244 CHONDROGENIC PELLET CULTURES FOR CARTILAGE TISSUE ENGINEERING GROW BY DEPOSITION OF MATRIX AND NOT BY CELLULAR PROLIFERATION

Pellet cultures are commonly used to study chondrogenic differentiation in vitro. Our laboratory has demonstrated pellets made with chondrocytes grow in size during culture and produce cartilage matrix, but pellets made with adipose-derived mesenchymal stem cells (ASC) grow only slightly, producing little cartilage matrix. The objective of this study was to determine if differences in chondrocyte and ASC pellet growth result from differences in cell proliferation or in deposition of extracellular matrix. Primary chondrocytes and ASC from adult pigs were cultured in Dulbecco’s modified Eagle’s medium (DMEM) with 10% fetal bovine serum. To determine baseline proliferation rates in monolayer culture, cells were grown on coverslips in 10 µM bromodeoxyuridine (BrdU) for 24 h and immunostained for BrdU labelling. For pellet cultures, 5 × 105 cells were placed in 15 mL-conical tubes, pelleted by centrifugation in 1.0 mL of chondrogenic base media (CBM: DMEM + 40 µg mL–1 of proline, 50 µM ascorbic acid-2-phosphate, 100 nM dexamethasone, and 1× insulin-transferrin-selenium), and cultured in CBM for 1, and 4 weeks. To detect proliferation in pellets, 1- and 2-week cultured samples were labelled with 10 µM BrdU for 24 h before harvest. Pellets were fixed with 4% paraformaldehyde, embedded, and sectioned on a Leica CM1900 cryostat (Leica Microsystems, Wetzlar, Germany). To assess chondrogenic differentiation and matrix expression, sections were stained for collagen II, keratin sulfate, and chondroitin sulfate. Images were captured and distance between adjacent nuclei in 1- and 4-week pellets were measured using Zeiss imaging software. As expected, cells on coverslips showed BrdU labelling, with higher labelling in ASC cultures indicating faster proliferation (n = 5, 77.3 ± 3.74% chondrocyte v. 92.1 ± 2.88% ASC; α = 0.05; P < 0.0001; Student’s t-test). However, BrdU labelling was not seen in sections from ASC or chondrocyte pellets (n = 5), at either 1 or 2 weeks. Absence of cellular proliferation in pellets was verified by negative staining for the mitotic marker Aurora KinaseB (AurKB). Cartilage matrix staining was strong in chondrocyte pellets at all time points and absent in ASC pellets. Cell nuclei were closely packed in both ASC and chondrocyte pellets at 1 week, but a significant increase in distance between adjacent nuclei with interspersed matrix staining was noted in chondrocyte pellets at 4 weeks (n = 4, 11.88 ± 0.67 µm at 1 week v. 26.85 ± 2.06 µm at 4 weeks; α = 0.05; P < 0.0001; Student’s t-test). As TGFβ3 has been shown to induce chondrogenesis in ASC, ASC pellets were cultured in CBM + 10 ng of TGFβ3 for 1 and 2 weeks (n = 4). The TGFβ3 treatment did not induce cell proliferation in pellets, as sections were negative for BrdU. However, expression of cartilage markers keratan sulfate and chondroitin were noted. Based on our data, neither ASC nor chondrocytes proliferate in pellet culture, and chondrocyte pellet growth is due to extracellular matrix deposition.

Biopsy case mix and diagnostic yield at a Malawian central hospital

Cancer is a major disease burden worldwide resulting in high morbidity and mortality. It is the leading cause of mortality in developed countries and is one of the three leading causes of death for adults in developing countries. Pathological examination of tissue biopsies with histological confirmation of a correct cancer diagnosis is central to cancer care. Without an accurate and specific pathologic diagnosis, effective treatment cannot be planned or delivered. In addition, there are marked geographical variations in incidence of cancer overall, and of the specific cancers seen. Much of the published literature on cancer incidence in developing countries reflects gross estimates and may not reflect reality. Performing baseline studies to understand these distributions lays the groundwork for further research in this area of cancer epidemiology. Our current study surveys and ranks cancer diagnoses by individual anatomical site at Queen Elizabeth Central Hospital (QECH) which is the largest teaching and referral hospital in Malawi. A retrospective study was conducted reviewing available pathology reports over a period of one full year from January 2010 to December 2010 for biopsies from patients suspected clinically of having cancer. There were 544 biopsies of suspected cancer, taken from 96 anatomical sites. The oesophagus was the most common biopsied site followed by breast, bladder, bone, prostate, bowel, and cervical lymph node. Malignancies were found in biopsies of the oesophagus biopsies (squamous cell carcinoma, 65.1%; adenocarcinoma, 11.6%), breast (57.5%), bladder (squamous cell carcinoma, 53.1%) and stomach (37.6%). Our study demonstrates that the yield of biopsy for clinically suspected malignancy was greater than 50% for the 11 most common sites and provides a current survey of cancer types by site present in the population reporting to our hospital.

Cognitive neuroscience: the biology of the mind and findings and current opinion in cognitive neuroscience

Cognitive Neuroscience: The Biology of the Mind by Michael Gazzaniga, Richard Ivry and George Mangun, W.W. Norton, 1998. £24.95 (xv+587 pages) ISBN 0 393 97219 4 Findings and Current Opinion in Cognitive Neuroscience by Larry Squire and Stephen Kosslyn, MIT Press, 1998. $35.00 (vii+381 pages) ISBN 0 262 69204 X.

Prolonged hypothermia following respiratory syncytial viral infection in infancy

Following proven respiratory syncytial viral infection, a previously healthy 2 year old boy displayed notable persistent hypothermia-the lowest temperature being 34.2 degrees C. No obvious ill effects were observed.

