regard; however, discrepancies among population studies have surfaced. Particularly limited is the information on the fate of Lp(a) that enters the arterial wall, in terms of mechanisms of endothelial transport and interactions with cells and macromolecules of the extracellular matrix. A typical Lp(a) represents a low-density lipoprotein (LDL)-like particle having as a protein moiety apo B-100 linked by a single interchain disulfide bond to a unique multikringle glycoprotein, called apolipoprotein(a) (apo[a]). In vitro studies have shown that Lp(a) can be dissected into its constituents, LDL and apo(a). In turn, the latter can be cleaved by enzymes of the elastase and metalloproteinase families into fragments that exhibit a differential behavior in terms of binding to macromolecules of the extracellular matrix: fibrinogen, fibronectin, and proteoglycans. By immunochemical criteria, apo(a) predominantly localizes in areas of human arteries affected by the atherosclerotic process, where elastase and metalloproteinase enzymes operate and where apo(a) fragments are potentially generated. The accumulation of these fragments in the vessel wall is likely to depend on their affinity for the constituents of the extracellular matrix. Thus, factors that modulate inflammation and inflammation-mediated fragmentation of Lp(a)/apo(a) may play an important role in the cardiovascular pathogenicity of Lp(a). This pathogenicity may be attenuated by measures directed at preventing the activation of those vascular cells that secrete enzymes with a proteolytic potential for Lp(a)/apo(a), namely, leukocytes, macrophages, and T cells.

Congenital carotid-jugular fistula in an elderly patient

Carotid-jugular arteriovenous fistulas (AVF) are extremely rare with only 20 cases reported in the literature up to December 1996. The case of a 74-year-old man (the oldest reported in the literature) with abnormal communications between the external carotid artery and the internal jugular vein is reported. The condition was treated by platinum coil embolization via catheterization and by repeated operations to ligate the branches of the external carotid artery, besides removal of the tissue containing the fistula and ligation of the external carotid at its origin. The result was incomplete because about 6 months after the last operation the patient showed the same symptoms, although in a milder form. Until standard treatment is established, the appropriate technique should be decided on a patient-to-patient basis.

Apolipoprotein(a) binds via its C-terminal domain to the protein core of the proteoglycan decorin. Implications for the retention of lipoprotein(a) in atherosclerotic lesions

Although it is known that lipoprotein(a) (Lp(a)) binds to proteoglycans, the mechanism for this binding has not been fully elucidated. In order to shed light on this subject, we examined the interactions of decorin, a proteoglycan with a well defined protein core and a single glycosaminoglycan (GAG) chain, with Lp(a) and derivatives, namely Lp(a) deprived of apo(a), or Lp(a-), free apo(a), and the two main proteolytic fragments, F1 and F2. By circular dichroism criteria, the decorin preparations used had the same secondary structure as that previously reported for native decorin. Authentic low density lipoprotein from the same human donor was used as a control. In a solid phase system, Lp(a-)and low density lipoprotein bound to decorin in a comparable manner. This binding required Ca2+/Mg2+ ions, was lysine-mediated, and was markedly decreased in the presence of GAG-depleted decorin, suggesting the ionic nature of the interaction likely involving apoB100 and the GAG component of decorin. Free apo(a) also bound to decorin; however, the binding was neither cation-dependent nor lysine-mediated, unaffected by sialic acid depletion of apo(a), and markedly decreased when either reduced and alkylated apo(a) or reduced and alkylated decorin was used in the assay. Of note, the binding of apo(a) was unaffected when it was incubated with a spectrally native decorin that had been renatured from either 4 M guanidine hydrochloride by extensive dialysis or cooled from 65 to 25 degrees C. On the other hand, the binding significantly increased when decorin was depleted of GAGs, which by themselves had no affinity for apo(a). The binding of apo(a) to the decorin protein core was also elicited by the C-terminal domain of apo(a), and it was favored by high NaCl concentrations, 1 to 2 M. No binding was exhibited by the N-terminal domain accounting for the lack of effect of apo(a) size polymorphism on the binding. In the case of whole Lp(a), the binding to immobilized decorin was mostly GAG-dependent and ionic in nature. A minor contribution by apo(a) was detected when GAG-depleted decorin was used in the assay. Our results indicate that the binding of Lp(a) to decorin involves interactions both electrostatic (apoB100-GAG) and hydrophobic (apo(a)-decorin protein core), and that the binding of apo(a) requires decorin protein core to be in its native state.

