Measurement and visualisation of focal cartilage thickness change by MRI in a study of knee osteoarthritis using a novel image analysis tool.

We describe the application of a novel analysis method that provides detailed maps of changes in cartilage thickness measured from MRI scans for individuals and cohorts of patients together with regional measures. A cohort of osteoarthritis patients was imaged using a 1.0 T MR scanner over a 36-month period. Hyaline cartilage was manually segmented from a three-dimensional (3D) spoiled gradient-echo sequence with fat suppression. Representative outlines of the bone surfaces of the distal femur and proximal tibia were automatically generated from T2 weighted images using statistical models of the shape and appearance of the bones. Cartilage thickness was measured from a dense set of points representing the bony surface. The models of the bones provided a common frame of reference, relative to which change maps were generated and aggregated across the cohort and anatomically corresponding subregions of the joint to be identified. In the reproducibility arm involving six patients, the thickness of cartilage had coefficients of variation of 2.66% within the tibiofemoral joint and 2.94% within the medial femoral condyle region. In the 9 patients (6 female, 3 male) who completed the 36-month study, the most striking observation was that lack of change in global measures of cartilage thickness concealed substantial focal changes. Specifically, the cartilage thickness within the tibiofemoral joint decreased by 0.85% per annum (95% CI -2.13% to 0.45%) with the medial femoral condyle as the region with the most significant change, decreasing by 2.43% per annum (uncorrected 95% CI -4.31% to 0.51%).

Long-term follow up of patients with toenail onychomycosis after treatment with terbinafine.

The long-term outcome of 111 patients treated with oral terbinafine for toenail onychomycosis with a novel treatment protocol was assessed a median of 138 weeks after entry into the trial. All but three patients had either one or two 12 week courses of terbinafine 250 mg daily. Of the 77 evaluable patients, 72.7% were still classified as responders (i.e. negative mycological culture and at least 3 mm of new unaffected nail growth) on reassessment. The present study shows that a favourable long-term outcome can be achieved in patients who have been treated with at least one 12 week course of terbinafine.

Non-dermatophytes in onychomycosis of the toenails.

A multicentre trial for the treatment of dermatophyte onychomycosis of the toenails with terbinafine was carried out in Australia and New Zealand. Between eight and 12 nail samples were obtained from each of the 118 patients in the 48-week trial, and each sample was investigated by direct microscopy and culture for dermatophyte and non-dermatophyte fungi. Patients were randomized to treatment with terbinafine at 250 mg/day or placebo for the first 12 weeks of the study, then non-responders were offered a 12-week course of terbinafine from week 28. All patients had a dermatophyte infection. In 42 patients (36%) microscopy and mycological culture identified dermatophytes alone. In the remaining 76 patients (64%), a non-dermatophyte mould or yeast was also isolated at some stage during the trial, but in only three patients did the same non-dermatophyte persist in two or more successive nail specimens. The presence of a fungal contaminant in addition to a dermatophyte had no apparent effect on the efficacy of treatment with terbinafine. We conclude that non-dermatophyte moulds and yeasts are generally found as contaminating organisms in dermatophyte onychomycosis, secondary to the dermatophytes, and that they do not influence the outcome of treatment.

Significance of non-dermatophyte moulds and yeasts in onychomycosis.

In a multicentre, randomised, double-blind, 48-week clinical trial, 118 patients with toe-nail onychomycosis were given terbinafine (250 mg daily) or placebo for 12 weeks, followed by 12 weeks of observation. Non-responders were offered 12 further weeks of terbinafine (250 mg daily) from week 28. Each patient had 8-12 consecutive nail specimens collected from the same nail, allowing for an assessment of the fungal nail flora from 1,321 nail specimens. By week 48, the overall mycological cure rate for terbinafine patients was 94%. 64% of patients had an underlying dermatophyte infection with at least 1 non-dermatophyte mould or yeast isolated from at least 1 specimen. These contaminants often overgrow or mask the presence of a dermatophyte. In only 2.5% of all patients was the same non-dermatophyte isolated from 2 or more consecutive specimens, probably representing secondary colonisation which exploits nutrients released by the underlying dermatophyte. The presence of incidental non-dermatophyte contaminants or secondary colonisers did not affect treatment outcome, and in this study treatment of the primary dermatophyte pathogen with terbinafine cleared the nails from infection in all cases. 80% of patients remained mycologically negative after 2 years.

