Intraoperative Evaluation of Breast Tissues During Breast Cancer Operations Using the MasSpec Pen

Importance

Surgery with complete tumor resection remains the main treatment option for patients with breast cancer. Yet, current technologies are limited in providing accurate assessment of breast tissue in vivo, warranting development of new technologies for surgical guidance.

Objective

To evaluate the performance of the MasSpec Pen for accurate intraoperative assessment of breast tissues and surgical margins based on metabolic and lipid information.

Design, Setting, and Participants

In this diagnostic study conducted between February 23, 2017, and August 19, 2021, the mass spectrometry-based device was used to analyze healthy breast and invasive ductal carcinoma (IDC) banked tissue samples from adult patients undergoing breast surgery for ductal carcinomas or nonmalignant conditions. Fresh-frozen tissue samples and touch imprints were analyzed in a laboratory. Intraoperative in vivo and ex vivo breast tissue analyses were performed by surgical staff in operating rooms (ORs) within 2 different hospitals at the Texas Medical Center. Molecular data were used to build statistical classifiers.

Main Outcomes and Measures

Prediction results of tissue analyses from classification models were compared with gross assessment, frozen section analysis, and/or final postoperative pathology to assess accuracy.

Results

All data acquired from the 143 banked tissue samples, including 79 healthy breast and 64 IDC tissues, were included in the statistical analysis. Data presented rich molecular profiles of healthy and IDC banked tissue samples, with significant changes in relative abundances observed for several metabolic species. Statistical classifiers yielded accuracies of 95.6%, 95.5%, and 90.6% for training, validation, and independent test sets, respectively. A total of 25 participants enrolled in the clinical, intraoperative study; all were female, and the median age was 58 years (IQR, 44-66 years). Intraoperative testing of the technology was successfully performed by surgical staff during 25 breast operations. Of 273 intraoperative analyses performed during 25 surgical cases, 147 analyses from 22 cases were subjected to statistical classification. Testing of the classifiers on 147 intraoperative mass spectra yielded 95.9% agreement with postoperative pathology results.

Conclusions and Relevance

The findings of this diagnostic study suggest that the mass spectrometry-based system could be clinically valuable to surgeons and patients by enabling fast molecular-based intraoperative assessment of in vivo and ex vivo breast tissue samples and surgical margins.

Abstract P3-18-10: Current options and future perspectives for breast margin assessment in clinical practice

Background: Ensuring negative margins at the time of breast conserving surgery for invasive breast cancer or ductal carcinoma in situ is necessary to minimize the chance of local recurrence and avoid re-excisions that cause patient concern and may delay adjuvant therapy. However, about 25% of women who have lumpectomy have a second surgery to remove residual disease, suggesting an ongoing need for improved methods of intraoperative margin assessment. This study aimed to perform a contemporary review of methods of intraoperative margin assessment during breast conservation surgery. Methods: A review of the scientific literature from 2009 to 2021 comprising 62 manuscripts of the current and proposed. intraoperative techniques for breast margin assessment during breast conservation surgery was conducted via PubMed and Google Scholar. The methods assessed were grouped into 10 categories based on the technology employed: bioimpedance/radiofrequency, high-resolution imaging, optical imaging, mass spectrometry, magnetic-resonance imaging, 2D/3D specimen CT, X-ray, multimodal optical microscopy, pharmacologic and pathological margin assessment. All technologies were reviewed for overall effectiveness in lowering re-excision rates derived from their respective advantages, limitations, sensitivity, and specificity. Results: Overall, 8 current and 7 technologies under development were assessed (Table 1). Frozen section and cytology yielded the highest diagnostic accuracy; however, these can be time-consuming, resource-intensive, and have limited sampling points. Conversely, 2D specimen CT provides rapid results but is limited by relatively low sensitivity. Future technologies such as optical coherence tomography showed promising results in demonstrating higher diagnostic accuracy for lumpectomy and margin shaves, but remain to be proven in clinical practice. Conclusion: Intraoperative margin assessments can lower final positive margins and subsequent re-excisions rates. A number of current and upcoming technologies that assess margin status range in their respective efficacies and limitations. There remains demand for improved margin assessment at the time of breast conserving surgery, but which technologies will become standard of care remains, at present, unclear.

Table 1.Methods of intraoperative margin assessmentMethod:Brand:Sensitivity:Specificity:Source:Bioimpedence• ClearEdge™87.3%75.6%Dixon et al. 2016• MarginProbe75.2%70-87%Schanabel et al., 2014Cytology:• Imprint72%97%Esbona & Zhanhai 2012; Qui et al., 2018Frozen Section–83%95%Schmidt et al, 2020; Schwarz & Schmidt, 2020Mass Spectrometry• iKnife93.4-94.7%94.7-96.2%St. John et al., 2017• MasSpec Pen83-95%95-100%Garza et al., 2020Multimodal optical microscopy• fluorescence imaging combination withRCM/OCT subsystemTBDTBDScimone et al., 2021MRI• ClearSight™93%92%Moshe et al., 2016Optical Coherence Tomography (OCT)• OTIS™96%92%Mojahed et al., 2020; Schmidt et al. 2020Pharmacology• Bevacizumab98%79%Koch et al., 2017• Lumicell2-3D specimen CT• Mozart®93%78%Black et al., [poster]• Faxitron78.6-85.6%100%Emmadi & Wiley 2012; Bathla et al. 2011• MicroCT56%100%Qiu et al. 2018X-ray• XPCI83%83%Massimi et al. 2021

Citation Format: Huma Javaid, Ivan Marin, Jessica Montalvan, Logan Healy, Brian Menegaz, Cary Hsu, Eric Silberfein, Elizabeth Bonefas, Stacey A. Carter, Alastair M. Thompson. Current options and future perspectives for breast margin assessment in clinical practice [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-18-10.

Infant milk feeding and bone health in later life: findings from the Hertfordshire cohort study

Using data from the Hertfordshire cohort study, this study examined the effect of breastfeeding and bottle feeding on adult lumbar spine and femoral neck bone mineral content (BMC) and bone mineral density (BMD). The type of infant milk feeding was significantly associated with lumbar spine BMD in males.

INTRODUCTION

Using data from the Hertfordshire cohort study (HCS), this study aims to examine the effect of infant milk feeding on bone health in later life by comparing the effect of breastfeeding and bottle feeding on lumbar spine and femoral neck BMC and BMD.

METHODS

Information about infant milk feeding, birth weight (kg) and weight at 1 (kg) was collected by health visitors between 1931 and 1939 in Hertfordshire. BMC and BMD measurements were taken by DXA scan between 1998 and 2004. Linear regression models adjusted for conditional weight at 1, age at DXA scan, sex, adult BMI, smoking behaviour, alcohol consumption, physical activity, dietary calcium, and prudent diet score.

RESULTS

Infant milk feeding was significantly associated with lumbar spine BMD (b = - 0.028; 95% CI, - 0.055; - 0.000; p value, 0.047) in males. On average, males who consumed breastmilk alternatives in infancy had lower lumbar spine BMD measurements than those who were fed only breastmilk. These associations remained significant in fully adjusted models. There were no significant associations between infant milk feeding and bone health for females.

CONCLUSIONS

Significant associations between infant milk feeding and lumbar spine BMD in males indicate that breastmilk may be protective for the bone health of male babies. The evidence presented here underscores the potential lifelong benefits of breastfeeding and may highlight the differences between osteoporotic risk factors for males and females.

