Surgical Electrotechnology: Quo Vadis?

The development of the modern electrosurgical generator and its accessories is outlined. The use of the electrosurgical scalpel is compared to other thermal knives: the plasma scalpel and the laser. The evolution of the dispersive electrode is summarized. Some of the innovations in endoscopic electrosurgery and the associated problems are discussed, along with a summary of some current research in hazard detection and waveform generating techniques and its impact on the next generation of electrosurgical generators.     

Serial soluble interleukin 2 receptor levels in rheumatoid arthritis: differences in response to glucocorticoid treatment and chrysotherapy

OBJECTIVE: To analyze the changes in soluble interleukin 2 receptor (sIL-2R) levels following treatment of patients with rheumatoid arthritis (RA). METHODS: Serial measurements of sIL-2R levels were made over 24 weeks in 40 patients with RA, treated with intramuscular (im) gold plus 3 im injections of either 120 mg methylprednisolone acetate or placebo. RESULTS: sIL-2R levels were reduced in the glucocorticoid treated group in contrast to the gold only group, where levels initially increased. At 24 weeks, mean sIL-2R levels did not significantly differ from pretreatment levels in either group, despite improvements in clinical measures. CONCLUSIONS: In our study, sIL-2R levels do not correlate with short term clinical measures of disease activity. Their significance for longer term prognostic use remains to be determined.     

The role of interleukin-8 and other cytokines in the pathogenesis of Felty's syndrome

OBJECTIVE: Felty's syndrome (FS) is defined as rheumatoid arthritis (RA) with neutropenia and, in some cases, splenomegaly; the outcome is primarily determined by the risk of infection, which is related to the degree of neutropenia. We analysed whether the clinical manifestations of FS, especially neutropenia, could be explained by abnormalities in cytokine production. METHODS: We examined the production in FS of five cytokines involved in the maturation and activation of polymorphonuclear cells (PMNs): IL-1 beta, TNF alpha, IL-8, G-CSF and GM-CSF. Because of the role of systemic IL-8 in neutrophil migration, serum IL-8 levels were also evaluated. RESULTS: Spontaneous and anti-CD16 stimulated cytokine production was similar in FS, RA and healthy controls (NC). However, anti-CD3 stimulated IL-8 production was significantly increased compared to NC in both RA and FS. FS patients who spontaneously produced G-CSF in culture were protected from bacterial infections. Serum IL-8 levels were elevated in FS and RA compared to NC (p < 0.001 for both groups). In FS, serum IL-8 was higher in patients with a history of bacterial infections compared to those without (p < 0.01) and there was a weak inverse correlation between neutropenia and serum IL-8 levels (Kendal's tau B = -0.31, p = 0.05). CONCLUSION: The neutropenia of FS cannot be explained by changes in peripheral blood cytokine production, although changes in the bone marrow microenvironment cannot be excluded. Our data do suggest a possible role for G-CSF and IL-8 in the development of certain FS complications.     

Lead suppresses chimeric human transferrin gene expression in transgenic mouse liver

The major iron-transport protein in serum is transferrin (TF) which also has the capacity to transport other metals. This report presents evidence that synthesis of human TF can be regulated by the metal lead. Transgenic mice carrying chimeric human TF-chloramphenicol acetyl transferase (CAT) genes received lead or sodium salts by intraperitoneal injections or in drinking water. Transgene expression in liver was suppressed 31 to 50% by the lead treatment. Lead regulates human TF transgenes at the mRNA level since liver CAT enzyme activity, CAT protein, and TF-CAT mRNA levels were all suppressed. The dosages of lead did not alter synthesis of the other liver proteins, mouse TF and albumin, as measured by Northern blot analysis of total liver RNA and rocket immunoelectrophoresis of mouse sera. Moderate levels of lead exposure were sufficient to evoke the human TF transgene response; blood lead levels in mice that received lead acetate in drinking water ranged from 30 micrograms/dl to 56 micrograms/dl. In addition to suppressing expression of TF-CAT genes in transgenic mice, lead also suppressed synthesis of TF protein in cultured human hepatoma HepG2 cells. The regulation of human TF apparently differs from the regulation of mouse TF which is unresponsive to lead exposure.     

Grain structure of bainitic and martensitic steels

In contrast to austenitic and ferritic microstructures, in the case of bainite and martensite the identification of that structural unit representing a grain is less straightforward. There is a general agreement in the literature that the γ → α-transformation follows the Kurdjumow-Sachs relationship (KSR). For the complex microstructures resulting, however, the investigations include practically exclusively lath-type structures. These relatively simple structures may be described as follows. Within the original austenite grain there are several lath packets with only a few variants of the KSR occuring within one bainite or martensite packet. Opinions diverge with regard to the relative orientations within a packet and thus the type of grain boundaries occurring. Most authors, however, agree that a micro-structural unit – such as the grain in the ferrite structure – which determines both the yield strength and toughness properties, does not exist in lath-type structures, and that the yield strength mainly depends on the lath dimensions. The toughness properties, especially the transition temperature, are governed by the packet size, and possibly by the width of the co-variant packet.