Oxyhemoglobin desaturation and aberrant carbon dioxide homeostasis during electrically stimulated exercise in a ventilator-dependent tetraplegic patient

This single-subject case examined oxyhemoglobin saturation and alveolar end-tidal carbon dioxide levels in a ventilator-dependent tetraplegic patient undergoing electrical stimulation cycle ergometry. When exercising with a closed tracheostomy cuff under resting ventilator settings (resting intermittent mandatory ventilation; frequency = 6breaths/min, tidal volume = 83.3mL, minute ventilation =5L/min), his oxyhemoglobin saturation decreased from 100% to 92%, while alveolar endtidal carbon dioxide increased linearly to 47mmHg. These undesirable changes were corrected under adjusted intermittent mandatory ventilation conditions (frequency = 12breaths/min, tidal volume = 83.3mL, minute ventilation = 10L/min), during which oxyhemoglobin saturation remained above 98% and the alveolar end-tidal carbon dioxide trend resembled that of ventilator-independent tetraplegic individuals undergoing the same exercise. Because the subject's heart rate was higher under adjusted ventilation conditions, these responses may have been caused by augmented venous return resulting from greater abdominothoracic pumping at the higher breathing frequency. These findings support the need to modify ventilator settings in ventilator-dependent tetraplegic persons while undergoing exercise to maintain oxyhemoglobin saturation and carbon dioxide homeostasis.     

Enterococcus faecalis localization in experimental endophthalmitis: role of plasmid-encoded aggregation substance

Enterococci have emerged as leading agents of nosocomial infection, yet relatively little is known about the pathogenesis of enterococcal disease. In previous studies, we developed an Enterococcus faecalis endophthalmitis infection model which provides unique opportunities to study the evolution of enterococcal disease by direct observation, as well as through sensitive electrophysiologic measures of organ function. The present study was designed to determine whether E. faecalis possesses traits that permit its attachment to mammalian tissues during infection. It was also of interest to determine whether a plasmid-encoded adhesin, aggregation substance, contributes to enterococcal localization or otherwise mediates adherence to alternate sites. These studies found that, in this model, enterococci attach to membranous structures occurring within the vitreous but that this attachment or the course or severity of disease is unaffected by the aggregation substance phenotype.     

Blast furnace burden softening and melting phenomena: Part I. Pellet bulk interaction observation

The cohesive zone in the blast furnace, where ferrous burden materials soften and melt, greatly affects the furnace’s performance. Minimizing the size and lowering the position of the cohesive zone will improve productivity and decrease the coke rate. This work was designed to better understand the softening and melting phenomena of ferrous feed materials. Different experimental techniques were used to allow the observation of different stages of softening and melting. This article examines the interaction between pellets at high temperatures under load. The pellets were reduced to 60 or 80 pct reduction degree (oxide basis), placed in a graphite crucible, and heated under N₂ gas flow, while X-ray pictures were taken at regular intervals. In addition, the contractions of the pellets and temperature were recorded. These experiments were performed with individual pellet types as well as with a mixed burden of fluxed with acid pellets at a ratio of 2:1. The dripping of liquid from the pellets occurred at different conditions depending on different reduction degrees. In those experiments where the pellets were reduced to 60 pct, the dripping also varied significantly between the basic fluxed and the other types of pellets. The meltdown of the pellets reduced to 80 pct seems to be controlled by the metallic iron shell. In the pellets reduced to 60 pct, it appears that both the metallic iron and the liquid slag determine the meltdown.     

Protective effect of curcuminoids on epidermal skin cells under free oxygen radical stress

Curcuminoids from Curcuma longa L. (Zingiberaceae) protected normal human keratinocytes from hypoxanthine/ xanthine oxidase injury. Since curcuminoids synergistically inhibited nitroblue tetrazolium reduction, a decrease in superoxide radical formation leading to lower levels of cytotoxic hydrogen peroxide was proposed as an explanation for this protective effect.     

Criteria to assess in vivo performance and bioequivalence of generic controlled-release formulations of carbamazepine

Ocular surface mucin is secreted from both goblet cells in the conjunctival epithelium and corneal epithelial cells. To clarify its mechanism of secretion in corneal epithelial cells, a rat cornea organ culture system was used to evaluate the second messenger roles of cyclic-AMP (cAMP), cyclic-GMP (cGMP) and protein kinase C (PKC) in modulating mucin-like glycoprotein secretion. Rat cornea sections (3 mm diameter) were cultured in TC-199 medium, and radiolabeled with sodium sulfate for 18 hr. After washing, the corneas were treated with various second messenger modulating agents for 30 min. The culture media were reacted with Dolichos biflorus (DBA)-lectin, and mucin-like glycoprotein was isolated. Then the radioactivity of DBA-binding mucin-like glycoprotein was isolated. Then the radioactivity of DBA-binding mucin-like glycoprotein was measured. There was a time-dependent increase in mucin-like glycoprotein was measured. There was a time-dependent increase in mucin-like glycoprotein secretion, whereas after corneal epithelial debridement the secretion was markedly inhibited by 81%. Mucin-like glycoprotein secretion was stimulated in a dose-dependent manner following elevation of cAMP levels by exposure to either forskolin, dibutyryl cAMP or 3-isobutyl-1-methylxanthine. Concomitant exposure to the cAMP dependent protein kinase inhibitor, KT5720 completely inhibited their stimulatory effects. Neither exposure to dibutyryl cGMP nor nitroprusside affected mucin-like glycoprotein secretion. Stimulation by PKC, phorbol 12, 13-dibutyrate (PDBu) also increased mucin-like glycoprotein secretion in a dose-dependent fashion. The PKC inhibitor, calphostin C completely inhibited the stimulation by PDBu of mucine-like glycoprotein secretion. These results demonstrate that corneal epithelial cells secrete mucin-like glycoprotein, which is mediated by cAMP and PKC signal transduction pathways.     