Multicenter Study Using Desorption-Electrospray-Ionization-Mass-Spectrometry Imaging for Breast-Cancer Diagnosis

The histological and molecular subtypes of breast cancer demand distinct therapeutic approaches. Invasive ductal carcinoma (IDC) is subtyped according to estrogen-receptor (ER), progesterone-receptor (PR), and HER2 status, among other markers. Desorption-electrospray-ionization-mass-spectrometry imaging (DESI-MSI) is an ambient-ionization MS technique that has been previously used to diagnose IDC. Aiming to investigate the robustness of ambient-ionization MS for IDC diagnosis and subtyping over diverse patient populations and interlaboratory use, we report a multicenter study using DESI-MSI to analyze samples from 103 patients independently analyzed in the United States and Brazil. The lipid profiles of IDC and normal breast tissues were consistent across different patient races and were unrelated to country of sample collection. Similar experimental parameters used in both laboratories yielded consistent mass-spectral data in mass-to-charge ratios ( m/ z) above 700, where complex lipids are observed. Statistical classifiers built using data acquired in the United States yielded 97.6% sensitivity, 96.7% specificity, and 97.6% accuracy for cancer diagnosis. Equivalent performance was observed for the intralaboratory validation set (99.2% accuracy) and, most remarkably, for the interlaboratory validation set independently acquired in Brazil (95.3% accuracy). Separate classification models built for ER and PR statuses as well as the status of their combined hormone receptor (HR) provided predictive accuracies (>89.0%), although low classification accuracies were achieved for HER2 status. Altogether, our multicenter study demonstrates that DESI-MSI is a robust and reproducible technology for rapid breast-cancer-tissue diagnosis and therefore is of value for clinical use.

Detection of Metastatic Breast and Thyroid Cancer in Lymph Nodes by Desorption Electrospray Ionization Mass Spectrometry Imaging

Ambient ionization mass spectrometry has been widely applied to image lipids and metabolites in primary cancer tissues with the purpose of detecting and understanding metabolic changes associated with cancer development and progression. Here, we report the use of desorption electrospray ionization mass spectrometry (DESI-MS) to image metastatic breast and thyroid cancer in human lymph node tissues. Our results show clear alterations in lipid and metabolite distributions detected in the mass spectra profiles from 42 samples of metastatic thyroid tumors, metastatic breast tumors, and normal lymph node tissues. 2D DESI-MS ion images of selected molecular species allowed discrimination and visualization of specific histologic features within tissue sections, including regions of metastatic cancer, adjacent normal lymph node, and fibrosis or adipose tissues, which strongly correlated with pathologic findings. In thyroid cancer metastasis, increased relative abundances of ceramides and glycerophosphoinisitols were observed. In breast cancer metastasis, increased relative abundances of various fatty acids and specific glycerophospholipids were seen. Trends in the alterations in fatty acyl chain composition of lipid species were also observed through detailed mass spectra evaluation and chemical identification of molecular species. The results obtained demonstrate DESI-MSI as a potential clinical tool for the detection of breast and thyroid cancer metastasis in lymph nodes, although further validation is needed. Graphical Abstract Desorption electrospray ionization mass spectrometry imaging is used to differentiate metastatic cancer from adjacent lymph node tissue.

Organ Protection During Thoracoabdominal Aortic Surgery: Rationale for a Multimodality Approach

Surgical repair of thoracoabdominal aortic aneurysms (TAAAs) remains a technically challenging operation that requires a systematic approach to prevent ischemic complications and achieve excellent clinical outcomes. Techniques for organ protection have evolved substantially over the past 20 years. This review describes our current multimodality approach to organ protection during TAAA repair.

Operative and Oncologic Outcomes in 9861 Patients with Operable Breast Cancer: Single-Institution Analysis of Breast Conservation with Oncoplastic Reconstruction

BACKGROUND

Oncoplastic reconstruction is an approach that enables patients with locally advanced or adversely located tumors to undergo breast conserving surgery (BCS). The objectives were to identify the use of BCS with oncoplastic reconstruction (BCS + R) and determine the operative and oncologic outcomes compared with other breast surgical procedures for breast cancer.

METHODS

This retrospective cohort study interrogated a single institution's prospectively maintained databases to identify patients who underwent surgery for breast cancer between 2007 and 2014. Surgeries were categorized as BCS, BCS + R, total mastectomy (TM), or TM with immediate reconstruction (TM + R). Demographic and clinicopathologic characteristics and postoperative complications were analyzed.

RESULTS

There were 10,607 operations performed for 9861 patients. Median follow-up was 3.4 years (range, 0-9.1 years). The use of BCS + R had a nearly fourfold increase in the percentage of all breast cancer surgeries during the study period; 75 % of patients who underwent BCS + R had a T1 or T2 tumor. There was no difference in the use of BCS + R compared with BCS for any quadrant of the breast except the lower outer quadrant (11.1 vs. 6.8 %; p < .0001). BCS + R had a lower rate of seroma formation (13.4 vs. 18 %; p = .002) and positive or close margins compared with BCS (5.8 vs. 8.3 %; p = .04). There was no difference in overall survival or recurrence-free survival when comparing BCS and BCS + R.

CONCLUSIONS

Patients undergoing BCS + R are not disadvantaged in terms of complications and short-term (3-year) outcomes compared with BCS patients or patients who underwent TM.

Four pediatric patients with autosomal recessive polycystic kidney disease developed new-onset diabetes after renal transplantation

NODAT is increasingly prevalent. Compared with adult recipients, NODAT is less prevalent in pediatric renal transplant recipients; however, some risk factors for its development in young patients have been defined. We report four pediatric renal transplant recipients with ARPKD who developed NODAT. We review the current pediatric NODAT literature and hypothesize that ARPKD may be an additional risk factor for NODAT.

Recurrence and pseudorecurrence after laparoscopic ventral hernia repair: predictors and patient-focused outcomes

Laparoscopic ventral hernia repair (LVHR) is gaining popularity as an option to repair abdominal wall hernias. Bulging after repair remains common after this technique. This study evaluates the incidence and factors associated with bulging after LVHR. Between 2000 and 2010, 201 patients underwent LVHR at two affiliated institutions. Patients who developed recurrence or pseudorecurrence (seroma or eventration) were analyzed with univariate and multivariate analyses to identify predictors of these complications. Of the 201 patients who underwent LVHR, 40 (19.9%) patients developed a seroma, 63 (31.3%) patients had radiographically proven eventration, and 25 (12.4%) patients had a hernia recurrence. On multivariate analysis, seromas were associated with number of prior ventral hernia repairs, surgical site infections, and prostate disease. Mesh eventration was associated with hernia size and surgical technique. Tissue eventration was associated with primary hernias and surgical technique. Hernia recurrence was associated with incisional hernias and mesh type used. Recurrence and pseudorecurrence are important complications after LVHR. Large hernia size, infections, and surgical technique are important clinical factors that affect outcomes after LVHR.

