Early-life external exposome in children 2-5 years old in Colombia

Exposome studies are advancing in high-income countries to understand how multiple environmental exposures impact health. However, there is a significant research gap in low- and middle-income and tropical countries. We aimed to describe the spatiotemporal variation of the external exposome, its correlation structure between and within exposure groups, and its dimensionality. A one-year follow-up cohort study of 506 children under 5 in two cities in Colombia was conducted to evaluate asthma, acute respiratory infections, and DNA damage. We examined 48 environmental exposures during pregnancy and 168 during childhood in eight exposure groups, including atmospheric pollutants, natural spaces, meteorology, built environment, traffic, indoor exposure, and socioeconomic capital. The exposome was estimated using geographic information systems, remote sensing, spatiotemporal modeling, and questionnaires. The median age of children at study entry was 3.7 years (interquartile range: 2.9-4.3). Air pollution and natural spaces exposure decreased from pregnancy to childhood, while socioeconomic capital increased. The highest median correlations within exposure groups were observed in meteorology (r = 0.85), traffic (r = 0.83), and atmospheric pollutants (r = 0.64). Important correlations between variables from different exposure groups were found, such as atmospheric pollutants and meteorology (r = 0.76), natural spaces (r = -0.34), and the built environment (r = 0.53). Twenty principal components explained 70%, and 57 explained 95% of the total variance in the childhood exposome. Our findings show that there is an important spatiotemporal variation in the exposome of children under 5. This is the first characterization of the external exposome in urban areas of Latin America and highlights its complexity, but also the need to better characterize and understand the exposome in order to optimize its analysis and applications in local interventions aimed at improving the health conditions and well-being of the child population and contributing to environmental health decision-making.

Characterization of the external exposome and its contribution to the clinical respiratory and early biological effects in children: The PROMESA cohort study protocol

BACKGROUND

Air pollution contains a mixture of different pollutants from multiple sources. However, the interaction of these pollutants with other environmental exposures, as well as their harmful effects on children under five in tropical countries, is not well known.

OBJECTIVE

This study aims to characterize the external exposome (ambient and indoor exposures) and its contribution to clinical respiratory and early biological effects in children.

MATERIALS AND METHODS

A cohort study will be conducted on children under five (n = 500) with a one-year follow-up. Enrolled children will be followed monthly (phone call) and at months 6 and 12 (in person) post-enrolment with upper and lower Acute Respiratory Infections (ARI) examinations, asthma development, asthma control, and genotoxic damage. The asthma diagnosis will be pediatric pulmonologist-based and a standardized protocol will be used. Exposure, effect, and susceptibility biomarkers will be measured on buccal cells samples. For environmental exposures PM2.5 will be sampled, and questionnaires, geographic information, dispersion models and Land Use Regression models for PM2.5 and NO2 will be used. Different statistical methods that include Bayesian and machine learning techniques will be used for the ambient and indoor exposures-and outcomes. This study was approved by the ethics committee at Universidad Pontificia Bolivariana.

EXPECTED STUDY OUTCOMES/FINDINGS

To estimate i) The toxic effect of particulate matter transcending the approach based on pollutant concentration levels; ii) The risk of developing an upper and lower ARI, based on different exposure windows; iii) A baseline of early biological damage in children under five, and describe its progression after a one-year follow-up; and iv) How physical and chemical PM2.5 characteristics influence toxicity and children's health.

Etiology and the challenge of diagnostic testing of community-acquired pneumonia in children and adolescents

Background

Pneumonia is the leading cause of mortality in pediatric population. The etiology of pneumonia in this population is variable and changes according to age and disease severity and where the study is conducted. Our aim was to determine the etiology of community-acquired pneumonia (CAP) in children aged 1 month to 17 years admitted to 13 Colombian hospitals.

Methods

Prospective cohort study. Hospitalized children with radiologically confirmed CAP and ≤ 15 days of symptoms were included and followed together with a control group. Induced sputum (IS) was submitted for stains and cultures for pyogenic bacteria and Mycobacterium tuberculosis, and multiplex PCR (mPCR) for bacteria and viruses; urinary antigens for pneumococcus and Legionella pneumophila; nasopharyngeal swabs for viruses, and paired serology for atypical bacteria and viruses. Additional cultures were taken at the discretion of primary care pediatricians.

Results

Among 525 children with CAP, 71.6% had non-severe pneumonia; 24.8% severe and 3.6% very severe pneumonia, and no fatal cases. At least one microorganism was identified in 84% of children and 61% were of mixed etiology; 72% had at least one respiratory virus, 28% pyogenic bacteria and 21% atypical bacteria. Respiratory syncytial virus, Parainfluenza, Rhinovirus, Influenza, Mycoplasma pneumoniae, Adenovirus and Streptococcus pneumoniae were the most common etiologies of CAP. Respiratory syncytial virus was more frequent in children under 2 years and in severe pneumonia. Tuberculosis was diagnosed in 2.3% of children. IS was the most useful specimen to identify the etiology (33.6%), and blood cultures were positive in 3.6%. The concordance between all available diagnostic tests was low. A high percentage of healthy children were colonized by S. pneumoniae and Haemophilus influenzae, or were infected by Parainfluenza, Rhinovirus, Influenza and Adenovirus.

Conclusions

Respiratory viruses are the most frequent etiology of CAP in children and adolescents, in particular in those under 5 years. This study shows the challenges in making an etiologic diagnosis of CAP in pediatric population because of the poor concordance between tests and the high percentage of multiple microorganisms in healthy children. IS is useful for CAP diagnosis in pediatric population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03235-z.

