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Biomedical subjects

P Rodriguez

Publications and source records attributed to P Rodriguez.

At least 19 recordsLinked to original sources
PubMed2001

Medical assistance during commercial airline flights: analysis of 11 years experience of the Paris Emergency Medical Service (SAMU) between 1989 and 1999.

Emergencies arising during commercial airline flights may have serious consequences. We report the experience of the Paris Emergency Medical Service (SAMU) in providing in-flight assistance to Air France between 1989 and 1999. During this period medical advice was sought 380 times during the carriage of about 350 million passengers. Analysis of the patient files suggests that serious emergencies were rare and that cardiopulmonary resuscitation was required only exceptionally. However the relative frequency of cardiac and neurological emergencies in our analysis supports the necessity of carrying adequate medical equipment and of having direct access to expert medical advice. The results suggest the requirement for a rigorous prospective epidemiological study of in-flight emergencies to evaluate the effectiveness of current practice and possible modifications of equipment and protocols for patient management.

Adolescent↗
PubMed2001

A model of hippocampal activity in trace conditioning: where's the trace?

The hippocampus is generally thought to play a modulating role in the timing of conditioned responses in classical trace conditioning. One hypothesis is that the hippocampus stores a memory trace of the conditioned stimulus (CS) during the stimulus-free period. Cellular recordings, however, do not show any obvious CS storage. This article examines this issue by using a biologically plausible model of the CA3 region of the hippocampus. Simulations of the model reproduce both behavioral and physiological experimental data. On the basis of neural codes that develop in the model, the authors hypothesize that the hippocampus functions as a time-indexed encoding device for the CS and not as a CS storage buffer. Specifically, the CS initiates a sequence of neural activity during the trace interval that only indirectly represents the CS. The model yields 2 predictions: Some cells will increase in activity only during the trace interval, and some unconditioned stimulus (US)-coding cells will shift in time and fire before US onset.

Animals↗
PubMed2001

An assessment of the impact of Health Workers for Change in Avellaneda, province of Buenos Aires, Argentina.

This paper describes the evaluation of the Health Workers for Change (HWFC) workshop series in a primary health care clinic in Avellaneda, Argentina. The study found that there was an important impact at the facility level 2 months after the intervention (T2). Health workers were motivated and willing to examine their own practices critically in an effort to improve quality of care. Informants from the community also perceived that patients were being treated more kindly. Eleven months later (T3), however, the impact at the facility level had receded significantly. At the system level the main benefit of the workshops was to focus attention on the health workers themselves, particularly their perception that there was little communication with the authorities. As a result, the number of system level supervisors increased and they were urged to spend more time in the clinics. Reasons for the limited impact at T3 are discussed and suggestions are made for improving the intervention.

Adolescent↗
PubMed2001

Role of type of vascular access in erythropoietin and intravenous iron requirements in haemodialysis.

BACKGROUND: Recent data have suggested the existence of a relationship between the use of synthetic vascular accesses and increased erythropoietin (Epo) requirements. The present study aimed to evaluate the possible role of the type of vascular access in both Epo and intravenous (i.v.) iron requirements. METHODS: One-hundred-and-seven individuals without recognized causes of Epo resistance, 62 of them undergoing chronic haemodialysis through native arteriovenous fistulae (AVF) and 45 through PTFE grafts, were retrospectively studied (one-year follow-up). Sixty-nine patients, i.e. all but three with a PTFE graft and 27 with native AVF, were taking anti-platelet agents. Doses of i.v. iron and Epo and laboratory parameters were recorded. RESULTS: Erythropoietin and i.v. iron requirements were higher in the patients dialysed through PTFE grafts compared with those with native AVF (Epo: 103.8+/-58.4 vs 81.0+/-44.5 U/kg/week, P=0.025; i.v. iron: 178.9+/-111 vs. 125.9+/-96 mg/month, P=0.01). On a yearly basis, the difference in Epo dose represented a total of 94582+/-16789 U Epo/patient/year. Moreover, the patients with PTFE grafts received more red blood cell transfusions than patients with native AVF (P=0.021). No differences between laboratory, dialysis kinetics, demographic or comorbidity parameters were found. The type of vascular access was the best predictor of the requirement of > or =150 U/kg/week Epo (P=0.03). Even though the patients who received anti-platelet therapy required more i.v. iron (167.5+/-103.6 vs. 114.5+/-101.4 mg/month, P=0.008) but not more Epo (P=NS), the possibility of an accessory role of anti-platelet agents in the increased Epo requirements with PTFE grafts cannot be ruled out. CONCLUSIONS: The use of a PTFE graft and anti-platelet drugs represents a previously undescribed association related to higher Epo and i.v. iron requirements. The association described herein adds new arguments to the debate concerning the choice of vascular access in chronic haemodialysis patients.