Recurrence and Pseudorecurrence after Laparoscopic Ventral Hernia Repair: Predictors and Patient-focused Outcomes

Laparoscopic ventral hernia repair (LVHR) is gaining popularity as an option to repair abdominal wall hernias. Bulging after repair remains common after this technique. This study evaluates the incidence and factors associated with bulging after LVHR. Between 2000 and 2010, 201 patients underwent LVHR at two affiliated institutions. Patients who developed recurrence or pseudorecurrence (seroma or eventration) were analyzed with univariate and multivariate analyses to identify predictors of these complications. Of the 201 patients who underwent LVHR, 40 (19.9%) patients developed a seroma, 63 (31.3%) patients had radiographically proven eventration, and 25 (12.4%) patients had a hernia recurrence. On multivariate analysis, seromas were associated with number of prior ventral hernia repairs, surgical site infections, and prostate disease. Mesh eventration was associated with hernia size and surgical technique. Tissue eventration was associated with primary hernias and surgical technique. Hernia recurrence was associated with incisional hernias and mesh type used. Recurrence and pseudorecurrence are important complications after LVHR. Large hernia size, infections, and surgical technique are important clinical factors that affect outcomes after LVHR.

Lipoprotein lipase is frequently overexpressed or translocated in cervical squamous cell carcinoma and promotes invasiveness through the non-catalytic C terminus

Background:

We studied the biological significance of genes involved in a novel t(8;12)(p21.3;p13.31) reciprocal translocation identified in cervical squamous cell carcinoma (SCC) cells.

Methods:

The rearranged genes were identified by breakpoint mapping, long-range PCR and sequencing. We investigated gene expression in vivo using reverse-transcription PCR and tissue microarrays, and studied the phenotypic consequences of forced gene overexpression.

Results:

The rearrangement involved lipoprotein lipase (LPL) and peroxisome biogenesis factor-5 (PEX5). Whereas LPL–PEX5 was expressed at low levels and contained a premature stop codon, PEX5–LPL was highly expressed and encoded a full-length chimeric protein (including the majority of the LPL coding region). Consistent with these findings, PEX5 was constitutively expressed in normal cervical squamous cells, whereas LPL expression was negligible. The LPL gene was rearranged in 1 out of 151 cervical SCCs, whereas wild-type LPL overexpression was common, being detected in 10 out of 28 tissue samples and 4 out of 10 cell lines. Forced overexpression of wild-type LPL and PEX5–LPL fusion transcripts resulted in increased invasiveness in cervical SCC cells, attributable to the C-terminal non-catalytic domain of LPL, which was retained in the fusion transcripts.

Conclusion:

This is the first demonstration of an expressed fusion gene in cervical SCC. Overexpressed wild-type or translocated LPL is a candidate for targeted therapy.

Severe aortic and arterial aneurysms associated with a TGFBR2 mutation

BACKGROUND

A 24-year-old man presented with previously diagnosed Marfan's syndrome. Since the age of 9 years, he had undergone eight cardiovascular procedures to treat rapidly progressive aneurysms, dissection and tortuous vascular disease involving the aortic root and arch, the thoracoabdominal aorta, and brachiocephalic, vertebral, internal thoracic and superior mesenteric arteries. Throughout this extensive series of cardiovascular surgical repairs, he recovered without stroke, paraplegia or renal impairment.

INVESTIGATIONS

CT scans, arteriogram, genetic mutation screening of transforming growth factor beta receptors 1 and 2.

DIAGNOSIS

Diffuse and rapidly progressing vascular disease in a patient who met the diagnostic criteria for Marfan's syndrome, but was later rediagnosed with Loeys-Dietz syndrome. Genetic testing also revealed a de novo mutation in transforming growth factor beta receptor 2.

MANAGEMENT

Regular cardiovascular surveillance for aneurysms and dissections, and aggressive surgical treatment of vascular disease.

Delayed Spinal Cord Deficits After Thoracoabdominal Aortic Aneurysm Repair

BACKGROUND

Limited information is available about the treatment and outcomes of delayed paraplegia after thoracoabdominal aortic aneurysm (TAAA) repair. The objective of this study was to assess factors that precipitate and favorably affect delayed-onset neurologic deficits.

METHODS

Over a 19-year period, 2,368 TAAA repairs were performed. Of the 93 patients (3.9%) who had postoperative paraplegia or paraparesis, 34 (37%) initially had intact neurologic function, but a delayed spinal cord deficit developed. We retrospectively examined clinical factors and events associated with development of the deficits, treatments used, and outcomes. Factors related to functional status were evaluated by comparing survivors who were ambulatory at discharge or transfer with those who were not.

RESULTS

The delayed deficits occurred between 13 hours and 91 days postoperatively and were associated with a period of hypotension in 9 patients (26%). Two patients (6%) died in hospital. Of the 32 patients discharged or transferred, 13 (41%) were ambulatory. Poor functional outcomes were associated with female sex, intraoperative cerebrospinal fluid drainage, fewer intercostal arteries reattached, and administration of corticosteroids or osmotic diuretics. The actuarial survival rate at 2 years was 80% +/- 13% for the ambulatory patients and 32% +/- 12% for the nonambulatory patients (p = 0.002).

CONCLUSIONS

Although precipitating episodes of hypoperfusion were common, most cases of delayed paraplegia occurred without such events, suggesting that other factors may play an important role in the development of this complication. Ambulatory status at discharge significantly predicts midterm survival.

Electrochemical and optical characterization of p- and n-doped poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene]

We study electrochemical p- and n-type doping in the well-known light-emitting polymer poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV). Doping reactions are characterized using cyclic voltammetry. Optical measurements including photoluminescence and UV/Vis/NIR transmission were performed on doped samples. We find that oxidation in MEH-PPV is a highly reversible reaction resulting in stable freestanding doped films, while the reduced form is unstable and the reaction irreversible. We discuss the dependence of doping reactions on scan rate, film thickness, salt type and concentration, and working electrode type. We observe the development of two additional broad absorption bands in both lightly and heavily doped films accompanied by a slight blueshift in the primary optical transition, suggesting bipolaron band formation. Finally we find that both p and n dopings result in extremely sensitive photoluminescence quenching. We propose a physical model for understanding electrochemical doping in MEH-PPV and the implications this has on the development of such technologies as polymer light-emitting electrochemical cells, electrochromic devices, actuators, and sensors.

Increased collagen deposition and elevated expression of connective tissue growth factor in human thoracic aortic dissection

BACKGROUND

Thoracic aortic dissection (TAD) is characterized by dysregulated extracellular matrix. Little is known about the alterations of collagen and stimulators of collagen synthesis, eg, connective tissue growth factor (CTGF), in patients with TAD. In this study, we examined their roles in TAD.

METHODS AND RESULTS

Surgical specimens of the aortic wall of TAD patients (n=10) and controls (n=10) were tested for collagen types I and III and CTGF expression. When compared with controls, protein levels of type I and III collagen and CTGF were significantly increased by 3.2-, 3.7-, and 5.3-fold, respectively (P<0.05 for all). Similar patterns were shown in mRNA levels of type Ialpha and Ialpha2 collagen and CTGF. Using immunohistochemistry and trichrome staining, we also observed elevated levels of collagen in the aortic media and adventitia. Treatment with recombinant human CTGF increased collagen synthesis in cultured aortic smooth muscle cells in a dose- and time-dependent fashion, in which expression of collagens increased from 506+/-108 counts per minute to 2764+/-240 cpm by 50 ng/mL CTGF, and from 30+/-43 cpm to 429+/-102 cpm at 48 hours.

CONCLUSIONS

TAD patients exhibited significantly increased expression of aortic collagen types I and III as well as CTGF, which is likely to be responsible for the compromised aortic distensibility and systemic compliance. Because CTGF can increase collagen expression, CTGF may be a new target molecule in the pathogenesis and progression of TAD.

