The introduction of fentanyl on the US-Mexico border: An ethnographic account triangulated with drug checking data from Tijuana.

BACKGROUND: Illicitly-manufactured fentanyls (fentanyl) have changed the risk environment of people who use drugs (PWUD). In California and many western US states, the opioid overdose rate spiked from 2016 to 2021, driven largely by fentanyl. Mexican border cities act as transit through-points for the illicit drug supply and similar evolving health risks are likely to be present. Nevertheless, due to data gaps in surveillance infrastructure, little is known about fentanyl prevalence in Mexico. METHODS: We employ intensive ethnographic participant-observation among PWUD, as well as key informants including harm reduction professionals, EMTs, and physicians on the front lines in Tijuana, Mexico. We triangulate interview data and direct observations of consumption practices with n=652 immunoassay-based fentanyl tests of drug paraphernalia from mobile harm reduction clinics in various points throughout the city. RESULTS: PWUD informants described a sharp increase in the psychoactive potency and availability of powder heroin-referred to as "china white"-and concomitant increases in frequency of overdose, soft tissue infection, and polysubstance methamphetamine use. Fentanyl positivity was found among 52.8% (95%CI: 48.9-56.6%) of syringes collected at harm reduction spaces, and varied strongly across sites, from 2.7% (0.0-5.7%) to 76.5% (68.2-84.7%), implying strong market heterogeneity. Controlling for location of collection, syringe-based fentanyl positivity increased by 21.7% (10.1-42.3%) during eight months of testing. Key informants confirm numerous increased public health risks from fentanyl and describe the absence of a systematic or evidence-based governmental response; naloxone remains difficult to access and recent austerity measures have cut funding for harm reduction in Mexico. CONCLUSIONS: Fentanyl, linked to powder heroin, is changing the risk environment of PWUD on the US-Mexico border. Improved surveillance is needed to track the evolving street drug supply in Mexico and related health impacts for vulnerable populations. Structural factors limiting access to naloxone, harm reduction, substance use treatment, and healthcare, and minimal overdose surveillance, must be improved to provide an effective systemic response.

Electroencefalograma cuantitativo en la predicción precoz de la isquemia cerebral tardía en hemorragia subaracnoidea aneurismática: reporte de un caso / Quantitative electroencephalogram for prediction of delayed ischemia in subarachnoid haemorrhage: report of one case

Subarachnoid hemorrhage (SAH) is a devastating disease, with a mortality rate of 35%. Among patients who survive the initial bleeding, the leading cause of morbidity and mortality is delayed cerebral ischemia (DCI). Electroencephalography (EEG) can detect cerebral ischemia in the early stages. We report a 66-year-old female patient who consulted for ictal headache and impaired consciousness. On admission, she was confused, dysarthric, and with meningeal signs. Brain angio-CT showed SAH FISHER IV and an aneurysm of the left posterior cerebral artery. After excluding the aneurysm (by coiling), the patient recovered the altered consciousness. Continuous EEG monitoring was initiated. On the sixth day of follow up, she had a transient headache and apathy. The brain MRI showed low cerebral blood flow in the left frontotemporal area, without ischemic lesions. On the seventh day, she presented expression aphasia and right facial-brachial paresis. Angiography confirmed severe vasospasm in M1 and M2 segments bilaterally. Pharmacological angioplasty with nimodipine was performed, with an excellent radiological response, although not clinical. A second MRI was carried out on the eighth day, which showed a left insular infarction and generalized vasospasm. A second therapeutic angiography was performed; the patient persisted with aphasia and left central facial paresis. The quantitative EEG analysis performed retrospectively showed a generalized reduction in the spectral edge frequency 95 (SEF95; meaning slowing in the EEG signal) at the fourth day of follow up, three days earlier than the clinical and imaging diagnosis of DCI was established.

[Quantitative electroencephalogram for prediction of delayed ischemia in subarachnoid haemorrhage. Report of one case]. / Electroencefalograma cuantitativo en la predicción precoz de la isquemia cerebral tardía en hemorragia subaracnoidea aneurismática.Reporte de un caso.