Acute Intrathoracic Tuberculosis in Children and Adolescents with Community-Acquired Pneumonia in an Area with an Intermediate Disease Burden

Tuberculosis (TB) in the pediatric population is a major challenge. Our objective was to describe the clinical and microbiological characteristics, radiological patterns, and treatment outcomes of children and adolescents (from 1 month to 17 years) with community-acquired pneumonia (CAP) caused by TB. We performed a prospective cohort study of a pediatric population between 1 month and 17 years of age and hospitalized in Medellín, Colombia, with the diagnosis of radiologically confirmed CAP that had ≤ 15 days of symptoms. The mycobacterial culture of induced sputum was used for the bacteriological confirmation; the history of TB contact, a tuberculin skin test, and clinical improvement with treatment were used to identify microbiologically negative TB cases. Among 499 children with CAP, TB was diagnosed in 12 (2.4%), of which 10 had less than 8 days of a cough, 10 had alveolar opacities, 9 were younger than 5 years old, and 2 had close contact with a TB patient. Among the TB cases, 50% (6) had microbiological confirmation, 8 had viral and/or bacterial confirmation, one patient had multidrug-resistant TB, and 10/12 had non-severe pneumonia. In countries with an intermediate TB burden, Mycobacterium tuberculosis should be included in the etiological differential diagnosis (as a cause or coinfection) of both pneumonia and severe CAP in the pediatric population.

Medical decisions concerning the end of life for cancer patients in three Colombian hospitals - a survey study

Background

Cancer patients’ end-of-life care may involve complex decision-making processes. Colombia has legislation regarding provision of and access to palliative care and is the only Latin American country with regulation regarding euthanasia. We describe medical end-of-life decision-making practices among cancer patients in three Colombian hospitals.

Methods

Cancer patients who were at the end-of-life and attended in participating hospitals were identified. When these patients deceased, their attending physician was invited to participate. Attending physicians of 261 cancer patients (out of 348 identified) accepted the invitation and answered a questionnaire regarding end-of-life decisions: a.) decisions regarding the withdrawal or withholding of potentially life-prolonging medical treatments, b.) intensifying measures to alleviate pain or other symptoms with hastening of death as a potential side effect, and c.) the administration, supply or prescription of drugs with an explicit intention to hasten death. For each question addressing the first two decision types, we asked if the decision was fully or partially made with the intention or consideration that it may hasten the patient’s death.

Results

Decisions to withdraw potentially life-prolonging treatment were made for 112 (43%) patients, 16 of them (14%) with an intention to hasten death. For 198 patients (76%) there had been some decision to not initiate potentially life-prolonging treatment. Twenty-three percent of patients received palliative sedation, 97% of all patients received opioids.

Six patients (2%) explicitly requested to actively hasten their death, for two of them their wish was fulfilled. In another six patients, medications were used with the explicit intention to hasten death without their explicit request. In 44% (n = 114) of all cases, physicians did not know if their patient had any advance care directives, 26% (n = 38) of physicians had spoken to the patient regarding the possibility of certain treatment decisions to hasten death where this applied.

Conclusions

Decisions concerning the end of life were common for patients with cancer in three Colombian hospitals, including euthanasia and palliative sedation. Physicians and patients often fail to communicate about advance care directives and potentially life-shortening effects of treatment decisions. Specific end-of-life procedures, patients’ wishes, and availability of palliative care should be further investigated.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12904-021-00853-9.

Decision making in the end-of-life care of patients who are terminally ill with cancer - a qualitative descriptive study with a phenomenological approach from the experience of healthcare workers

BACKGROUND

In Colombia, recent legislation regarding end-of-life decisions includes palliative sedation, advance directives and euthanasia. We analysed which aspects influence health professionals´ decisions regarding end-of-life medical decisions and care for cancer patients.

METHODS

Qualitative descriptive-exploratory study based on phenomenology using semi-structured interviews. We interviewed 28 oncologists, palliative care specialists, general practitioners and nurses from three major Colombian institutions, all involved in end-of-life care of cancer patients: Hospital Universitario San Ignacio and Instituto Nacional de Cancerología in Bogotá and Hospital Universitario San José in Popayan.

RESULTS

When making decisions regarding end-of-life care, professionals consider: 1. Patient's clinical condition, cultural and social context, in particular treating indigenous patients requires special skills. 2. Professional skills and expertise: training in palliative care and experience in discussing end-of-life options and fear of legal consequences. Physicians indicate that many patients deny their imminent death which hampers shared decision-making and conversations. They mention frequent ambiguity regarding who initiates conversations regarding end-of-life decisions with patients and who finally takes decisions. Patients rarely initiate such conversations and the professionals normally do not ask patients directly for their preferences. Fear of confrontation with family members and lawsuits leads healthcare workers to carry out interventions such as initiating artificial feeding techniques and cardiopulmonary resuscitation, even in the absence of expected benefits. The opinions regarding the acceptability of palliative sedation, euthanasia and use of medications to accelerate death without the patients´ explicit request vary greatly. 3. Conditions of the insurance system: limitations exist in the offer of oncology and palliative care services for important proportions of the Colombian population. Colombians have access to opioid medications, barriers to their application are largely in delivery by the health system, the requirement of trained personnel for intravenous administration and ambulatory and home care plans which in Colombia are rare.

CONCLUSIONS

To improve end-of-life decision making, Colombian healthcare workers and patients need to openly discuss wishes, needs and care options and prepare caregivers. Promotion of palliative care education and development of palliative care centres and home care plans is necessary to facilitate access to end-of-life care. Patients and caregivers' perspectives are needed to complement physicians' perceptions and practices.

Early high levels of regulatory T cells and T helper 1 may predict the progression of recurrent hepatitis C after liver transplantation

BACKGROUND

Immune response failure against hepatitis C virus (HCV) has been associated with an increased regulatory T cell (Treg) activity. After liver transplantation (LT), 80% of patients experience an accelerated progression of hepatitis C recurrence. The aim of this work was to assess the involvement of Tregs, T helper (Th) 1, 2 and 17 cells in recurrent hepatitis C.

