Clinical handover communication at maternity shift changes and women's safety in Banjul, the Gambia: a mixed-methods study.

BACKGROUND: Clinical handover is a vital communication process for patient safety; transferring patient responsibility between healthcare professionals (HCPs). Exploring handover processes in maternity care is fundamental for service quality, addressing continuity of care and maternal mortality. METHODS: This mixed-methods study was conducted in all three maternity hospitals in Banjul, The Gambia. Shift-to-shift maternity handovers were observed and compared against a standard investigating content and environment. Semi-structured interviews and focus group discussions with doctors, midwives and nurses explored handover experience. RESULTS: One hundred ten nurse/midwife shift-to-shift handovers were observed across all shift times and maternity wards; only 666 of 845 women (79%) were handed over. Doctors had no scheduled handover. Shift-leads alone gave/received handover, delayed [median 35 min, IQR 24-45] 82% of the time; 96% of handovers were not confidential and 29% were disrupted. Standardised guidelines and training were lacking. A median 6 of 28 topics [IQR 5-9] were communicated per woman. Information varied significantly by time, high-risk classification and location. For women in labour, 10 [IQR 8-14] items were handed-over, 8 [IQR 5-11] for women classed 'high-risk', 5 [IQR 4-7] for ante/postnatal women (p < 0.001); > 50% had no care management plan communicated. Twenty-one interviews and two focus groups were conducted. Facilitators and barriers to effective handover surrounding three health service factors emerged; health systems (e.g. absence of formalised handover training), organisation culture (e.g. absence of multidisciplinary team handover) and individual clinician factors (e.g. practical barriers such as transportation difficulties in getting to work). CONCLUSION: Maternity handover was inconsistent, hindered by contextual barriers including lack of team communication and guidelines, delays, with some women omitted entirely. Findings alongside HCPs views demonstrate feasible opportunities for enhancing handover, thereby improving women's safety.

Facilitating better postnatal care with women-held documents in The Gambia: a mixed-methods study.

BACKGROUND: Women-held documents are a basic component of continuity of maternity care. The use and completion of women-held documents following discharge could improve treatment and care for postnatal women. Using a mixed-methods study design, we aimed to assess the number, type, quality and completeness of women-held discharge documents, identify factors contributing to document completeness and facilitators or barriers for effective use of the documents. METHODS: Documents given to women at discharge from three hospitals in the Greater Banjul Area, The Gambia, were reviewed for content and quality. All women completed a questionnaire on the use of the documents. Poisson regression was used to estimate factors predicting document completion. Semi-structured interviews (n = 21) and focus groups (n = 2) were carried out with healthcare professionals (HCPs). RESULTS: Nearly all (n = 211/212; 99%) women were given a document to take home. The most complete document (maternal record) had on average 17/26 (65%) items completed and 10% of women held an illegible document. None of the women's sociodemographic or clinical characteristics predicted document completeness. The following facilitators for effective use of documents were identified from the women's responses to the questionnaire and interviews with HCPs: 94% of women thought written information is important, 99% plan to have postnatal check-ups and 67% plan to use their documents, HCPs understand the importance of the documents and were familiar with the document's use and content. The following barriers for effective use of documents were identified: HCPs had too many women-held documents to complete at discharge, there is no national protocol and HCPs think women do not understand the documents due to a lack of education and that women often lose or forget their documents. CONCLUSIONS: Women-held documents are well established in The Gambia; though quality and completeness needs improving. Future research should determine the impact of using only one document at discharge, protocols and training on completeness, among other outcomes, and on ways to ensure all women are using the documents for their postnatal care.

Evaluation of the Microvascular Blood Flow, Oxygenation, and Survival of Tarsoconjunctival Flaps Following the Modified Hughes Procedure.