Subarachnoid hemorrhage (SAH) is a devastating disease, with a mortality rate of 35%. Among patients who survive the initial bleeding, the leading cause of morbidity and mortality is delayed cerebral ischemia (DCI). Electroencephalography (EEG) can detect cerebral ischemia in the early stages. We report a 66-year-old female patient who consulted for ictal headache and impaired consciousness. On admission, she was confused, dysarthric, and with meningeal signs. Brain angio-CT showed SAH FISHER IV and an aneurysm of the left posterior cerebral artery. After excluding the aneurysm (by coiling), the patient recovered the altered consciousness. Continuous EEG monitoring was initiated. On the sixth day of follow up, she had a transient headache and apathy. The brain MRI showed low cerebral blood flow in the left frontotemporal area, without ischemic lesions. On the seventh day, she presented expression aphasia and right facial-brachial paresis. Angiography confirmed severe vasospasm in M1 and M2 segments bilaterally. Pharmacological angioplasty with nimodipine was performed, with an excellent radiological response, although not clinical. A second MRI was carried out on the eighth day, which showed a left insular infarction and generalized vasospasm. A second therapeutic angiography was performed; the patient persisted with aphasia and left central facial paresis. The quantitative EEG analysis performed retrospectively showed a generalized reduction in the spectral edge frequency 95 (SEF95; meaning slowing in the EEG signal) at the fourth day of follow up, three days earlier than the clinical and imaging diagnosis of DCI was established.

Fentanyl is used in Mexico's northern border: current challenges for drug health policies.

BACKGROUND AND AIMS: Results from a recent study among 750 heroin users in three Mexico's northern border cities revealed an increase in white powder availability (also known as China white) and preference for this product among heroin users, as well as a general perception of increased overdose cases among this population. Here, we questioned whether those findings reflect an increased presence of heroin laced with fentanyl, which is associated with greater risks of overdose but that, until now, has not been described in Mexico. DESIGN: We tested fentanyl using highly sensitive test strips in syringe plungers, metal cookers and drug wrappings associated with heroin use. SETTING: Three injection sites in Tijuana, Baja California, México. PARTICIPANTS: Eighty-nine heroin users who interchanged paraphernalia for new syringes. MEASUREMENTS: We tested 59 residues of 'pure' white powder. The rest were white powder with black tar (n = 5) or white powder with crystal meth (n = 9), black tar with crystal meth (n = 1), black tar only (n = 13) and crystal meth only (n = 2). FINDINGS: Users believed that they consumed either white powder heroin, white powder heroin with crystal meth, white powder with black tar heroin or black tar heroin only. Analyses revealed that 93% (n = 55) of the 'pure' white powder samples had fentanyl. All (n = 9) the white powder samples mixed with crystal meth and 40% (n = 2) of the white powder with black tar were also laced with fentanyl. CONCLUSIONS: In a sample of 89 heroin users in Mexico, most white powder heroin users were unknowingly exposed to fentanyl, with fentanyl detected in 93% of white powder samples.

Bioactive peptide amphiphile nanofiber gels enhance burn wound healing.

BACKGROUND: Burns are physically debilitating and potentially fatal injuries. The standard-of-care for burn wounds is the coverage with gauze dressings designed to minimize trauma to the regenerating epidermis and dermis during dressing changes. However, deep partial- and full-thickness burns always heal slowly when standard wound care alone is performed. We have previously reported that peptide amphiphile (PA) gels, pH-induced self-assembling nanostructured fibrous scaffolds, promote cell proliferation and have great potential in regenerative medicine for rapid repair of tissues. In this study, we hypothesized that the PA gels are capable of accelerating wound healing in burn injury. METHODS: Artificially generated thermally damaged fibroblasts and human umbilical vein endothelial cells were seeded onto the various PA nanofiber gels including bioactive and nonbioactive peptide sequences. Cell proliferation was assessed at different time points, and thermally damaged fibroblasts and HUVECs manifested increased proliferation with time when cultured with various PA gels. To determine in vivo effects, burn wounds of rats were treated with the bioactive Arg-Gly-Asp-Ser (RGDS)-modified gel that showed greater cell proliferation in vitro. The wound closure was observed, and skin samples were harvested for histologic evaluation. RESULTS: Cell proliferation using the RGDS-PA gel was significantly higher than that observed in other gels. The RGDS-PA gel significantly enhanced re-epithelialization during the burn wound healing process between days 7 and 28. Application of PA gels accelerates the recovery of deep partial-thickness burn wounds by stimulation of fibroblasts and the creation of an environment conducive to epithelial cell proliferation and wound closure. CONCLUSIONS: This biomaterial represents a new therapeutic strategy to overcome current clinical challenges in the treatment of injuries resulting from burns.

Application of Hydroxycholesterols for Alveolar Cleft Osteoplasty in a Rodent Model.

