Arthroscopic surgery for degenerative knee arthritis and meniscal tears: a clinical practice guideline

The role of arthroscopic surgery in degenerative knee disease was evaluated in this guideline.

Unscheduled undergraduate teaching in surgery: a multi-institutional analysis.

A significant amount of valuable undergraduate medical teaching may be informal, unscheduled and delivered by non-consultant hospital doctors (NCHDs). 800 Questionnaires were distributed to consultants, NCHDs and medical students in Irish teaching hospitals. The aim was to quantify the level of unscheduled teaching carried out in these hospitals and the manner in which it was performed. The response rate was 46% (364/800). 71% of doctors who replied are independently teaching undergraduate medical students (77/109), including 71% of interns and senior house officers (48/68). Students tend to prefer small group teaching. Fifty-six percent of students suggest they would benefit from more surgical teaching time (144/255). No interns surveyed were scheduled to teach as part of a formal curriculum. A significant amount of unscheduled teaching by interns and senior house officers takes place in Irish hospitals. It may prove beneficial to incorporate interns into scheduled surgical teaching curricula.

The effect of pasture pregrazing herbage mass on methane emissions, ruminal fermentation, and average daily gain of grazing beef heifers.

The objective of this study was to determine the effect of pregrazing pasture herbage mass (HM) on CH4 emissions, ruminal fermentation, and ADG of grazing beef heifers at 2 stages of the grazing season. Thirty Limousin cross heifers were allocated to 1 of 2 target pregrazing HM treatments [a low HM (LHM) or high HM (HHM) treatment] for 126 d in a randomized block design experiment. Pasture herbage and heifer rumen fluid samples were collected, and enteric CH4 emissions were determined using an SF6 tracer technique during two 5-d measurement periods [MP; MP 1 (25 to 29 May) and MP 2 (6 to 10 September)]. Both DMI and GE intake (GEI) were measured during MP 2, and ADG of the heifers was measured every 14 d throughout the 126-d grazing period. Mean HM for the LHM and HHM treatments were 1,300 and 2,000 kg DM/ha, respectively, during MP 1 and 2,800 and 3,200 kg DM/ha, respectively, during MP 2. The CP concentration of the offered herbage was greater (P < 0.01) for the LHM treatment during MP 1 and tended (P < 0.1) to be greater for the LHM herbage during MP 2. No difference (P > 0.10) in the NDF concentration of the herbage was found between the HM treatments during MP 1 or 2. There was no effect (P > 0.10) of HM treatment on total CH4 emissions (g/d) for either MP [mean value across HM treatments of 121 (SED 5.4) g/d during MP 1 and 132 (8.8) g/d during MP 2], but CH4 emissions (g) per kilogram of ADG were reduced (P < 0.05) from heifers fed the LHM treatment during MP 1 and 2 [mean values for LHM and HHM of 135 and 163 (SED 9.5) g/kg, respectively, during MP 1 and corresponding values of 150 and 194 (9.9) g/kg during MP 2]. Heifers fed the LHM treatment had greater (P < 0.001) ADG throughout the grazing period [mean value across the 126-d grazing period of 0.88 (SEM 0.032) kg/d] than those fed the HHM treatment [corresponding value of 0.73 (0.034)]. For MP 2, CH4 emissions per kilogram of DMI (g CH4/kg DMI) and per megajoule of GEI (MJ CH4/MJ GEI) tended (P ≤ 0.08) to be less for heifers fed the LHM [19.3 (0.08) g/kg and 0.056 (0.0020) MJ/MJ, respectively] than for the HHM (21.1 g/kg and 0.061 MJ/MJ) treatment, and there were no differences (P > 0.10) in DMI or GEI of the heifers between the HM treatments. The results of this study suggest that offering a low pregrazing HM sward will reduce enteric CH4 emissions relative to ADG throughout the grazing season because of increased ADG.

The role of mitochondrial function and cellular bioenergetics in ageing and disease.