PURPOSE: For the modified Hughes procedure, a tarsoconjunctival flap from the upper eyelid is used to reconstruct large, full-thickness, lower eyelid defects. The conjunctival pedicle is divided once vascularization is deemed to be adequate. The importance of maintaining a flap pedicle to ensure adequate perfusion of the graft has been questioned. The purpose of the study was to investigate the microvascular blood flow, oxygenation, and survival of a tarsoconjunctival flap in an experimental porcine model of the modified Hughes procedure. METHODS: The modified Hughes procedure was performed in 9 pigs. Microvascular blood flow was measured by laser Doppler velocimetry. Tissue oxygenation was measured using a Licox system, and tissue survival was determined by analyzing histologic sections of biopsy specimens from the lower edge of the flap. RESULTS: Blood flow and the oxygenation of the tissue decreased gradually during dissection and advancement of the tarsoconjunctival flap. At the time when the flap was sutured into place, there was virtually no blood flow or oxygenation of the tissue. However, flap survival did not seem to be compromised, as shown by the absence of pyknotic cell nuclei necrosis in the biopsy specimens, 12 hours after the procedure. CONCLUSIONS: The pedicle of the tarsoconjunctival flap does not seem to contribute to the nourishment of the tarsoconjunctival flap. Nourishment may be supplied by the rich vascularization of the remaining eyelid and tear film. If this is the case, single-stage grafting of a free tarsal plate may be performed, thus avoiding the eyelid-sharing stage of the procedure, without compromising the survival of the graft.

Comparison of bacteria and fungus-binding mesh, foam and gauze as fillers in negative pressure wound therapy--pressure transduction, wound edge contraction, microvascular blood flow and fluid retention.

Bacteria- and fungus-binding mesh binds with and inactivates bacteria and fungus, which makes it an interesting alternative, wound filler for negative pressure wound therapy (NPWT). This study was conducted to compare the performance of pathogen-binding mesh, foam and gauze as wound fillers in NPWT with regard to pressure transduction, fluid retention, wound contraction and microvascular blood flow. Wounds on the backs of 16 pigs were filled with pathogen-binding mesh, foam or gauze and treated with NPWT. The immediate effects of 0, -40, -60, -80 and -120 mmHg, on pressure transduction and blood flow were examined in eight pigs using laser Doppler velocimetry. Wound contraction and fluid retention were studied during 72 hours of NPWT at -80 and -120 mmHg in the other eight pigs. Pathogen-binding mesh, gauze and foam provide similar pressure transduction to the wound bed during NPWT. Blood flow was found to decrease 0.5 cm laterally from the wound edge and increase 2.5 cm from the wound edge, but was unaltered 5.0 cm from the wound edge. The increase in blood flow was similar with all wound fillers. The decrease in blood flow was more pronounced with foam than with gauze and pathogen-binding mesh. Similarly, wound contraction was more pronounced with foam, than with gauze and pathogen-binding mesh. Wound fluid retention was the same in foam and pathogen-binding mesh, while more fluid was retained in the wound when using gauze. The blood flow 0.5-5 cm from the wound edge and the contraction of the wound during NPWT were similar when using pathogen-binding mesh and gauze. Wound fluid was efficiently removed when using pathogen-binding mesh, which may explain previous findings that granulation tissue formation is more rapid under pathogen-binding mesh than under gauze. This, in combination with its pathogen-binding properties, makes this mesh an interesting wound filler for use in NPWT.

Omicron infection following vaccination enhances a broad spectrum of immune responses dependent on infection history.

Pronounced immune escape by the SARS-CoV-2 Omicron variant has resulted in many individuals possessing hybrid immunity, generated through a combination of vaccination and infection. Concerns have been raised that omicron breakthrough infections in triple-vaccinated individuals result in poor induction of omicron-specific immunity, and that prior SARS-CoV-2 infection is associated with immune dampening. Taking a broad and comprehensive approach, we characterize mucosal and blood immunity to spike and non-spike antigens following BA.1/BA.2 infections in triple mRNA-vaccinated individuals, with and without prior SARS-CoV-2 infection. We find that most individuals increase BA.1/BA.2/BA.5-specific neutralizing antibodies following infection, but confirm that the magnitude of increase and post-omicron titres are higher in the infection-naive. In contrast, significant increases in nasal responses, including neutralizing activity against BA.5 spike, are seen regardless of infection history. Spike-specific T cells increase only in infection-naive vaccinees; however, post-omicron T cell responses are significantly higher in the previously-infected, who display a maximally induced response with a highly cytotoxic CD8+ phenotype following their 3rd mRNA vaccine dose. Responses to non-spike antigens increase significantly regardless of prior infection status. These findings suggest that hybrid immunity induced by omicron breakthrough infections is characterized by significant immune enhancement that can help protect against future omicron variants.

Longitudinal Lung Function Assessment of Patients Hospitalized With COVID-19 Using 1H and 129Xe Lung MRI.