The effect of broken conjugation on the excited state: Ether linkage in the cyano-substituted poly(p-phenylene vinylene) conjugated polymer poly(2,5,2′,5′-tetrahexyloxy-8,7′-dicyano-di-p-phenylene vinylene)

We investigate the effect of broken conjugation on the excited state dynamics of excimers in cyano-substituted phenylene-vinylene polymers. We compare previous studies on the well-characterized poly(2,5,2',5'-tetrahexyloxy-8,7'-dicyano-di-p-phenylene vinylene) (CN-PPV) with poly[oxa-1,4-phenylene-1,2-(1-cyano)-ethenylene-2,5-dioctyloxy-1,4-phenylene-1,2-(2-cyano)-ethenylene-1,4-phenylene] (CN-ether-PPV), in which the conjugation is disrupted by the insertion of an oxygen atom within the polymer backbone. Despite the broken conjugation, the spectroscopic behavior of the two materials is similar, indicating that the cyano group dominates the photophysics in these materials. The emission in CN-ether-PPV is due to a single-chain exciton in solution and due to an interchain excimer in thin film, as previously reported for CN-PPV; however, the excimer absorption and emission in thin film are blueshifted by approximately 0.2 eV relative to CN-PPV, implying that the excimer in CN-ether-PPV is less stable. Furthermore, substitution of an ether group along the chain results in decay times in both solution and film that are twice as long than in CN-PPV due to the broken conjugation which restricts the exciton within a conjugation segment and reduces its access to internal quenching sites. These properties result in a decay time of 14 ns for CN-ether-PPV film, one of the longest decay times observed in a conjugated polymer film. The long lifetime indicates a large exciton diffusion length, making these species particularly vulnerable to quenching by other materials. This work has implications for the design of conjugated polymers for efficient optoelectronic devices, such as photovoltaics.

Spectrum of Aortic Operations in 300 Patients With Confirmed or Suspected Marfan Syndrome

BACKGROUND

Cardiovascular disease is the main cause of morbidity and mortality in patients with Marfan syndrome. Many patients with presumed Marfan syndrome do not meet current diagnostic criteria. This study reviews the surgical aspects of aortic disease in 300 patients referred with the diagnosis of Marfan syndrome.

METHODS

During a 16-year period, 300 patients with presumed Marfan syndrome underwent 398 operations on the aorta and branch arteries, including 125 aortic root operations, 59 aortic arch repairs, 31 descending thoracic aortic repairs, and 178 thoracoabdominal aortic repairs. Based on medical record review, patients were classified as confirmed Marfan syndrome if documented features satisfied current diagnostic criteria; patients not meeting these criteria were classified as suspected Marfan syndrome.

RESULTS

There were 17 operative deaths (4.3%) after the 398 operations. Survival after the initial referral operation was 96.2% +/- 1.5% at 1 year, 82.7% +/- 2.4% at 5 years, and 74.6% +/- 3.1% at 10 years. Presentations, operative details, and outcomes were remarkably similar in the 137 patients (45.7%) with confirmed Marfan syndrome and the 163 patients (54.3%) with suspected Marfan syndrome. Freedom from repair failure, however, was significantly better in patients with confirmed Marfan syndrome (90.3% +/- 2.3% at 10 years) than in those with suspected Marfan syndrome (82.0% +/- 3.1% at 10 years; p = 0.001).

CONCLUSIONS

Operative treatment of the full spectrum of aortic disease in Marfan patients enables excellent long-term survival. Similarities in surgical aspects of aortic disease suggest that patients with features of Marfan syndrome who do not meet diagnostic criteria should be managed in the same manner as patients with confirmed Marfan syndrome.

A single nucleotide polymorphism in the matrix metalloproteinase 9 gene (-8202A/G) is associated with thoracic aortic aneurysms and thoracic aortic dissection

OBJECTIVE

Matrix metalloproteinase 9 plays an important role in the maintenance of the aortic extracellular matrix. Genetic variations that affect protease expression or activity might contribute to thoracic aortic disease. The purpose of this study was to determine whether 3 single nucleotide polymorphisms in the matrix metalloproteinase 9 gene are associated with thoracic aortic aneurysms and dissection.

METHODS

Genomic DNA was isolated from blood or aortic tissue from 28 patients with degenerative thoracic aortic aneurysms, 60 patients with thoracic aortic dissection, and 111 control patients. The frequency distributions of 3 matrix metalloproteinase 9 single nucleotide polymorphisms (-8202A/G, IVS4+3G/T, and 2003A/G [Q668R]) were determined by using genotyping accomplished with a real-time detection system. Associations between polymorphisms and disease were estimated with odds ratios and their 95% confidence intervals.

RESULTS

The frequency of the -8202G allele was significantly higher in patients with thoracic aortic aneurysms and aortic dissection (0.52 and 0.56, respectively) than in control subjects (0.36, P < .001). Patients with thoracic aortic aneurysms or dissection were nearly 5 times more likely than control subjects to have the G allele (adjusted odds ratio, 4.87; 95% confidence interval, 2.04-11.64). There were no significant associations between the IVS4+3G/T or 2003A/G polymorphisms and thoracic aortic disease.

CONCLUSIONS

The matrix metalloproteinase 9 -8202A/G polymorphism is associated with thoracic aortic aneurysms and dissection. Further studies are warranted to elucidate the functional role of the -8202A/G variant in matrix metalloproteinase 9 expression.

The Elephant Trunk Technique for Staged Repair of Complex Aneurysms of the Entire Thoracic Aorta

BACKGROUND

Extensive thoracic aortic aneurysms that involve the ascending, arch, and descending segments require challenging repairs associated with substantial morbidity and mortality. The purpose of this report is to evaluate contemporary outcomes after surgical repair of extensive thoracic aortic aneurysms using a two-stage approach with the elephant trunk technique.

METHODS

During a 15 1/2-year period, 148 consecutive patients underwent total aortic arch replacement using the elephant trunk technique. Seventy-six of these patients (51%, 76/148) returned for second-stage repair of the descending thoracic or thoracoabdominal aorta 4.9 +/- 7.5 months after the first stage.

RESULTS

Operative mortality after the proximal aortic stage was 12% (18/148). Seven patients (5%) had strokes. Among the patients who subsequently underwent distal aortic repair, operative mortality was 4% (3/76). Two patients (3%) developed paraplegia. Long-term survival after completing the second stage of repair was 70 +/- 6% at 5 years and 59 +/- 7% at 8 years.

CONCLUSIONS

Contemporary management of extensive thoracic aortic aneurysms using the two-stage elephant trunk technique yields acceptable short-term and long-term outcomes. This technique remains an important component of the surgical armamentarium.

The relationship of the transcutaneous oxygen tension, pulse waves and systolic pressures to the risk for limb amputation in patients with peripheral arterial disease and skin ulcers or gangrene

AIM

Our aim was to determine how the risk associated with presence of low transcutaneous oxygen tension (tcPO2) for subsequent major amputation in patients with skin ulcers or gangrene and peripheral arterial disease, compares with the risks associated with low peripheral pressures and low amplitude of pulse waves. Secondly, we determined whether combination of measurements of oxygen tension with that of the pressures or pulse wave amplitude predicts amputation better than pressure, wave or oxygen tension measurements alone.

METHODS

Measurements were carried out to obtain foot tcPO2, ankle and toe pressures, pressure indices, and toe pulse wave amplitude in 75 limbs with skin lesions and arterial disease of 66 patients referred to the vascular laboratory. These variables were related to the risk of a subsequent major amputation during a median time of 4.2 years, using Cox proportional hazards model.

