Retail Display Lighting and Packaging Type May Influence Beef Flavor and Oxidative Stability

ObjectivesThis study aimed to evaluate the impact of retail display lighting and packaging type on beef flavor and lipid oxidation in five muscles.Materials and MethodsSubprimals (n = 40 strip loins, 60 shoulder clods, 60 tenderloins, 24 inside rounds, 60 top butts) were randomly collected from separate carcasses. At 7d postmortem muscles (Longissimus lumborum, LL; Triceps brachii, TB; Psoas major, PM; Semimembranosus, SM; Gluteus medius, GM) were fabricated and sliced to 2.54cm steaks. Per muscle, 120 steaks were randomly assigned to packaging treatments: vacuum rollstock (ROLL); high-oxygen (80% O2/20% CO2; HIOX); overwrapped in a motherbag with carbon monoxide (0.4%CO/30%CO2/69.6%N2; CO); and traditional overwrap (OW), which was vacuum packaged until immediately prior to display. Packages were stored in the dark at 2°C an additional 13 d prior to retail display, then were displayed under fluorescent lights (FL) or light-emitting diodes (LED) with a third treatment in dark storage (DARK). All were held in their respective light treatments at 2°C for 72h, then assigned for trained panels or chemical analysis, vacuum packaged and frozen at –20°C. For sensory analysis steaks were thawed to 4°C and cooked to 71°C. Panelists (n = 8) were trained to evaluate twelve flavors, overall juiciness and tenderness, which were scored on a 100-point scale (0 = not present; 100 = extremely present). Lipid oxidation of raw steaks was quantified as 2-thiobarbituric acid reactive substances (TBARS; mg malondialdehyde (MDA)/kg beef).ResultsNo three-way interaction (P ≥ 0.10) or lighting effect (P ≥ 0.09) was observed for trained panels or TBARS. Cardboard flavor had a muscle×lighting interaction (P = 0.02). In GM, FL had greater (p < 0.05) cardboard than other lighting; in other muscle types lighting was similar. Muscle×packaging influenced three attributes (P ≤ 0.02). Steaks in ROLL were sweeter (p < 0.05) than other packaging in GM, PM and TB; ROLL was juicier (p < 0.05) than other packaging in GM, PM, and SM. Across all packaging types tenderness was greatest for PM, while SM was least tender (p < 0.05) in CO, HIOX and OW packaging. Packaging influenced nine flavors (P ≤ 0.01); ROLL was greatest in beef ID, bloody/serumy, fat-like, umami, and salty, while HIOX scored greatest for oxidized, bitter, and sour. Brown/roasted was greatest (p < 0.05) in HIOX and CO. Muscle impacted liver-like flavor (P = 0.01), which was lower (p < 0.05) in SM than all other muscle types; LL, TB, PM and GM were similar (p > 0.05) for liver-like. Packaging influenced TBARS (p < 0.01); HIOX had the greatest concentration of MDA, followed by CO, OW and ROLL with the lowest (p ≤ 0.05). Muscle influenced TBARS (P < 0.01), where TB was greatest (p < 0.05), followed by SM, PM, and GM, which were similar (p > 0.05); LL had the lowest MDA concentration. Oxidized (P < 0.01, r = 0.34), cardboard (P < 0.01, r = 0.30), bitterness (P < 0.01, r = 0.23), and sourness (P < 0.01; r = 0.22) were positively correlated with TBARS, while beef ID (P < 0.01, r = –0.23), umami (P < 0.01, r = –0.23), and tenderness (P < 0.01; r = –0.21) were negatively correlated.ConclusionRetail display lighting did not directly influence sensory characteristics or lipid oxidation; lighting only impacted cardboard flavor in an interaction with muscle type. These results suggest after 72h retail display, flavor differences between steaks of similar muscle and packaging displayed under LED or fluorescent lights may not be distinguishable.