Mitochondria constitute an important topic of biomedical enquiry (one paper in every 154 indexed in PubMed since 1998 is retrieved by the keyword 'mitochondria') because of widespread recognition of their importance in cell physiology and pathology. Mitochondrial dysfunction is widely implicated in ageing and in the diseases of ageing, through dysfunction in adenosine triphosphate (ATP) synthesis, Ca(2+) homeostasis, central metabolic pathways or radical production. Nonetheless, the mechanisms and regulation of superoxide and hydrogen peroxide formation by mitochondria remain poorly described. Measurement of the capacities of different sites of superoxide and hydrogen peroxide production in isolated skeletal muscle mitochondria show that the maximum capacities of sites in complexes I, II and III and in several associated redox enzymes greatly exceed the native rates observed in the absence of respiratory chain inhibitors. In vitro, the native rates and the relative importance of different sites both depend on the substrate being oxidized, with sites IQ, IIF, GPDH, IF and IIIQo each being important with particular substrates. The techniques involved in measuring rates from each site should become applicable to cell cultures and in vivo in the future.

Cronkhite Canada syndrome with early colorectal carcinoma in a patient.

We relate the first case in the Republic of Ireland of Cronkhite Canada Syndrome (CCS). The patient presented with weight loss, alopecia, nail dystrophy, taste disturbance and classic radiologic and endoscopic features of CCS. She continued to dramatically lose weight and early repeat colonoscopy showed the interim development of an invasive sigmoid adenocarcinoma.J

Gitelman's syndrome: a rare presentation mimicking cauda equina syndrome.

We describe a case of bilateral weakness of the lower limbs, sensory disturbance and intermittent urinary incontinence, secondary to untreated Gitelman's syndrome, in a 42-year-old female who was referred with presumed cauda equina syndrome. On examination, the power of both legs was uniformly reduced, and the perianal and lower-limb sensation was altered. However, MRI of the lumbar spine was normal. Measurements of serum and urinary potassium were low and blood gas analysis revealed metabolic alkalosis. Her symptoms resolved following potassium replacement. We emphasise the importance of measurement of the plasma and urinary levels of electrolytes in the investigation of patients with paralysis of the lower limbs and suggest that they, together with blood gas analysis, allow the exclusion of unusual causes of muscle weakness resulting from metabolic disorders such as metabolic alkalosis.

In vitro cytotoxicity of a composite resin and compomer.

AIM: This work was designed to investigate the potential cytotoxicity of two of the newer dental restorative materials. Spectrum composite resin and Dyract AP compomer. METHODOLOGY: Cultured human endothelial cells (ECV-304) were exposed to each of the restorative materials through a 70-microm dentine barrier to simulate the in vivo clinical situation. Cell viability was measured by the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide) assay and lactate dehydrogenase release assay. The effects of different extents of light-curing were also examined by microscopic examination of stained human promyelocytic leukemia cells (HL-60). Caspase-3 activation was determined as a measure of apoptotic cell death. RESULTS: Assessment of cellular viability indicated that both materials cause cell death, with Spectrum being the more toxic. The cytotoxicity was considerably increased in the absence of the dentine barrier. Direct exposure to Spectrum for 12 h resulted in the death of 69% of the cells after full light-curing (78% of total death was by apoptosis) and 96% after partial light-curing (73% of total death was by necrosis). Assessment of caspase activation, in the absence of the dentine barrier, showed that longer curing-times resulted in an increase in the proportion of the cells dying through apoptosis, rather than necrosis, for both materials tested. CONCLUSIONS: These results indicate the restorative materials to be potentially toxic, particularly if the degree of light-cure is inadequate.

VOC elimination in a compost biofilter using a previously acclimated bacterial inoculum.

A comparison of biodegradation efficiencies was done for volatile benzene, toluene, ethylbenzene, m-xylene, p-xylene, and o-xylene elimination in a compost biofilter. The column was first exposed to a synthetic mixture and then a free phase product mixture containing these compounds at increasing pollutant loads. The optimal moisture content of the system was determined, and this was used in the biodegradation experiments. An acclimated culture was used as an inoculum for the biofilter, the matrix of which consisted of composted forestry products, composted sewage sludge, lime, and perlite. Inlet and outlet concentrations were measured, and pollutant loads, elimination capacities, and removal efficiencies were determined for each of the compounds. Optimal moisture content for this system was found to be 40%, and the short lag times (one to five days) in acclimating to the compounds was ascribed to the presence of the well-acclimated inoculum. The compounds in the synthetic mixture had higher removal efficiencies (80-99%) even at the higher pollutant loads experienced, with the exception of o-xylene. Dynamic removal efficiencies and acclimation periods were seen in the free phase product mixture, with a removal efficiency range from 70 to 95%. This was attributed to the presence of chlorinated aliphatics in the free phase product.