BACKGROUND: Microvascular abnormalities and impaired gas transfer have been observed in patients with COVID-19. The progression of pulmonary changes in these patients remains unclear. RESEARCH QUESTION: Do patients hospitalized with COVID-19 without evidence of architectural distortion on structural imaging exhibit longitudinal improvements in lung function measured by using 1H and 129Xe MRI between 6 and 52 weeks following hospitalization? STUDY DESIGN AND METHODS: Patients who were hospitalized with COVID-19 pneumonia underwent a pulmonary 1H and 129Xe MRI protocol at 6, 12, 25, and 51 weeks following hospital admission in a prospective cohort study between November 2020 and February 2022. The imaging protocol was as follows: 1H ultra-short echo time, contrast-enhanced lung perfusion, 129Xe ventilation, 129Xe diffusion-weighted, and 129Xe spectroscopic imaging of gas exchange. RESULTS: Nine patients were recruited (age 57 ± 14 [median ± interquartile range] years; six of nine patients were male). Patients underwent MRI at 6 (n = 9), 12 (n = 9), 25 (n = 6), and 51 (n = 8) weeks following hospital admission. Patients with signs of interstitial lung damage were excluded. At 6 weeks, patients exhibited impaired 129Xe gas transfer (RBC to membrane fraction), but lung microstructure was not increased (apparent diffusion coefficient and mean acinar airway dimensions). Minor ventilation abnormalities present in four patients were largely resolved in the 6- to 25-week period. At 12 weeks, all patients with lung perfusion data (n = 6) showed an increase in both pulmonary blood volume and flow compared with 6 weeks, although this was not statistically significant. At 12 weeks, significant improvements in 129Xe gas transfer were observed compared with 6-week examinations; however, 129Xe gas transfer remained abnormally low at weeks 12, 25, and 51. INTERPRETATION: 129Xe gas transfer was impaired up to 1 year following hospitalization in patients who were hospitalized with COVID-19 pneumonia, without evidence of architectural distortion on structural imaging, whereas lung ventilation was normal at 52 weeks.

Fatal case of delayed-onset haemolytic anaemia after oral artemether-lumefantrine.

Artemisinin derivatives are used globally in the management of falciparum malaria. Postartemisinin delayed haemolysis (PADH) is a recognised adverse event contributing to severe anaemia. To the best of our knowledge, we report the first recorded fatal case of PADH. A 60-year-old woman presented with two episodes of collapse at home and feeling generally unwell. She had recently been treated for uncomplicated falciparum malaria 1 month prior with artemether 80 mg/lumefantrine 480 mg in Congo. Her results on admission revealed an anaemia (haemoglobin 43 g/L), raised lactate dehydrogenase and positive direct antiglobulin test that suggested an intravascular haemolytic process. She made a capacitous decision to refuse blood products in line with her personal beliefs. Despite best supportive treatment, she did not survive. This case highlights the importance of postartemisinin follow-up and should encourage discussion and careful consideration of its use in the context of lack of access to/patient refusal of blood products.

Tumor necrosis factor and its receptors in the neuroretina and retinal vasculature after ischemia-reperfusion injury in the pig retina.

PURPOSE: Numerous studies have been performed aimed at limiting the extent of retinal injury after ischemia, but there is still no effective pharmacological treatment available. The aim of the present study was to examine the role of tumor necrosis factor (TNF)α and its receptors (TNF-R1 and TNF-R2), especially considering the neuroretina and the retinal vasculature since the retinal blood vessels are key organs in circulatory failure. METHODS: Retinal ischemia was induced in pigs by elevating the intraocular pressure to 80 mmHg in one eye, while the other eye served as a control (sham-operated). One hour of ischemia was followed by 5 or 12 h of reperfusion. Retinal circulation was examined in vivo by fundus imaging and fluorescein angiography. TNF-α levels were measured in the vitreous using an angiogenesis antibody array test. The presence and amounts of TNF-α, TNF-R1, and TNF-R2 were investigated in the neuroretina and in the retinal blood vessels, using immunofluorescence staining and real-time PCR techniques. RESULTS: Fundus imaging showed obstructed blood flow when ischemia was induced, and reperfusion was clearly visualized using fluorescein angiography. Ischemia resulted in elevated levels of TNF-α protein in the vitreous and TNF-α mRNA in the neuroretina. TNF-α immunofluorescence staining was localized to the Müller cells and the outer plexiform layer of the neuroretina. The expression of TNF-R1 and TNF-R2 mRNA was increased in both the neuroretina and retinal arteries following ischemia-reperfusion. Immunofluorescence double staining for TNF-R1 and either smooth muscle actin or 4',6-diamidino-2-phenylindole (DAPI) indicated expression in the cell membranes of the vascular smooth muscle cells. Double staining with TNF-R1 and calbindin showed localization to the horizontal cells in the outer plexiform layer of the neuroretina. CONCLUSIONS: Retinal ischemia results in increased expression of TNF-α and its receptors (TNF-R1 and TNF-R2). Cellular signaling pathways involving TNF may be important in the development of retinal injury following ischemia and thus an interesting target for future development of pharmacological therapeutics.