Beef Flavor Evaluation on Top Loin Steaks, Sirloin Steaks, Chuck Roasts, and 80/20 Ground Beef Over The Retail Case

ObjectivesConsumer acceptability in meat flavor is one of the driving factors of acceptability. Many studies have found factors that affect beef flavor, but little is known about variability of major beef cuts in the retail meat case where meat is displayed, and customers can choose from.Materials and MethodsFour beef cuts (chuck roast, top sirloin steaks, top loin steaks, and 80/20 ground beef) were obtained from retail stores in Miami, Los Angeles, Portland, New York, and Denver within a 2-mo period. The study wanted a variety of samples that were from different production systems or contained certain claims that would be available to customers. The meat was shipped with dry ice and stored at –9°C. For evaluation steaks, roasts, and ground beef were thawed 24 h at 4°C. Prior to cooking, chuck roasts were cut 10.16 × 12.7cm from the center of the roast. Each ground beef sample was formulated into 3, approximately 150 g patties. Chuck roasts were placed in a roasting pan on a roasting rack and 2 cups of water. Beef steaks and ground beef patties were cooked on a stovetop grill and cooked to 71°C, steaks and patties were flipped when temperature reached 35°F. Chuck roasts were cut into 1.27cm cubes with no visible connective tissue, fat, or outside browning. Steaks were cut into 1.27cm cubes with no connective tissue or fat. Ground beef patties were cut into 6 wedges. Panelists were served either 2 wedges or 2 1.27 cm samples for evaluation. An expert trained descriptive flavor and texture sensory panel was conducted where panelists evaluated beef flavors and textures. Beef flavor and texture attributes were analyzed using SAS (version 9.4, SAS Institute, Inc., Cary, NC) and principal component (PCA) bi-plots were generated using XLSTAT (Addinsoft, Inc., Long Island City, NY) using P < 0.05.ResultsChuck roasts were associated with bloody/serumy flavor aromatics. Ground beef patties were clustered with fat-like, overall sweet, green hay, and buttery flavor aromatics. Top sirloin steaks samples were more highly associated with off flavors such as liver, cardboardy, and sour flavor aromatics. Top loin steaks were clustered with positive attributes such as umami, beef flavor identity, and brown, roasted flavor aromatics. For the PCA biplot, factor 1 accounted for 60% and factor 2 accounted for 28% of variation. Ground beef was higher (P < 0.0001) in brown, fat like, green hay, sour milk/sour dairy, flavor aromatics, and had more salty and sweet basic taste than the other cuts. Ground beef patties had the least amount (P < 0.0001) of bloody/serumy, metallic, and liver like flavor aromatics. Chuck roasts had the least (P < 0.0001) beef flavor id, brown, roasted flavor aromatics and salt and umami basic taste. Sirloin steaks had the lowest (P < 0.0001) fat like flavor aromatic and the highest levels (P < 0.0001) of burnt and cardboardy flavor aromatics and bitter and sour basic taste. Sirloin steaks and chuck roasts had more metallic and liver like (P < 0.0001) flavor aromatics than other cuts. Top loin steaks were intermediate in flavor attributes.ConclusionFlavor descriptive attributes of four beef cuts differed. Results indicated that chuck roasts and top sirloin steaks were associated with negative flavor attributes. Ground beef contained sweeter, fat like attributes with exceptions of green hay, while top loin steaks were associated with more positive beef flavor attributes.

Impacts of Various Dry-Aging Methods on Meat Quality and Palatability Attributes of Beef Loins from Cull Cow