BACKGROUND: Bone morphogenetic proteins (BMPs) have played a central role in the regenerative therapies for bone reconstruction, including alveolar cleft and craniofacial surgery. However, the high cost and significant adverse effect of BMPs limit their broad application. Hydroxycholesterols, naturally occurring products of cholesterol oxidation, are a promising alternative to BMPs. The authors studied the osteogenic capability of hydroxycholesterols on human mesenchymal stem cells and the impact of hydroxycholesterols on a rodent alveolar cleft model. METHODS: Human mesenchymal stem cells were treated with control medium or osteogenic medium with or without hydroxycholesterols. Evaluation of cellular osteogenic activity was performed. A critical-size alveolar cleft was created and one of the following treatment options was assigned randomly to each defect: collagen sponge incorporated with hydroxycholesterols, BMP-2, or no treatment. Bone regeneration was assessed by means of radiologic and histologic analyses and local inflammation in the cleft evaluated. Moreover, the role of the hedgehog signaling pathway in hydroxycholesterol-mediated osteogenesis was examined. RESULTS: All cellular osteogenic activities were significantly increased on human mesenchymal stem cells treated with hydroxycholesterols relative to others. The alveolar cleft treated with collagen sponge with hydroxycholesterols and BMP-2 demonstrated robust bone regeneration. The hydroxycholesterol group revealed histologically complete bridging of the alveolar defect with architecturally mature new bone. The inflammatory responses were less in the hydroxycholesterol group compared with the BMP-2 group. Induction of hydroxycholesterol-mediated in vitro osteogenesis and in vivo bone regeneration were attenuated by hedgehog signaling inhibitor, implicating involvement of the hedgehog signaling pathway. CONCLUSION: Hydroxycholesterols may represent a viable alternative to BMP-2 in bone tissue engineering for alveolar cleft.

Evaluating the impact of global fund withdrawal on needle and syringe provision, cost and use among people who inject drugs in Tijuana, Mexico: a costing analysis.

OBJECTIVE: From 2011 to 2013, the Global Fund (GF) supported needle and syringe programmes in Mexico to prevent transmission of HIV among people who inject drugs. It remains unclear how GF withdrawal affected the costs, quality and coverage of needle and syringe programme provision. DESIGN: Costing study and longitudinal cohort study. SETTING: Tijuana, Mexico. PARTICIPANTS: Personnel from a local needle and syringe programme (n=6) and people who inject drugs (n=734) participating in a longitudinal study. PRIMARY OUTCOME MEASURES: Provision of needle and syringe programme services and cost (per contact and per syringe distributed, in 2017 $USD) during GF support (2012) and after withdrawal (2015/16). An additional outcome included needle and syringe programme utilisation from a concurrent cohort of people who inject drugs during and after GF withdrawal. RESULTS: During the GF period, the needle and syringe programme distributed 55 920 syringes to 932 contacts (60 syringes/contact) across 14 geographical locations. After GF withdrew, the needle and syringe programme distributed 10 700 syringes to 2140 contacts (five syringes/contact) across three geographical locations. During the GF period, the cost per harm reduction contact was approximately 10-fold higher compared with after GF ($44.72 vs $3.81); however, the cost per syringe distributed was nearly equal ($0.75 vs $0.76) due to differences in syringes per contact and reductions in ancillary kit components. The mean log odds of accessing a needle and syringe programme in the post-GF period was significantly lower than during the GF period (p=0.02). CONCLUSIONS: Withdrawal of GF support for needle and syringe programme provision in Mexico was associated with a substantial drop in provision of sterile syringes, geographical coverage and recent clean syringe utilisation among people who inject drugs. Better planning is required to ensure harm reduction programme sustainability is at scale after donor withdrawal.

Knowledge and Practices of Toxoplasmosis among Clinical Laboratory Professionals: A Cross-Sectional Study in Durango, Mexico.

Background: The aim of this study was to determine the level of knowledge and practices about toxoplasmosis in a sample of clinical laboratory professionals in Mexico. Methods: 192 clinical laboratory professionals were surveyed. They were asked about (1) Toxoplasma gondii; (2) clinical manifestations, diagnosis, treatment, and epidemiology of toxoplasmosis; and (3) their practices with respect to toxoplasmosis. Results: The range of animals infected by T. gondii was known by 44.8% of participants. Clinical aspects of toxoplasmosis were known by up to 44.3% of subjects. Correct answers about the interpretation of serological markers of T. gondii infection were provided by up to 32.8% of participants. A minority (32.2%) of participants knew about a high number of false positive results of anti-T. gondii IgM antibody tests. Most participants (90.1%) did not know what the anti-T. gondii IgG avidity test was. Up to 55.7% of participants provided incorrect answers about the interpretation of serology tests for the treatment of pregnant women. Common routes of T. gondii infection were known by <15% of participants. Most (84.4%) participants had not performed tests for detection T. gondii infection. Conclusions: Results indicate incomplete knowledge of T. gondii infection and toxoplasmosis and a limited practice of laboratory tests among the professionals surveyed.