Measuring the potency of pulp mill effluents for induction of hepatic mixed-function oxygenase activity in fish.

A bioassay protocol was optimized for measuring the potency of effluents or waterborne chemicals for inducing mixed-function oxygenase (MFO) activity of rainbow trout (Oncorhynchus mykiss). Measurements of ethoxyresorufin O-deethylase (EROD) can be made with an established endpoint assay using large volumes of reagents and tissue. However, a new kinetic microplate assay offers significant savings in time, reagents, and sample volumes. Data are distributed lognormally and must be log transformed before statistical analyses. EROD activity increases with exposure time to pulp mill effluent, and a 4-d exposure provides a near-maximal response. Optimum fish size conforms to standard practices in fish toxicology; loading rates should not exceed 1 g of fish per liter of test solution per day. Feed should be withheld from test fish 48 h before testing to reduce the variance of measured activity, and anaesthetizing fish with MS-222 does not affect their response to MFO inducers. Pulp mill effluents do not lose their potency during 2-3 wk of exposure at temperatures ranging from -20 to 13 degrees C, whether stored in plastic or glass. Steel containers were associated with slight losses in potency. Bioassays of MFO induction in fish exposed to liquid effluents are practical and conform to standard practice for testing the lethality of waterbone chemicals. The results are sufficiently precise that differences among means based on live fish per treatment can be discriminated statistically when activity changes by threefold or more.

Photosynthetic Gas Exchange and Discrimination against 13CO2 and C18O16O in Tobacco Plants Modified by an Antisense Construct to Have Low Chloroplastic Carbonic Anhydrase.

The physiological role of chloroplastic carbonic anhydrase (CA) was examined by antisense suppression of chloroplastic CA (on average 8% of wild type) in Nicotiana tabacum. Photosynthetic gas-exchange characteristics of low-CA and wild-type plants were measured concurrently with short-term, on-line stable isotope discrimination at varying vapor pressure deficit (VPD) and light intensity. Low-CA and wild-type plants were indistinguishable in the responses of assimilation, transpiration, stomatal conductance, and intercellular CO2 concentration to changing VPD or light intensity. At saturating light intensity, low-CA plants had lower discrimination against 13CO2 than wild-type plants by 1.2 to 1.8[per mille (thousand) sign]. Consequently, tissue of the low-CA plants was higher in 13C than the control plants. It was calculated that low-CA plants had chloroplast CO2 concentrations 13 to 22 [mu]mol mol-1 lower than wild-type plants. Discrimination against C18O16O in low-CA plants was 20% of that of the wild type, confirming a role of chloroplastic CA in the mechanism of discrimination against C18O16O ([delta]C18O16O). As VPD increased, stomatal closure caused a reduction in chloroplastic C02 concentration, and since VPD and chloroplastic CO2 concentration act in opposing directions on [delta]C18O16O, no effect of VPD was seen on [delta]C18O16O.

Restructuring critical care services. Part III: Successful implementation preparation.

Successful implementation in a redesigning organization does not happen without a sound design, good implementation planning and effective leadership. The focus of the implementation preparation must change prior to and after the "go live" implementation date. Implementation preparation requires intentional steps to build systems, communicate effectively and develop operational understanding among clinicians, physicians and management. Early effort should focus on planning for efficient day-to-day operations, development of measurement systems and contingency planning. Immediately prior to and after implementation the focus should be on communication, goal setting, issues prioritization and fact-based issues resolution. After the first couple of months of implementation, the focus should move toward mentoring teams/individuals, building outcome measurement systems, identifying sources of future improvement and transferring more authority as appropriate to teams. Commit to comprehensive implementation preparation. Time spent on implementation preparation will pay large dividends during the challenging times of transitioning your organization to a redesigned world.

Quantification of the Contribution of CO2, HCO3-, and External Carbonic Anhydrase to Photosynthesis at Low Dissolved Inorganic Carbon in Chlorella saccharophila.