ObjectivesBeef from cull cows has been traditionally perceived as low-quality/value meat due to its inferior flavor and tenderness. Given the negative consumer perception of highly processed fresh meat, there is a need to develop a natural post-harvest aging system to improve eating quality attributes of beef products, particularly from cull cows. Dry aging has been practiced for decades as a traditional and natural butchery process, which is also known to improve palatability characteristics. Thus, the main objective of this study was to evaluate the impact of different dry-aging methods on meat quality, microbiological properties and palatability attributes of loins from cull cow beef.Materials and MethodsPaired beef loins from 13 carcasses (Holstein, 30+ mo) were obtained at 5d postmortem, divided into 4 equal length sections and randomly assigned to four aging methods: wet-aging (WA), dry-aging (DA), dry-aging in water permeable bag (DWA) and UV-light dry-aging (UDA; 2 treatment/day, 5 J/s/treatment). Sections were aged for 28d at 2°C, 65% RH and 0.8 m/s air flow. After aging, dry-aged sections (DA, DWA and UDA) were trimmed of dehydrated surface, and trim loss and total saleable yield were recorded. The pH, proximate composition, shear force, water-holding capacity, initial color (instrumental and trained panelist), lipid oxidation (2-thiobabituric acid reactive substances, TBARS), microbial properties (aerobic plate count (APC), lactic acid bacteria (LAB), and yeast and mold (YM) counts) and trained sensory evaluation (11 panelists) were determined. Experimental design was a balanced complete block design. All data were analyzed using PROC MIXED procedure of SAS, and least squares means for all traits were separated (P < 0.05).ResultsDA and UDA had a substantial moisture loss during the aging process, accompanied with higher trim loss compared to other methods (P < 0.05). This resulted in DA having the lowest yield followed by UDA, DWA and WA with the highest saleable yield (P < 0.05). No significant differences were observed on cook loss, WBSF and TBARS between the treatments. DWA had the lowest pH out of all treatments (P < 0.05). UDA had the lowest moisture content and highest drip loss (P < 0.05). Color measurement showed that both DA and WA had significantly higher L* and lower b* values compared to UDA and DWA (P < 0.05). However, a* and lean surface color were not significantly different between the treatments (P > 0.05). For the trim, UDA had the lowest microbial growth among all treatments (P < 0.05). For the lean, UDA had the lowest count for LAB (P < 0.05), WA had the lowest in YM (P < 0.05) and no difference was found for APC between treatments (P > 0.05). Trained sensory panelist found that UDA and WA had higher fat and sour flavor (P < 0.05), and a trend (P = 0.07) of higher oxidized flavor when compared to DWA and DA.ConclusionThe results showed that dry-aging would result in no adverse impact on shear force, cooking loss, initial color and lipid oxidation of mature beef loins. Further, sour and oxidized flavor was lower in dry-aged beef, indicating its potential as value adding process. UV light application minimized microbial growth during dry-aging process, although more analyses are needed to understand its full impact on dry-aged meat quality. Further studies on determining the consumer acceptability as well as flavor-related compound analyses are currently under investigation.

The Lifestyle Medicine Outpatient Clinic at Loma Linda University Health

Medical management of chronic health concerns relies heavily on behavioral change, most specifically medication adherence. Yet approximately 50% of patients with chronic illnesses are not thought to take their medications as prescribed. Moreover, it is recognized that lifestyle and behavioral changes can reduce the need for medication. It is well documented that patient outcomes and their success in achieving behavioral change is improved with engagement and support from a medical care team. As the inpatient lifestyle medicine service was being conceptualized at Loma Linda University Health (LLUH), it became apparent that an outpatient service would be necessary for follow-up care of the patients and support the lifestyle medicine treatments initiated in the hospital. Additionally, an outpatient clinic would be available to the patient population at Loma Linda and potentially prevent hospitalizations, morbidity, and mortality with proactive lifestyle medicine treatment. The initial outpatient clinic opened in February 2017 and was soon expanded to meet patient demand. Currently, the LLUH Lifestyle Medicine Outpatient Clinic is available 5 days a week, utilizing 5 physicians.

Lifestyle Medicine Inpatient Consultation Services at Loma Linda University Health: A Novel Approach in a Tertiary Care Center

As a nation facing primary care provider shortages, an expanding chronic disease burden, and rising health care costs, lifestyle medicine interventions have become critical for patient care and management. The current fee-for-service health care system in the United States is designed for delivering acute care but has made it challenging to deliver and be reimbursed sufficiently for lifestyle interventions that can help prevent and treat chronic disease. Loma Linda University Health began to address these concerns through the creation of an inpatient consultation service for the neurology rehabilitation stroke team. Initiation of the consultation service took 2 years of planning, testing, and resource development. Currently, the consultation service operates one half-day per week in the rehabilitation hospital utilizing 1 attending physician and 2 residents. Visiting residents and medical students are also permitted to rotate with the new service. In coordination with billing experts, a standard number of 21.2 to 25.4 RVUs (relative value units) has been established for the half-day service. As the service continues to expand, future considerations include adding consultation availability to other departments and increasing the consultation workforce.

Two-dimensional charge transport in disordered organic semiconductors

We analyze the effect of carrier confinement on the charge-transport properties of organic field-effect transistors. Confinement is achieved experimentally by the use of semiconductors of which the active layer is only one molecule thick. The two-dimensional confinement of charge carriers provides access to a previously unexplored charge-transport regime and is reflected by a reduced temperature dependence of the transfer curves of organic monolayer transistors.