METHODS

Peripheral blood cells obtained before and one month after LT from 22 recipients were analysed. Forty-four key molecules related to Treg, Th1, 2 and 17 responses, were evaluated using qRT-PCR. Liver recipients were classified in two groups according to graft fibrosis evaluated by the METAVIR score on the biopsy performed one year after LT (mild: F ≤ 1, n = 13; severe: F > 1, n = 9). Patients developing a severe recurrence were compared with patients with a mild recurrence.

RESULTS

mRNA levels of Treg markers obtained one month after LT were significantly increased in patients with a severe disease course when compared to patients with a mild recurrence. Markers of the Th1 response were elevated in the same group. No differences in the markers determined before LT were observed.

CONCLUSION

These findings suggest that Treg, induced by a multifactorial process, which could include a strong Th1 response itself, may play a role in suppressing the early antiviral response, leading to a severe recurrence of hepatitis C.

Cancer vaccine characterization: from bench to clinic

BACKGROUND

The development of safe, effective, and affordable vaccines has become a global effort due to its vast impact on overall world health conditions. A brief overview of vaccine characterization techniques, especially in the area of high-resolution mass spectrometry, is presented. It is highly conceivable that the proper use of advanced technologies such as high-resolution mass spectrometry, along with the appropriate chemical and physical property evaluations, will yield tremendous in-depth scientific understanding for the characterization of vaccines in various stages of vaccine development. This work presents the physicochemical and biological characterization of cancer vaccine Racotumomab/alumina, a murine anti-idiotypic antibody that mimics N-glycolyl-GM3 gangliosides. This antibody has been tested as an anti-idiotypic cancer vaccine, adjuvated in Al(OH)3, in several clinical trials for melanoma, breast, and lung cancer.

METHODS

Racotumomab was obtained from ascites fluid, transferred to fermentation in stirred tank at 10 L and followed to a scale up to 41 L. The mass spectrometry was used for the determination of intact molecule, light and heavy chains masses; amino acids sequence analysis, N- and C-terminal, glycosylation and posttranslational modifications. Also we used the DLS for the size distribution and zeta potential analysis. The biological analyses were performed in mice and chickens.

RESULTS

We observed differences in glycosylation pattern, charge heterogeneity and structural stability between in vivo-produced and bioreactor-obtained Racotumomab products. Interestingly, these modifications had no significant impact on the immune responses elicited in two different animal models.

CONCLUSIONS

We are demonstrated that this approach could potentially be more efficient and effective for supporting vaccine research and development.

Corticosteroids do not reverse the inhibitory effect of cyclosporine on regulatory T-cell activity in contrast to mycophenolate mofetil

BACKGROUND

Inevitable hepatitis C virus recurrence after liver transplantation, a major barrier to survival of the transplanted liver may be promoted by immunosuppression and by CD4(+)CD25(+) regulatory T cells (Treg). Treg cells are essential for the induction and maintenance of immunologic self-tolerance as well as transplant tolerance. Moreover, we have previously described low doses of cyclosporine (CsA) to inhibit Treg activity by inducing interleukin-2 and interfron-γ. We investigated here in, the effect of mycophenolate mofetil (MMF) and corticosteroids, usually used in combination with a calcineurin inhibitor on human CD4(+)CD25(+) Treg cells.

METHODS

Human CD4(+)CD25(+) cells isolated from healthy donors were cultured in the presence of CsA +/- corticoids or MMF. Suppressive activity of regulatory T cells was assessed in mixed leukocyte reactions including CD25(+) solvents with autologous activated peripheral blood mononuclear cells (PBMC).

RESULTS

MMF and dexamethasone inhibited PBMC and Treg proliferation in dose-dependent fashing, maintaining the suppressive activity of Treg cells. However, the association of corticoids with CsA could not reverse the inhibitory effects of CsA on Treg activity, unlike the MMF and CsA combination.

CONCLUSION

We have previously shown CsA to significantly impair the function of CD4(+)CD25(+) Treg cells. Herein we reports that corticoids were not able to reverse this effect, whereas MMF couterbalanced it, suggesting that the combination of MMF with CsA maintains regulatory T cells activity promoting tolerance.

[Isonymy analysis in a sample of parents of cystic fibrosis patients from Antioquia, Colombia]

INTRODUCTION

Cystic fibrosis (CTFR) is one of the most common autosomal recessive disorders in European descendants. Geographic distribution of CFTR gene mutations vary worldwide.

OBJECTIVE

The degree of isonimy was evaluated in a sample of parents with children affected by cystic fibrosis.

MATERIALS AND METHODS

Observed and expected isonimy as well as endogamy components (Fr, Fn, Ft, and the values α and B) were calculated for 35 parents of children diagnosed with cystic fibrosis. These parameters were calculated for both the total population of Antioquia Province and for an eastern subpopulation of Antioquia.

RESULTS

The values obtained for Fr, Fn, Ft, α and B were 0.01, 0.007, 0.019, 268 and 0.44, respectively for the total population of Antioquia. For the eastern subpopulation, the values were 0.026, 0.0017, 0.027, 135 and 0.62. The most frequent last-names in the total sample (n=70) were Gómez (6%), Alzate (4%), and González (3.7 %), whilst for the eastern subpopulation (n=32) were Gómez (8%) and Marín (6%).

CONCLUSIONS

A high percentage of last-names was shared, as is reflected in the isonimy values. Similarly, the presence of a reduced number of last-names in an important percentage of the population is reflected in the Fr values obtained for both analyses, which suggest homogeneity. Thus, it is expected a low number of CFTR mutations in the children from Antioquia with cystic fibrosis.

