Experimental demonstration of energy-chirp control in relativistic electron bunches using a corrugated pipe

The first experimental study is presented of a corrugated wall device that uses wakefields to remove a linear energy correlation in a relativistic electron beam (a "dechirper"). Time-resolved measurements of both longitudinal and transverse wakefields of the device are presented and compared with simulations. This study demonstrates the feasibility to employ a dechirper for precise control of the beam phase space in the next generation of free-electron-lasers.

Co-culture of melanocytes with adipose-derived stem cells as a potential substitute for co-culture with keratinocytes

Cell-to-cell interactions between melanocytes and keratinocytes increase the proliferation and migration of melanocytes. In fact, mixed keratinocyte and melanocyte cultures have been used for autologous cell transplantation for treatment of vitiligo. However, this may require taking an amount of skin tissue large enough to leave scars. In this study, the in vitro effect of adipose-derived stem cells (ADSCs) on proliferation, differentiation and migration of melanocytes was compared with that of keratinocytes using immunohistochemistry and a Boyden chamber migration assay. The proliferation and migration of melanocytes was significantly stimulated by co-culture with ADSCs compared with melanocyte monocultures, al-though the effect of ADSCs was less powerful than that of keratinocytes. This may be related to increases in stem cell factor and basic fibroblast growth factor, growth factors for melanocytes, produced by the ADSCs. The ratios of melanocytes stained with antibodies against Trp-2, E-cadherin and N-cadherin were significantly increased by co-culturing with ADSCs compared with co-culturing with keratinocytes as well as melanocyte monocultures. The proportion of less-pigmented melanocytes was also increased and sustained for a longer duration in the presence of ADSCs. Our data show that co-culturing with ADSCs results in increased melanocyte proliferation and migration while reducing differentiation, and could provide a means to treat disorders such as vitiligo.

Administration of poly(I:C) improved dermatophagoides farinae-induced atopic dermatitis-like skin lesions in NC/Nga mice by the regulation of Th1/Th2 balance

Atopic dermatitis (AD) is characterized by a chronic and replapsing skin disease with Th2-dominant allergic inflammation. Poly(I:C) has been shown to have immunopotentiator properties, but its effect on AD has not been examined. In this study, the immunomodulatory effects of poly(I:C), using dermatophagoides farinae (Df)-induced AD-like skin lesions in NC/Nga mice, were investigated. The clinical scores were reduced significantly by the treatment with poly(I:C) at 25 and 50 μg/mouse. Histological analysis of the skin also revealed that treatment of poly(I:C) at 25 and 50 μg/mouse significantly reduced the inflammatory cellular infiltrate, including mast cells and eosinophils. Moreover, poly(I:C) increased the level of IFN-γ, a Th1 cytokine, whereas decreasing that of selective Th2 cytokine both in vivo and in vitro. The levels of serum IgE and Th2 chemokines such as eotaxin, TARC, in spleen cells were also reduced by poly(I:C). These results suggest that poly(I:C) inhibit the development of Df-induced AD-like skin lesions in NC/Nga mice through regulation of the Th1/Th2 balance. Therefore, our results indicate that poly(I:C) might be a useful immunomodulatory agent for the treatment of human AD.

Glucosamine improved atopic dermatitis-like skin lesions in NC/Nga mice by inhibition of Th2 cell development

Dysregulated Th subset responses, characterized by Th2-dominant allergic inflammation, are thought to be central to the pathogenesis of atopic dermatitis (AD). Glucosamine has been shown to have immunosuppressive properties, but its effect on AD has not been examined. In this study, the immunoregulatory effects of glucosamine, using dermatophagoides farinae (Df)-induced AD-like skin lesions in NC/Nga mice, were investigated. The clinical scores were reduced significantly by the treatment with glucosamine at 10 and 20 mg/day. Histological analysis of the skin also revealed that treatment of glucosamine at 10 and 20 mg/day significantly reduced the inflammatory cellular infiltrate, including mast cells and eosinophils. The levels of serum IgE and Th2 cytokines in spleen cells were reduced, whereas no significant change was detected in IFN-γ, a Th1 cytokine. To determine the mechanism associated with inhibition of the Th2 immune response, the effects of glucosamine on the selective differentiation pathway of the Th subset in vitro was examined in NC/Nga mice. The results showed that glucosamine suppressed the differentiation of naïve CD4(+) T cells to Th2 cells in vitro. On the basis of in vivo and in vitro results of the NC/Nga mice, the immunobiological effects of glucosamine on peripheral blood mononuclear cells from patients with AD were examined. The production of Th2 cytokines, such as IL-4 and IL-5, was significantly decreased after in vitro administration of glucosamine, which suggest that glucosamine might be a useful immunomodulatory agent for the treatment of human AD.