Superior mesenteric artery aneurysm: an uncommon disease with potentially serious complications

Superior mesenteric artery aneurysms (SMAAs) are visceral arterial aneurysms that can result from a variety of conditions. About half of SMAAs are mycotic and occur subsequent to infective endocarditis. The clinical presentation of SMAA is nonspecific, and some patients may be asymptomatic while others may report mild to severe abdominal pain. Herein, we present a case of a 53-year-old man who presented to the emergency department with abdominal pain 5 months after receiving medical treatment for infective endocarditis. CT scan demonstrated an aneurysm in the superior mesenteric artery and a splenic infarct. The patient underwent surgical excision with an uneventful recovery. Although rare, SMAAs are associated with a high risk of death secondary to rupture. They are difficult to detect through physical examination and the history is usually nonspecific. In this report we discuss the etiology of SMAA, diagnostic work-up and treatment options aiming for early diagnosis and management of this potentially fatal condition.

Survey of the effective exercise habits of the formerly obese

BACKGROUND AND OBJECTIVE

Patients must subscribe to behavioral and lifestyle modifications for continued success after weight loss surgery (WLS). Few data exist about the ideal type, duration, and intensity of exercise for WLS patients. After surgery, should we mandate that patients exercise like a young, lean individual does? To reconcile this, we compared the exercise habits of successful bariatric surgery patients with physically fit controls.

METHODS

One hundred individuals were enrolled. The operative group (OG) included 50 laparoscopic Roux-Y gastric bypass patients (LRYGB) who achieved excess weight loss of at least 80% one year after the surgery. The control group (CG) included 50 individuals of normal BMI who exercised regularly and did not undergo LRYGB. The exercise habits were compared using Fisher's exact and Mantel-Haenszel chi square tests.

RESULTS

The 2 groups had equivalent BMIs (24.7 vs. 23.4 kg/m(2)). The OG was older (39.5 years) than the CG (26.2 years). There was a statistically significant difference between the groups regarding cardiovascular exercise, 80% walking (OG) vs. 60% running (CG). OG patients exercised longer and with similar frequency as CG did. A high proportion of CG lifted weights (86%) vs. OG (44%). Sixty percent of CG performed recreational sports compared with 34% of OG.

CONCLUSION

Regular exercise is of utmost importance in maximizing and maintaining weight loss after WLS. Although patients who undergo WLS are older than the typical exercise enthusiast, they can achieve excellent weight loss and sustain a normal BMI with regular exercise habits that are quite distinct from younger individuals whose bodies were never undermined by obesity.

IgM colocalises with complement and C reactive protein in infarcted human myocardium

AIMS

Reperfusion of ischaemic myocardium after acute myocardial infarction (AMI) can induce ischaemia/reperfusion (I/R) injury, as a result of local activation of the complement system. C reactive protein (CRP) is involved in this activation. This study analysed the potential role of IgM in complement activation in the infarcted human myocardium.

METHODS

Immunochemical analysis was carried out on heart specimens from 59 patients who died from AMI. Serial slides of frozen tissue from the infarction site were stained for IgM, complement factors C3d and C5b-9 (membrane attack complex), and CRP.

RESULTS

IgM deposits were found on the plasma membrane, cross striations, and in the cytoplasm of jeopardised cardiomyocytes in infarcts of one to five days duration. IgM depositions were remarkably similar to those of CRP and both complement factors. The relative staining intensities of IgM and CRP varied greatly among patients.

CONCLUSIONS

Similar to CRP, IgM targets complement locally to jeopardised cardiomyocytes in the human heart after AMI. Localisation patterns and relative staining intensities suggest that IgM and CRP recognise similar epitopes in the ischaemic heart, but that the relative contribution of each protein to complement activation in the ischaemic myocardium differs among patients.

Expression of VEGF isoforms by epiphyseal chondrocytes during low-oxygen tension is HIF-1 alpha dependent

OBJECTIVE

To establish the role of hypoxia and HIF-1 alpha for VEGF expression of murine epiphyseal chondrocytes. To analyze the effect of hypoxia on VEGF isoform expression.