Increased expression of regulatory Tr1 cells in recurrent hepatitis C after liver transplantation

Immune response failure during HCV infection has been associated with the activity of regulatory T cells. Hepatitis C-related cirrhosis is the main reason for liver transplantation. However, 80% of transplanted patients present an accelerated recurrence of the disease. This study assessed the involvement of regulatory T-cell subsets (CD4+CD25+ cells: 'Treg' and CD49b+CD18+ cells: 'T regulatory-1' cells), in the recurrence of HCV after liver transplantation, using transcriptomic analysis, ELISA assays on serum samples and immunohistochemistry on liver biopsies from liver recipients 1 and 5 years after transplantation. Three groups of patients were included: stable HCV-negative recipients and those with mild and severe hepatitis C recurrence. At 5 years, Treg markers were overexpressed in all HCV+ recipients. By contrast, Tr1 markers were only overexpressed in patients with severe recurrence. At 1 year, a trend toward the overexpression of Tr1 was noted in patients evolving toward severe recurrence. IL-10 production, a characteristic of the Tr1 subset, was enhanced in severe recurrence at both 1 and 5 years. These results suggest that Tr1 are enhanced during severe HCV recurrence after liver transplantation and could be predictive of HCV recurrence. High levels of IL-10 at 1 year could be predictive of severe recurrence, and high IL-10 producers might warrant more intensive management.

Increased expression of regulatory Tr1 cells in recurrent hepatitis C after liver transplantation

Immune response failure during HCV infection has been associated with the activity of regulatory T cells. Hepatitis C-related cirrhosis is the main reason for liver transplantation. However, 80% of transplanted patients present an accelerated recurrence of the disease. This study assessed the involvement of regulatory T-cell subsets (CD4+CD25+ cells: 'Treg' and CD49b+CD18+ cells: 'T regulatory-1' cells), in the recurrence of HCV after liver transplantation, using transcriptomic analysis, ELISA assays on serum samples and immunohistochemistry on liver biopsies from liver recipients 1 and 5 years after transplantation. Three groups of patients were included: stable HCV-negative recipients and those with mild and severe hepatitis C recurrence. At 5 years, Treg markers were overexpressed in all HCV+ recipients. By contrast, Tr1 markers were only overexpressed in patients with severe recurrence. At 1 year, a trend toward the overexpression of Tr1 was noted in patients evolving toward severe recurrence. IL-10 production, a characteristic of the Tr1 subset, was enhanced in severe recurrence at both 1 and 5 years. These results suggest that Tr1 are enhanced during severe HCV recurrence after liver transplantation and could be predictive of HCV recurrence. High levels of IL-10 at 1 year could be predictive of severe recurrence, and high IL-10 producers might warrant more intensive management.

Comparison of morphine, ketorolac, and their combination for postoperative pain: results from a large, randomized, double-blind trial

BACKGROUND

Meta-analyses report similar numbers needed to treat for nonsteroidal antiinflammatory drugs (NSAIDs) and opioids. Differences in baseline pain intensity among the studies from which these numbers needed to treat were derived may have confounded the results. NSAIDs have an opioid-sparing effect, but the importance of this effect is unclear. Therefore, the authors sought to compare the proportions of subjects who obtain pain relief with ketorolac versus morphine after surgery and to determine whether the opioid-sparing effect of an NSAID reduces the magnitude of opioid side effects.

METHODS

The study was a double-blind, randomized controlled trial. The authors randomly assigned 1,003 adult patients to receive 30 mg ketorolac or 0.1 mg/kg morphine intravenously. They calculated the proportion of subjects who achieved at least 50% reduction in pain intensity 30 min after analgesic administration. Further, so long as pain intensity 30 min after analgesic administration was 5 or more out of 10, patients received 2.5 mg morphine every 10 min until pain intensity was 4 or less out of 10. The authors assessed the presence of opioid-related side effects.

RESULTS

Five hundred patients received morphine and 503 received ketorolac. Fifty percent of patients in the morphine group achieved pain relief, compared with 31% in the ketorolac group (difference, 19%; 95% confidence interval, 13-25%). The ketorolac-morphine group required less morphine (difference, 6.5 mg; 95% confidence interval, -5.8 to -7.2) and had a lower incidence of side effects (difference, 11%; 95% confidence interval, 5-16%) than the morphine group.

CONCLUSIONS

Opioids are more efficacious analgesics than NSAIDs, although historic data for these two drugs yield similar numbers needed to treat. Adding NSAIDs to the opioid treatment reduces morphine requirements and opioid-related side effects in the early postoperative period.

Computed tomography--a possible aid in the diagnosis of smoke inhalation injury?

Inhalation injury is an important contributor to morbidity and mortality in burn victims and can trigger acute lung injury and acute respiratory distress syndrome (ARDS) (1-3). Early diagnosis and treatment of inhalation injury are important, but a major problem in planning treatment and evaluating the prognosis has been the lack of consensus about diagnostic criteria (4). Chest radiographs on admission are often non-specific (5, 6), but indicators include indoor fires, facial burns, bronchoscopic findings of soot in the airways, and detection of carbon monoxide or cyanide in the blood (7). Changes in the lungs may be detected by bronchoscopy with biopsy, xenon imaging, or measurement of pulmonary extracellular fluid (4, 5, 8). These methods have, however, been associated with low sensitivity and specificity, as exemplified by the 50% predictive value in the study of Masanes et al. (8). Computed tomographs (CTs) are better than normal chest radiographs in the detection of other pulmonary lesions such as pulmonary contusion (9, 10). The importance of CT scans in patients with ARDS has been reviewed recently (9), but unfortunately there has been no experience of CT in patients with smoke inhalation injury. To our knowledge, there are only two animal studies reporting that smoke inhalation injury can be detected by CT (4, 11); specific changes in human CT scans have not yet been described. Therefore, confronted with a patient with severe respiratory failure after a burn who from the history and physical examination showed the classic risk factors for inhalation injury, we decided to request a CT.

