The ground water behaviour pattern and foundation stabilisation practice at hartebeestfontein

Hartebeestfontein Gold Mining Company Limited, which produces 100 kg of gold per working day, has a mining lease area situated mainly over dolomite. A major river nearby governs the regional drainage. The formation of sinkholes and dolines, caused by fluctuations in the water table and the flow of water underground, often accelerated as the result of unavoidable or inadvertent surface activities, is common in such terranes. To maintain production, meticlous ground investigations under new installations plus periodic re-examination and stabilisation under existing ones, particularly key installations, is necessary. The local ground water behaviour pattern is controlled by three impervious major dykes and two major fissure zones, the latter draining surface water into the mine workings. Monthly water table measurements over 25 years show a steady rise to a limit over the area of one fissure zone and a drastic lowering over the other. The value of gravity techniques and thermal infra-red line scanning for cavity detection in the Hartebeestfontein context, is discussed. The procedures followed, for stabilising ground and foundations, are illustrated by means of case histories. The extension of the techniques, learnt from the stabilisation experience, to limiting water seepage into shafts sunk through dolomite, is also discussed.     

System Operational Evaluation of Mine Monitoring Systems

In the testing of mine monitoring systems, a software package was developed for the mine monitoring test facility designed at West Virginia University. The software establishes delay times of sensor input to annunciation for single alarms and multiple simultaneous alarms. The alarm measurement techniques for the test fixture are described, as is the software developed to analyze and graph monitoring system response data. Also included is the analysis capability of the facility, the criteria for evaluating mine monitoring systems, and typical test data from a sample system.     

COPD: using nutrition to prevent respiratory function decline

Close to three-fourths of patients with chronic obstructive pulmonary disease (COPD) suffer from weight loss. Identifying a single cause for this is difficult, as several factors-including chronic mouth breathing, dyspnea, aerophagia, certain medications, and depression-often act in concert. Malnutrition can exacerbate symptoms of COPD by decreasing ventilatory muscle strength, exercise tolerance, and immunocompetence, and by increasing the risk of depression and anxiety. Goals of nutrition intervention are to prevent or reverse malnutrition without worsening the disease process and to improve respiratory function, thereby reducing morbidity and delaying mortality. Recommendations for intake of fats, carbohydrates, protein, and water must be individualized.     

Metastatic phenotype correlates with high expression of membrane-associated complete beta-human chorionic gonadotropin in vivo

BACKGROUND: Investigations using living human cancer cells and the nude mouse model were conducted to evaluate the expression of human chorionic gonadotropin (hCG) in various cancers grown in vitro and in vivo. The aim was to determine whether membrane-associated hCG in any of its forms is a characteristic metastatic marker, and at what levels or ratios. METHODS: Human cancer cell lines known to produce tumors that metastasize spontaneously when grown in nude mice (n = 4) were compared with those that do not produce such tumors (n = 4) using analytical (quantitative) flow cytometry. Monoclonal antibodies directed to epitopes of intact hCG (hCG-holo) and its subunits, including beta-human chorionic gonadotropin with its carboxy-terminal peptide (hCG beta-CTP), allowed for the determination of hCG beta-CTP/hCG-holo ratios. RESULTS: No significant difference in hCG beta-CTP/hCG-holo ratios was found between the cultured human cancer cells that do not metastasize spontaneously (ratio = 2.39) and those that do (ratio = 2.13), and no difference was seen in their growth rate in nude mice. However, the cells isolated from tumors that do not metastasize spontaneously showed a decrease in their ratios to values less than 1. They reverted to their original values after reestablishment in culture and subsequent passages. In contrast, the ratios shown by cells isolated from tumors that metastasize spontaneously increased to 3 to 6 times their original values in culture, then reverted to their original values after reestablishment in culture and subsequent passages. CONCLUSIONS: To our knowledge, these data demonstrate the following for the first time: 1) There is a direct in vivo correlation between human cancer cells that metastasize spontaneously in nude mice and the expression of membrane-associated complete hCG beta (hCG beta-CTP); and the correlation identifies this molecule as a characteristic metastatic phenotype marker. 2) The marked ratio variations under different conditions indicate that the metastatic phenotype is an unstable event. 3) Growth and local invasion in vivo correlates with the expression of hCG-holo.     