MATERIALS AND METHODS

VEGF mRNA and VEGF isoform expression was investigated in epiphyses of murine newborns by in situ hybridization and real-time PCR. Further, epiphyseal chondrocytes were isolated from newborn mice with homozygous flanking of the HIF-1 alpha gene with lox-P sites. HIF-1 alpha was deleted by infection with adenovirus containing cre-recombinase. After chondrocytes reached confluency they were exposed to 0.5% or 20% oxygen, respectively. Total VEGF and VEGF isoform mRNA expression levels were measured by real-time PCR. Secreted VEGF protein was determined by ELISA.

RESULTS

VEGF mRNA signals were detected in the hypertrophic zone and in the center of the proliferative zone of the murine epiphysis, which is considered to be hypoxic. Real-time PCR revealed that VEGF(120)is the dominant isoform in vivo. In cultured epiphyseal chondrocytes strongly increased VEGF gene expression levels were detected after exposure to hypoxia. Furthermore, secretion of VEGF protein was significantly enhanced under 0.5% oxygen. Remarkably, functional inactivation of HIF-1 alpha abolished the hypoxic increase of VEGF expression in chondrocytes completely. Furthermore, the soluble isoforms VEGF(120)and VEGF(164)are the most abundantly expressed splice variants in chondrocytes exposed to low oxygen levels.

CONCLUSIONS

The data presented here clearly indicate that hypoxia is able to induce the synthesis of soluble VEGF isoforms by epiphyseal chondrocytes, most likely through stabilization of HIF-1 alpha. Thus it can be speculated that HIF-1 alpha is an essential prerequisite for hypoxic VEGF synthesis in the epiphysis, thereby contributing to the formation and invasion of blood vessels in long bone development.

Vascular endothelial growth factor in articular cartilage of healthy and osteoarthritic human knee joints

OBJECTIVE

To determine the levels of vascular endothelial growth factor (VEGF) mRNA and protein expression in normal and osteoarthritic (OA) human articular cartilage, and whether VEGF expression alters during the progression of OA.

METHODS

Sections from normal and OA human knee cartilage were immunotained with a polyclonal antibody recognising VEGF. In addition, total RNA was isolated from normal and osteoarthritic human knee cartilage and analysed by reverse transcriptase-polymerase chain reaction (RT-PCR) for VEGF mRNA expression.

RESULTS

VEGF was found to be present in normal and OA human knee cartilage in all cartilage layers. A significant increase of VEGF immunopositive chondrocytes to up to approximately 82% was detected in severe OA cartilage compared with normal articular cartilage (approximately 56% of immunopositive chondrocytes). RT-PCR analysis showed the expression of VEGF also on the mRNA level.

CONCLUSIONS

VEGF is expressed by articular chondrocytes in normal and OA human knee cartilage. The percentage of VEGF immunopositive chondrocytes significantly increases in late stages of the disease. The VEGF transcript levels encoding all four isoforms shows a big variability in samples from different donors, suggesting a distinct regulation of the expression of the four VEGF isoforms in normal and OA cartilage.

Gastrin induces expression and promoter activity of the vesicular monoamine transporter subtype 2