Concordance of Toxoplasma gondii Infection Markers Among Heterosexual Couples.

BACKGROUND: Very little is known about concordance of Toxoplasma gondii (T. gondii) infection markers among couples. Through a cross-sectional study, we sought to determine the correlation of T. gondii infection in a sample of 119 heterosexual couples in Durango State, Mexico. METHODS: Participants were examined for the presence of anti-T. gondii IgG and IgM antibodies using enzyme-linked immunoassays. IgG and IgM seropositive couples were further analyzed for the presence of T. gondii DNA by using polymerase chain reaction (PCR). RESULTS: Anti-T. gondii IgG antibodies were found in 71 (59.7%) men and in 63 (52.9%) women (odds ratio (OR) = 1.31; 95% confidence interval (CI): 0.78 - 2.19; P = 0.29). Of the 71 seropositive men, 40 (56.3%) had a seropositive couple; in contrast, of the 63 seropositive women, 40 (63.5%) had a seropositive couple (OR = 0.74; 95% CI: 0.37 - 1.48; P = 0.39). In total, 65 (54.6%) couples had concordant results (both IgG positive or both IgG negative), and 54 (45.4%) had discordant results (a seropositive man with a seronegative woman, or a seropositive woman with a seronegative man) (kappa index = 0.08; 95% CI: -0.09 - 0.26). With respect to high (> 150 IU/mL) levels of anti-T. gondii IgG antibodies, 79 (66.4%) of the 119 couples had concordant results and 40 (33.6%) had discordant results (kappa index = -0.15; 95% CI: -0.03 - 0.33). Forty couples were positive for anti-T. gondii IgM antibodies. Of them, 21 (52.5%) had concordant results, and 19 (47.5%) had discordant results (kappa index = -0.01; 95% CI: -0.39 - 0.28). Concerning PCR, eight (50%) of 16 couples were positive for T. gondii DNA. Of them, 11 (68.8%) had concordant results, and five (31.2%) had discordant results (kappa index = 0.31; 95% CI: -0.17 - 0.79). CONCLUSIONS: Results suggest a poor concordance of serological and molecular markers of T. gondii infection among heterosexual couples. Further studies to confirm our results should be conducted.

Oxy133, a novel osteogenic agent, promotes bone regeneration in an intramembranous bone-healing model.

Current reconstructive techniques for complex craniofacial osseous defects are challenging and are associated with significant morbidity. Oxysterols are naturally occurring cholesterol oxidation products with osteogenic potential. In this study, we investigated the effects of a novel semi-synthetic oxysterol, Oxy133, on in vitro osteogenesis and an in vivo intramembranous bone-healing model. Rabbit bone marrow stromal cells (BMSCs) were treated with either Oxy133 or BMP-2. Alkaline phosphatase (ALP) activity, expression of osteogenic gene markers and in vitro mineralization were all examined. Next, collagen sponges carrying either Oxy133 or BMP-2 were used to reconstruct critical-sized cranial defects in mature rabbits and bone regeneration was assessed. To determine the mechanism of action of Oxy133 both in vitro and in vivo, rabbit BMSCs cultures and collagen sponge/Oxy133 implants were treated with the Hedgehog signalling pathway inhibitor, cyclopamine, and similar outcomes were measured. ALP activity in rabbit BMSCs treated with 1 µm Oxy133 was induced and was significantly higher than in control cells. These results were mitigated in cultures treated with cyclopamine. Expression of osteogenic gene markers and mineralization in BMSCs treated with 1 µm Oxy133 was significantly higher than in control groups. Complete bone regeneration was noted in vivo when cranial defects were treated with Oxy133; healing was incomplete, however, when cyclopamine was added. Collectively, these results demonstrate that Oxy133 has the ability to induce osteogenic differentiation in vitro in rabbit BMSCs and to promote robust bone regeneration in vivo in an animal model of intramembranous bone healing. Copyright © 2015 John Wiley & Sons, Ltd.