Addition of ultralow dose naloxone to postoperative morphine PCA: unchanged analgesia and opioid requirement but decreased incidence of opioid side effects

Ultralow doses of naloxone (0.001-0.1 microg/kg) produce analgesia in animal models. However, no clinical study has evaluated the combination of ultralow dose naloxone and morphine using patient-controlled analgesia (PCA). This randomized, double blind controlled study sought to determine if the combination of ultralow dose naloxone and morphine in PCA solutions affects opioid requirements, analgesia, and side effects. Two-hundred and sixty-five patients (18-65 years old) undergoing operations were randomized to receive PCA morphine 1 mg/ml (n=129) or PCA morphine 1 mg/ml plus naloxone 0.6 microg/ml (n=136). We evaluated the numbers of supplemental rescue doses, the cumulative dose of each PCA solution, pain intensity, pain relief, and opioid side effects during the first 24 h after surgery. We found that opioid requirements did not differ significantly between groups. The morphine+naloxone group on average required 0.07 mg more morphine (95% CI -1.1 to 1.3) during the 24 h than the morphine group. Pain intensity levels were also similar in both groups. The morphine+naloxone group had 0.06 units lower (95% CI -0.5 to 0.4) pain intensity levels than the morphine group. The morphine+naloxone group had a lower incidence of nausea and pruritus than the morphine group (P=0.01 for both symptoms). However, the incidence of vomiting, time to tolerate fluids, sedation, and urinary retention were similar between groups (all P values >0.1). The combination of ultralow dose naloxone and morphine in PCA does not affect analgesia or opioid requirements, but it decreases the incidence of nausea and pruritus.

[Prospective follow-up of a HIV infected population with and without access to antiretroviral therapy: impact of survival and complications]

BACKGROUND

Three-drug antiretroviral therapy (ART-3) has reduced complications and improved survival in HIV+ patients. The Chilean Public Health System began dual therapy (ART-2) in 1997, covering approximately 40% of patients in need.

AIM

To report the results of a follow-up of patients with and without access to ART in a Chilean public hospital.

PATIENT AND METHODS

Prospective follow-up of patients with ART-2 and 3 (cases) and patients with no access to ART (controls). All patients needed ART but it was available to a minority of them. Selection for ART was at random. Follow-up was between 6-24 months (11/96 to 3/99). Basal and periodic clinical and laboratory parameters were determined. Mortality and occurrence of new AIDS-defining events (ADE) were compared statistically using chi square.

RESULTS

One hundred and fifty cases (106 ART2, 28 ART3 and 16 ART2 expanded to ART3) and 166 controls were studied. Basal parameters were similar except prior ART (32.7 and 18.7% in cases and controls respectively). Close to 1/3 patients had AIDS. Cases had a mean follow up of 527 days; controls, 478. Six cases (4%) (5 in ART-2) and 17 controls (10%) died. Mortality x 100/pts/yr was 2.7 in cases and 7.7 in controls, p < 0.05. ADE per 100/pts/yr was 21 in cases (24.4 in ART2, 15.1 in TAR3) and 54.5 in controls, p < 0.05. Cases had a reduction of: esophageal candidiasis (84%), tuberculosis (75%), cryptococcosis and toxoplasmosis (66%), P carinii pneumonia (55%) and bacterial pneumonia (46%) and they had fewer hospitalizations (73%). Late assessment: 70 of 101 ART-2 patients had changed to ART-3 (1 death); 22 of 101 kept original ART-2 (12 dead, 10 alive), 39 of 43 ART-3 patients were alive and 1 died.

CONCLUSIONS

Short-term ART-2 and 3 significantly reduced mortality (60% and 73%) ADE (65% and 76% respectively) and hospitalizations. Benefits of ART-2 were short lived. Resource-constrained countries cannot depend on weaker than standard ART for proper care of people with HIV disease.

Growth hormone-regulated intracellular signaling in UMR 106 osteosarcoma cells

Growth hormone (GH) and insulin-like growth factor 1 (IGF-1) are important growth factors for postnatal longitudinal bone growth. Although many effects of GH on bone growth are mediated by IGF-1, GH can directly influence bone cells. Limited knowledge exists regarding specific intracellular signaling pathways and genes activated by GH in bone cells. GH is known to activate several intracellular signaling pathways, among them the Janus kinase (JAK)/signal transducers and activators of transcription (STAT) pathway. GH mainly activates JAK2 and both isoforms of STAT5, A and B. STAT5 gene deletion experiments have shown the importance of these transcription factors for growth. To understand the molecular mechanism(s) behind this, different experimental models are needed. The UMR 106 cell line is a rat clonal osteosarcoma cell line with osteoblast-like phenotypic properties, one is the endogenous expression of GH receptor (GHR). The present study focused on whether these cells express a functional GH-responsive JAK2/STAT5 pathway. Analysis of cell extracts by immunoprecipitation and Western blot showed that physiological concentrations of GH activated JAK2. Western blot analysis of nuclear extracts from GH-stimulated UMR 106 cells showed that physiological concentrations of GH induced nuclear translocation of both STAT5 isoforms, but with STAT5A being predominant. Both isoforms displayed similar nuclear turnover after GH stimulation of cells. Gel electrophoretic mobility shift assay (GEMSA) of nuclear extract revealed that both STAT5A and STAT5B obtained DNA-binding capacity after GH stimulation. Thus, we have shown, for the first time, the expression and GH-induced activation of JAK2 and STAT5A/B in UMR 106 osteoblast-like cells. This study also shows that this cell line is a suitable experimental model to study unique GH effects in osteoblasts mediated by STAT5.

