Trypanosoma cruzi infection in mammals in Florida: New insight into the transmission of T. cruzi in the southeastern United States.

In Latin America, synanthropic mammalian reservoirs maintain Trypanosoma cruzi, a parasitic protozoan, where they facilitate the transmission of the parasite to humans and other reservoir hosts in peridomestic settings. In the United States, raccoons (Procyon lotor) and Virginia opossums (Didelphis virginiana) are known synanthropic T. cruzi reservoir hosts; however, the role these species have in the peridomestic transmission cycle in the US is not well understood. This study aimed to identify the suite of mammalian reservoirs of T. cruzi in Florida. We also compared infection prevalence in raccoon populations sampled from within and outside of the estimated distribution of the common T. cruzi vector in Florida to gain insight into how the arthropod vector distribution impacts the distribution of infected reservoirs in the state. Finally, to investigate the impact of peridomestic landscapes on parasite prevalence, we compared the prevalence of T. cruzi-infected raccoons and opossums across five paired peridomestic and sylvatic sites. We live-trapped and collected peripheral blood samples from 135 raccoons, 112 opossums, 18 nine-banded armadillos (Dasypus novemcinctus), and nine species of rodents in north central Florida. Using quantitative PCR methods, we found that raccoons (42.2%, 95% CI [34.2-50.7%]) and opossums (50.9%, 95% CI [41.8-60.0%]) were infected with T. cruzi and the prevalence across habitats was similar for both raccoons (peridomestic: n = 77, 44.2%, 95% CI [33.6-55.3%], sylvatic: n = 58, 39.7%, 95% CI [28.1-52.5%]) and opossums (peridomestic: n = 66, 48.5%, 95% CI [36.8-60.3%], sylvatic: n = 46, 54.3%, 95% CI [40.2-67.8%]). Raccoons sampled outside the estimated distribution of Triatoma sanguisuga were not infected with T. cruzi (n = 73, 0.0%, 95% CI [0.0-5.0%]). Our study did not indicate that peridomestic habitats in Florida maintained a higher infection prevalence than their sylvatic counterparts; however, we did find a difference in prevalence within vs. outside the estimated vector distribution in Florida.

[2022 Practice guidelines for the management of arterial hypertension of the Spanish Society of Hypertension]. / Guía práctica sobre el diagnóstico y tratamiento de la hipertensión arterial en España, 2022. Sociedad Española de Hipertensión - Liga Española para la Lucha contra la Hipertensión Arterial (SEH-LELHA).

Hypertension is the most important risk factor for global disease burden. Detection and management of hypertension are considered as key issues for individual and public health, as adequate control of blood pressure levels markedly reduces morbidity and mortality associated with hypertension. Aims of these practice guidelines for the management of arterial hypertension of the Spanish Society of Hypertension include offering simplified schemes for diagnosis and treatment for daily practice, and strategies for public health promotion. The Spanish Society of Hypertension assumes the 2018 European guidelines for management of arterial hypertension developed by the European Society of Cardiology and the European Society of Hypertension, although relevant aspects of the 2017 American College of Cardiology/American Heart Association guidelines and the 2020 International Society of Hypertension guidelines are also commented. Hypertension is defined as a persistent elevation in office systolic blood pressure ≥ 140 and/or diastolic blood pressure ≥ 90 mmHg, and assessment of out-of-office blood pressure and global cardiovascular risk are considered of key importance for evaluation and management of hypertensive patients. The target for treated blood pressure should be < 130/80 for most patients. The treatment of hypertension involves lifestyle interventions and drug therapy. Most people with hypertension need more than one antihypertensive drug for adequate control, so initial therapy with two drugs, and single pill combinations are recommended for a wide majority of hypertensive patients.

Feasibility of 31 P spectroscopic imaging at 7 T in lung carcinoma patients.