Gastric enterochromaffin-like cells produce histamine in response to the antral hormone gastrin and accumulate the biogenic amine in secretory organelles via vesicular monoamine transporter subtype 2. The putative effects of gastrin on vesicular monoamine transporter subtype 2 expression and promoter activity are poorly understood. In the present study we used highly enriched rat enterochromaffin-like cells (purity, >90%) and rat pheochromocytoma cells stably transfected with a gastrin/cholecystokinin B receptor to investigate the expression and transcriptional regulation of vesicular monoamine transporter subtype 2. Stimulation of vesicular monoamine transporter subtype 2 mRNA and protein expression was observed in isolated enterochromaffin-like cells after 3- to 7-h incubation with gastrin (10(-7) M), forskolin (10(-5) M), or ionomycin (10(-5) M). Deletion analysis of the rat vesicular monoamine transporter subtype 2 promoter defined the minimal promoter sequence necessary for full basal activity as a -121 bp segment upstream of exon 1 containing two Sp1 sites (-97 to -88 bp and -68 to -59 bp) and a cAMP-responsive element (-44 to -35 bp). Gastrin (10(-7) M) stimulated extracellular signal related kinase1/2 phosphorylation, activated Sp1 and cAMP-responsive element-binding protein, and further induced activity of the complete rat vesicular monoamine transporter subtype 2 promoter (-800 bp) in gastrin/cholecystokinin B receptor cells. The -121-bp fragment was able to confer full gastrin responsiveness, and site-directed mutagenesis of the Sp1 and cAMP-responsive element motifs demonstrated their crucial importance for basal and inducible activities. Comparison of promoter activity of histidine decarboxylase, chromogranin A, or vesicular monoamine transporter subtype 2 in transfected cell lines revealed significant differences in basal and gastrin-stimulated activities. Our current study provides the first evidence that gastrin directly stimulates the expression and promoter activity of vesicular monoamine transporter subtype 2. Sp1 and cAMP-responsive element-binding protein recognition motifs located within 121 bp upstream of exon 1 appear to be indispensable for full basal and inducible promoter activities. Diverging effects of gastrin on histidine decarboxylase, chromogranin A, and vesicular monoamine transporter subtype 2 promoter may account for the coordinated synthesis and storage of histamine in this neuroendocrine cell type.

Neuroendocrine-specific and gastrin-dependent expression of a chromogranin A-luciferase fusion gene in transgenic mice

BACKGROUND AND AIMS

Chromogranin A (CgA) is a multifunctional acidic protein specifically expressed in neuroendocrine cells. In the stomach, CgA is found predominantly in enterochromaffin-like (ECL) cells, where it is regulated by gastrin. We investigated the ability of a promoter fragment comprising 4.8 kb of 5'-flanking DNA of the mouse CgA (mCgA) gene to direct cell-specific expression as well as gastrin responsiveness in the gastroenteropancreatic neuroendocrine system.

METHODS

Two independent lines of mCgA 4.8 kb-luc transgenic mice were created. Transgene expression was assessed by determination of luciferase activity and reverse-transcription polymerase chain reaction analysis of luciferase messenger RNA. Cell specificity of transgene expression was investigated by immunohistochemical analysis. The influence of hypergastrinemia on transgene expression was determined after repeated omeprazole injections.

RESULTS

In both transgenic lines, mCgA 4.8 kb-luc expression paralleled the expression pattern of the endogenous CgA gene. ECL cells were identified as the major gastric cell population expressing the transgene. Omeprazole treatment stimulated expression of the transgene and the endogenous CgA gene selectivity in the gastric corpus (3-4-fold).

CONCLUSIONS

mCgA 5'-flanking DNA (4.8 kb) contain the major cis-regulatory element(s) required for cell-specific CgA expression in the neuroendocrine system and gastrin-responsiveness in the gastric corpus. Further analysis of the CgA promoter in transgenic studies may elucidate the general molecular mechanisms underlying cell-specific gene expression in the gastroenteropancreatic neuroendocrine system.

Dual mechanism of vascular endothelial growth factor upregulation by hypoxia in human hepatocellular carcinoma

BACKGROUND/AIMS

Vascular endothelial growth factor (VEGF) plays a key role in regulation of tumour associated angiogenesis. In the current study we analysed expression of VEGF and its receptors in human hepatocellular carcinoma (HCC) and investigated the molecular mechanisms of VEGF regulation by hypoxia.

METHODS

VEGF, kinase domain region (KDR)/fetal liver kinase 1 (flk-1), and flt-1 expression were examined by immunohistochemistry and in situ hybridisation in 15 human HCC tissues. Expression of VEGF and regulation by hypoxia were assessed in three human HCC cell lines using a quantitative competitive reverse transcription-polymerase chain reaction, ELISA, and a series of 5' deletion reporter gene constructs of the human VEGF promoter in transient transfection assays.

RESULTS

We observed over expression of VEGF mRNA and protein in HCC compared with cirrhosis or normal liver. Expression of VEGF in tumour cells was strongly increased in areas directly adjacent to necrotic/hypoxic regions. Both VEGF receptors were detected in vascular endothelia of HCC while only KDR/flk-1 receptors were detected in endothelial cells of cirrhotic livers. Expression of VEGF was observed in all human HCC cell lines examined. Hypoxia (1% oxygen) resulted in profound upregulation of VEGF mRNA and protein levels. Furthermore, hypoxia treatment resulted in a doubling of VEGF mRNA stability. Deletion analysis of the human VEGF 5' flanking region -2018 and +50 demonstrated induction of VEGF promoter activity under hypoxic conditions which was significantly decreased following deletion of the region -1286 and -789 suggesting a substantial contribution of the -975 putative hypoxia inducible factor 1 binding site to hypoxia mediated transcriptional activation of the VEGF gene.