RESULTS

Low oxygen tension was associated with increased risk of amputation (relative risks 2.16 and 2.55 for tcPO2 < or = 10 mmHg and < or = 20 mmHg, respectively, P<0.05; relative risk 2.22 for tcPO2 < or = 30 mmHg, P=0.07). The relative risks associated with cutoff values of ankle and toe pressures and pressure indices varied from 2.53 (toe < or = 20 mmHg, P<0.05) to 5.83 (ankle < or = 50 mmHg, P<0.001) and the relative risk associated with low wave amplitude (< or = 4 mm) was 3.41, P<0.01. The cutoff values of tcPO2 became insignificant when included in the models together with each pressure variable or pulse amplitude separately. In contrast, wave amplitude remained significantly associated with increased risk of amputation after controlling for each pressure variable (P<0.05).

CONCLUSIONS

TcPO2 < or = 10 mmHg and < or = 20 mmHg are related significantly to increased risk of amputation in patients with skin lesions and arterial disease, but these relative risks are similar in magnitude or smaller than those associated with low cutoff values of pressures, pressure indices or pulse wave amplitude. Low wave amplitude does provide significant information in addition to peripheral pressures with respect to the risk of amputation. On the other hand, low tcPO2 does not provide significant information in addition to peripheral pressures or pulse wave amplitude.

The Reversed Elephant Trunk Technique Used for Treatment of Complex Aneurysms of the Entire Thoracic Aorta

OBJECTIVE

A preferred technique for the staged treatment of patients with aneurysms involving the entire thoracic aorta is the elephant trunk technique, with replacement of the proximal (ascending and transverse aortic arch) aorta as the initial procedure. Some patients, however, need to have the distal aortic segments (descending and thoracoabdominal aorta) addressed during the first operation. We evaluated outcomes in a series of patients who underwent distal aortic replacement first using the reversed elephant trunk technique.

METHODS

Thirty-eight patients underwent first-stage graft repair of the descending thoracic (n = 3) or thoracoabdominal (n = 35) aorta using the reversed elephant trunk technique. Twelve patients (32%) ultimately underwent second-stage aortic arch replacement after a mean interval of 3.9 months (range, 1.6-14 months).

RESULTS

The operative mortality for the initial procedure was 16% (6/38 patients). One patient had a stroke (3%) and 1 patient developed paraparesis (3%). In the interval between the 2 procedures, there were 4 late deaths (4/32; 13%), 1 due to respiratory failure and 3 due to unknown causes. After the 12 completion procedures, there was 1 in-hospital death (8%) and there were no strokes. Five-year survival for the overall group was 51.3 +/- 10.8%.

CONCLUSIONS

Surgical treatment of aneurysms involving the entire thoracic aorta remains challenging and is associated with substantial morbidity and mortality. The reversed elephant trunk technique facilitates staged repair in patients who require distal aortic replacement during the first operation.

Decreased expression of fibulin-5 correlates with reduced elastin in thoracic aortic dissection

BACKGROUND

Thoracic aortic aneurysmal diseases are characterized by degeneration of elastin within the aortic wall. Although proteinases, such as matrix metalloproteinase, appear to contribute to elastin degradation, little is known about the role of elastic fiber assembly in such diseases. Fibulin-5 is an extracellular protein that is expressed in the vascular basement membrane and regulates elastic fiber assembly by microfibril machinery. In this study, we examined whether thoracic aortic dissection (TAD) is associated with abnormal fibulin-5 expression.

METHODS

Intraoperative aortic samples were obtained from 21 patients with proximal aortic dissection. Control aortic tissue was obtained from 11 organ donors, heart transplant recipients, and patients undergoing coronary artery bypass. An in vitro culture of vascular smooth muscle cells was obtained from 2 TAD patients and 1 control subject. To evaluate elastin expression, we stained tissue sections with Verhoeff-Van Gieson stain. Fibulin-5 messenger RNA (mRNA) expression was determined by quantitative real-time reverse-transcriptase-polymerase chain reaction.

RESULTS

Aortic fibulin-5 mRNA and elastin content were decreased in TAD patients, compared with controls (P=.001 and P=.02, respectively). Decreased fibulin-5 expression strongly correlated with decreased amounts and fragmentation of elastin in aortic samples from patients with TAD (r=0.83, P < .0001 and F=20.7, P < .0001 respectively). The fibulin-5 mRNA in aortic vascular smooth muscle cells collected from TAD demonstrated a 38% decrease in expression, compared with the control.

CONCLUSIONS

Patients with proximal aortic dissection exhibited significantly decreased expression of aortic fibulin-5. Decreased fibulin-5 may contribute to the pathogenesis of aortic dissection by impairing elastic fiber assembly.

The Threat of Adhesive Embolization: BioGlue Leaks Through Needle Holes in Aortic Tissue and Prosthetic Grafts

BACKGROUND

BioGlue Surgical Adhesive (CryoLife, Inc, Kennesaw, GA) is used to reinforce anastomoses during cardiovascular operations. Previous reports have raised concerns that adhesives may leak through suture-line needle holes and that resulting intraluminal glue may embolize. The purpose of this study was to determine if BioGlue leaks through anastomotic needle holes in aortic tissue and two common prosthetic graft materials.

METHODS

Polypropylene suture was used to create end-to-end anastomoses in gelatin-sealed woven polyester grafts (n = 45), expanded polytetrafluoroethylene (ePTFE) grafts (n = 45), and fresh porcine aortas (n = 45). An additional 45 anastomoses were created in ePTFE grafts using ePTFE sutures. The outer surface of each anastomosis was covered with BioGlue. Anastomoses underwent inspection with direct magnification or histology.

RESULTS

BioGlue leaked through needle holes and into the lumen in 10% of anastomoses (18 of 180). Leaks were significantly more common in fresh aorta (10 of 45, 22%) than in prosthetic grafts (8 of 135, 6%; p = 0.003). Suture size did not significantly affect the incidence of leak. The use of ePTFE sutures did not eliminate BioGlue leakage. Prosthetic graft leaks created discreet round adhesive particles. In contrast, aortic tissue leaks resulted in thin, friable flakes of glue extending along the intimal surface. Aortic histology confirmed that BioGlue reached the vessel lumen via the suture channels.

CONCLUSIONS

BioGlue leaked through the needle holes in fresh aortic tissue and prosthetic grafts. Intraluminal adhesive particles were easily dislodged, supporting concerns regarding embolization. The potential for adhesive embolization should be a factor when considering the relative risks and benefits of using BioGlue.

The threat of adhesive embolization: BioGlue leaks through needle holes in aortic tissue and prosthetic grafts

BACKGROUND

BioGlue Surgical Adhesive (CryoLife, Inc, Kennesaw, GA) is used to reinforce anastomoses during cardiovascular operations. Previous reports have raised concerns that adhesives may leak through suture-line needle holes and that resulting intraluminal glue may embolize. The purpose of this study was to determine if BioGlue leaks through anastomotic needle holes in aortic tissue and two common prosthetic graft materials.

METHODS

Polypropylene suture was used to create end-to-end anastomoses in gelatin-sealed woven polyester grafts (n = 45), expanded polytetrafluoroethylene (ePTFE) grafts (n = 45), and fresh porcine aortas (n = 45). An additional 45 anastomoses were created in ePTFE grafts using ePTFE sutures. The outer surface of each anastomosis was covered with BioGlue. Anastomoses underwent inspection with direct magnification or histology.