Currently, it is difficult to predict effective therapy response to molecular therapies for the treatment of lung cancer based solely on anatomical images. 31 P MR spectroscopic imaging could provide as a non-invasive method to monitor potential biomarkers for early therapy evaluation, a necessity to improve personalized care and reduce cost. However, surface coils limit the imaging volume in conventional 31 P MRSI. High-energetic adiabatic RF pulses are required to achieve flip angle homogeneity but lead to high SAR. Birdcage coils permit use of conventional amplitude modulated pulses, even over large FOV, potentially decreasing overall SAR massively. Here, we investigate the feasibility of 3D 31 P MRSI at 7 T in lung carcinoma patients using an integrated 31 P birdcage body coil in combination with either a dual-coil or a 16-channel receiver. Simulations showed a maximum decrease in SNR per unit of time of 8% for flip angle deviations in short TR low flip-angle excitation 3D CSI. The minimal SNR loss allowed for fast 3D CSI without time-consuming calibration steps (>10:00 min.). 31 P spectra from four lung carcinoma patients were acquired within 29:00 minutes and with high SNR using both receivers. The latter allowed discrimination of individual phosphodiesters, inorganic phosphate, phosphocreatine and ATP. The receiver array allowed for an increased FOV compared to the dual-coil receiver. 3D 31 P-CSI were acquired successfully in four lung carcinoma patients using the integrated 31 P body coil at ultra-high field. The increased spectral resolution at 7 T allowed differentiation of multiple 31 P metabolites related to phospholipid and energy metabolism. Simulations provide motivation to exclude 31 P B1 calibrations, potentially decreasing total scan duration. Employing large receiver arrays improves the field of view allowing for full organ coverage. 31 P MRSI is feasible in lung carcinoma patients and has potential as a non-invasive method for monitoring personalized therapy response in lung tumors.

Natural Pigments and Biogas Recovery from Microalgae Grown in Wastewater.

This study assessed the recovery of natural pigments (phycobiliproteins) and bioenergy (biogas) from microalgae grown in wastewater. A consortium of microalgae, mainly composed by Nostoc, Phormidium, and Geitlerinema, known to have high phycobiliproteins content, was grown in photobioreactors. The growth medium was composed by secondary effluent from a high rate algal pond (HRAP) along with the anaerobic digestion centrate, which aimed to enhance the N/P ratio, given the lack of nutrients in the secondary effluent. Additionally, the centrate is still a challenging anaerobic digestion residue since the high nitrogen concentrations have to be removed before disposal. Removal efficiencies up to 52% of COD, 86% of NH4 +-N, and 100% of phosphorus were observed. The biomass composition was monitored over the experimental period in order to ensure stable cyanobacterial dominance in the mixed culture. Phycocyanin and phycoerythrin were extracted from harvested biomass, achieving maximum concentrations of 20.1 and 8.1 mg/g dry weight, respectively. The residual biomass from phycobiliproteins extraction was then used to produce biogas, with final methane yields ranging from 159 to 199 mL CH4/g VS. According to the results, by combining the extraction of pigments and the production of biogas from residual biomass, we would not only obtain high-value compounds, but also more energy (around 5-10% higher), as compared to the single recovery of biogas. The proposed process poses an example of resource recovery from biomass grown in wastewater, moving toward a circular bioeconomy.

Rhodamine B - as New Chromophore for the Determination of Melatonin in Biological, Food, and Pharmaceutical Samples.

AIM AND OBJECTIVE: Melatonin is an essential biomarker for sleep-related disorders. Reliable methods of analysis are needed for melatonin. Therefore, a new chromophore (Rhodamine B) was proposed for the assay of melatonin; this method succeeded to enlarge the working concentration range and to decrease the limit of determination comparing with the method that just used the native fluorescence of melatonin. MATERIALS AND METHODS: Rhodamine B was proposed as a new chromophore for the assay of melatonin in biological, food, and pharmaceutical samples. Fluorescence was used for the determination of melatonin. RESULTS: The results obtained using Rhodamine B were compared with those obtained by the native fluorescence of melatonin. Using the new chromophore, melatonin was determined in the concentration range between 0.01 and 50 pmol L-1, with the detection limit of 2.4 fmol L-1. The recovery of melatonin was higher than 98.00% with a relative standard deviation of less than 0.10%, when the method was applied for the assay of melatonin in samples such as breast milk, whole blood, milk powder, and pharmaceutical formulations. CONCLUSION: Utilization of Rhodamine B enlarged the linear concentration range for the assay of melatonin and decreased the detection limit, making possible the assay of melatonin in a variety of samples such as pharmaceuticals, food, and biological samples.

Cerebral small vessel disease: cognition, mood, daily functioning, and imaging findings from a small pilot sample.