CONCLUSION

These data suggest hypoxia as a central stimulus of angiogenesis in human HCC through upregulation of VEGF gene expression by at least two distinct molecular mechanisms: activation of VEGF gene transcription and an increase in VEGF mRNA stability.

De novo expression of vascular endothelial growth factor in human pancreatic cancer: evidence for an autocrine mitogenic loop

BACKGROUND & AIMS

The role of vascular endothelial growth factor (VEGF) and its receptors in tumor angiogenesis has been well established. We analyzed the expression pattern and biologic significance of VEGF and its receptors in human pancreatic cancer.

METHODS

VEGF, KDR/flk-1, and flt-1 expression were examined by immunohistochemistry, in situ hybridization, reverse-transcription polymerase chain reaction, enzyme-linked immunosorbent assay, and receptor phosphorylation. VEGF-stimulated mitogenesis was investigated by mitogen-activated protein kinase (MAPK) phosphorylation, transactivation of a c-fos promoter reporter construct, DNA synthesis assays, and stable transfection of a dominant-negative flk-1 complementary DNA (cDNA) construct.

RESULTS

Compared with normal pancreas and chronic pancreatitis, VEGF and its receptors were overexpressed in pancreatic cancer. KDR and flt-1 were detected not only in endothelial cells but also in tumor cells. VEGF expression was observed in all human pancreatic tumor cell lines examined, and the KDR/flk-1 and flt-1 receptor was detected in 2 cell lines. VEGF treatment results in phosphorylation of MAPKs, transactivation of a c-fos promoter construct, and growth stimulation in KDR/flk-1-expressing cell lines, which could be blocked by VEGF antagonists. Furthermore, stable transfection of a dominant-negative flk-1 cDNA significantly inhibited tumor cell growth.

CONCLUSIONS

These results not only support the important role of the VEGF/VEGF receptor system in pancreatic tumor biology but also suggest the existence of an autocrine/paracrine mitogenic loop for pancreatic cancer cells.

Energy dissipation and path instabilities in dynamic fracture of silicon single crystals

Brittle fracture usually proceeds at crack driving forces which are larger than those needed to create the new fracture surfaces. This surplus can lead to faster crack propagation or to the onset of additional dissipation mechanisms. Dynamic fracture experiments on silicon single crystals reported here show several distinct transitions between different dissipation mechanisms. Cleavage fracture is followed by the propagation of a faceted crack front, which is finally followed by a path instability and the propagation of multiple cracks. The fracture surface qualitatively corresponds to the mirror, mist, and hackle morphology of amorphous materials. However, the corresponding fracture mechanisms, which remain largely unknown in the amorphous materials, can clearly be identified here.

Expression of thrombospondin-1 and its receptor CD36 in human osteoarthritic cartilage

OBJECTIVE

Thrombospondin-1 (TSP-1), a trimeric glycoprotein, is involved in cell-matrix interactions of various tissues, particularly in cartilage. Biochemical analyses show expression of TSP-1 in human cartilage, but its cellular source as well as the presence of its main surface receptors CD36 and CD51 in normal and osteoarthritic cartilage remain unknown. Therefore, to localise TSP-1 and its receptors immunohistochemistry and in situ hybridisation were used.

METHODS

Radioactive in situ hybridisations with an RNA probe that encodes TSP-1 combined with immunostaining were carried out to investigate the expression patterns of TSP-1, CD36, and CD51 in seven normal and 23 osteoarthritic human cartilage samples.

RESULTS

In normal cartilage TSP-1 was present mainly in the middle and upper deep zone. RNA expression was predominantly seen over chondrocytes of the middle zone. CD36 was found in chondrocytes of the superficial and upper middle zone. In mild and moderate osteoarthritic cartilage an increased number of TSP-1 expressing chondrocytes were seen and an increased pericellular staining close to the surface. In severe osteoarthritic cartilage a decrease in the number of TSP-1 synthesising chondrocytes and a strong reduction in matrix staining were observed. Most of these severe osteoarthritic samples showed a strongly enhanced number of CD36 positive chondrocytes.

