The sensitivity of transbronchial biopsy for the diagnosis of acute lung rejection

Transbronchial biopsy has become the procedure of choice for the diagnosis of acute lung rejection after transplantation, but the sensitivity of the technique in this setting remains unknown. In this study, 14 mongrel dogs underwent left lung transplantation, after which triple-drug immunosuppression was given for 5 days and then all immunosuppression was stopped. All animals had clear chest radiographs at this time. Transbronchial biopsy was performed in nine lung regions (two to six pieces of lung tissue were obtained per region, with a mean of 4.3 pieces per region) before the animals were killed 2 to 4 days later, at which time varying degrees of rejection had occurred. Rejection was graded histologically on a scale of 0 to 3 (0 = no rejection, 1 = mild rejection, 2 = moderate rejection, 3 = severe rejection) in each piece of lung tissue obtained at transbronchial biopsy. After the dogs were put to death, the true state of lung rejection was determined by histologic examination of the entire lung. We calculated the sensitivity of transbronchial biopsy with 95% confidence intervals. Five pieces of lung tissue were needed to yield a sensitivity of 92% (82%, 100%) to identify mild rejection in the entire lung with transbronchial biopsy. Three pieces of lung tissue were needed to yield a sensitivity of 92% (84%, 100%) to identify the presence of moderate to severe rejection in the entire lung (that is, rejection that requires pulse therapy) on transbronchial biopsy. These results indicate that three to five pieces of lung tissue that are suitable for diagnostic purposes obtained at transbronchial biopsy are adequate for the diagnosis of acute pulmonary rejection after lung transplantation.     

ARS Presidential Address: Estrogen therapy: a causal role in endometrial cancer?

Publicity associated with recent reports of a greater frequency of adenocarcinoma of the endometrium among women who take exogenous estrogens has created confusion among physicians and fear among patients. An objective review of available data on estrogen effects and current epidemiologic evidence suggests that estrogen may play an indirect role in the development of endometrial carcinoma. Until definitive data are available, physicians should exercise caution in prescribing estrogens, monitoring the status of the endometrium at regular intervals by sampling and pathologic analysis.     

Mechanism of work hardening in Hadfield manganese steel

When Hadfield manganese steel in the single-phase austenitic condition was strained in tension, in the temperature range - 25 to 300 °C, it exhibited jerky (serrated) flow, a negative (inverse) strain-rate dependence of flow stress and high work hardening, characteristic of dynamic strain aging. The strain rate-temperature regime of jerky flow was determined and the apparent activation energies for the appearance and disappearance of serrations were found to be 104 kJ/mol and 146 kJ/mol, respectively. The high work hardening cannot be a result of mechanical twinning because at -50 °C numerous twins were produced, but the work hardening was low and no twins were formed above 225 °C even though work hardening was high. The work hardening decreased above 300 °C because of the cessation of dynamic strain aging and increased again above 400 °C because of precipitation of carbides. An apparent activation energy of 138 kJ/mol was measured for static strain aging between 300 and 400 °C, corresponding closely to the activation energies for the disapperance of serrations and for the volume diffusion of carbon in Hadfield steel. Evidence from the present study, together with the known effect of manganese on the activity of carbon in austenite and previous internal friction studies of high-manganese steels, lead to the conclusion that dynamic strain aging, brought about by the reorientation of carbon members of C-Mn couples in the cores of dislocations, is the principal cause of rapid work hardening in Hadfield steel.     

Global warming and sustainable energy supply with CANDU nuclear power systems

The United Nation's Intergovernmental Panel on Climate Change (IPCC) review of global warming issues suggests man's activities have resulted in a discemible influence on global climate. The panel identifies options which could be employed to ameliorate the climate influencing greenhouse effect which is attributed primarily to carbon dioxide and other gaseous emissions from fossil fuel energy sources. One option identified is nuclear power, as an alternative energy source which would reduce these emissions. The panel observes that, although nuclear power is a relatively greenhouse gas free energy source, there are a number of issues related to it's use which are slowing it's deployment. This paper enumerates the issues raised by the IPCC and addresses each in turn in the context of CANDU reactors and sustainable development. It is concluded that the issues are not fundamental barriers to expanded installation of nuclear fission energy systems. Nuclear reactors, and CANDU reactors in particular, can meet the energy needs of current generations while enhancing the technological base which will allow future generations to meet their energy needs. The essential requirements of a sustainable system are thus met.     