Mitogen-activated protein kinases in the porcine retinal arteries and neuroretina following retinal ischemia-reperfusion.

PURPOSE: The aim of the present study was to examine changes in the expression of intracellular signal-transduction pathways, specifically mitogen-activated protein kinases, following retinal ischemia-reperfusion. METHODS: Retinal ischemia was induced by elevating the intraocular pressure in porcine eyes, followed by 5, 12, or 20 h of reperfusion. The results were compared to those of the sham- operated fellow eye. The retinal arteries and neuroretina were isolated separately and examined. Tissue morphology and DNA fragmentation were studied using histology. Extracellular signal-regulated kinase 1 and 2 (ERK1/2), p38, c-junNH(2)-terminal kinases (JNK), and c-jun protein and mRNA expression were examined using immunofluorescence staining, western blot, and real-time PCR techniques. RESULTS: Pyknotic cell nuclei, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells, and glial fibrillary acidic protein mRNA expression were increased in ischemia, suggesting injury. Phosphorylated ERK1/2 protein levels were increased in the neuroretina following ischemia, while mRNA levels were unaltered. p38 protein and mRNA levels were not affected by ischemia. Immunofluorescence staining for phosphorylated p38 was especially intense in the retinal blood vessels, while only weak in the neuroretina. Phosphorylated JNK protein and mRNA were slightly decreased in ischemia. Phosphorylated c-jun protein and mRNA levels were higher in the neuroretina after ischemia-reperfusion. CONCLUSIONS: Retinal ischemia-reperfusion alters expression of mitogen-activated protein kinases, particularly ERK1/2, in the neuroretina and retinal arteries. The development of pharmacological treatment targeting these intracellular transduction pathways may prevent injury to the eye following retinal circulatory failure.

Micro- and macromechanical effects on the wound bed of negative pressure wound therapy using gauze and foam.

Negative pressure wound therapy (NPWT) results in 2 types of tissue deformation, macrodeformation (ie, wound contraction) and microdeformation (ie, the interaction of tissue and dressing on a microscopic level). These effects have been delineated for one type of wound filler, foam, but not for gauze. The mechanical deformation initiates a signaling cascade which ultimately leads to wound healing. The aim of the present study was to examine the effect of gauze and foam on macro- and microdeformation during treatment with negative pressure. An in vivo porcine peripheral wound model was used. NPWT was applied for 72 hours at 0, -75, and -125 mm Hg, using either foam or gauze as wound filler. The mechanical effects of NPWT were examined by measuring the wound surface area reduction and by histologic analysis of the wound bed tissue. Similar degrees of wound contraction (macrodeformation) were seen during NPWT regardless if foam or gauze was used. After negative pressure had been discontinued, the wound stayed contracted. There was no difference in wound contraction between -75 and -125 mm Hg. Biopsies of the wound bed revealed a repeating pattern of wound surface undulations and small tissue blebs ("tissue mushrooms") were pulled into the pores of the foam dressing and the spaces between the threads in the gauze dressing (microdeformation). This pattern was obvious in wounds treated both with foam and gauze, at atmospheric pressure (0 mm Hg) as well as at subatmospheric pressures (-75 and -125 mm Hg). The degrees of micro- and macrodeformation of the wound bed are similar after NPWT regardless if foam or gauze is used as wound filler.

The content and completeness of women-held maternity documents before admission for labour: A mixed methods study in Banjul, The Gambia.