CONCLUSION

The cellular source of TSP-1 in normal cartilage is mainly mid-zone chondrocytes, which also express CD36. In early osteoarthritic cartilage lesions an increase of TSP-1 was seen, whereas reduced TSP-1 synthesis is paralleled by a strong decrease in TSP-1 protein staining in severe osteoarthritis. Furthermore, in severe osteoarthritic cartilage the number of CD36 immunostained chondrocytes is significantly increased.

Hepatocyte growth factor in human osteoarthritic cartilage

OBJECTIVE

Hepatocyte growth factor/scatter factor is a potent mitogen, morphogen and motogen for a variety of mainly epithelial cells. Hepatocyte growth factor is synthesized by mesenchymal cells and can be found in various tissues. The objective of this study was to investigate the expression and distribution patterns of this pleiotropic growth factor and its receptor, the product of the proto-oncogene c-met in normal and osteoarthritic human knee cartilage.

METHODS

Five normal and 14 osteoarthritic human cartilage samples graded histomorphologically by Mankin Score, were studied by radioactive in-situ hybridization and immunohistochemistry for the expression of Hepatocyte growth factor and the c-met receptor.

RESULTS

Hepatocyte growth factor could be found by immunohistochemistry in the territorial matrix surrounding the chondrocytes of calcified cartilage and within the deep zone of normal cartilage. Chondrocytes of these cartilage zones showed also positive c-met receptor-staining. Moreover, a small number of chondrocytes in the superficial and intermediate zone showed c-met staining. In accordance with the increased hepatocyte growth factor staining of osteoarthritic cartilage, an enhanced expression of hepatocyte growth factor-RNA by chondrocytes of the deep zone as well as the deeper mid zone was observed. Contrary to normal cartilage, c-met was identified immunohistochemically in osteoarthritic chondrocytes of all cartilage zones.

CONCLUSION

These results indicate that hepatocyte growth factor seems to be acting in an autocrine/paracrine manner in normal and osteoarthritic cartilage. The ubiquitous presence of the HGF/HGF-receptor complex in osteoarthritic chondrocytes suggests that hepatocyte growth factor may contribute to the altered metabolism in osteoarthritic cartilage.

Three-dimensional ultrasonographic telepresence

We have developed a three-dimensional ultrasound telepresence system for remote consultation. Three-dimensional ultrasound data-sets can be acquired by relatively unskilled operators. The data are stored in the remote unit and then transmitted to a consultant equipped with a similar unit. A telepresence pointing device enables the consultant to re-slice that data-set in any plane. During the study period, 72 volumetric scans of male and female volunteers aged 18-45 years were performed in Bosnia. Field users of limited ultrasound experience (most with less than 30 min of training) were able to acquire volumetric scans, send volume data and interact with remote consultants over standard communications lines at distances of up to 20,000 km. Communications links from 9.6 to 1500 kbit/s were used. Technical limitations included lack of motion data, lack of colour data, scan artefacts and increased scan-to-diagnosis time. However, our preliminary experience indicates that this technique may eventually prove to be a useful adjunct to telesonography. Further studies of the technique are needed to determine its value in the broader clinical setting.

Isotope-geochemical and mineralogical-petrographic characteristics of the pergamon altar marble

Abstract We report preliminary results of our provenance study of marble from the Telephos Frieze of the Pergamon altar. The emphasis here is on the stable isotope geochemistry of marble. The obtained δ(13)C values (2.4 to 3.5‰) vary insignificantly. However, the δ(18)O values give two clusters. The isotopically light marbles (close to -9.5‰) derive from panels 1-8 and the heavy marbles (-3.5 to -1.0‰) derive from panels 11-50. Mineralogical, petrographic and geochemical investigations (accessory minerals, grain size distribution, rare earth elements) further refined the marble characteristics. In spite of certain differences observed (grain size distributions, isotopy and contents of certain elements) for the two marble groups, the present data support a common provenance. So far, east Aegean islands and the Marmara region are favored.