Aged↗
PubMed2001

Simple recurrent networks learn context-free and context-sensitive languages by counting.

It has been shown that if a recurrent neural network (RNN) learns to process a regular language, one can extract a finite-state machine (FSM) by treating regions of phase-space as FSM states. However, it has also been shown that one can construct an RNN to implement Turing machines by using RNN dynamics as counters. But how does a network learn languages that require counting? Rodriguez, Wiles, and Elman (1999) showed that a simple recurrent network (SRN) can learn to process a simple context-free language (CFL) by counting up and down. This article extends that to show a range of language tasks in which an SRN develops solutions that not only count but also copy and store counting information. In one case, the network stores information like an explicit storage mechanism. In other cases, the network stores information more indirectly in trajectories that are sensitive to slight displacements that depend on context. In this sense, an SRN can learn analog computation as a set of interdependent counters. This demonstrates how SRNs may be an alternative psychological model of language or sequence processing.

Models, Neurological↗
PubMed2001

Blood cultures for women hospitalized with acute pelvic inflammatory disease. Are they necessary?

OBJECTIVE: To determine the incidence of positive blood cultures and if the results affect the clinical management or the duration of hospital stay in patients with acute pelvic inflammatory disease (PID). STUDY DESIGN: Retrospective study of all patients hospitalized with a diagnosis of acute PID from January 1, 1996, to December 31, 1997. RESULTS: Of 93 patients in the study, 3 had significant bacterial growth from blood culture specimens. The results of blood culture specimens did not affect clinical management. CONCLUSION: Routine specimens for blood culture may not be needed from patients hospitalized with acute PID.

Acute Disease↗
PubMed2000

NAP-2: histone chaperone function and phosphorylation state through the cell cycle.

We have recently cloned the human nucleosome assembly protein 2 (NAP-2). Here, we demonstrate that casein kinase 2 (CKII) from HeLa cell nuclear extracts interacts with immobilized NAP-II, and phosphorylates both NAP-2 and nucleosome assembly protein 1 (NAP-1) in vitro. Furthermore, NAP-1 and NAP-2 phosphorylation in crude HeLa cell extracts is abolished by heparin, a specific inhibitor of CKII. Addition of core histones can stimulate phosphorylation of NAP-1 and NAP-2 by CKII. NAP-2 is also a phosphoprotein in vivo. The protein is phosphorylated at the G0/G1 boundary but it is not phosphorylated in S-phase. Here, we show that NAP-2 is a histone chaperone throughout the cell cycle and that its cell-cycle distribution might be governed by its phosphorylation status. Phosphorylated NAP-2 remains in the cytoplasm in a complex with histones during the G0/G1 transition, whereas its dephosphorylation triggers its transport into the nucleus, at the G1/S-boundary, with the histone cargo, suggesting that binding to histones does not depend on phosphorylation status. Finally, indirect immunofluorescence shows that NAP-2 is present during metaphase of HeLa and COS cells, and its localization is distinct from metaphase chromosomes.