BACKGROUND: Women-held maternity documents are well established for enabling continuity of maternity care worldwide, with the World Health Organisation (WHO) recommending their use in effective decision-making. We aimed to assess the presence, content and completeness of women-held maternity documents at admission to hospitals in The Gambia, and investigate barriers and facilitators to their completion. METHODS: We interviewed 250 women on maternity wards of all 3 Banjul hospitals and conducted content analysis of documentation brought by women on admission for their completeness against WHO referrals criteria. Logistic regression models were used to estimate the odds of the minimum criteria being met. Two focus groups and 21 semi-structured interviews (8 doctors, 8 midwives and 5 nurses) were conducted with healthcare practitioners to explore barriers and facilitators to documented clinical information availability on admission. FINDINGS: Of the women admitted, all but 10/250 (4%) brought either a maternity card or a structured referral sheet. Of all forms of documentation, women most frequently brought the government-issued maternity card (235/250, 94%); 16% of cards had all 9 minimum criteria completed. Of the 79 referred women, 60% carried standardised referral forms. Only 30% of 97 high-risk women had risk-status recorded. Women were less likely to have documents complete if they were illiterate, had not attended three maternity appointments, or lived more than one hour from hospital. During qualitative interviews, three themes were identified: women as agents for transporting information and documents (e.g. remembering to bring maternity cards); role of individual healthcare professionals' actions (e.g. legibility of handwriting); system and organisational culture (e.g. standardised referral guidelines). CONCLUSION: Women rarely forgot their maternity card, but documents brought at admission were frequently incomplete. This is a missed opportunity to enhance handover and quality of care, especially for high-risk women. National guidelines were recognised by providers as needed for good document keeping and would enhance the women-held maternity documents' contribution to improving both safety and continuity of care.

HAMLET (human alpha-lactalbumin made lethal to tumor cells) triggers autophagic tumor cell death.

HAMLET, a complex of partially unfolded alpha-lactalbumin and oleic acid, kills a wide range of tumor cells. Here we propose that HAMLET causes macroautophagy in tumor cells and that this contributes to their death. Cell death was accompanied by mitochondrial damage and a reduction in the level of active mTOR and HAMLET triggered extensive cytoplasmic vacuolization and the formation of double-membrane-enclosed vesicles typical of macroautophagy. In addition, HAMLET caused a change from uniform (LC3-I) to granular (LC3-II) staining in LC3-GFP-transfected cells reflecting LC3 translocation during macroautophagy, and this was blocked by the macroautophagy inhibitor 3-methyladenine. HAMLET also caused accumulation of LC3-II detected by Western blot when lysosomal degradation was inhibited suggesting that HAMLET caused an increase in autophagic flux. To determine if macroautophagy contributed to cell death, we used RNA interference against Beclin-1 and Atg5. Suppression of Beclin-1 and Atg5 improved the survival of HAMLET-treated tumor cells and inhibited the increase in granular LC3-GFP staining. The results show that HAMLET triggers macroautophagy in tumor cells and suggest that macroautophagy contributes to HAMLET-induced tumor cell death.

Protein kinase C in porcine retinal arteries and neuroretina following retinal ischemia-reperfusion.

PURPOSE: Identification of the intracellular signal-transduction pathways activated in retinal ischemia may be important in revealing novel pharmacological targets. To date, most studies have focused on identifying neuroprotective agents. The retinal blood vessels are key organs in circulatory failure, and this study was therefore designed to examine the retinal vasculature separately from the neuroretina. METHODS: Retinal ischemia was induced by elevating the intraocular pressure in porcine eyes, followed by 5, 12, or 20 h of reperfusion. Protein kinase C (PKC)alpha, PKCbeta1, and PKCbeta2 mRNA levels, and protein expression were determined using real-time PCR, western blot, and immunofluorescence staining techniques. RESULTS: The retinal arteries could easily be dissected free and studied separately from the neuroretina in this porcine model. The PKCalpha, PKCbeta1, and PKCbeta2 mRNA levels tended to be lower in ischemia-reperfused than in sham-operated eyes in both the retinal arteries and the neuroretina. This was most prominent after 5 h, and less pronounced after 12 h and 20 h of reperfusion. Likewise, the protein levels of PKCalpha, PKCbeta1, and PKCbeta2 were slightly lower following ischemia-reperfusion when compared to sham-operated eyes. PKCalpha, PKCbeta1, and PKCbeta2 immunostaining were observed in bipolar cells of the neuroretina and in endothelial cells, and to a low extent in the smooth muscle layer, of the retinal arteries. CONCLUSIONS: Retinal ischemia followed by reperfusion results in lower levels of PKC in both the neuroretina and retinal arteries. New targets for pharmacological treatment may be found by studying the retinal vasculature so as to identify the intracellular signal-transduction pathways involved in the development of injury following retinal circulatory failure.