Cerebral small vessel disease, a leading cause of cognitive decline, is considered a relatively homogeneous disease process, and it can co-occur with Alzheimer's disease. Clinical reports of magnetic resonance imaging (MRI)/computed tomography and single photon emission computed tomography (SPECT) imaging and neuropsychology testing for a small pilot sample of 14 patients are presented to illustrate disease characteristics through findings from structural and functional imaging and cognitive assessment. Participants showed some decreases in executive functioning, attention, processing speed, and memory retrieval, consistent with previous literature. An older subgroup showed lower age-corrected scores at a single time point compared to younger participants. Performance on a computer-administered cognitive measure showed a slight overall decline over a period of 8-28 months. For a case study with mild neuropsychology findings, the MRI report was normal while the SPECT report identified perfusion abnormalities. Future research can test whether advances in imaging analysis allow for identification of cerebral small vessel disease before changes are detected in cognition.

Acute ischemic stroke and infections.

We present an overview of multiple infections in relation to acute ischemic stroke and the therapeutic options available. Conditions that are a direct cause of stroke (infectious endocarditis, meningoencephalitides, and human immunodeficiency virus infection), the pathophysiologic mechanism responsible for stroke, and treatment dilemmas are presented. Independently or in conjunction with conventional risk factors, chronic and acute infections can trigger an acute ischemic stroke through an accelerated process of atherosclerosis and immunohematologic alterations. Acute ischemic stroke has a negative impact on the antibacterial immune response, leading to stroke-induced immunodepression and infections, the most common poststroke medical complications. Poststroke infections are independent predictors of poor outcome. Antibiotic trials for poststroke infection prevention are reviewed. Although antibiotic prophylaxis is not the standard of care in acute stroke, current guidelines support prompt treatment of stroke-related infections.

Considerations concerning design and mechanism of action of a new class of anticancer dual DNA intercalators.

Cancer is one of the most serious and merciless health problems of the mankind, about seven million people dying of cancer every year. Two of the most important and promising targets in cancer chemotherapy include DNA alkylating agents and DNA intercalators. The emphasis of this work was to design, synthetize and formulate a mechanism of action for a new class of dual DNA intercalators. The dual DNA intercalators have three main parts: an alkylating unit (represented by two halo-alkyl-ester chains), an intercalator unit (five- or six-membered ring nitrogen heterocycle) and an acetophenone skeleton linker. As mechanism of action, we consider that these compounds act as dual DNA intercalators, the alkylating unit realizing a covalent bonding via DNA protein "cross-linking effect" while nitrogen heterocycles will realize noncovalent bonding via DNA intercalation with purine and pyrimidine bases from DNA and the amino acids from topoisomerases enzymes. Our hypothesis was confirmed by in vitro anticancer tests against HeLa cell lines, where the newly obtained compounds demonstrated a very good activity.

Timing of symptomatic vasospasm in aneurysmal subarachnoid hemorrhage: the effect of treatment modality and clinical implications.

A better prediction of the time course of symptomatic vasospasm (SVSP) might have a significant impact on the management and prevention of delayed neurologic ischemic deficit (DIND). We studied the influence of the treatment for ruptured aneurysm on SVSP timing. We retrospectively analyzed data of consecutive patients with aneurysmal subarachnoid hemorrhage (aSAH) admitted in our center between 1999 and 2005, treated within 72 hours of the rupture by surgical clipping or endovascular coiling and in accordance with our neuroscience unit protocol. We analyzed the presence of SVSP and recorded the timing of occurrence after the aneurysmal repair intervention. Data on demographics, premorbid conditions, time elapsed from the subarachnoid hemorrhage onset and intervention, and clinical and radiologic characteristics at admission were collected. The first occurrence of postintervention SVSP was recorded and compared between the 2 treatment groups using a proportional hazards regression model, including significant covariates. Of the 67 patients analyzed, 21 (31%) underwent endovascular coiling and 46 (69%) underwent surgical clipping. The baseline variables were similar in the 2 groups. The median time from the procedure to clinical vasospasm was 4 days in the coiled patients and 7 days in the clipped patients. In a proportional hazards model regression analysis including age, sex, Fisher and Hunt-Hess grades, time between onset to procedure, and intervention type, only intervention type emerged as a significant predictor of time to SVSP after intervention (likelihood ratio chi2 = 16.8; P < .00). Treatment modality of ruptured intracranial aneurysm may influence the timing of SVSP occurrence.

Safety and effectiveness of endovascular therapy after 8 hours of acute ischemic stroke onset and wake-up strokes.