RESULTS

BioGlue leaked through needle holes and into the lumen in 10% of anastomoses (18 of 180). Leaks were significantly more common in fresh aorta (10 of 45, 22%) than in prosthetic grafts (8 of 135, 6%; p = 0.003). Suture size did not significantly affect the incidence of leak. The use of ePTFE sutures did not eliminate BioGlue leakage. Prosthetic graft leaks created discreet round adhesive particles. In contrast, aortic tissue leaks resulted in thin, friable flakes of glue extending along the intimal surface. Aortic histology confirmed that BioGlue reached the vessel lumen via the suture channels.

CONCLUSIONS

BioGlue leaked through the needle holes in fresh aortic tissue and prosthetic grafts. Intraluminal adhesive particles were easily dislodged, supporting concerns regarding embolization. The potential for adhesive embolization should be a factor when considering the relative risks and benefits of using BioGlue.

Matrix metalloproteinases in ascending aortic aneurysms: bicuspid versus trileaflet aortic valves

BACKGROUND

Abnormal matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) expression contributes to the development of abdominal aortic aneurysms. Recent data suggest that MMP-2 and MMP-9 may also play a role in thoracic aortic disease. We sought to determine (1) whether ascending aortic aneurysms are associated with increased MMP expression and (2) whether aortic inflammation and MMP expression differ between patients with congenital bicuspid aortic valves (BAVs) and those with trileaflet aortic valves (TAVs).

MATERIALS AND METHODS

Samples of ascending aortic aneurysms were obtained from 29 patients; 14 patients had BAVs and 15 had TAVs. Control ascending aorta was obtained from 14 organ donors or heart transplant recipients. Aortic histology and immunohistochemistry were performed to evaluate elastin degradation, inflammatory changes, and MMP-2 and MMP-9 expression. Aortic levels of MMP-2, MMP-9, TIMP-1, and TIMP-2 were measured using ELISA.

RESULTS

Aneurysms in the TAV patients exhibited marked inflammation, high CD68 expression, diminished elastin content, increased MMP-9 expression, and normal MMP-2 levels. In contrast, BAV aneurysms were characterized by a relative lack of inflammation, preservation of elastin content, normal MMP-9 levels, and elevated MMP-2 expression. TIMP-1 and TIMP-2 levels were not significantly different among the three groups.

CONCLUSIONS

Ascending aortic aneurysms exhibited increased MMP expression. The pattern of MMP expression and the degree of inflammation, however, differed between aneurysms associated with BAVs and those with TAVs. Variations in the molecular mechanisms underlying different types of thoracic aortic aneurysms warrant further investigation.

Infections of the subcutis and skin of dogs caused by rapidly growing mycobacteria

Nine dogs with panniculitis due to rapidly growing mycobacteria (RGM) were examined over 17 years. Dogs were two to 15 years; five were male, four were female. All were obese or in good condition. Antecedent injury, typically a dog bite or vehicular trauma, could be identified in some patients, while one bitch had hyperadrenocorticism. Infections involved different locations, although the cervicothoracic region, dorsum or flank were most often affected. Patients were systemically well, apart from one dog with pyrexia and two with pain or lameness. Cytology demonstrated pyogranulomatous inflammation, but in only one case was it possible to see acid-fast bacilli (AFB) in smears. Histology demonstrated chronic active pyogranulomatous panniculitis and dermatitis; AFB could be detected in only four specimens. Culture of aspirates or resected tissues demonstrated RGM in all cases, comprising six Mycobacterium smegmatis group and three Mycobacterium fortuitum group isolates. Resection of infected tissues, perioperative injectable antimicrobials and long courses of oral antimicrobials chosen according to susceptibility data generally effected a cure, although some cases recurred.

Deployment of balloon expandable stents during open repair of thoracoabdominal aortic aneurysms: a new strategy for managing renal and mesenteric artery lesions*1

OBJECTIVE

Patients undergoing graft repair of thoracoabdominal aortic aneurysms (TAAAs) often require concomitant correction of ostial stenoses or dissection involving visceral branches. The purpose of this report is to describe our initial experience with a new strategy for addressing these lesions during open TAAA repair-direct deployment of balloon expandable stents into the renal and mesenteric arteries.

METHODS

Over a two-year period, 367 patients have undergone TAAA surgery. Balloon expandable stents were used to manage visceral branch lesions during open TAAA repair in 93 (25.3%) of these patients. Fifteen patients (16%) had preoperative renal insufficiency. After opening the aneurysm and exposing the branch artery ostia, premounted balloon expandable stents were deployed in the affected vessels under direct vision. Stents were deployed after an endarterectomy in 40 patients (43%). Eighty patients (86%) had stents placed in one or both renal arteries and 36 (39%) had stents placed in the celiac axis and/or superior mesenteric artery. Postoperative renal function was monitored with daily serum creatinine levels.

RESULTS

There were nine early operative deaths (10%). Two patients (2%) had bleeding complications related to stenting, one of which died after developing multiple organ failure. Twelve patients (13%) developed renal failure, eight of which required dialysis.

CONCLUSIONS

This study demonstrates the feasibility of treating ostial lesions of the visceral branches with balloon expandable stents during open TAAA repair. Despite a high prevalence of preoperative renal insufficiency, the incidence of postoperative renal failure was acceptable. This new strategy may be a valuable adjunct to TAAA repair and warrants further investigation.

The value of toe pulse waves in determination of risks for limb amputation and death in patients with peripheral arterial disease and skin ulcers or gangrene

OBJECTIVES

The purpose of this study was to determine whether the presence of low amplitude of pulse waves recorded from the toes is related to the risk of subsequent amputation and death in patients with skin ulcers or gangrene and peripheral arterial disease, and how the risk of low wave amplitude relates to the risk associated with low peripheral pressures.

METHODS

A total of 309 patients with 346 limbs with skin lesions and arterial disease referred to the vascular laboratory were followed up for an average of 5 years (range, 1-8 years). Measurements were carried out to obtain ankle and toe pressures, pressure indices, and toe pulse wave amplitude. These variables were related to the risks of major amputation and total and cardiovascular death by means of the Cox proportional hazards model.

RESULTS

Low toe pulse wave amplitude (< or = 4 mm) was associated with increased risk of amputation (relative risks 4.20 in all limbs and 2.63 in those with toe pressure < or = 30 mm Hg; P <.01). Wave amplitude remained significantly associated with increased risk of amputation after controlling for each pressure variable (P <.01). Low pulse wave amplitude and toe/brachial index were associated with increased risks of both total and cardiovascular death in all patients (relative risks ranged from 1.43-1.73; P <.05) and in those with toe pressure of 30 mm Hg or less (relative risks 1.56-1.90; P <.05).

CONCLUSIONS

Low toe pulse wave amplitude is related significantly to increased risks of amputation and death in patients with skin lesions and arterial disease. The presence of low wave amplitude provides significant information in addition to peripheral pressures with respect to the risk of amputation.