Endothelin receptor-mediated vasodilatation: effects of organ culture.

Culture of intact arteries is a frequently employed experimental model for investigating the mechanisms governing the regulation of vascular endothelin receptors. Endothelin type A (ET(A)) and type B (ET(B)) receptors on vascular smooth muscle cells are up-regulated in organ culture and the enhanced vasoconstriction mimics the changes that occur in cardiovascular disease. The effect of organ culture on endothelial dilatory endothelin ET(B) receptors is not known. We hypothesize that organ culture decreases the endothelin receptor-mediated dilatation and that this is one possible mechanism by which the effects of the endothelin in blood vessels are altered during culture. Porcine coronary arteries were studied before and after 24 h of culture, using in vitro pharmacology and immunofluorescence. Sarafotoxin 6c and endothelin-1 were used to examine the endothelin ET(A) and ET(B) receptor effects, and the antagonists, Nomega-nitro-l-arginine (l-NOARG) for nitric oxide (NO), indomethacin for prostaglandins and charybdotoxin in combination with apamin for endothelium-derived hyperpolarizing factor (EDHF), were used to study the endothelium-derived dilatory mediators. Organ culture induced up-regulation of the sarafotoxin 6c (ET(B) receptor agonist) and endothelin-1 (ET(A) receptor agonist) elicited vasoconstriction. The sarafotoxin 6c contraction was stronger after endothelium denudation, suggesting endothelium-dependent dilatation. The endothelin-1 contraction was not affected by endothelium denudation. The increase in sarafotoxin 6c contraction after removal of the endothelium was more pronounced before than after organ culture, suggesting down-regulated endothelial endothelin ET(B) receptors. Also, the immunofluorescence staining intensities for endothelial endothelin ET(B) receptors were higher before than after organ culture. Pre-incubation with inhibitors for dilatory mediators suggested that both NO and EDHF play a vasodilatory role, while prostaglandins are not involved. In conclusion, endothelial endothelin ET(B) receptors induce NO and EDHF mediated vasodilatation in porcine coronary arteries. In organ culture, endothelial endothelin ET(B) receptors are down-regulated, mimicking the changes that occur in cardiovascular disease. Down-regulation of endothelial endothelin ET(B) receptors may in part explain the increased endothelin ET(B) receptor-mediated vasoconstriction frequently studied in organ culture.

PKC and MAPK signalling pathways regulate vascular endothelin receptor expression.

Up-regulation of vascular endothelin type A (ET(A)) and type B (ET(B)) receptors are implicated in the pathogenesis of cardiovascular disease. Culture of arteries has been shown to induce similar receptor alterations and has therefore been suggested as a suitable method for in detail delineation of the regulation of endothelin receptors. We hypothesize that protein kinase C (PKC) and mitogen-activated kinases (MAPK) are involved in the regulation of endothelin receptors. Porcine coronary arteries were studied before and after 24 h of culture, using in vitro pharmacology, real-time PCR and immunofluorescence techniques. Sarafotoxin 6c and endothelin ET-1 were used to examine the endothelin ET(A) and ET(B) receptor effects. The involvement of PKC and MAPK in the receptor regulation was examined by culture in the presence of antagonists. Organ culture resulted in increased sarafotoxin 6c and endothelin-1 contractions, endothelin ET(A) and ET(B) receptor immunofluorescence staining intensities and endothelin ET(B), but not ET(A), receptor mRNA levels. The general PKC inhibitors, bisindolylmaleimide I (10 microM) or Ro-32-0432 (10 microM), inhibited these effects. Also, the increase in sarafotoxin 6c contraction, endothelin ET(B) receptor and mRNA levels and endothelin ET(A) and ET(B) immunofluorescence staining intensities were inhibited by MAPK inhibitors for extracellular signal related kinases 1 and 2 (ERK1/2), PD98059 (10 microM), C-jun terminal kinase (JNK), SP600125 (10 microM), but not by p38 MAPK, SB203580 (10 microM). In conclusion, PKC and MAPK seem to be involved in the regulation of endothelin receptor expression in porcine coronary arteries. Inhibiting these intracellular signal transduction pathways may provide a future therapeutic target for hindering the development of vascular endothelin receptor changes in cardiovascular disease.