Depth of a central venous catheter tip: length of insertion guideline for pediatric patients

BACKGROUND

In pediatric patients, several studies have been undertaken to establish central venous catheter (CVC) tip optimal depth. Assessments of catheter tip position using chest radiographs may be misleading, whereas transesophageal echocardiography (TEE) has been shown to accurately monitor catheter tip placement at the superior vena cava-right atrial (SVC-RA) junction. The aim of this study was to issue a guideline for ideal catheter insertion depth, from the right internal jugular vein (IJV) using TEE to confirm the position of the catheter tip at the SVC-RA junction.

METHODS

Over a 6-month period, we studied 60 right internal jugular vein catheterizations in infants and children undergoing surgery for congenital heart disease. Positions of CVC tips were confirmed to be at the SVC-RA junction by TEE. Distance from the skin puncture site to the SVC-RA junction, height, weight, and age were recorded.

RESULTS

Distances measured were found to be highly correlated with patient height. The following guideline allows the CVC tip to be positioned above the RA in 97.5% of patients with an accuracy of 95%: optimal depth of insertion (cm) = 1.7 + (0.07 x height) in patients whose height is between 40 and 140 cm.

CONCLUSION

The model proposed for the insertion of the CVC tip in pediatric patients could be used to prevent inadvertent catheter tip placement into the atrium.

Human B cell interleukin 10

Interleukin 10 (IL-10) is a novel lymphokine which exhibits strong DNA and amino acid sequence homology to BCRF1, an open reading frame in the Epstein-Barr virus genome. Using a wide panel of EBV positive and EBV negative cell lines, it has been shown that EBV positive B cell lines derived from patients with AIDS and Burkitt's lymphoma (AABCL) secrete large quantities of B cell IL-10, compared with EBV-positive B cell lines obtained from patients with undifferentiated lymphomas of Burkitt's and non-Burkitt's types. In contrast, EBV-negative B cell lines do not express IL-10 by Northern blot analysis, ELISA or even PCR. B cell IL-10 is confined to a narrow window in the B cell differentiation pathway, and whereas IL-10 expression is detected in mature and preplasmacytic stages, none of the pro-B, pre-B, or myeloma cell lines produce IL-10. EBV exerts direct effect on the production of B cell IL-10, and purified tonsillar B cells infected with EBV were triggered to secrete IL-10. The large amount of IL-10 secreted by B cells derived from AIDS-related lymphomas suggests that HIV-1 also exerts direct effect on IL-10 secretion. B cell IL-10 may function as autocrine growth factor for B cell lymphomas, and both IL-10 and BCRF1 seem to be involved in the pathophysiology of non-Hodgkin's lymphomas.

End of life care for infants with AIDS: ethical and legal issues

Complex cases involving end-of-life care for infants with AIDS raise a variety of ethical and legal concerns. Health care providers should understand the issues involving proper treatment, including adequate relief of pain at the end of life, and a context for examining the suffering of caregivers.

Comparison of a daily and three intermittent retreatment regimens for pulmonary tuberculosis administered under programme conditions

One daily and 3 thrice weekly retreatment regimens given for 12 months under programme conditions were compared. The daily regimen was rifampicin and ethambutol (RE7). The three intermittent regimens also contained rifampicin and ethambutol: one of them, rifampicin and ethambutol throughout (RE3); the next one supplemented with pyrazinamide for the first 3 months (REZ3); the last one supplemented with prothionamide for the first 3 months (REPt3). The pyrazinamide containing regimen was subdivided into ordinary and high dose groups. The subjects for retreatment were those who have had, at least, more than 6 months of initial triple chemotherapy of isoniazid, PAS and streptomycin at the health centres, and failed to convert to bacteriologically negative status. Among 419 patients who were available for sensitivity tests before commencing retreatment, 393 (94.3%) were resistant to isoniazid. Six hundred and seventy-four patients (674) were allocated randomly to the regimens: 64 patients were excluded due to various pretreatment reasons and 109 did not complete 12 months of chemotherapy. There remain 501 patients who completed their retreatment. As assessed at 12 months, a bacteriologically favourable response was achieved in 68% of 135 RE7 patients, 62% of 129 RE3 patients, 74% of 132 REZ3 patients, and in 79% of 108 REPt3 patients. Adverse reactions were uncommon: 4% in RE7, 5% in RE3 and 9% in REZ3, but 32% in REPt3. Relapse rates during 2 years after termination of chemotherapy were 15% in RE7, 14% in RE3 and REZ3, and 26% in REPt3, as calculated by life table analysis.