[Antiretroviral therapy. Announcement of the Advisory Committee of the Chilean Society of Infectology on AIDS]

There are treatments to induce the long term suppression of viral replication and that delays the progression of HIV disease. To be effective, these treatments require the uninterrupted use of a combination of drugs (ideally three), patients must be highly compliant, must be instituted in early stages of the disease and drugs must be used for prolonged periods and given by specialists. These treatments are indicated in all symptomatic patients and in those with early immunologic deterioration or high viral load. Recent infection and acute primary retroviral infections should also be considered for treatment. The treatment sponsored and financed by the ministry of health for its beneficiaries is insufficient at this time, since it is received by a minority of eligible patients due to budgetary reasons, and only two drugs are given which is considered such optimal by most experts. The committee considers that the responsibility for financing, providing and delivering these treatments in proper combination and dosages exceeds the duty of the Ministry of Health and should include all the involved parties. However, the state and its official institutions have a special responsibility to provide with adequate treatments to the poorer segments of our population. They also should promote, supervise and control the proper access of the rest of the population to efficient treatments. The committee also considers that the efforts to prevent new infections must not be neglected and that individuals under successful treatment should not consider themselves as non infectious.

Spherex (degradable starch microspheres) chemo-occlusion--enhancement of tumor drug concentration and therapeutic efficacy: an overview

The efficacy of systemic chemotherapy in the treatment of primary and secondary liver cancer is poor. Intra-arterial delivery of fluoropyrimidines resulted in a significantly higher tumor response, but survival was prolonged by only a few months. Obviously, there is still a great need for improved therapeutic strategies. As the regional blood flow is of importance for the advantage of intra-arterial administration of cytotoxic drugs, degradable starch microspheres (DSMs) have been developed specifically to achieve temporary vascular occlusion during coadministration of cytotoxic drugs. Peak plasma concentrations, as well as the area under the concentration-time curve (AUC) of mitomycin C in plasma have been found to be significantly reduced following intra-arterial coadministration with DSMs. Similar results were also obtained with other drugs, such as nitrosoureas, doxorubicin, and 5-fluorouracil. The temporary vascular occlusion induced by DSMs enables a coadministered drug to be lodged in the target area for a prolonged period of time, resulting in a selectively increased uptake of labeled low molecular weight markers and several cytotoxic drugs into liver tumors compared with normal liver tissue. Vascular occlusion induced by DSMs has been demonstrated to redistribute the blood flow to hypovascular areas, which might be of particular importance for improving the efficacy of intra-arterial chemotherapy of hypovascular liver tumors. Passage through arteriovenous shunts was generally increased after DSM injection. However, this was without clinical significance as respiratory distress symptoms were found in only 1% of the sessions and were not considered to be serious in any of these patients. To take advantage of the pharmacokinetic modulation of coinjected drugs and, in addition, the redistribution of blood flow to hypovascular tumor areas, the goal is to achieve an almost complete vascular occlusion by injection of DSMs. Therefore, due to the wide variation between patients in the size and vascularity of liver tumors, the dose of DSMs has to be individualized. Degradable starch microspheres have been shown to enhance the antitumor efficacy of several cytotoxic drugs in animal experimental models and in noncomparative and randomized clinical studies.

Atelectasis and oxygenation in major surgery with either propofol with or without nitrous oxide or isoflurane anaesthesia

Forty-two patients undergoing major colonic surgery were assigned at random to receive isoflurane-fentanyl anaesthesia with nitrous oxide in oxygen, propofol-fentanyl anaesthesia with air in oxygen or propofol-fentanyl anaesthesia with nitrous oxide in oxygen. The groups were comparable in demographic data. Atelectases were identified, and the area measured by computerised tomography of the chest 203 +/- 69 min after extubation, and oxygenation was determined by arterial blood gas samples taken during operation at 30, 60, 90 and 120 min after extubation and on postoperative days 1, 2 and 3. Atelectases were seen in all three groups with no differences in the mean area between groups. After operation, the effect of 4 l.min-1 of oxygen by nasal catheter on PaO2 was similar in all groups. A significant decrease in PaO2 was found during the first 3 days after surgery, and was also the same in all groups. There was no correlation between area of atelectasis and postoperative PaO2. We conclude there is no difference in the incidence of postoperative atelectasis or oxygenation when using propofol, with or without nitrous oxide or isoflurane.

Fibrin sleeve formation after long term brachial catheterisation with an implantable port device. A prospective venographic study

OBJECTIVE

To evaluate the risk of thrombosis after long term venous access with an implantable port device (PAS-Port system).

DESIGN

Open study.

SETTING

University Hospital, Linköping, Sweden.

SUBJECTS

Sixteen patients who required central venous catheters for long term chemotherapy were prospectively followed for 218 patient months (median 12.5 months/patient, range 3-34).

INTERVENTIONS

Venogram taken while the catheters were being withdrawn. Venography was also done in 10 patients 1-29 months after the catheter had been removed.

RESULTS

The venograms showed that fibrin sleeves had developed along the route of the catheter in all cases (cubital vein to the superior vena cava n = 7; to subclavian vein alone n = 8; and basilic vein alone n = 1). One of the 10 patients who underwent venography 1-29 months later had developed an occlusive subclavian vein thrombosis with well developed collateral vessels 10 months after the catheter had been removed.

CONCLUSION

Because of the high incidence of formation of extensive fibrin sleeves, implantable port devices should be removed as soon as they have served their purpose. If catheters malfunction they should be evaluated radiographically.