BACKGROUND AND PURPOSE: This is a retrospective review of patients who underwent endovascular recanalization > or = 8 hours after acute ischemic stroke symptom onset, including wake-up strokes, between June 2005 and June 2008. METHODS: Thirty patients with a premorbid modified Rankin score < or = 1 and NIHSS between 5 and 22 were included. All had admission CT, CTA, and CT perfusion scans to evaluate for salvageable brain tissue. Recanalization effectiveness was assessed by angiograms obtained within 30 hours after intervention. Patient, treatment characteristics, and immediate and 3-month outcomes were analyzed. RESULTS: Mean NIHSS at presentation was 13 (median=12). Mean interval between time last-seen well and angiogram was 12.75 hours (median=10). Twenty-six patients (86.7%) presented with complete-to-near-complete vessel occlusion (thrombolysis in myocardial infarction [TIMI] 0/1); 4 had partial vessel occlusion (TIMI 2). Interventions included intra-arterial pharmacological thrombolysis (n=10), mechanical thrombectomy(n=21; Merci, 16; intracranial stent, 9; extracranial stent, 3), angioplasty (n=14; intracranial, 11; extracranial, 3). Nine patients received GPIIb/IIIa inhibitors (eptifibatide); all received heparin. Partial-to-complete recanalization (TIMI 2/3) was achieved in 20 patients (66.7%). Procedure-related complications included vascular perforations (n=3) and femoral access site complication (n=1). One patient had an embolic anterior cerebral artery infarct during intervention; another had progression of brain stem infarct. Symptomatic intracerebral hemorrhage occurred in 3 patients (10%), with 2 being primarily subarachnoid in location. Total in-hospital mortality including procedural mortality, disease progression, or other comorbidities was 23.3% (n=7). Mean discharge NIHSS was 9.5, representing an overall NIHSS 3.5-point improvement. Overall, mean modified Rankin score at death or last follow-up (mean=10.6 months) was 4.2. At 3 months, total mortality was 33.3% (n=10), 20% had modified Rankin score < or = 2, and 33% had modified Rankin score < or = 3. Among survivors, mean modified Rankin score at 3-month follow-up was 3. CONCLUSION: Our data show that delayed endovascular revascularization of carefully selected patients is safe, effective, and improves clinical outcome.

Acute ischemic stroke and thrombolysis location: comparing telemedicine and stroke center treatment outcomes.

BACKGROUND: Telemedicine has been increasingly used as an option for acute ischemic stroke treatment at hospitals where neurological expertise is not available. The aim of this study was to compare the outcome of stroke patients treated with systemic thrombolysis at our academic hub regional stroke centers (hub) versus our spoke hospital telemedicine locations (spoke) METHODS: Data were retrospectively reviewed for consecutive patients admitted for stroke treatment with intravenous tissue plasminogen activator at our hub (128 patients) and at the spoke centers (27 patients) over a 2-year period. Mortality was selected as a primary outcome measure, and post-thrombolysis intracranial hemorrhage (PT-ICH) rate, hospital length of stay (LOS), and discharge modified Rankin Scale (mRS) score were selected as secondary outcome measures. Logistic regression models were used to determine the effect of thrombolysis treatment site on stroke outcomes. RESULTS: Demographic and clinical variables of patients treated at the hub versus spoke sites were similar, except for a lower initial platelet count and a shorter time from ictus onset to needle in the spoke group. With covariates, the treatment site (hub vs spoke) did not have a significant impact on mortality (10.9% vs 11.1%; P = 0.34), nor on PT-ICH (20.3% vs 33.3%; P < 0.35). Site did not reach significance in affecting discharge outcome: 52.3% versus 51.9% of patients had good outcomes (mRS 0-3) and 47.7% versus 48.1% patients had poor outcomes (mRS, 4-6; P = 0.16). Length of stay was also not significantly affected by site: 8.8 days versus 10.7 days (P < 0.23). CONCLUSION: The hub-and-spoke telemedicine model for acute ischemic stroke treatment seems to carry similar efficacy and safety outcomes at the regional academic hub and spoke centers.

MRI assessment followed by successful mechanical recanalization of a complete tandem (internal carotid/middle cerebral artery) occlusion and reversal of a 10-hour fixed deficit.