An equation has been developed incorporating whole-cell rate constants for CO2 and HCO3- that describes accurately photosynthesis (Phs) in suspensions of unicellular algae at low dissolved inorganic carbon. At pH 8.0 the concentration of CO2 available to the algal cells depends on the rate of supply from, and the loss to, HCO3- and the rate of use by the cells. At elevated cell densities (>30 mg chlorophyll [Chl] L-1), at which CO2 use by the cells is high, the slope of a graph of absolute Phs versus Chl concentration approaches the rate of Phs on a milligram of Chl basis because of HCO3- use alone. The slope of a graph of Phs versus HCO3- will be the rate constant for HCO3-, and for Chlorella saccharophila it was 0.16 L mg-1 Chl h-1. The difference between the constants for dissolved inorganic carbon (measured in cells with external carbonic anhydrase) and HCO3-1 is the constant for CO2, which was 26 L mg-1 Chl h-1. This difference causes the half-saturation constant for Phs to increase 5- to 6-fold at high cell densities. The increase in CO2 use as a result of external carbonic anhydrase is described mathematically as a function of cell density.

Death of a classified worker probably caused by overexposure to gamma radiation.

This paper describes the case of an industrial radiographer who was seriously overexposed to gamma radiation. The exact circumstances of this exposure were not established but it was concluded that he was repeatedly irradiated probably to a total average whole body dose of at least 10 Gy over several years. Also, a much larger dose to a hand required its partial amputation. He developed myelodysplasia, which progressed to acute myeloid leukaemia from which he died. Karyotypic examination of the leukaemic blasts showed changes very similar to those associated with secondary leukaemia that may develop after radio or chemotherapy. The paper describes his medical case history, the investigation of his workplace, and the attempts to estimate his radiation dose by chromosomal analysis of blood lymphocytes and electron spin resonance of dental enamel and bone.

Rigorous management of insulin-dependent diabetes mellitus during pregnancy.

The effect of rigorous management of insulin-dependent diabetes mellitus (IDDM) during pregnancy on the perinatal outcome was assessed by comparing 78 prepartum gravid patients with IDDM managed prospectively with 78 matched controls. The diabetic women were treated with insulin by either infusion pump or split-dose therapy, with the goal of normalization of the fasting blood sugars and hemoglobin Hb A1c values. Differences in the perinatal outcome were evaluated by either chi-square or analysis of variance. Of the women with IDDM, 14% where White class B, 43% class C, 26% class D, 17% classes R and F. The mean Hb A1c value in the first half of pregnancy was 8.49% +/- 2.30%, and 7.34% +/- 1.79% in the second half. Women with IDDM had higher rates of premature delivery (31% vs. 10%, P = 0.003), pre-eclampsia (15% vs. 5%, P = 0.035), and cesarean section (55% vs. 27%, P = 0.002). Complications of infants born to diabetic mothers included large size for gestational age (41% vs. 16%, P = 0.0002), hypoglycemia (14% vs. 1%, P = 0.0025), hyperbilirubinemia (46% vs. 23%, P = 0.0002), and respiratory distress (12% vs. 1%, P = 0.008). The Apgar scores and mortality were similar. Congenital malformations occurred in 7.7% of infants of diabetic mothers and 1.3% of controls (P = 0.05). The maternal Hb A1c level did not correlate with the infant size for gestation. Although the improved medical management of IDDM has decreased neonatal mortality, significant perinatal complications persist.

Identification of Distinct Internal and External Isozymes of Carbonic Anhydrase in Chlorella saccharophila.

External carbonic anhydrase (CA) was detected in whole cells of alkaline-grown Chlorella saccharophila but was suppressed by growth at acid pH or growth on elevated levels of CO2. Internal CA activity was measured potentiometrically as an increase in activity in cell extracts over that of intact cells. Cells grown under all conditions had equal levels of internal CA activity. Two isozymes were identified after electrophoretic separation of soluble proteins on cellulose acetate plates. The fast isozyme was found in cells grown under all conditions, whereas the slow isozyme was found only in cells grown at alkaline pH. Western blot analysis following sodium dodecyl sulfate-polyacrylamide gel electrophoresis using antibodies produced against the periplasmic form of CA from Chlamydomonas reinhardtii revealed a single band at 39 kD, which did not change in intensity between growth conditions and was associated only with proteins eluted from the fast band. The slow isozyme was inactivated by incubation of cell extract at 30[deg]C and by incubation in 10 mM dithiothreitol, whereas the internal form was unaffected. These results indicate that external and internal forms of CA differ in structure and their activities respond differently to environmental conditions.