Vascular invasion routes and systemic accumulation patterns of tobacco mosaic virus in Nicotiana benthamiana

Plant viruses must enter the host vascular system in order to invade the young growing parts of the plant rapidly. Functional entry sites into the leaf vascular system for rapid systemic infection have not been determined for any plant/virus system. Tobacco mosaic virus (TMV) entry into minor, major and transport veins from non-vascular cells of Nicotiana benthamiana in source tissue and its exit from veins in sink tissue was studied using a modified virus expressing green fluorescent protein (GFP). Using a surgical procedure that isolated specific leaf and stem tissues from complicating vascular tissues, we determined that TMV could enter minor, major or transport veins directly from non-vascular cells to produce a systemic infection. TMV first accumulated in abaxial or external phloem-associated cells in major veins and petioles of the inoculated leaf and stems below the inoculated leaf. It also initially accumulated exclusively in internal or adaxial phloem-associated cells in stems above the inoculated leaf and petioles or major veins of sink leaves. This work shows the functional equivalence of vein classes in source leaves for entry of TMV, and the lack of equivalence of vein classes in sink leaves for exit of TMV. Thus, the specialization of major veins for transport rather than loading of photoassimilates in source tissue does not preclude virus entry. During transport, the virus initially accumulates in specific vascular-associated cells, indicating that virus accumulation in this tissue is highly regulated. These findings have important implications for studies on the identification of symplasmic domains and host macromolecule vascular transport.

Mice overexpressing human uncoupling protein-3 in skeletal muscle are hyperphagic and lean

Uncoupling protein-3 (UCP-3) is a recently identified member of the mitochondrial transporter superfamily that is expressed predominantly in skeletal muscle. However, its close relative UCP-1 is expressed exclusively in brown adipose tissue, a tissue whose main function is fat combustion and thermogenesis. Studies on the expression of UCP-3 in animals and humans in different physiological situations support a role for UCP-3 in energy balance and lipid metabolism. However, direct evidence for these roles is lacking. Here we describe the creation of transgenic mice that overexpress human UCP-3 in skeletal muscle. These mice are hyperphagic but weigh less than their wild-type littermates. Magnetic resonance imaging shows a striking reduction in adipose tissue mass. The mice also exhibit lower fasting plasma glucose and insulin levels and an increased glucose clearance rate. This provides evidence that skeletal muscle UCP-3 has the potential to influence metabolic rate and glucose homeostasis in the whole animal.

Skin perfusion pressure of the foot is a good substitute for toe pressure in the assessment of limb ischemia

PURPOSE

Noninvasive measurements of limb systolic pressures are used routinely in the assessment of the severity of peripheral arterial disease, including the evaluation for critical limb ischemia. However, ankle pressures cannot be measured reliably in patients with medial calcification, which is especially common among patients with diabetes. Skin lesions on the toes or previous digital amputations may preclude the measurement of toe pressures. Measurements of skin perfusion pressure (SPP) are not subject to such limitations and were shown to be useful in the assessment of the severity of peripheral arterial disease. Because toe pressure is often used in the evaluation of severity of arterial disease and in the assessment for critical ischemia, we undertook to study whether there is a sufficient correlation between toe pressure and foot SPP that would allow the use of SPP measurements when toe pressures cannot be measured.

METHODS

Measurements were carried out in 85 limbs of 71 patients referred to the vascular laboratory for evaluation for peripheral arterial disease. Diabetes mellitus was present in 43 patients. Each patient had foot SPP and toe pressure measurements. Toe pressures measured with photoplethysmography were correlated with foot SPP measured with laser Doppler scanning.

RESULTS

There was a strong linear correlation between SPP and toe pressure (r = 0.87; P <.01). Also, significant correlation was found in both the patients with diabetes and the patients without diabetes (r = 0.85 and 0.93, respectively; P <.01 in both cases).

CONCLUSIONS

We concluded that SPP measured in the foot correlates well with toe pressure and can be substituted for toe pressure measurement in patients in whom toe pressures cannot be measured.

Monitoring the assembly of Ig light-chain amyloid fibrils by atomic force microscopy

Aggregation of Ig light chains to form amyloid fibrils is a characteristic feature of light-chain amyloidosis, a light-chain deposition disease. A recombinant variable domain of the light chain SMA was used to form amyloid fibrils in vitro. Fibril formation was monitored by atomic force microscopy imaging. Single filaments 2.4 nm in diameter were predominant at early times; protofibrils 4.0 nm in diameter were predominant at intermediate times; type I and type II fibrils 8.0 nm and 6.0 nm in diameter, respectively, were predominant at the endpoints. The increase in number of fibrils correlated with increased binding of the fluorescent dye thioflavin T. The fibrils and protofibrils showed a braided structure, suggesting that their formation involves the winding of protofibrils and filaments, respectively. These observations support a model in which two filaments combine to form a protofibril, two protofibrils intertwine to form a type I fibril, and three filaments form a type II fibril.

ATP2A2 mutations in Darier's disease: variant cutaneous phenotypes are associated with missense mutations, but neuropsychiatric features are independent of mutation class

Darier's disease (DD) is an autosomal dominant skin disorder characterized clinically by multiple keratotic papules, and histologically by focal loss of adhesion between epidermal cells (acantholysis) and by abnormal keratinization. Variant forms of cutaneous phenotype, sometimes familial, have been described. Associated neuropsychiatric features, including mental handicap, schizophrenia, bipolar disorder and epilepsy, have also been reported. The cause of DD was shown recently to be mutation in the ATP2A2 gene at 12q24.1, which encodes the sarco-endoplasmic reticulum calcium ATPase type 2 (SERCA2). Here, we show that while both common isoforms of SERCA2 are expressed in the cytoplasm of cultured keratinocytes and fibroblasts, in adult skin sections only the longer isoform, SERCA2b, was expressed abundantly in epidermal structures. Extended mutation analysis in European DD patients using single-strand conformation polymorphism and/or direct sequencing identified 40 different patient-specific mutations in 47 families. The majority (23/40) were likely to result in nonsense-mediated RNA decay. The remaining 17 were missense mutations distributed throughout the protein and were associated significantly with atypical clinical features. The clearest association was with the familial haemorrhagic variant where all four families tested had a missense mutation. Three of the families (one Scottish family and two unrelated Italian families) exhibited the same N767S substitution in the M5 transmembrane domain, and a fourth family, from Sweden, had a C268F substitution in the M3 transmembrane domain. Neuropsychiatric features did not appear to be associated with a specific class of mutation and may be an intrinsic, but inconsistent, effect of defective ATP2A2 expression.

The challenge and importance of defining critical limb ischemia

Patients with critical limb ischemia are at risk of limb loss and have very high cardiovascular and total mortality rates, which are greater than can be accounted for by the usual risk factors for atherosclerosis. A definition of critical ischemia is necessary to determine the natural history of the disease and to assess and compare the efficacy of various forms of therapy. The definition needs to be based on hemodynamic criteria because clinical manifestations and outcomes are not reliable. The reasons for the difficulties in arriving at a generally acceptable definition are explored. Building on the previous work of others, modified hemodynamic definitions for critical and subcritical ischemia, which include measurements of pressures and of indices of microcirculation, are proposed.

Refined genetic mapping of the darier locus to a <1-cM region of chromosome 12q24.1, and construction of a complete, high-resolution P1 artificial chromosome/bacterial artificial chromosome contig of the critical region

Darier disease (DD) (MIM 124200) is an autosomal dominant skin disorder characterized by loss of adhesion between epidermal cells and by abnormal keratinization. We present linkage analysis showing, in four families, key recombination events that refine the location of the DD locus on chromosome 12q23-24.1 to a region of <1 cM. We have constructed a YAC/P1 artificial chromosome (PAC)/bacterial artificial chromosome (BAC)-based physical map that encompasses this refined DD region. The map consists of 35 YAC, 69 PAC, 16 BAC, and 2 cosmid clones that were ordered by mapping 54 anonymous sequence-tagged sites. The critical region is estimated to be 2.4 Mb in size, with an average marker resolution of 37.5 kb. The refinement of the critical interval excludes the ALDH2, RPL6, PTPN11, and OAS genes, as well as seven expressed sequence tags (ESTs) previously mapped in the DD region. The three known genes (ATP2A2, PPP1CC, and SCA2) and the 10 ESTs mapped within the critical region are not obvious candidates for the DD gene. Therefore, this detailed integrated physical, genetic, and partial transcript map provides an important resource for the isolation of the DD gene and, possibly, other disease genes.