BACKGROUND: Mechanical clot extraction up to 8 hours after stroke onset is an alternative strategy for opening large vessels, especially for patients ineligible for intravenous thrombolysis. Safety beyond this therapeutic window is untested. METHODS: An 81-year-old woman presented 8 hours after she developed left-sided weakness and dysarthria with a National Institutes of Health Stroke Scale (NIHSS) score fluctuating between 6 and 13. Neuroimaging revealed a large perfusion deficit with no diffusion abnormalities. An emergent cerebral angiogram revealed a complete internal carotid artery terminus occlusion. RESULTS: Successful mechanical thrombectomy was performed without complication and resulted in almost complete reversal of the patient's deficit to an NIHSS score of 1, 10 hours after stroke onset. CONCLUSION: Patients with large hypoperfused areas and minimal diffusion abnormalities on the MRI may benefit from mechanical thrombectomy beyond an 8-hour window.

The value of CT angiography and transcranial doppler sonography in triaging suspected cerebral vasospasm in SAH prior to endovascular therapy.

BACKGROUND: Transcranial Doppler sonography (TCD) is a noninvasive method for detecting arterial cerebral vasospasm (CVS) in aneurysmal subarachnoid hemorrhage (SAH). Computed tomographic angiography (CTA) has been increasingly used for CVS diagnosis. The purpose of this study was to evaluate the degree of agreement between TCD and CTA in diagnosing clinical CVS following SAH, and to define the role of CTA in triaging patients prior to digital subtraction angiography (DSA) and endovascular intervention. METHODS: Fifty-five consecutive patients with aneurysmal SAH who underwent sequential TCD and CTA were analyzed. TCD CVS was defined as anterior circulation peak mean velocity (PMV) >160 cm/s, basilar artery (BA) PMV >90 cm/s, and Lindegaard ratio (LR) >6. CTA CVS was defined as >50% luminal narrowing in the affected vessel. Clinical CVS was defined as the onset of new focal neurological deficit attributed to delayed ischemic injury. RESULTS: Thirteen patients (24%) had clinical CVS and 42 patients (76%) were asymptomatic. All patients with clinical CVS had also radiological evidence of CVS (agreement 100%). In 35 patients without clinical CVS, both tests agreed for absence of CVS in 28 cases (agreement 83%). The remaining 7 asymptomatic patients had radiological CVS only, in disagreement with clinical absence of CVS (17%). CONCLUSIONS: Clinical evaluation and TCD can reliably diagnose CVS in symptomatic patients and PMV >180 cm/s, or can rule out CVS in asymptomatic patients with PMV <140 cm/s. In this category of patients, adding a CTA to clinical evaluation and TCD may not be warranted.

Systemic hemostasis with recombinant-activated factor VII followed by local thrombolysis with recombinant tissue plasminogen activator in intraventricular hemorrhage.

INTRODUCTION: A 51-year-old woman on warfarin thromboprophylaxis for transient ischemic attacks developed sudden onset nausea, vomiting, and decreased mental status, rapidly becoming comatose. Head computed tomography (CT) showed intracerebral hemorrhage, extending into all ventricular chambers, and acute obstructive hematocephalus requiring urgent ventricular drainage. CT angiogram showed no evidence of an aneurysm or vascular malformation. METHODS: The pretreatment international normalized ratio (INR) of 4.9 was rapidly corrected with recombinant activated factor VII and an external ventricular drain was placed. Despite accurate positioning, the ventriculostomy thrombosed and became nonfunctional. Recombinant tissue plasminogen activator was given intraventricularly and resulted in partial ventricular decompression within 24 hours, with dramatic improvement in the patient's level of consciousness. RESULTS: Repeated intraventricular fibrinolysis resulted in further reduction of the intraventricular hematoma within a few days and a good patient outcome. The patient did not require permanent ventricular shunt. CONCLUSION: To our knowledge, this is the first reported case of combined systemic enhancement of hemostasis and local fibrinolysis as a life-saving measure in intracranial hemorrhage.

What proportion of stroke is not explained by classic risk factors?

Ischemic stroke is a complex entity with multiple etiologies and variable clinical manifestations. The most frequent cause of stroke is atherosclerosis of cerebral vasculature followed by cardioembolism. Two thirds of strokes are explained by identifiable risk factors. Age, hypertension, and nonvalvular atrial fibrillation are by far the most frequent and well documented ones. Approximately 5% of strokes are caused by conditions other than atherosclerosis or heart disease, i.e., cervical arteries dissections, nonatherosclerotic vasculopathies, infectious or systemic vasculitis, and collagen vascular diseases. In spite of a thorough diagnostic evaluation, 30% of strokes remain cryptogenic, i.e., no specific cause is identified and the classic risk factors are not present. Identification of unknown environmental or genetic risk factors should be the subject of further research.