Accelerated reaction of nitric oxide with O2 within the hydrophobic interior of biological membranes

We demonstrate herein dramatic acceleration of aqueous nitric oxide (NO) reaction with O2 within the hydrophobic region of either phospholipid or biological membranes or detergent micelles and demonstrate that the presence of a distinct hydrophobic phase is required. Per unit volume, at low amounts of hydrophobic phase, the reaction of NO with O2 within the membranes is approximately 300 times more rapid than in the surrounding aqueous medium. In tissue, even though the membrane represents only 3% of the total volume, we calculate that 90% of NO reaction with O2 will occur there. We conclude that biological membranes and other tissue hydrophobic compartments are important sites for disappearance of NO and for formation of NO-derived reactive species and that attenuation of these potentially damaging reactions is an important protective action of lipid-soluble antioxidants such as vitamin E.     

Biochemical composition of human peripheral arteries examined with near-infrared Raman spectroscopy

OBJECTIVE: To describe the clinical, serologic, and immunogenetic features of familial idiopathic inflammatory myopathy (IIM) and to compare these with the features of sporadic IIM. METHODS: Clinical signs and symptoms, autoantibodies, HLA-DRB1 and DQA1 alleles, and GM/KM phenotypes were compared among 36 affected and 28 unaffected members of 16 unrelated families in which 2 or more blood relatives developed an IIM. In addition, findings in patients with familial IIM were compared with those in 181 patients with sporadic IIM. The families included 3 pairs of monozygotic twins with juvenile dermatomyositis, 11 families with other siblings or relatives with polymyositis or dermatomyositis, and 2 families with inclusion body myositis. RESULTS: The clinical features of familial IIM were similar to those of sporadic IIM, although the frequency of myositis-specific autoantibodies was lower in familial than in sporadic IIM. DRB1*0301 was a common genetic risk factor for familial and sporadic IIM, but contributed less to the genetic risk of familial IIM (etiologic fraction 0.35 versus 0.51 in sporadic IIM). Homozygosity at the HLA-DQA1 locus was found to be a genetic risk factor unique to familial IIM (57% versus 24% of controls; odds ratio 4.2, corrected P = 0.002). CONCLUSION: These findings emphasize that 1) familial muscle weakness is not always due to inherited metabolic defects or dystrophies, but may be the result of the development of IIM in several members of the same family, and 2) multiple genetic factors are likely important in the etiology and disease expression of familial IIM, as is also the case for sporadic myositis, but DQA1 homozygosity is a distinct risk factor for familial IIM.     

Minilaparotomy staging pelvic lymphadenectomy follow-up: a safe alternative to standard and laparoscopic pelvic lymphadenectomy

Granulocyte transfusion therapy has been used infrequently in the last 10 to 15 years, in large part because its efficacy in the treatment of infected neutropenic patients has not been impressive. This perceived lack of efficacy has been attributed primarily to the fact that the dose of granulocytes obtainable with standard leukapheresis techniques has been inadequate. With the availability of recombinant granulocyte colony-stimulating factor (G-CSF) to stimulate neutrophilia in normal donors and increase the number of granulocytes that can be collected, there is now renewed interest in this form of transfusion therapy. Recent studies have shown that stimulation with G-CSF, with or without corticosteroids, is well tolerated by normal donors and that granulocyte yields are increased three- to four-fold. Blood neutrophil counts in patients receiving these large cell doses rise substantially, often to normal or near normal levels, and commonly remain elevated for 24 hours or more. In vitro and in vivo measurements have shown that the functional capabilities of granulocytes collected from G-CSF stimulated donors appear to be normal. Although early reports have been encouraging, the clinical efficacy of this new level of granulocyte transfusion therapy has been yet to be determined.     

Citrobacter freundii empyema in a patient with occult pulmonary histoplasmosis

The genus Citrobacter includes three species of organisms that are uncommonly associated with human infection. When they are pathogenic, there are usually one or more associated respiratory, urinary, skin-soft tissue, and central nervous system infections and neonatal sepsis. These infections occur in the wake of significant systemic illness or complicate antibiotic usage. Rarely, infection has been associated with active tuberculosis. The authors report a case of Citrobacter freundii empyema in a patient with occult pulmonary histoplasmosis.