Tardive presentation of congenital cystic adenomatoid malformation of the lung

Congenital cystic adenomatoid malformation (CCAM) of the lung is a neonatal disease not often found after the first year of life and extremely rare in adults. Three cases of CCAM, one in a ten-year-old girl and two in adults, are reported. An understanding of this disease is important because, although relatively rare, it is one of the most frequent causes of neonatal respiratory distress. Greater awareness of the condition and its early detection would also reduce the number of cases found at a later age.

Lipoprotein(a): identification of subjects with a superbinding capacity for fibrinogen

We have previously shown that the binding of lipoprotein(a) [Lp(a)] to immobilized fibrinogen involves the domain located in kringles IV-5 to IV-8, but not kringle IV-10. In extending those studies to subjects living in Chicago and in the island of Sardinia, we found that about 6% of them had an Lp(a) with Bmax values of 27.7+/-6.0 fmol, which were about 5-8-fold higher than those of controls (3.4+/-2.8 fmol) and in the range of those observed for free apo(a) derived from the Lp(a) of controls (36.6+/-2.9 fmol). This superbinding phenotype was unaffected by age, sex, type of lipid disorder and hypolipidemic agents, and also had a familial incidence. We are currently exploring the hypothesis that this fibrinogen superbinding phenotype is due to conformational changes of apolipoprotein(a) [apo(a)] resulting from the lipid content and composition of the Lp(a) particle and/or sequence anomalies in the kringle domain IV-5 to IV-8.

Learning about the structure and biology of human lipoprotein [a] through dissection by enzymes of the elastase family: facts and speculations

Lipoprotein[a], Lp[a], represents a class of lipoprotein particles that have as a protein moiety apoB-100 linked by a disulfide bridge to a multi-kringle structure, apolipoprotein[a], or apo[a]. It is now possible to separate from Lp[a] a free apo[a] able to reassociate with apoB-100-containing lipoproteins to restore the parent lipoprotein complex. Apo[a], whether free or a constitutive component of Lp[a], can be cleaved at interkringle sites by the action of enzymes of the elastase family generating fragments that differ in structural, functional, and metabolic properties. In the case of Lp[a], elastase digestion generates a miniLp[a] particle, which contains the apo[a] COOH-terminal domain able to bind to lysine, fibrinogen, fibronectin, and proteoglycans. This domain may also be generated by elastase type enzymes secreted by activated macrophages and smooth muscle cells in the arterial intima as a part of the chronic inflammation that characterizes the atherosclerotic process. Thus, the apo[a] immunoreactive material, which has been described in the atherosclerotic plaque, may represent miniLp[a] and/or apo[a] fragments accumulating in the vessel wall as a function of their relative affinity for the components of the extracellular matrix and producing complexes with an atherothrombogenic potential. This potential may depend on several factors: kringle folding and conformation, susceptibility of the linkers to proteolytic cleavage, binding specificity of given apo[a] fragments to the matrix components of the arterial intima, and the overall inflammatory status of the arterial wall.

Videothoracoscopic removal of a mediastinal teratoma

We describe a case of a mature mediastinal teratoma resected by videothoracoscopy. This new procedure, now widely adopted for many intrathoracic conditions, has proved to be easy, safe, and advantageous also in the treatment of rare tumors, such as mature mediastinal teratomas. We recommend its use in all cases like the one described.

