Biomedical subjects

R C Ramos

Publications and source records attributed to R C Ramos.

6 recordsLinked to original sources

PubMed2005

Spectroscopy of three-particle entanglement in a macroscopic superconducting circuit.

We study the quantum mechanical behavior of a macroscopic, three-body, superconducting circuit. Microwave spectroscopy on our system, a resonator coupling two large Josephson junctions, produced complex energy spectra well explained by quantum theory over a large frequency range. By tuning each junction separately into resonance with the resonator, we first observe strong coupling between each junction and the resonator. Bringing both junctions together into resonance with the resonator, we find spectroscopic evidence for entanglement between all 3 degrees of freedom and suggest a new method for controllable coupling of distant qubits, a key step toward quantum computation.

Journal Article↗

PubMed2003

Entangled macroscopic quantum States in two superconducting qubits.

We present spectroscopic evidence for the creation of entangled macroscopic quantum states in two current-biased Josephson-junction qubits coupled by a capacitor. The individual junction bias currents are used to control the interaction between the qubits by tuning the energy level spacings of the junctions in and out of resonance with each other. Microwave spectroscopy in the 4 to 6 gigahertzrange at 20 millikelvin reveals energy levels that agree well with theoretical results for entangled states. The single qubits are spatially separate, and the entangled states extend over the 0.7-millimeter distance between the two qubits.

Journal Article↗

PubMed2001

Hydroxychloroquine (HCQ) in lupus pregnancy: double-blind and placebo-controlled study.

We conducted a randomized, controlled study to assess the need for hydroxychloroquine (HCQ) during lupus pregnancy and to assess safety. Twenty consecutive pregnant patients with similar characteristics were enrolled. The HCQ group included eight patients with systemic lupus erythematosus (SLE) and two with discoid lupus erythematosus (DLE). The placebo (PL) group included nine patients with SLE and one with DLE. The HCQ group had no flare-ups. SLEPDAI scores were similar at study entry, and at conclusion the placebo group had significantly higher scores. One patient had improvement of skin lesions and another of arthritis, allowing a decrease of prednisone dose. There were no retinal effects. Three patients in the PL group flared up, two with skin rashes, one also with arthritis and uveitis, and one (previously in remission on HCQ) with hemolytic anemia, polyserositis and anti-dsDNA antibody. Toxemia was diagnosed in only three patients in the PL group (one fetal death). Comparing prednisone dosage change, we noted a decrease in the HCQ and an increase in the PL group. Delivery age and Apgar scores were higher in the HCQ group. Neonatal examination did not reveal congenital abnormalities, nor did a neuro-ophthalmological and auditory evaluation at 1.5-3 y of age. In spite of the small number of patients studied, we noted beneficial effects of HCQ during lupus pregnancy, as measured by SLEPDAI and decrease in prednisone dose with no detriment to patients' health.

Adult↗

PubMed2000

Laparoscopic pneumoperitoneum in acute peritonitis does not increase bacteremia or aggravate metabolic or hemodynamic disturbances.

The use of laparoscopy in generalized peritonitis has become increasingly frequent in recent years. However, CO2 pneumoperitoneum in association with increased intraperitoneal pressure may have deleterious effects in patients with hemodynamic or metabolic disturbances caused by bacterial peritonitis. The purpose of this study was to investigate the effect of CO2 pneumoperitoneum on bacteremia, mean arterial pressure, and blood gas disturbances in an animal model of bacterial peritonitis. Dogs were anesthetized, orally intubated, and subjected to experimental peritonitis by intraperitoneal inoculation of a suspension containing Escherichia coli and sterile dog feces. The animals were randomly assigned to two groups: control animals were maintained under anesthesia, and the insufflated animals were subjected to intraperitoneal CO2 insufflation. Bacterial peritonitis provoked the appearance of bacteremia and a significant decrease in mean arterial pressure, pH, bicarbonate, and base deficit. The induction of bacterial peritonitis did not significantly influence pH in the control group and partial pressure of arterial CO2 in either group. Thirty minutes of CO2 pneumoperitoneum did not influence the effect of bacterial peritonitis on the analyzed variables. These results suggest that laparoscopic CO2 pneumoperitoneum does not aggravate bacteremia or metabolic and hemodynamic disturbances induced by bacterial peritonitis.

Animals↗

PubMed1999

Glucose 6-phosphate and fructose 1,6-bisphosphate can be used as ATP-regenerating systems by cerebellum Ca2+-transport ATPase.

In this work, it is shown that the Ca2+-transport ATPase found in the microsomal fraction of the cerebellum can use both glucose 6-phosphate/hexokinase and fructose 1,6-bisphosphate/phosphofructokinase as ATP-regenerating systems. The vesicles derived from the cerebellum were able to accumulate Ca2+ in a medium containing ADP when either glucose 6-phosphate and hexokinase or fructose 1,6-bisphosphate and phosphofructokinase were added to the medium. There was no Ca2+ uptake if one of these components was omitted from the medium. The transport of Ca2+ was associated with the cleavage of sugar phosphate. The maximal amount of Ca2+ accumulated by the vesicles with the fructose 1,6-bisphosphate system was larger than that measured either with glucose 6-phosphate or with a low ATP concentration and phosphoenolpyruvate/pyruvate kinase. The Ca2+ uptake supported by glucose 6-phosphate was inhibited by glucose, but not by fructose 6-phosphate. In contrast, the Ca2+ uptake supported by fructose 1,6-bisphosphate was inhibited by fructose 6-phosphate, but not by glucose. Thapsigargin, a specific SERCA inhibitor, impaired the transport of Ca2+ sustained by either glucose 6-phosphate or fructose 1,6-bisphosphate. It is proposed that the use of glucose 6-phosphate and fructose 1,6-bisphosphate as an ATP-regenerating system by the cerebellum Ca2+-ATPase may represent a salvage route used at early stages of ischemia; this could be used to energize the Ca2+ transport, avoiding the deleterious effects derived from the cellular acidosis promoted by lactic acid.

Adenosine Triphosphate↗

PubMed1975

The basis for differences in ethanol-induced myocardial depression in normal subjects.

The acute effects of ethanol (ETOH) on cardiac function in 32 normal subjects has been studied utilizing systolic time intervals. Seven (group I) 13 (group II), and 12 subjects (group III), reported an average daily consumption of less than 1 oz, 1-2 oz, and more than 2 oz of ETOH, respectively. Progressively higher control values from group I to group III in PEP, PEPI, ICT and PET/LVET were observed (PEP-I vs PEPI-III: P smaller than 0.05; PEP/LVET-I vs PEP/LVET-II and PEP/LVET-III: P smaller than 0.05). There was progressively less change in these variables following acute ETOH (P smaller than 0.02-0.05 in group I; P equals NS in group III, group II intermediate). This indicates some degree of chronic myocardial impairment in group II and especially in group III, which tends to be proportionate to the degree of chronic ETOH exposure. These data are not necessarily disparate with previous reports of little or even a salutary hemodynamic effect of ETOH in normal subjects. Thus, the relative stability of LVET post ETOH, coupled with the observed increase in heart rate, is consistent with previous reports of ETOH-induced rate-dependent increments in cardiac output with unchanging stroke volumes, in spite of the presence of acute myocardial depression. The observations reported herein demonstrate the probable incremental influence of ETOH consumption in a chain of events which may culminate in alcoholic cardiomyopathy.

Adult↗