Pancreaticogastrostomy: a further evaluation

The anastomosis between the remaining pancreas and the intestinal tract after various types of pancreatic resection has been the site of complications responsible for considerable morbidity and mortality. After Whipple resections reestablishment of pancreatic-intestinal continuity has generally been accomplished in some manner between the pancreas and upper jejunum. This suture line has at times failed, often as the result of postoperative pancreatitis, giving rise to hemorrhage, abscess, and fistula formation. Since 1963, 25 patients undergoing pancreaticoduodenal resection have had some portion of their pancreas implanted into the back wall of the stomach. The operations have been done by the resident and senior staff of the Department of Surgery at the University of Pennsylvania. Morbidity has decreased and operative mortality has fallen from 20-30% to 8%. The technique is not difficult and there seems to be less tendency for the anastomosis to leak. Pancreatic function is usually adequate. The procedure is useful after radical resection of the pancreaticoduodenal region or at times after pancreatic trauma.

Physiologic correction of transposition of the great arteries. Indications for and results of operation in 32 patients

The total management of a group of 32 patients with transposition of the great arteries (TGA) is reported. All but one had required creation of an atrial septal defect in infancy. Eighteen patients had no associated cardiac defects, and physiologic correction was performed between 8 months and 9½ years of age. The only death in this group occurred 9 months after operation. Eight of nine patients with TGA and an associated ventricular septal defect (VSD) had required pulmonary artery banding in infancy. Physiologic correction was performed between 2¼ and 6 years of age. Three of these patients died during the postoperative period, and one died 9 months after operation. Two patients had TGA and pulmonary stenosis (PS). Physiologic correction was performed at 2 1/3 and 3¾ years of age. Both patients have done well. Three patients had TGA, VSD, and PS. Total correction was performed between 2 1/3 and 3½ years of age. All three patients died in the postoperative period. The over-all operative mortality was 19%.

Our present plan of management has evolved from the experience reported above. All infants with TGA have balloon atrioseptostomy. If no VSD is present, physiologic correction is performed between 1 and 2 years of age. Patients with TGA and a VSD are catheterized at 8 months of age, and pulmonary banding is performed if pulmonary artery hypertension is present. Physiologic correction is performed at about 4 years of age. Patients with TGA, VSD, and PS may require systemicpulmonary artery anastomosis. Correction at 5 years of age with the use of a homograft from the right ventricle to the pulmonary artery, as described by Rastelli and his associates, is recommended because of the poor results obtained with an intra-atrial baffle in this group.

Changes in pulmonary vascular resistance following closure of ventricular septal defects

In five patients with pulmonary arterial hypertension (PAH) associated with ventricular septal or endocardial cushion defects, measurements of pulmonary vascular resistance (PVR) were made up to seven days after surgical closure. Before operation, the ratio of mean pulmonary arterial pressure [See Equation in PDF File] to mean systemic arterial pressure [See Equation in PDF File] averaged 0.77 . Catheters placed at operation were used to measure pressure in the pulmonary artery, a systemic artery, and right and left atria. Cardiac output was determined by dye dilution. Controlled mechanical ventilation maintained a normal alveolar ventilation and arterial PO 2 .

Postoperative [See Equation in PDF File], [See Equation in PDF File], and PVR were initially elevated, averaging 42 mm Hg, 0.57, and 1,132 dyne sec cm -5 , respectively. These values decreased to 29, 0.38, and 459 in three to seven days in the four survivors, but rose in the single death. With unassisted ventilation and 100% 0 2 , or with acidosis (pH 7.21), [See Equation in PDF File] and PVR increased as much as +177% and 570%, respectively.

These studies show the relative pulmonary vasoconstricting effect of systemic acidosis and of spontaneous unassisted breathing with 100% O 2 . In patients with markedly elevated, but reversible, hyperkinetic pulmonary vascular resistance, the beneficial effects of prolonged mechanical ventilation enabled the pulmonary circulation to return toward normal.