High Prevalence of Toxoplasma gondii Infection in Miners: A Case-Control Study in Rural Durango, Mexico.

BACKGROUND: Very little is known about the seroepidemiology of infection with the parasite Toxoplasma gondii (T. gondii) in miners. We determine the association of T. gondii infection and the occupation of miner, and the association of seropositivity for T. gondii with the socio-demographic, clinical, work and behavioral characteristics of the miners. METHODS: Through a case-control study, 125 miners working in Durango State, Mexico and 250 age- and gender-matched non-miner subjects were examined for the presence of anti-T. gondii IgG and IgM antibodies using enzyme-linked immunoassays. In addition, the presence of T. gondii DNA in miners was determined using polymerase chain reaction. Bivariate and multivariate analyses were used to determine the association of socio-demographic, work, clinical and behavioral characteristics of miners with T. gondii infection. RESULTS: Anti-T. gondii IgG antibodies were detected in 75 (60.0%) of 125 miners and in 55 (22.0%) of 250 controls (odds ratio (OR) = 5.31; 95% confidence interval (CI): 3.33 - 8.47; P < 0.001). Among IgG seropositive subjects, the frequency of anti-T. gondii IgM antibodies was significantly higher in miners (39/75, 52%) than in controls (8/55, 14.5%) (P < 0.001). All T. gondii seropositive miners referred themselves as healthy. Multivariate analysis of socio-demographic, housing, and behavioral characteristics of miners showed that T. gondii seropositivity was positively associated with being born in Durango State (OR = 3.44; 95% CI: 1.09 - 10.7; P = 0.03), consumption of boar meat (OR = 5.53; 95% CI: 1.49 - 20.3; P = 0.01), living in an overcrowded home (OR = 5.83; 95% CI: 1.49 - 22.8; P = 0.01), and was negatively associated with cleaning cat excrement (OR = 0.33; 95% CI: 0.11 - 0.90; P = 0.03) and consuming goat meat (OR = 0.16; 95% CI: 0.03 - 0.76; P = 0.02). CONCLUSIONS: Surprisingly, our results indicate that miners represent a risk group for T. gondii infection. This is the first age- and gender-matched case-control study on the association of T. gondii infection and the occupation of miner. Further studies to identify the exact cause of high seropositivity in miners in rural Durango are needed.

Toxoplasma Gondii Infection and Depression: A Case-Control Seroprevalence Study.

We assessed the association of Toxoplasma gondii infection and depression in a sample of psychiatric patients and control subjects without depression. We performed an age- and gender-matched case-control study of 89 patients suffering from depression attended in a public psychiatric hospital in Durango City, Mexico and 356 control subjects without depression from the general population of the same city. Participants were tested for the presence of anti-Toxoplasma IgG and IgM antibodies using enzyme-linked immunoassays. Anti-T. gondii IgG antibodies were found in 11 (12.4%) of the 89 cases and in 22 (6.2%) of the 356 controls (OR = 2.14; 95% CI: 1.00-4.59; P = 0.04). Anti-T. gondii IgM antibodies were found in four (19%) of 21 anti-T. gondii IgG seropositive controls but not in 11 anti-T. gondii IgG seropositive cases (P = 0.27). Patients aged 30 years old and younger had a significantly higher seroprevalence of T. gondii infection than controls of the same age group (P = 0.001). Results of the present study suggest a potential association between T. gondii infection and depression. Furthers studies to confirm our results and to determine the epidemiology of T. gondii in young depressed patients should be conducted.

Toxoplasma gondii Infection and Mixed Anxiety and Depressive Disorder: A Case-Control Seroprevalence Study in Durango, Mexico.