Up-regulation of endothelin type B receptors in the human internal mammary artery in culture is dependent on protein kinase C and mitogen-activated kinase signaling pathways.

BACKGROUND: Up-regulation of vascular endothelin type B (ETB) receptors is implicated in the pathogenesis of cardiovascular disease. Culture of intact arteries has been shown to induce similar receptor alterations and has therefore been suggested as a suitable method for, ex vivo, in detail delineation of the regulation of endothelin receptors. We hypothesize that mitogen-activated kinases (MAPK) and protein kinase C (PKC) are involved in the regulation of endothelin ETB receptors in human internal mammary arteries. METHODS: Human internal mammary arteries were obtained during coronary artery bypass graft surgery and were studied before and after 24 hours of organ culture, using in vitro pharmacology, real time PCR and Western blot techniques. Sarafotoxin 6c and endothelin-1 were used to examine the endothelin ETA and ETB receptor effects, respectively. The involvement of PKC and MAPK in the endothelin receptor regulation was examined by culture in the presence of antagonists. RESULTS: The endothelin-1-induced contraction (after endothelin ETB receptor desensitization) and the endothelin ETA receptor mRNA expression levels were not altered by culture. The sarafotoxin 6c contraction, endothelin ETB receptor protein and mRNA expression levels were increased after organ culture. This increase was antagonized by; (1) PKC inhibitors (10 microM bisindolylmaleimide I and 10 microM Ro-32-0432), and (2) inhibitors of the p38, extracellular signal related kinases 1 and 2 (ERK1/2) and C-jun terminal kinase (JNK) MAPK pathways (10 microM SB203580, 10 microM PD98059 and 10 microM SP600125, respectively). CONCLUSION: In conclusion, PKC and MAPK seem to be involved in the up-regulation of endothelin ETB receptor expression in human internal mammary arteries. Inhibiting these intracellular signal transduction pathways may provide a future therapeutic target for hindering the development of vascular endothelin ETB receptor changes in cardiovascular disease.

Apoptosis and tumor cell death in response to HAMLET (human alpha-lactalbumin made lethal to tumor cells).

HAMLET (human alpha-lactalbumin made lethal to tumor cells) is a molecular complex derived from human milk that kills tumor cells by a process resembling programmed cell death. The complex consists of partially unfolded alpha-lactalbumin and oleic acid, and both the protein and the fatty acid are required for cell death. HAMLET has broad antitumor activity in vitro, and its therapeutic effect has been confirmed in vivo in a human glioblastoma rat xenograft model, in patients with skin papillomas and in patients with bladder cancer. The mechanisms of tumor cell death remain unclear, however. Immediately after the encounter with tumor cells, HAMLET invades the cells and causes mitochondrial membrane depolarization, cytochrome c release, phosphatidyl serine exposure, and a low caspase response. A fraction of the cells undergoes morphological changes characteristic of apoptosis, but caspase inhibition does not rescue the cells and Bcl-2 overexpression or altered p53 status does not influence the sensitivity of tumor cells to HAMLET. HAMLET also creates a state of unfolded protein overload and activates 20S proteasomes, which contributes to cell death. In parallel, HAMLET translocates to tumor cell nuclei, where high-affinity interactions with histones cause chromatin disruption, loss of transcription, and nuclear condensation. The dying cells also show morphological changes compatible with macroautophagy, and recent studies indicate that macroautophagy is involved in the cell death response to HAMLET. The results suggest that HAMLET, like a hydra with many heads, may interact with several crucial cellular organelles, thereby activating several forms of cell death, in parallel. This complexity might underlie the rapid death response of tumor cells and the broad antitumor activity of HAMLET.

Pressure transduction to the thoracic cavity during topical negative pressure therapy of a sternotomy wound.