Endotoxin release and cytokine production in acute and chronic meningococcaemia

Muscle activity produces an electrical signal termed the myo-electric signal (MES). The MES is a useful clinical tool, used in diagnostics and rehabilitation. This signal is typically stored in 2 bytes as 12-bit data, sampled at 3 kHz, resulting in a 6 kbyte s-1 storage requirement. Processing MES data requires large bit manipulations and heavy memory storage requirements. Adaptive differential pulse code modulation (ADPCM) is a popular and successful compression technique for speech. Its application to MES would reduce 12-bit data to a 4-bit representation, providing a 3:1 compression. As, in most practical applications, memory is organised in bytes, the realisable compression is 4:1, as pairs of data can be stored in a single byte. The performance of the ADPCM compression technique, using a real-time system at 1 kHz, 2 kHz and 4 kHz sampling rates, is evaluated. The data used include MES from both isometric and dynamic contractions. The percent residual difference (PRD) between an unprocessed and processed MES is used as a performance measure. Errors in computed parameters, such as median frequency and variance, which are used in clinical diagnostics, and waveform features employed in prosthetic control are also used to evaluate the system. The results of the study demonstrate that the ADPCM compression technique is an excellent solution for relieving the data storage requirements of MES both in isometric and dynamic situations.     

Evaluation of the effect of ivermectin administered topically at zero and six weeks after turnout on gastrointestinal nematode infection in first-season grazing cattle

OBJECTIVES: Slow potentials appearing during simple repetitive acral limb movement were investigated. Twenty-six patients suffering from drug resistant partial epilepsies and explored with implanted intracerebral electrodes were examined using two protocols. METHODS: In 18 patients, readiness potential (RP), in 13 patients contingent negative variation (CNV), and in 7 patients both protocols, were tested. The recordings from leads with evident pathological EEG activity were excluded from evaluation. The results concerning the slow potentials preceding the movements in RP and CNV protocols have already been published. RESULTS: The movement-accompanying slow potentials (MASP) were polyphasic or monophasic, started before or during the movement. In the primary motor cortex they followed the pre-movement potentials depending on the protocol: in the RP paradigm they were present only contralateral to the movement, but were bilateral in the CNV protocol. In other areas they either followed the potentials preceding the movement, in some cases with opposite polarity, or they occurred alone. MASP was recorded in motor and supplementary motor, premotor and prefrontal, midtemporal, somatosensory, superior parietal and cingular cortices. The cingular cortex was heavily involved in the self-paced movements but rarely in the cued movements. CONCLUSION: The major involvement of the cingular gyrus contrasted with the absence of slow potentials in temporal limbic structures. MASP is evidently a heterogenic phenomenon. Its genesis could be involved in a spread of information through the relevant structures.     

Region-specific decrease of dopamine and its metabolites in brains of mice given ergotamine

Under in vitro conditions, muscle larvae of Trichinella spiralis secreted minute amounts of a cysteine proteinase into the outer environment from the stichosome. The proteinase hydrolyzed azocoll at pH 5.0 but not a number of synthetic N-blocked and N-unsubstituted proteinase substrates at this pH. The reducing compound dithioerythritol enhanced the enzyme activity, but the thiol-blocking reagent sodium-p-hydroxymercuribenzoate (0.1 mM) was without effect. Phenylmethylsulfonyl fluoride (PMSF) (2 mM) and leupeptin (100 mM) produced partial and complete inhibition, respectively, whereas soybean trypsin inhibitor, pepstatin A, and 1,10-phenanthroline were non-inhibitory. Calcium (1 mM) produced a slight decrease in the activity that was reversed by 1 mM EGTA. Although multiple proteinase activities were detected histochemically in the somatic muscles, stichosome, midgut, and genital primordium of the muscle larvae, none of these enzymes appeared to be the one secreted. Several histochemically demonstrable proteinases were also found in the cells of 48- to 72-h-old juveniles of the parasite. One was localized in the esophageal lumen and at or around the anterior esophagus of the larvae, where developing stichocytes are believed to occur. The proteinase hydrolyzed N-acetyl-L-methionine-L-naphthyl ester and was sensitive to the metal cation-complexing compound EGTA as well as to PMSF, an inhibitor of serine proteinases.