BACKGROUND: The parasite Toxoplasma gondii (T. gondii) may invade the brain and might induce behavioral changes. We sought to determine the association of T. gondii infection and mixed anxiety and depressive disorder. METHODS: Through an age- and gender-matched case-control seroprevalence study, we examined 65 patients suffering from mixed anxiety and depressive disorder (WHO ICD-10 code: F41.2) attending in a public hospital of mental health and 260 control subjects without this disorder from the general population. Sera of participants were analyzed for anti-Toxoplasma IgG and IgM antibodies using enzyme-linked immunoassays. RESULTS: Fifteen (23.1%) of the 65 patients and 18 (6.9%) of the 260 controls had anti-T. gondii IgG antibodies (odds ratio (OR): 4.03; 95% confidence interval (CI): 1.90 - 8.53; P < 0.001). The frequency of high (> 150 IU/mL) anti-T. gondii IgG levels was similar in cases and controls (OR: 0.25; 95% CI: 0.05 - 1.06; P = 0.05). Seroprevalence was similar in male cases and controls (P = 1.0); however, seroprevalence was significantly higher in female cases than in female controls (OR: 7.08; 95% CI: 2.83 - 17.67; P < 0.00001). Patients aged 31 - 50 years old had a significantly higher seroprevalence of T. gondii infection than controls of the same age group (OR: 21.04; 95% CI: 5.22 - 84.80; P < 0.00001). Anti-T. gondii IgM antibodies were found in four (26.7%) of the 15 anti-T. gondii IgG seropositive cases and in 10 (55.6%) of the 18 anti-T. gondii IgG seropositive controls (P = 0.15). CONCLUSIONS: Results support for the first time an association between seropositivity to T. gondii and mixed anxiety and depressive disorder. Further research to confirm this association and to determine the seroepidemiology of T. gondii infection in patients with this disorder is needed.

Natural Killer Cells Differentiate Human Adipose-Derived Stem Cells and Modulate Their Adipogenic Potential.

BACKGROUND: Natural killer cells are thought to represent more than 30 percent of all lymphocytes within the stromal vascular fraction of lipoaspirates. However, their physiologic interaction with adipocytes and their precursors has never been specifically examined. The authors hypothesized that natural killer cells, by means of cytokine secretion, are capable of promoting the differentiation of adipose-derived stem cells. METHODS: Human natural killer cells purified from healthy donors' peripheral blood mononuclear cells were activated with a combination of interleukin-2 and anti-CD16 monoclonal antibody; natural killer cell supernatant was collected. Adipose-derived stem cells isolated from raw human lipoaspirates from healthy patients were treated with growth media, growth media with natural killer cell supernatant, adipogenic media, and adipogenic media with natural killer cells supernatant. Flow cytometric analysis was performed on cells using antibodies against B7H1, CD36, CD44, CD34, CD29, and MHC-1. Adipogenic-related gene expression (PPAR-γ, LPL, GPD-1, and aP2) was assessed. Oil Red O staining was performed as a functional assay of adipocyte differentiation and adipogenesis. RESULTS: Adipose-derived stem cells maintained in growth media with natural killer cell supernatant lost markers of "stemness," including CD44, CD34, and CD29; and expressed markers of differentiation, including B7H1 and MHC-1. Adipose-derived stem cells treated with natural killer cell supernatant accumulated small amounts of lipid after 10 days of natural killer cell supernatant treatment. Adipose-derived stem cells treated with natural killer cell supernatant showed altered expression of adipogenesis-associated genes compared with cells maintained in growth media. Adipose-derived stem cells maintained in adipogenic media with natural killer cell supernatant accumulated less lipid than those cells in adipogenic media alone. CONCLUSIONS: The authors demonstrate that, through secreted factors, natural killer cells are capable of differentiating adipose-derived stem cells. In cells maintained in adipogenic media, treatment with natural killer cell supernatant modulated adipogenic potential.

Supporting the minority physician pipeline: providing global health experiences to undergraduate students in the United States-Mexico border region.

BACKGROUND: The sizeable US Latino population calls for increasing the pipeline of minority and bilingual physicians who can provide culturally competent care. Currently, only 5.5% of US providers are Hispanic/Latino, compared with 16% of the US population (i.e., >50.5 million persons). By 2060, it is predicted that about one-third of all US residents will be of Latino ethnicity. ACTIVITIES AND OUTCOMES: This article describes the Health Frontiers in Tijuana Undergraduate Internship Program (HFiT-UIP), a new quarterly undergraduate internship program based at a US-Mexico binational student-run free clinic and sponsored by the University of California, San Diego School of Medicine and the Universidad Autónoma de Baja California in Tijuana, Mexico. The HFiT-UIP provides learning opportunities for students and underrepresented minorities interested in medical careers, specifically Latino health. DISCUSSION: The HFiT-UIP might serve as a model for other educational partnerships across the US-Mexico border region and may help minority and other undergraduates seeking academic and community-based enrichment experiences. The HFiT-UIP can also support students' desires to learn about Latino, border, and global health within resource-limited settings.

Development of chemotactic smart scaffold for use in tissue regeneration.