Polymorphonuclear cells isolated from human peripheral blood cleave lipoprotein(a) and apolipoprotein(a) at multiple interkringle sites via the enzyme elastase. Generation of mini-Lp(a) particles and apo(a) fragments

Incubation of polymorphonuclear cells (PMN), isolated from human peripheral blood, with either lipoprotein(a) (Lp(a)) or free apolipoprotein(a) (apo(a)), derived from the parent Lp(a), caused in both cases a multisite fragmentation of apo(a) inhibited by methoxysuccinyl-Ala-Ala-Pro-Val-CH2Cl, a specific elastase inhibitor. The major cut site was at the interkringle region between apo(a) kringles IV-4 and IV-5 (Ile3520-Leu3521). The other cleavages were between kringles IV-7 and IV-8 (Thr3846-Leu3847) and between kringles IV-10 and V (Ile4196-Gln4197). The elastase-induced fragmentation of apo(a) was the same whether free or as a member of Lp(a), indicating that the disulfide bond between apo(a) and the apoB100 component of Lp(a) did not hinder the elastase action. Lp(a) fragments containing kringle IV-9 retained the linkage to apoB100 via the disulfide bond, forming mini-Lp(a) particles in which the size of apo(a) varied according to the size of the fragments produced by the elastase digestion. The proteolytic fragmentation was unaffected by apo(a) size polymorphism within the range examined. PMN elastase also caused a partial proteolysis of apoB100 whether as a component of Lp(a), Lp(a) freed of apo(a), or authentic low density lipoprotein without an apparent destabilization of these lipoprotein particles. Proteolysis of Lp(a) by PMN was due to an elastase activity that was 3.5% of that observed when PMN were activated by N-formyl-Met-Leu-Phe. A portion of the released elastase was found to be associated in an active form with both Lp(a) and low density lipoprotein even in an ultracentrifugal field at high salt concentrations. Taken together, our results indicate that apo(a) undergoes important proteolytic modifications by PMN elastase, which exhibits specificity for peptide bonds located in the interkringle domains of apo(a). In the case of Lp(a), elastase cleavage causes the formation of mini-Lp(a) particles with a protein moiety containing a truncated apo(a). Elastase-mediated proteolytic events may occur in vivo under conditions associated with either an excessive leakage of elastase from PMN and/or deficiencies of natural inhibitors of this enzyme.

Role of hypercholesterolemia in accelerated transplant coronary vasculopathy: results of surgical therapy with partial ileal bypass in rabbits undergoing heterotopic heart transplantation

BACKGROUND

We tested the hypothesis that plasma cholesterol lowering action of partial ileal bypass (PIB) is beneficial in mitigating accelerated transplantation coronary vasculopathy.

METHODS

Forty-one New Zealand white rabbits were randomized to receive a normal (n = 21) or 1% cholesterol diet (n = 20). They underwent heterotopic heart transplantation with sham-PIB (n = 19) or PIB (n = 22) and immunosuppression with cyclosporine A (CyA).

RESULTS

CyA increased plasma cholesterol of rabbits receiving a normal diet. This effect was mitigated by PIB (101 +/- 50 mg/dl CyA vs baseline 24 +/- 8, p < 0.001; vs 54 +/- 25 mg/dl with PIB, p < 0.05). In cholesterol-fed rabbits, PIB decreased plasma cholesterol levels (520 +/- 236 mg/dl PIB vs baseline 720 +/- 359, p < 0.05; vs 1502 +/- 253 mg/dl with sham PIB, p < 0.00001). Coronary arteries (CA) of 21 5-week survivors were evaluated by light microscopy and digital morphometry. No rejection was noted. Histologic study revealed vasculopathy in 3% of 705 native and 18% of 654 transplant CA (p < 0.05). Graft vasculopathy (GV) was present in 25% of 365 CA of sham-PIB and 10% of 289 CA of PIB rabbits (p = 0.07). In cholesterol-fed rabbits, GV was characterized by fatty proliferative lesions in 75% of 91 pathologic CA of sham and 21% of 28 pathologic CA of PIB rabbits (p < 0.05). Graft intimal hyperplasia was not correlated with cholesterol intake or PIB and was present in 18 of 119 pathologic CA.

CONCLUSIONS

GV was characterized by fatty intimal proliferation, fibrous intimal hyperplasia, and a "mixed type." Fibrous intimal hyperplasia developed in native and transplanted hearts, and CyA seemed to promote this state. Hypercholesterolemia promoted fatty proliferative lesions, worsening GV. PIB significantly decreased total cholesterol and retarded fatty proliferation of CA of native and transplanted hearts but did not prevent intimal hyperplastic vasculopathy. Therapy of hypercholesterolemia is recommended to at least mitigate the fatty intimal proliferation of GV.