Evaluation of preoperative computed tomography in gastric malignancy

Ninety patients with gastric malignancy underwent computed tomography (CT) before surgery. The CT findings regarding neoplastic invasion of adjacent organs and metastasis or enlarged lymph nodes were compared with the findings at laparotomy (85 cases) or autopsy (5 cases), thus permitting evaluation of the diagnostic accuracy of CT and its usefulness for predicting resectability. When present, neoplastic invasion of adjacent organs was overestimated or underestimated by CT in 21 cases. Invasion of adjacent organs according to CT was false positive in 17 cases and false negative in 11 cases. When liver metastasis or enlarged regional or distant lymph nodes were present, CT overestimated or underestimated their extent in 17 cases, and the diagnosis was false positive in one case and false negative in 33 cases. The positive and negative predictive values of CT concerning resectability of the tumor were 81% and 64%, respectively. Routine preoperative CT in gastric malignancy is concluded to be of limited value and surgical exploration, when feasible, remains the method of choice.

[Immunofluorescence in the diagnosis of acute bacterial meningitis]

We evaluated immunofluorescence techniques to investigate the presence of S pneumoniae, N meningitidis, H influenzae types a and b and L monocytogenes in 85 samples of CSF fluid: 60 were taken from patients suffering meningitis and 25 from a control group. Results were compared to conventional bacteriologic methods. There were no false positive results in the control group. In patients with meningitis, 28 were positive by both methods. Nine additional patients were positive only to immunofluorescence which allowed identification of S pneumoniae in 6, N meningitidis in 2 and H influenzae in 1. 37 samples were positive by immunofluorescence and 28 of them were positive to conventional bacteriology. There was only 1 case of Group B streptococcus identified by bacteriology which was not diagnosed by immunofluorescence. Thus, immunofluorescence increases the ability to make a bacteriologic diagnosis in patients with meningitis.

The effect of nimodipine on post-ischemic cerebral glucose utilization and blood flow in the rat

The authors hypothesized that pretreatment with the calcium entry blocker nimodipine would preserve cerebral glucose utilization and maintain favorable brain blood flow after cerebral ischemia. Three groups of pentobarbital anesthetized rats were studied: control (group 1), ischemia (group 2), and ischemia plus nimodipine pretreatment, 1 mg X kg-1 ip, 1 h prior to ischemia (group 3). Forebrain ischemia was induced with bilateral carotid clamping, administration of trimethaphan, and blood withdrawal to obtain a mean arterial pressure of 50 mmHg. The carotid clamps were released and blood re-infusion was begun 9 min after the onset of an isoelectric EEG signal. Ten minutes later, determination of regional cerebral glucose utilization (rCGU) was begun by injecting 3H-2-deoxyglucose in saline. After 60 min of reperfusion, regional cerebral blood flow (rCBF) was determined by the indicator fractionation method, using 14C-iodoantipyrine. The brain was divided into hemisphere, diencephalon, cerebellum, and brainstem. Tissue radioactivities were determined by standard techniques. Compared to group 1, hemispheric rCGU (mean +/- SEM, mumoles X 100 g-1) was significantly (P less than 0.05) reduced in groups 2 and 3 (40 +/- 3 vs. 27 +/- 2 and 22 +/- 2). Hemispheric rCGU was not significantly different in groups 2 and 3. Group 2 exhibited significantly (P less than 0.05) reduced rCBF (mean +/- SEM, ml X 100 g-1 X min-1) in the hemispheres compared to control (85 +/- 6 vs. 135 +/- 17). However, nimodipine pretreatment prevented this post-ischemic hypoperfusion in group 3 (133 +/- 18).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of microspheres in intra-arterial chemotherapy. A study of arterio-venous shunting and passage of a labelled marker

Degradable starch microspheres (DSM) mixed and injected with a cytostatic drug might improve intra-arterial chemotherapy by increasing the local drug concentration. Several factors are of importance for an optimal effect of the microspheres, e.g. size and vascularity of the tumour, arterial blood flow and arterio-venous shunts. Therefore, the dose of DSM has to be individualized. A method for continuous monitoring of the effect of DSM was developed. A radiolabelled marker was injected intra-arterially mixed with DSM and mitomycin C. Two kinetic parameters--Passing Fraction and Marker Flow Rate--were found to be influenced by the microspheres and thus seemed to be useful for monitoring the DSM-treatment. Arterio-venous shunting was measured as passage of 99Tcm-labelled macroaggregated albumin through the liver to the lungs. Significant increase of shunting after injection of DSM was demonstrated in 15 out of 19 patients. Almost no effect of the microspheres was seen in patients with marked arterio-venous shunting or minimal reduction of the marker flow rate, but in others the passage of the labelled marker could generally be significantly reduced.

Intra-arterial mitomycin C treatment of unresectable liver tumours. Preliminary results on the effect of degradable starch microspheres

Regional chemotherapy might be more efficient if the cytostatic drug is injected together with degradable starch microspheres (DSM), which induce temporary blockage of arterioles and trap the co-injected drug in tumour. Eighteen patients with non-resectable liver cancer were included. Mitomycin C (15 mg/m2) was injected intra-arterially mixed with 900 mg of DSM every six weeks. For estimation of the effect of DSM in the liver a radiolabelled tracer was injected via the same route. Its passage through the liver to the systemic circulation was continuously measured by a detector situated over peripheral blood vessels. The effect of DSM on the tracer passage varied considerably between different patients. The study also indicated opening of new vascular pathways some minutes after the initial injection. The dose of DSM for total blockage of the arterial blood flow, indicated by angiography, also varied. In some patients 540 mg induced total occlusion. In others neither angiographic nor tracer passage were affected by the microspheres although 900 mg (or even more) were injected. Factors such as size of the vascular bed, portal and arterial blood flow and arterio-venous shunting seemed to be of great importance and should be controlled in order to optimize the use of DSM in conjunction with chemotherapy of liver tumours.