BACKGROUND: Regenerative medicine aims to obviate the need for autologous grafting through the use of bioengineered constructs that combine stem cells, growth factors, and biocompatible vehicles. Human mesenchymal stem cells and vascular endothelial growth factor (VEGF) have both shown promise for use in this context, the former because of their pluripotent capacity and the latter because of its chemotactic activity. The authors harnessed the regenerative potential of human mesenchymal stem cells and VEGF to develop a chemotactic scaffold for use in tissue engineering. METHODS: Human mesenchymal stem cells were transduced with human VEGF via lentivirus particles to secrete VEGF. The chemotactic activity of the VEGF-transduced stem cells was evaluated via a trans-well assay. Migration through semipermeable membranes was significantly greater in chambers filled with medium conditioned by VEGF-transduced cells. VEGF-transduced cells were then seeded on apatite-coated poly(lactic-co-glycolic acid) scaffolds, thereby creating the Smart Scaffold. To determine in vivo angiogenesis, the Smart Scaffolds were implanted into subcutaneous pockets in the backs of nude mice. RESULTS: Significantly larger numbers of capillaries were observed in the Smart Scaffold compared with control implants on immunohistologic studies. For the chemotactic in vivo study, human mesenchymal stem cells tagged with a fluorescent dye (1,1-dioctadecyl-3,3,3,3-tetramethylindotricarbocyanine iodide) were injected intravenously via tail vein after the subcutaneous implantation of the Smart Scaffolds. In vivo fluorescent imaging revealed that fluorescent dye-tagged human mesenchymal stem cells successfully accumulated within the Smart Scaffolds. CONCLUSION: These observations suggest that VEGF may play a vital role in the design of clinically relevant tissue regeneration graft substitutes through its angiogenic effects and ability to chemoattract mesenchymal stem cells.

Toxoplasma gondii infection in interstate truck drivers: a case-control seroprevalence study.

BACKGROUND: Infection with Toxoplasma gondii can be acquired via the ingestion of undercooked or raw meat containing tissue cysts, or via ingestion of water contaminated with oocysts. Professional long distance truck driving may have epidemiological importance for food-borne infections since drivers eat out of home and in places where hygiene and cooking practices are uncertain. We aimed to determine whether interstate truck drivers in Durango, Mexico have an increased risk of infection with T. gondii as indicated by seropositivity; and to determine the socio-demographic, work, clinical, and behavioral characteristics associated with T. gondii seropositivity in interstate truck drivers. METHODS: Through a case-control study design, 192 truck drivers and 192 controls from the general population of the same region matched by gender and age were examined with enzyme-linked immunoassays for the presence of anti-Toxoplasma IgG and IgM antibodies. Socio-demographic, work, clinical and behavioral characteristics from the truck drivers were obtained. RESULTS: Anti-T. gondii IgG antibodies were found in 23 (12.0%) of 192 truck drivers and in 13 (6.8%) of 192 controls (OR = 21.0; 95% CI: 1.23-358.38; P = 0.002). Anti-T. gondii IgM antibodies were found in 7 (3.6%) cases and in 7 (3.6%) controls (P = 1.00). The seroprevalence of T. gondii infection was higher in drivers with reflex impairment than in those without this impairment (4/13, 30.8% vs 19/179, 10.6%, respectively; P = 0.05), and in drivers with hearing impairment than in those without this impairment (3/7, 42.9% vs 20/185, 10.8%, respectively; P = 0.03). Multivariate analysis of work and behavioral characteristics of truck drives showed positive associations of T. gondii exposure with trips to the south of Mexico (OR = 3.11; 95% CI: 1.02-9.44; P = 0.04) and consumption of horse meat (OR = 5.18; 95% CI: 1.62-16.55; P = 0.005). CONCLUSIONS: Results suggest that interstate truck drivers may have an increased risk for T. gondii infection, and that T. gondii exposure may be impacting neurological functions in truck drivers. Contributing factors for T. gondii exposure should be taken into account for the design of optimal prevention measures against T. gondii infection.

Seroprevalence of Toxoplasma gondii infection and associated risk factors in Huicholes in Mexico.