The present study was performed to examine pressure transduction to the thoracic cavity during topical negative pressure (TNP) therapy of a sternotomy wound. Seven pigs underwent median sternotomy. Pressure transduction catheters were placed on the anterior surface of the heart (under the foam), in the pericardium (under the heart), in the left pleura and in the oesophagus at the level of the heart. The wound was sealed as for TNP therapy. The vacuum source was set to deliver negative pressures between -50 and -200 mmHg. The pressure on the anterior surface of the heart changed in a linear relationship with the applied negative pressure and was slightly lower than the applied negative pressure (-102 +/- 9 mmHg at delivered -125 mmHg). Further down in the thoracic cavity, in the pericardium (under the heart), in the left pleura and in the oesophagus, the wound pressure was only slightly affected by TNP therapy. In conclusion during TNP therapy, negative pressure is effectively transmitted to anterior portions of the heart. This may explain our recent findings that TNP increases microvascular blood flow in the myocardium. The pressure difference between the anterior and the posterior portions of the heart causes the right ventricle to be sucked up towards the posterior parts of the sternum, where it might be exposed to the sharp edges of the sternal bone, which may result in heart injury.

Treatment of skin papillomas with topical alpha-lactalbumin-oleic acid.

BACKGROUND: We studied the effect on skin papillomas of topical application of a complex of alpha-lactalbumin and oleic acid (often referred to as human alpha-lactalbumin made lethal to tumor cells [HAMLET]) to establish proof of the principle that alpha-lactalbumin-oleic acid kills transformed cells but not healthy, differentiated cells. METHODS: Forty patients with cutaneous papillomas that were resistant to conventional treatment were enrolled in a randomized, placebo-controlled, double-blind study, in which alpha-lactalbumin-oleic acid or saline placebo was applied daily for three weeks and the change in the volume of each lesion was recorded. After this first phase of the study, 34 patients participated in the second phase, an open-label trial of a three-week course of alpha-lactalbumin-oleic acid. Approximately two years after the end of the open-label phase of the study, 38 of the original 40 patients were examined, and long-term follow-up data were obtained. RESULTS: In the first phase of the study, the lesion volume was reduced by 75 percent or more in all 20 patients in the alpha-lactalbumin-oleic acid group, and in 88 of 92 papillomas; in the placebo group, a similar effect was evident in only 3 of 20 patients (15 of 74 papillomas) (P<0.001). After the patients in the initial placebo group had been treated with alpha-lactalbumin-oleic acid in the second phase of the study, a median reduction of 82 percent in lesion volume was observed. At follow-up two years after the end of the second phase, all lesions had completely resolved in 83 percent of the patients treated with alpha-lactalbumin-oleic acid, and the time to resolution was shorter in the group originally assigned to receive alpha-lactalbumin-oleic acid than among patients originally in the placebo group (2.4 vs. 9.9 months; P<0.01). No adverse reactions were reported, and there was no difference in the outcomes of treatment between immunocompetent and immunosuppressed patients. CONCLUSIONS: Treatment with topical alpha-lactalbumin-oleic acid has a beneficial and lasting effect on skin papillomas.

Effect of vacuum-assisted closure on blood flow in the peristernal thoracic wall after internal mammary artery harvesting.

OBJECTIVE: Vacuum-assisted closure (VAC) is a recently introduced method for the treatment of poststernotomy mediastinitis. The aim was to examine the effects of VAC negative pressure on peristernal soft tissue blood flow after internal mammary artery harvesting. METHODS: Microvascular blood flow was measured using laser Doppler velocimetry in a porcine sternotomy wound model. The effect of VAC negative pressure on blood flow to the wound edge was investigated on the right side, where the internal mammary artery was intact, and on the left side, where the internal mammary artery had been removed. RESULTS: Before removal of the left internal mammary artery, the blood flow was similar in the right and left peristernal wound edges, 2.5 cm from the edge (27+/-4 perfusion units (PU) on the right side and 32+/-3 PU on the left side, in muscle tissue). When the left internal mammary artery was surgically removed, the blood flow on the left side decreased (19+/-3 PU, in muscle tissue), while the skin blood flow was not affected. VAC negative pressure induced an immediate increase in wound edge blood flow both on the right side (43+/-9 PU, in muscle tissue at -75 mmHg), where the internal mammary artery was intact, and on the left side, where the internal mammary artery had been removed (49+/-11 PU, in muscle tissue at -75 mmHg). The increase in blood flow was similar on both sides at -75 mmHg and at -125 mmHg. CONCLUSIONS: The peristernal wound edge microvascular blood flow is decreased when the left internal mammary artery is removed. VAC therapy stimulates blood flow in the peristernal thoracic wall after internal mammary artery harvesting.