Converging inputs to the entorhinal cortex from the piriform cortex and medial septum: facilitation and current source density analysis

Converging inputs to the entorhinal cortex from the piriform cortex and medial septum: facilitation and current source density analysis. J. Neurophysiol. 78: 2602-2615, 1997. The entorhinal cortex receives sensory inputs from the piriform cortex and modulatory inputs from the medial septum. To examine short-term synaptic facilitation effects in these pathways, current source density (CSD) analysis was used first to localize the entorhinal cortex membrane currents, which generate field potentials evoked by stimulation of these afferents. Field potentials were recorded at 50-micron intervals through the medial entorhinal cortex in urethan-anesthetized rats and the one-dimensional CSD was calculated. Piriform cortex stimulation evoked a surface-negative, deep-positive field potential component in the entorhinal cortex with mean onset and peak latencies of 10.4 and 18.4 ms. The component followed brief 100-Hz stimulation, consistent with a monosynaptic response. CSD analysis linked the component to a current sink, which often began in layer I before peaking in layer II. A later, surface-positive field potential component peaked at latencies near 45 ms and was associated with a current source in layer II. Medial septal stimulation evoked positive and negative field potential components which peaked at latencies near 7 and 16 ms, respectively. A weaker and more prolonged surface-negative, deep-positive component peaked at latencies near 25 ms. The early components were generated by currents in the hippocampal formation, and the late surface-negative component was generated by currents in layers II to IV of the entorhinal cortex. Short-term facilitation effects in conscious animals were examined using electrodes chronically implanted near layer II of the entorhinal cortex. Paired-pulse stimulation of the piriform cortex at interpulse intervals of 30 and 40 ms caused the largest facilitation (248%) of responses evoked by the second pulse. Responses evoked by medial septal stimulation also were facilitated maximally (59%) by a piriform cortex conditioning pulse delivered 30-40 ms earlier. Paired pulse stimulation of the medial septum caused the largest facilitation (149%) at intervals of 70 ms, but piriform cortex evoked responses were facilitated maximally (46%) by a septal conditioning pulse 100-200 ms earlier. Frequency potentiation effects were maximal during 12- to 18-Hz stimulation of either the piriform cortex or medial septum. Occlusion tests suggested that piriform cortex and medial septal efferents activate the same neurons. The CSD analysis results show that evoked field potential methods can be used effectively in chronically prepared animals to examine synaptic responses in the converging inputs from the piriform cortex and medial septum to the entorhinal cortex. The short-term potentiation phenomena observed here suggest that low-frequency activity in these pathways during endogenous oscillatory states may enhance entorhinal cortex responsivity to olfactory inputs.     

Cloning and expression of an endo-1,3-1,4-beta-glucanase gene from Bacillus macerans in Lactobacillus reuteri

Strains of the gastrointestinal species Lactobacillus reuteri were electrotransformed with plasmid constructs containing the endo-1,3-1,4-beta-glucanase gene (bglM) of Bacillus macerans. The enzyme was expressed and secreted by the lactobacilli. A plasmid construct containing the bglM gene lacking its promoter was derived and was demonstrated to be useful as a promoter probe vector.     

Effects of retinoic acid (all-trans and 9-cis) on tumor progression in small-cell lung carcinoma

ON direction-selective (DS) ganglion cells were identified by electrophysiological recordings in DAPI labeled, isolated rabbit retinas. Their responses to a flashing spot were sustained. Their responses to moving stimuli were strong in the preferred direction and weak in the null direction. Injection of the recorded cells with Lucifer yellow revealed that the cells had a distinct dendritic morphology, consistent with that described previously (Buhl & Peichl, 1986; Amthor et al., 1989; Famiglietti, 1992a). When neighboring cells were injected, an extensive dendritic co-fasciculation was observed. The pattern of fasciculation restricts the possible synaptic connections of the ON DS cell.     

The distribution of HBV, HCV and HGV among livers with fulminant hepatic failure of different aetiology

BACKGROUND/AIMS: The aim of the study was to assess the impact factor of HCV and HGV in fulminant hepatic failure. METHODS: The 5'-untranslated regions of HCV RNA and HGV RNA and a segment of the core antigen sequence of HBV were amplified after extracting the nucleic acids from snap-frozen tissue aliquots from explanted livers of 26 consecutive patients undergoing orthotopic liver transplantation for fulminant hepatic failure preoperatively diagnosed as either autoimmune (n=2), HAV/HBV (n=8), toxic (n=4) or aetiologically unknown (n=12). RESULTS: HCV RNA was detected in five of 26 (19.2%) livers with fulminant hepatic failure. All five HCV RNA-positive livers belonged to the group of non-toxic, non-autoimmune liver failure (n=20), three of them were found in the group of liver failure with unknown aetiology (n=12) and two in the group of HBV-associated liver failure (n=7), making an HCV incidence of 25%, 25% and 28.6%, in the different groups, respectively. HGV RNA was detected in 10 of 17 (58.8%) explants and in all four groups of fulminant hepatic failure as defined preoperatively. HBV DNA was identified in six livers of 26 patients (23.1%) with fulminant hepatic failure. Neither HCV RNA nor HBV DNA was detected in the livers of patients with toxic or autoimmune fulminant hepatic failure. CONCLUSIONS: These results indicate that HBV and HCV, but not HGV, play an aetiologic role in fulminant hepatic failure. HCV-positive cases were concentrated either in the group of otherwise unexplained fulminant hepatic failure or in the group of HBV fulminant hepatic failure. HGV-positive cases, on the other hand, were found within all four preoperatively defined groups, indicating a role as cofactor rather than as single aetiologic agent.