Animals↗
PubMed2000

Immune rejection of human dystrophin following intramuscular injections of naked DNA in mdx mice.

Intramuscular administration of plasmid expressing full-length human dystrophin in dystrophin-deficient adult mdx mice resulted in humoral and weak specific T cell responses against the human dystrophin protein. Following plasmid injection, human dystrophin was detected in the injected muscles at 7 days, but decreased thereafter. Anti-dystrophin antibodies were found 21 days following plasmid injection, which coincided with transient myositis. This immune rejection prevented the mice from expressing human dystrophin after a second plasmid injection. No anti-DNA antibodies were found. Anti-dystrophin antibodies were seen in a smaller proportion of plasmid-injected dystrophin-competent C57BL/10 mice, suggesting that the immune rejection of dystrophin may be explained partially by species differences in the dystrophin protein.

Animals↗
PubMed2000

Carbon monoxide stability in stored postmortem blood samples.

Carbon monoxide (CO) poisoning remains a common cause of both suicidal and accidental deaths in the United States. As a consequence, determination of the percent carboxyhemoglobin (%COHb) level in postmortem blood is a common analysis performed in toxicology laboratories. The blood specimens analyzed are generally preserved with either EDTA or sodium fluoride. Potentially problematic scenarios that may arise in conjunction with CO analysis are a first analysis or a reanalysis requested months or years after the initial toxicology testing is completed; both raise the issue of the stability of carboxyhemoglobin in stored postmortem blood specimens. A study was conducted at the Bexar County Medical Examiner's Office to evaluate the stability of CO in blood samples collected in red-, gray-, and purple-top tubes by comparing results obtained at the time of the autopsy and after two years of storage at 3 degrees C using either an IL 282 or 682 CO-Oximeter. The results from this study suggest that carboxyhemoglobin is stable in blood specimens collected in vacutainer tubes, with or without preservative, and stored refrigerated for up to two years.

Carbon Monoxide↗
PubMed2000

Maternal Trypanosoma cruzi infection upregulates capacity of uninfected neonate cells To produce pro- and anti-inflammatory cytokines.

The possibility of maternal in utero modulation of the innate and/or adaptive immune responses of uninfected newborns from Trypanosoma cruzi-infected mothers was investigated by studying the capacity of their whole blood cells to produce cytokines in response to T. cruzi lysate or lipopolysaccharide-plus-phytohemagglutinin (LPS-PHA) stimulation. Cells of such newborns occasionally released gamma interferon (IFN-gamma) and no interleukin-2 (IL-2) and IL-4 upon specific stimulation, while their mothers responded by the production of IFN-gamma, IL-2, and IL-4. Infection in mothers was also associated with a hyperactivation of maternal cells and also, strikingly, of cells of their uninfected neonates, since their release of proinflammatory (IL-1beta, IL-6, and tumor necrosis factor alpha [TNF-alpha]) as well as of anti-inflammatory (IL-10 and soluble TNF receptor) cytokines or factors was upregulated in the presence of LPS-PHA and/or parasite lysate. These results show that T. cruzi infection in mothers induces profound perturbations in the cytokine response of their uninfected neonates. Such maternal influence on neonatal innate immunity might contribute to limit the occurrence and severity of congenital infection.

Chagas Disease↗
PubMed1999

Conventional respiratory viruses recovered from immunocompromised patients: clinical considerations.

Lower respiratory tract infection is the most common complication in the immunocompromised patient. From January 1991 to December 1995, 785 consecutive patients with suspected respiratory tract infections were studied. One hundred ninety-nine viruses were isolated from 182 (23%) of 785 bronchoalveolar lavage fluid specimens. Cytomegalovirus was isolated from 131 patients, herpes simplex virus was recovered from 31, and conventional respiratory viruses (CRVs) were recovered from 36. There were 9 influenza A viruses, 2 influenza B viruses, 7 parainfluenza viruses, 5 respiratory syncytial viruses, 5 adenoviruses, 6 enteroviruses, and 3 rhinoviruses. We identified 22 patients from whom a CRV was the only microorganism recovered; 13 patients developed pneumonia, 10 had acute respiratory failure, 5 required support with mechanical ventilation, and 5 (23%) died. In conclusion, CRVs are frequent causes of respiratory illnesses and are associated with high rates of morbidity and mortality among immunocompromised patients.