[Mesenchymal stem cells. Differentiation and alternative source of neural tissue]. / Células mesenquimales de médula osea. Diferenciación y potencial reemplazo neuronal.

Embryonic stem cells are a population of cells located in the blastocyst, committed to specific differentiation according to spatial and temporal factors such as age and place of final location. Despite the final fate of hematic cells, hemopoietic cells retain a relative degree of plasticity dependent on environmental factors. Mesenchymal cells are a well differentiated population of bone marrow derived non hemopoietic cells with totipotential properties. The medical interest of such totipotentiality rests in the potential of such cells to repair damaged tissues. Particularly neuronal differentiation from progenitors obtained from mesenchymae non hemopoietic cells offers a new possibility in the field of neural transplantation and tissue engineering to repair functional entities in the nervous system.

Células mesenquimales de médula osea. Diferenciación y potencial reemplazo neuronal. / [Mesenchymal stem cells. Differentiation and alternative source of neural tissue]

Embryonic stem cells are a population of cells located in the blastocyst, committed to specific differentiation according to spatial and temporal factors such as age and place of final location. Despite the final fate of hematic cells, hemopoietic cells retain a relative degree of plasticity dependent on environmental factors. Mesenchymal cells are a well differentiated population of bone marrow derived non hemopoietic cells with totipotential properties. The medical interest of such totipotentiality rests in the potential of such cells to repair damaged tissues. Particularly neuronal differentiation from progenitors obtained from mesenchymae non hemopoietic cells offers a new possibility in the field of neural transplantation and tissue engineering to repair functional entities in the nervous system.

The history of the development of the cerebellar examination.

The cerebellar examination evolved from observations of experimental lesions made by neurophysiologists and clinical descriptions of patients with trauma to the cerebellum. At the beginning of the 19th century, neurophysiologists such as Luigi Rolando, Marie-Jean-Pierre Flourens, and John Call Dalton, Jr. ablated portions of the cerebellum of a variety of animals and observed staggering gait, clumsiness, and falling from side to side without loss of strength. They concluded that the cerebellum coordinated voluntary movements. In 1899, Joseph Francois Félix Babinski observed that patients with cerebellar lesions could not execute complex movements without breaking down into their elemental movements and described the defect as dysmetria. In 1902, Babinski coined the term dysdiodochokinesis to describe the inability to perform rapid execution of movements requiring alternate contractions of agonist and antagonist muscles. Gordon Holmes in 1904 described the phenomena of rebound, noting that if a limb ipsilateral to a cerebellar lesion is suddenly released from tension, the appendage will flail. In 1917, Gordon Holmes reported hypotonia and dysmetria in men wounded by gunshot wounds to their cerebellum. These observations were rapidly included in descriptions of the cerebellar examination in popular contemporaneous textbooks of neurology. Modern observations have demonstrated that the cerebellum influences such cognitive functions such as planning, verbal fluency, abstract reasoning, prosody, and use of correct grammar.

Características de las células primordiales germinales murinas y su relación con la hemopoyesis / Characteristics of murine primordial germ cells and their relation with hemopoiesis

Las células germinales primordiales (PGC) son una población de células positivas a la fosfatasa al- calina, que se suelen observar en embriones de 7.5 dias post coitum (dpc) y que migran luego por varios tejidos hasta alojarse en las gonadas. La hematopoyesis es un complejo sistema en el cual las células estaminales hemopoyéticas (HSC) se desarrollan a partir de una simple célula multipotente. Las PGC y HSC están reguladas por un conjunto de factores de crecimiento que controlan la proliferación y diferenciación de los mismos. El factor inhibidor leucémico (LIF) es una citoquina que regula la diferenciación y el fenotipo totipotencial de las PGC como también la capacidad proliferativa de las HSC. Recientemente otros factores de crecimiento: factor de células estaminales (SCF), factor macrofágico (MGF) y forskolin (FRSK) han sido propuestos como posibles reguladores de estos progenitores in vivo e in vitro La inducción a la hemopoyesis de células germinales embrionarias primitivas indica que las células germinales poseen la potencialidad de diferenciarse en el sistema hemopoyético. La coincidente presencia en la región donde la hemopoyesis temprana se establece, para PGC y HSC y el requerimiento de los mismos factores de crecimiento, apoyan la hipótesis que las PGC pueden ser consideradas como células iniciadoras de la hemopoyesis