Dissolved inorganic nitrogen budget for a forested catchment at Beddgelert, North Wales.

An input-output budget for dissolved inorganic-N in a small forested catchment in North Wales is presented. From 1982 to 1990, bulk precipitation inputs averaged 10.3 kg ha(-1) year(-1), whereas throughfall inputs in 1983-1984 were 20.3 kg ha(-1) year(-1). Streamwater outputs were consistently larger than bulk precipitation inputs, averaging 14.6 kg ha(-1) year(-1). Inorganic-N in the forest stream was predominantly nitrate and concentrations were substantially higher than in a nearby moorland stream. Both streams showed seasonal trends in nitrate concentration, with highest concentrations occurring in summer in the forest stream but in winter in the moorland stream. Nitrate concentration in the forest stream increased with increasing soil temperature up to approximately 7 degrees C and decreased at higher temperatures. Nitrification is thought to be responsible for nitrate production at temperatures both below and above 7 degrees C, but root uptake becomes significant only at the higher temperatures. In the forest, dry deposition and cloudwater inputs of inorganic-N are responsible for increased nitrogen fluxes in throughfall compared with wet deposition. Mineralization and nitrification in excess of plant needs causes the organic soil horizons to act as a net source of dissolved inorganic-N. Nitrogen transformations in the soil lead to soil acidification at a rate of 1.0 keq ha(-1) year(-1).

Duodenal perforation after laparoscopic cholecystectomy.

A case is reported of duodenal perforation complicating laparoscopic cholecystectomy performed by laser dissection. The importance of investigating a patient with persistent shoulder-tip pain following this technique to exclude a subphrenic abscess is emphasised.

Identification and localization of carbonic anhydrase in two chlorella species.

Carbonic anhydrase (CA) activity and localization have been examined in two species of the eukaryotic green alga Chlorella. Mass spectrometric and potentiometric assays of CA activity indicate that C. ellipsoidea contains very little extracellular CA activity whereas C. saccharophila exhibits significant extracellular activity when grown at alkaline pH values. Extracellular CA activity appears to be correlated with the presence of a 36 kilodalton polypeptide that was detected immunologically using a polyclonal antibody directed against the 37 kilodalton Chlamydomonas CA monomer. Both Chlorella species and enzymatically isolated C. ellipsoidea chloroplasts also contain an immunologically similar 38 kilodalton polypeptide that may be a cytosolic or chloroplastic form of CA.

Meconium aspiration syndrome: intrapartum and neonatal attributes.

To identify the fetus and newborn at risk for meconium aspiration syndrome the perinatal characteristics of 238 infants delivered through meconium-stained amniotic fluid were prospectively examined. All infants with meconium-stained amniotic fluid were routinely suctioned with a DeLee apparatus before tracheal intubation and suctioning. The type and presence of meconium in the trachea, neonatal breathing before intubation, and Apgar scores were recorded in the delivery room. Intrapartum fetal monitoring data were collected for 80% (190/238) of the mothers and umbilical artery pH for 74% (177/238) of the newborns. Despite suctioning with a DeLee apparatus and endotracheal suctioning, meconium was present in the trachea in 87/238 (37%) and meconium aspiration syndrome developed in 22 (9.2%). A total of 73% of newborns who had meconium aspiration syndrome were delivered through thick meconium. Thick meconium, the presence of fetal tachycardia, and absence of intrapartum fetal cardiac accelerations identified the fetus at high risk for meconium aspiration syndrome. The presence of these monitoring findings and thick meconium should alert obstetricians to the possibility of a fetus that requires intervention. Low umbilical artery pH, Apgar scores less than 5, and meconium in the trachea further characterized the newborn at high risk for meconium aspiration syndrome. The combination of these findings may best identify the infant delivered through meconium-stained amniotic fluid who requires close observation for meconium aspiration syndrome.