Adenoviridae↗
PubMed1999

Fluvoxamine distribution in postmortem cases.

Four postmortem cases are reported in which the selective serotonin re-uptake inhibitor fluvoxamine was identified. Fluvoxamine was detectable using a standard alkaline drug screen, chromatographed well using a HP-1 column, and did not require derivitization for quantitation. Two of the cases reported were drug intoxications; fluvoxamine was only an incidental finding in the other 2 cases. Central and peripheral blood values are reported, as well as antemortem blood, bile, vitreous fluid, and urine values. No solid organs were obtained in any of the cases. Quantitations were performed using both an analytical standard and a fluvoxamine tablet for the preparation of calibrators. A comparison of quantitative values was made to evaluate the feasibility of using a tablet as the drug source for the preparation of calibrators when a pure reference material is unavailable. Postmortem peripheral blood concentrations ranged from approximately 0.5 mg/L in a case of suicidal shooting to approximately 6 mg/L in a case of drug overdose. Evidence of postmortem redistribution was noted in the only case for which both central and peripheral blood were obtained. Quantitations using an extracted drug tablet for the preparation of calibrators correlated well with quantitations using a pure reference material.

Adult↗
PubMed1999

Needs and supports reported by Latino families of young children with developmental disabilities.

We interviewed 200 Latino parents (50 Mexican couples, 50 Puerto Rican couples) living in the United States to determine needs and supports related to raising a child with a disability and to identify variables related to reported needs and supports. The pattern of needs expressed was similar to that found in previous studies, but the number was substantially higher. More support was reported from family and formal sources than from friends or informal sources. Using repeated measures of analysis of covariance involving six family variables and three child variables, we found that English language proficiency was the only variable to account for significant variance in needs and supports.

Acculturation↗
PubMed1998

Protective effects of cyclopiazonic acid on ischemia-reperfusion injury in rabbit hearts.

The cardioprotective effects on myocardial ischemia of the sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA) inhibitor, cyclopiazonic acid (CPA), were studied. We used the isolated arterially perfused interventricular septum of the rabbit heart submitted to 30-min global ischemia/30-min reperfusion. Mechanical [maximal increase in resting tension (MIRT), and the recovery of developed tension (RDT)], and biochemical parameters [creatine phosphokinase activity (CPK) in the effluent] were analyzed. CPA, 1 microM, perfused 30 min before the ischemia intervention significantly increased RDT by 54% and lessened MIRT by 66%. CPA also decreased CPK in the perfusate by 67.7 and 71.4% at 0-2 and 5-7 min of reperfusion, respectively. No additional benefits were shown either when the drug was perfused, both during ischemia and reperfusion, or with higher CPA concentrations (10-30 microM). The CPA cardioprotection was lost when the drug was present only during the reperfusion period. CPA exhibits functional and biochemical cardioprotective effects on myocardial ischemia. We postulated a decreased SR calcium contribution to the initial cytoplasmic calcium overload as the most probable mechanism involved.

Animals↗
PubMed1998

Two marine Agrobacterium producers of sesbanimide antibiotics.

Sesbanimides are cytotoxic compounds, originally isolated in 1983 from seeds of the leguminous plants Sesbania drummondii and Sesbania punicea. In this paper we describe the bacterial production of sesbanimides by two "marine Agrobacterium"; strain PH-103 which produces Sesbanimide-A and strain PH-A034C which produces Sesbanimide-C. The isolation and taxonomy of the producing microorganisms, fermentation and isolation of sesbanimides are reported.

Alkaloids↗