The role of human papillomavirus in the development of pyogenic granulomas.

BACKGROUND: Pyogenic granulomas (lobular capillary hemangiomas) and condyloma acuminata share similar locations and risk factors. Human papillomavirus (HPV) types 6 and 11 are commonly associated with condyloma acuminata, but their association with pyogenic granulomas has not been evaluated. The purpose of this study was to determine whether pyogenic granulomas contain evidence of infection with condyloma-producing HPVs. METHODS: Polymerase chain reaction assays for the E6 and E7 gene sequences of HPV types 6 and 11 and another assay for the E7 region of HPV types 16, 31, 33, 35, 42, and 58 were used to evaluate deoxyribonucleic acid (DNA) extracted from archival pyogenic granuloma biopsies taken from cutaneous and oral epithelium. RESULTS: Neither cutaneous nor oral pyogenic granulomas contain amplifiable E6 or E7 sequences from any of these viruses. CONCLUSIONS: Pyogenic granulomas are not caused by HPV 6, 11, 16, 31, 33, 35, 42, or 58. This study does not exclude the possibility that other viruses may be responsible for these tumors.

Substrate specificities of caspase family proteases.

The caspase family represents a new class of intracellular cysteine proteases with known or suspected roles in cytokine maturation and apoptosis. These enzymes display a preference for Asp in the P1 position of substrates. To clarify differences in the biological roles of the interleukin-1beta converting enzyme (ICE) family proteases, we have examined in detail the specificities beyond the P1 position of caspase-1, -2, -3, -4, -6, and -7 toward minimal length peptide substrates in vitro. We find differences and similarities between the enzymes that suggest a functional subgrouping of the family different from that based on overall sequence alignment. The primary specificities of ICE homologs explain many observed enzyme preferences for macromolecular substrates and can be used to support predictions of their natural function(s). The results also suggest the design of optimal peptidic substrates and inhibitors.

9p21 deletions in primary melanoma.

Formalin-fixed, paraffin-embedded primary melanoma biopsies were evaluated for evidence of genomic loss on the short arm of chromosome 9 using microsatellite PCR assays for the D9S157, D9S161 and D9S171 loci. Paired normal and tumor DNA was extracted from the same block for comparison of microsatellite marker patterns. Some detectable abnormality was seen in at least one of these loci in 15 of 44 evaluable specimens (34%). Homozygous deletions were detectable at these loci in 8 of 44 informative specimens (18%) and hemizygous deletions were seen in 11 of 44 informative specimens (25%). Deletions at 9p were more likely to be found as primary tumor thickness increased (p < 0.05). This evidence supports the concept that 9p21 deletions are involved in primary sporadic melanomas, and that 9p deletions are not solely an in vitro phenomenon.

Proteolytic activation of protein kinase C delta by an ICE/CED 3-like protease induces characteristics of apoptosis.

Recent studies have shown that protein kinase C (PKC) delta is proteolytically activated at the onset of apoptosis induced by DNA-damaging agents, tumor necrosis factor, and anti-Fas antibody. However, the relationship of PKC delta cleavage to induction of apoptosis is unknown. The present studies demonstrate that full-length PKC delta is cleaved at DMQD330N to a catalytically active fragment by the cysteine protease CPP32. The results also demonstrate that overexpression of the catalytic kinase fragment in cells is associated with chromatin condensation, nuclear fragmentation, induction of sub-G1 phase DNA and lethality. By contrast, overexpression of full-length PKC delta or a kinase inactive PKC delta fragment had no detectable effect. The findings suggest that proteolytic activation of PKC delta by a CPP32-like protease contributes to phenotypic changes associated with apoptosis.