BACKGROUND: Very little is known about the seroepidemiology of Toxoplasma gondii infection in ethnic groups in Mexico. Huicholes are an indigenous ethnic group living in a remote mountainous region in Mexico. We sought to determine the prevalence of anti-Toxoplasma IgG and IgM antibodies in Huicholes; and to determine the association of Toxoplasma seropositivity with socio-demographic, behavioral, and clinical characteristics of Huicholes. METHODS: We performed a cross sectional survey in Huicholes from September 2013 to January 2014. A convenience sampling method was used. We investigated the prevalence of anti-Toxoplasma IgG and IgM antibodies in 214 Huicholes using enzyme-linked immunoassays. A standardized questionnaire was used to obtain the characteristics of the Huicholes. Bivariate and multivariate analyses were used to assess the association of Toxoplasma exposure and Huicholes' characteristics. RESULTS: Of the 214 Huicholes studied (mean age: 37.98 ± 15.80 years), 71 (33.2%) were positive for anti-T. gondii IgG antibodies and 47 (66.2%) of them were also positive for anti-T. gondii IgM antibodies. Seroprevalence of T. gondii infection did not vary with age, sex, or occupation. However, seroprevalence of anti-T. gondii IgM antibodies was significantly higher in female than in male Huicholes. Multivariate analysis of socio-demographic and behavioral characteristics showed that T. gondii exposure was associated with consumption of turkey meat (OR = 2.28; 95% CI: 1.16-4.46; P = 0.01). In addition, seroprevalence of T. gondii infection was significantly higher in Huicholes suffering from dizziness and memory impairment than those without such clinical characteristics. CONCLUSIONS: Our results demonstrate serological evidence of T. gondii exposure among Huicholes which may be impacting their health. Results of this first study of T. gondii infection in Huicholes may be useful for the design of optimal preventive measures against infection with T. gondii.

A bioengineered peripheral nerve construct using aligned peptide amphiphile nanofibers.

Peripheral nerve injuries can result in lifelong disability. Primary coaptation is the treatment of choice when the gap between transected nerve ends is short. Long nerve gaps seen in more complex injuries often require autologous nerve grafts or nerve conduits implemented into the repair. Nerve grafts, however, cause morbidity and functional loss at donor sites, which are limited in number. Nerve conduits, in turn, lack an internal scaffold to support and guide axonal regeneration, resulting in decreased efficacy over longer nerve gap lengths. By comparison, peptide amphiphiles (PAs) are molecules that can self-assemble into nanofibers, which can be aligned to mimic the native architecture of peripheral nerve. As such, they represent a potential substrate for use in a bioengineered nerve graft substitute. To examine this, we cultured Schwann cells with bioactive PAs (RGDS-PA, IKVAV-PA) to determine their ability to attach to and proliferate within the biomaterial. Next, we devised a PA construct for use in a peripheral nerve critical sized defect model. Rat sciatic nerve defects were created and reconstructed with autologous nerve, PLGA conduits filled with various forms of aligned PAs, or left unrepaired. Motor and sensory recovery were determined and compared among groups. Our results demonstrate that Schwann cells are able to adhere to and proliferate in aligned PA gels, with greater efficacy in bioactive PAs compared to the backbone-PA alone. In vivo testing revealed recovery of motor and sensory function in animals treated with conduit/PA constructs comparable to animals treated with autologous nerve grafts. Functional recovery in conduit/PA and autologous graft groups was significantly faster than in animals treated with empty PLGA conduits. Histological examinations also demonstrated increased axonal and Schwann cell regeneration within the reconstructed nerve gap in animals treated with conduit/PA constructs. These results indicate that PA nanofibers may represent a promising biomaterial for use in bioengineered peripheral nerve repair.

Effectiveness of mirtazapine in the treatment of sleep apnea/hypopnea syndrome (SAHS).

Several drugs have been described as possible treatments for Sleep Apnea/Hypopnea Syndrome (SAHS) but the data available does not support their use. In an animal model of central apnea the use of mirtazapine produced a significant reduction of apneas. We present a male patient, 82 years old, with excessive daytime sleepiness and loud snoring during at least 10 years. An overnight polysomnography (PSG) revealed an apnea/hypopnea index of 54.9 events per hour of sleep with a minimum pulse oximetric saturation (SaO(2)) of 78% and an arousal index of 40.4 per hour. A nasal CPAP titration in the second half of the night showed suppression of apneas with a CPAP level of 8 cmH(2)O. The patient refused to use the CPAP device and began with 15 mg of mirtazapine at bedtime. A second PSG performed after 3 months of mirtazapine showed a significant reduction in the apnea/hypopnea index (9.3 events per hour of sleep; 81% minimal oxygen saturation (SaO(2))). Clinically, the patient and his wife reported a clear reduction of excessive daytime sleepiness and an improvement in self-reported functioning and well-being without any important side effects. This successful case appears to be the first report with mirtazapine in human SAHS and supports the need for an appropriate clinical trial with this drug.