Invasion of minor veins of tobacco leaves inoculated with tobacco mosaic virus mutants defective in phloem-dependent movement

To fully understand vascular transport of plant viruses, the viral and host proteins, their structures and functions, and the specific vascular cells in which these factors function must be determined. We report here on the ability of various cDNA-derived coat protein (CP) mutants of tobacco mosaic virus (TMV) to invade vascular cells in minor veins of Nicotiana tabacum L. cv. Xanthi nn. The mutant viruses we studied, TMV CP-O, U1mCP15-17, and SNC015, respectively, encode a CP from a different tobamovirus (i.e., from odontoglossum ringspot virus) resulting in the formation of non-native capsids, a mutant CP that accumulates in aggregates but does not encapsidate the viral RNA, or no CP. TMV CP-O is impaired in phloem-dependent movement, whereas U1mCP15-17 and SNC015 do not accumulate by phloem-dependent movement. In developmentally-defined studies using immunocytochemical analyses we determined that all of these mutants invaded vascular parenchyma cells within minor veins in inoculated leaves. In addition, we determined that the CPs of TMV CP-O and U1mCP15-17 were present in companion (C) cells of minor veins in inoculated leaves, although more rarely than CP of wild-type virus. These results indicate that the movement of TMV into minor veins does not require the CP, and an encapsidation-competent CP is not required for, but may increase the efficiency of, movement into the conducting complex of the phloem (i.e., the C cell/sieve element complex). Also, a host factor(s) functions at or beyond the C cell/sieve element interface with other cells to allow efficient phloem-dependent accumulation of TMV CP-O.

The 126- and 183-kilodalton proteins of tobacco mosaic virus, and not their common nucleotide sequence, control mosaic symptom formation in tobacco

Nucleotide substitutions at two positions within the open reading frame encoding the 126-kDa protein in the attenuated masked (M) strain of tobacco mosaic tobamovirus (TMV) to those found in the virulent U1-TMV genome led to the induction of near U1-TMV-like symptoms on leaves of Nicotiana tabacum L. cv. Xanthi nn by progeny virus (M. H. Shintaku, S. A. Carter, Y. Bao, and R. S. Nelson, Virology 221:218-225, 1996). In this study, further site-directed mutations were made at these positions within the M strain cDNA to determine whether the protein or nucleotide sequence directly controlled the symptom phenotype. The protein and not the nucleotide sequence directly controlled the symptom phenotype when amino acid 360 within the 126-kDa protein sequence was altered and likely controlled the symptom phenotype when amino acid 601 was altered. The effects of the substitutions at amino acid position 360 on viral protein accumulation were studied by pulse-labeling proteins in infected protoplasts. Accumulation of the 126- and 183-kDa proteins was less for an attenuated mutant than for two virulent mutants, but the viral movement protein and coat protein accumulated to levels reported to be sufficient for normal systemic symptom development. The size of necrotic local lesions on N. tabacum L. cv. Xanthi NN was negatively correlated with symptom development and accumulation of the 126-kDa protein for these mutants. With reference to this last finding, an explanation of the cause of the differing symptoms induced by these viruses is presented.

Value of toe pulse waves in addition to systolic pressures in the assessment of the severity of peripheral arterial disease and critical limb ischemia

PURPOSE

Although pressure measurements are useful in the assessment of the severity of the arterial obstruction, they do not completely identify limbs with and without critical limb ischemia. Our objective was to test whether addition of the measurements of toe pulse waves (PW), which depend on distal perfusion, to pressure measurements could improve the determination of the severity of arterial disease and the presence of critical limb ischemia.

METHODS

We measured toe pressure (TSP) and ankle/brachial index (ABI) and recorded PW with photoplethysmography in 358 limbs of 182 patients.

RESULTS

TSP, ABI, and PW amplitude were lower in 67 limbs with rest pain, skin lesions, or both, with mean differences of 29 mm Hg, 0.12, and 16 mm, respectively (p < 0.01). Similarly, in the subgroup of 107 limbs with TSP < or = 30 mm Hg, TSP, and PW amplitude, but not ABI, were lower in 53 limbs with rest pain, skin lesions, or both, with mean differences of 10 mm Hg and 7 mm (p < 0.01). Multiple logistic regression showed that after controlling was done for TSP and ABI, the odds ratio for the presence of rest pain, skin lesions, or both associated with PW amplitude < or = 4 mm was 4.3 (95% confidence interval 1.7, 11.0; p < 0.01). In the subgroup with TSP < or = 30 mm Hg, this odds ratio was 3.5 (95% confidence interval 1.0, 11.6; p < 0.05).

CONCLUSIONS

The findings indicate that addition of PW recording to pressure measurements is likely to increase the accuracy of assessment for critical limb ischemia.

Mapping nucleotides in the 126-kDa protein gene that control the differential symptoms induced by two strains of tobacco mosaic virus

The differential symptom determinants of the Holmes' masked (M) and U1 strains of tobacco mosaic virus previously were mapped to the 5'-coterminal open reading frame (ORF) encoding the 126-kDa protein and the N-terminal two-thirds of the 183-kDa protein. Both proteins influence viral RNA accumulation, but the function of, and impact on, symptom formation by large domains within the 126-kDa gene, which are not conserved with sequences in analogous ORFs from other related viruses, are unknown. In the current study, cDNA clones representing each strain (i.e., MIC-TMV and U1-TMV) were mutated in these nonconserved domains to further define the nucleotides responsible for mosaic symptom induction on Nicotiana tabacum. Progeny virus of a mutant containing only eight nucleotide substitutions from the MIC-TMV sequence to the U1-TMV sequence within the 126-kDa protein ORF of MIC-TMV induced U1-TMV-like symptoms. Single or multiple substitutions among these eight nucleotides further defined residues critical for symptom modulation. Complementary substitutions in the MIC-TMV and U1-TMV sequences did not always yield progeny virus that induced complementary visual symptoms. Progeny of some mutants contained second-site spontaneous mutations at specific positions shown to influence symptom phenotype. For a subset of the stable site-directed mutants, there was no correlation between severity of systemic symptoms and chlorotic lesion size or virus accumulation in these chlorotic lesions on inoculated leaves.

Effects of ambulation on foot oxygen tension in limbs with peripheral atherosclerosis

As walking a few steps increases the arteriovenous pressure difference for blood flow through the feet, we studied the effect of a brief period of walking on transcutaneous oxygen tension (tcPO2). Foot tcPO2 was measured using Clarke type electrodes before, during and after a brief period of repetitive walking on the treadmill in 15 patients with various degrees of arterial obstruction. TcPO2 was significantly higher during walking, than while standing on the treadmill, in limbs with severe disease manifested by toe systolic pressure <30 mmHg (mean change 0.7 kPa or 5 mmHg, P=0.001). Also, supine tcPO2 was significantly higher following periods of walking than before in limbs with toe pressure both below and above 30 mmHg (mean change 1.5 kPa or 11 mmHg, P<0.001). The results indicate that a brief period of walking increases skin oxygenation. Regimens of such exercise may promote healing in some limbs with arterial disease.