Role of antidiuretic activity in the inhibition of renin secretion by vasopressin in anesthetized dogs

The nature of the activity of vasopressin which is responsible for the inhibition of renin secretion was studied by comparing the effects of vasopressin (AVP) and analogs of AVP in anesthetized water-loaded dogs. Infusion of AVP (1.0 ng/kg/min) increased mean arterial pressure (MAP) and decreased heart rate (HR) and free water clearance (CH2O). Plasma renin activity (PRA) decreased from 11.9 +/- 4.7 to 3.8 +/- 1.7 ng/ml/3 hr (p less than 0.05). A selective antidiuretic agonist, 1-deamino-8-D-arginine vasopressin (1.0 ng/kg/min), which had no effect on MAP or HR but was effective as AVP in decreasing CH2O, decreased PRA from 13.5 +/- 4.6 to 7.0 +/- 2.9 ng/ml/3 hr (p less than 0.05). Infusion of a selective vasoconstrictor agonist, 2-phenylalanine-8-ornithine oxytocin (1.0 ng/kg/min), increased MAP and decreased HR but did not decrease CH2O or PRA. A vasoconstrictor antagonist, d(CH2)5Tyr(Me)AVP (10 micrograms/kg), completely blocked the MAP and HR responses to AVP but did not block the decrease in CH2O or PRA (5.9 +/- 1.8 to 2.9 +/- 1.6 ng/ml/3 hr) (p less than 0.001). Infusion of the 0.45% saline vehicle had no significant effect on MAP, HR, CH2O or PRA. These results indicate that the inhibition of renin secretion by vasopressin in anesthetized water-loaded dogs is due to its antidiuretic activity.

Renal prostaglandin E2 and the renin-angiotensin system in hypertensive disorders in man

We studied renal vein concentrations of prostaglandin E2 (PGE2) and activity of the renin-angiotensin system in 9 normotensive young men (NT), 17 hypertensive patients with unilateral renal artery stenosis (URS), and 26 patients with essential hypertension (EH) of whom 12 had low renin essential hypertension (LRH). The PGE2 concentration, plasma renin activity (PRA), and angiotensin II (A II) were measured in the inferior vena cava and were compared with the mean concentration for both renal veins under basal conditions and without pharmacological interference. The renal vein PGE2 concentrations were higher in NT (p less than 0.01) and URS (p less than 0.05) than in LRH. However, there were no significant differences in A II concentrations between the groups, nor were there any correlations to PGE2 concentrations. The positive correlation between PRA and PGE2 (r = 0.29, p less than 0.02) indicates that PGE2 may contribute to the activation of the renin-angiotensin system or that there may be a common mechanism for stimulation of both hormonal systems. Our results are not compatible with the hypothesis that a reduction of PGE2 production is a specific feature of patients with EH.

Hormonal responses to change in posture in hypertensive man. Evaluation by measurements of prostaglandin E2, renin activity, angiotensin II, and norepinephrine in renal venous blood

The hormonal responses to the stimulus of changing from resting supine to sitting upright for 15 minutes were assessed in 20 patients with hypertension, divided into 2 groups. 8 patients had essential hypertension (EH) and 12 unilateral renal artery stenosis (URS). The prostaglandin E2 (PGE2) concentration, plasma renin activity (PRA), angiotensin II (A-II) concentration, and norepinephrine (NE) concentration were measured in renal vein blood using specific methods. The PGE2 concentration increased after sitting for 15 minutes in all patients (p less than 0.001), but the increment was significant only in those with URS. The PRA was lower both at rest and after sitting up in the EH group than in the URS group. After sitting up the A-II concentration increased more in patients with URS than in those with EH (p less than 0.05). NE levels rose significantly when all patients were included (p less than 0.01), mainly owing to changes in the EH group. Supine and sitting PRA and A-II were correlated (r=0.47 and r=0.52; both p less than 0.05), and also sitting PGE2 and A-II (r=0.46, p less than 0.05). The inverse relation between PGE2 and NE for the difference in hormone concentrations between supine and sitting (r=-0.44, p less than 0.05) may be explained by an inhibitory effect of PGE2 on renal NE release, earlier observed in experiments in vitro. Similar changes in PGE2 and the measured components of the renin-angiotensin system in response to change in posture may indicate these factors are interrelated.

Prostaglandin E2, renin and angiotensin II in renovascular hypertension

We studied a group of 12 hypertensive patients (seven men, five women) with unilateral renal arterial stenosis, and evaluated the morphological criteria on renal angiography for the significance of the stenosis and compared them with the prostaglandin-E2 (PGE2), plasma renin activity (PRA), and angiotensin II (ANG II) concentrations in both renal veins. PGE2 and PRA concentrations were significantly higher in renal veins of kidneys with arterial stenosis with patients supine and after sitting up for 15 min, but the ANG II concentration was raised only with the patient sitting. Assuming that a PRA ratio greater than 2 signifies stenosis of haemodynamic importance, correlation to the angiographic classification was seen in 11 of the 12 patients. The PGE2 ratios were better correlated to PRA ratios than to the angiographic findings. ANG II ratios showed an inconstant and variable pattern in relation to the morphological picture. Our results confirm that PGE2 concentrations in renal venous blood increase in parallel to PRA, and may be interpreted as a means of preserving the blood flow in a kidney with arterial stenosis. However, it is unclear whether this increase is the result of dilution factors or of increased net production of PGE2. Determination of PGE2 in renal vein blood apparently gives no additional information about the functional significance of renal arterial stenosis, and PRA determinations remain the best guide in the management of renovascular hypertension.