Two cholinesterase activities and genes are present in amphioxus

To obtain information about the evolution of the cholinesterases, acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in the vertebrates, we investigated the cholinesterase (ChE) activity of the cephalochordate amphioxus (Branchiostoma floridae and Branchiostoma lanceolatum). On the basis of evidence from enzymology, pharmacology, and molecular biology, we conclude that amphioxus possesses two ChE activities and two ChE genes. Two covalent inhibitors of cholinesterases were able to pharmacologically isolate the two activities as drug-sensitive ChE and drug-resistant ChE. Kinetically, in terms of substrate specificity, the drug-sensitive ChE resembles vertebrate AChE, and the drug-resistant ChE resembles the BuChE of cartilaginous and bony fish or the intermediate ChE of protostome invertebrates. We also used the polymerase chain reaction with degenerate oligonucleotide primers and genomic DNA to obtain clones of 1,574 and 1,011 bp corresponding to two cholinesterase genes from amphioxus, which we designated as ChE1 and ChE2. ChE2 codes for an enzyme with an acyl-binding pocket sequence, a portion of the protein that plays an important role in determining substrate specificity, typical of invertebrate ChE. ChE1, which contains a 503-bp intron, encodes a protein with a novel acyl binding site. Phylogenetic analysis of the sequences suggests that the two genes are a result of a duplication event in the lineage leading to amphioxus. We discuss the relevance of our results to the evolution of the cholinesterases in the chordates. Previously, we reported that amphioxus contained a single cholinesterase activity with properties intermediate to AChE and BuChE (Pezzementi et al. [1991] In: Cholinesterases: Structure, Function, Mechanism, Genetics and Cell Biology. J. Massoulié et al., eds. ACS: Washington, D.C., pp. 24-31).

Social support as a moderator of cardiovascular reactivity in women: a test of the direct effects and buffering hypotheses

This study examines the possibility that social support operates as a moderator of cardiovascular reactivity in women. Two models by which social support may operate were examined: the direct effects and buffering models. Twenty-six subjects were exposed to four conditions while playing a video game: two levels of stress (low, high) and two levels of social support (alone, together). Blood pressure and heart rate were monitored continuously. Ratings of stress were obtained for each condition. Results indicated that the support manipulation produced significant main effects for diastolic blood pressure and stress ratings, with lower diastolic blood pressure and ratings observed in the "together" condition, and that the interaction between support and stress produced lower reactivity for the cardiovascular measures in the high stress (but not the low stress) condition. No interaction was found for the stress ratings. We conclude that the results provide support for both the buffering and direct effects models. Implications concerning the (within-subjects) design of the study and the stress ratings are discussed.

Esophageal mucosal changes in children with an acutely ingested coin lodged in the esophagus

An important factor in choosing the method to remove an ingested coin lodged in the esophagus (endoscopy with forceps extraction, Foley catheter extraction, or bougienage advancement) is the duration of the ingestion and the risk for compromise to the esophageal mucosal integrity. We reviewed 50 consecutive cases occurring during a five-year period of children with a witnessed acutely ingested coin (less than 24 hours duration) that was lodged in the esophagus to determine the degree of compromise of the esophageal mucosal integrity. All coins were removed by endoscopic forceps extraction, with direct inspection of esophageal mucosa. The duration of ingestion was less than eight hours in 22 patients, nine to 16 hours in 16 patients, and 17 to 24 hours in 12 patients. Endoscopy showed that the esophageal mucosa had no abnormalities in 42 patients, "minimal erythema" in six patients, and "minimal abrasion" in two patients. There were no symptoms or complications referable to the gastrointestinal tract reported subsequent to coin removal in any case. Ingested coins that are lodged in the esophagus for fewer than 24 hours do not cause significant compromise to the integrity of the esophageal mucosa. We discuss the implications of these findings in the context of choosing an appropriate method for removing esophageal coins.

Maternal mortality in Europe

Maternal mortality rates (or ratios) are widely used as one indicator of the quality of medical care. There has been concern that conclusions may be drawn from unreliable data. A survey of practices in European countries confirms that there are differences in interpretation of definitions and evidence of significant under-reporting in official returns of vital statistics. Actual and potential sources of error are identified and a need for greater precision and uniformity of data collection is established.

Reports on confidential enquiries into maternal deaths: an audit of previous recommendations

An audit of facilities recommended to be available in consultant obstetric units (COUs) in the United Kingdom (UK) received responses from 248 (95%) of all 260 COUs. Of the respondents, 86% were on the site of an acute general hospital, 76% had an intensive therapy unit on site, and 87% had a blood bank on site. Eighty-two per cent had a protocol for management of massive haemorrhage, and 91% had a local protocol for the management of severe pre-eclampsia/eclampsia. The development of Regional protocols and advisory centres for the management of hypertensive disorders is at present fragmentary. Purchasers and providers should give urgent attention to correcting remaining deficiencies, and the availability of recommended facilities and protocols should be taken into account when units are assessed for recognition for training.

Environmental and typewriter control systems for high-level quadriplegic patients: evaluation and prescription

A formal 44-month clinical evaluation was conducted to determine the suitability of selected electronic equipment for use in high-level quadriplegia. A total of 52 traumatic high-level quadriplegic patients (C-2 to C-5,6) participated in the testing of 13 commercial electronic assistive devices including 8 environmental control units, 1 self-contained telephone, and 4 typewriter systems. Most devices were pneumatically ("breath") controlled. Devices were tested in an occupational therapy laboratory, bedside, and homes. Testing yielded data on device reliability, suitability, and acceptance by patients.