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Biomedical subjects

C Salinas

Publications and source records attributed to C Salinas.

At least 19 recordsLinked to original sources
PubMed2001

Electrochemical removal of ammonium ions from a bioreactor effluent.

Ammonium ions are byproducts of the oxidation of nitrogen-containing substances occurring in the initial treatment steps of water recovery systems. Removal of ammonium ions from the effluent stream from 1000 ppm to less than 0.25 ppm is an imperative need as a part of the space life support infrastructure. Drawbacks associated with processes proposed in the past include the generation of a secondary waste, cost, size, and/or the use of consumables that need to be stored or supplied. Lynntech has developed a technology that is based on an innovative, environmentally friendly electrochemical process for the effective removal of ammonium ions. The process does not use consumables except for oxygen gas from air, and does not generate a secondary waste. By controlling operational conditions, the ammonium ions may be transformed to nitrogen gas and/or to nitrate ions. Other advantages of the process include: it is energy efficient, operates at room temperature, and is microgravity compatible. Grant numbers: NAS9-00013.

Bioreactors↗
PubMed1998

The effects of the Northridge earthquake on the pattern of emergency department care.

This study's objective was to describe the types of injuries that should be anticipated after a major earthquake. Data for the 6 days prior to the earthquake, the 6 days after the earthquake, and for the day of the earthquake the previous year were obtained from the Emergency Department of Northridge Hospital, Northridge, CA. Demographic data, including age and sex, as well as the reason for the visit, were obtained from patient logs. The average number of patients per day was 110 before the earthquake and 185 after the earthquake. On the day of the earthquake, 343 patients were seen. Lacerations increased from 7.1% of all visits before the earthquake to 22.4% after the earthquake (P < .01). Immediately after the Northridge earthquake, there was a threefold increase in emergency patient visits. The biggest increase occurred in the number of patients presenting with contusions and lacerations. The number of pregnant women presenting in labor and with vaginal bleeding also increased. Disaster managers should take these patterns into account when planning for major seismic events.

Adolescent↗
PubMed1998

Estimation of ventricular volume and elastance from the arterial pressure waveform.

We propose that it is possible to estimate cardiovascular parameters from the arterial pressure waveform, including ventricular maximal elastance and end-diastolic volume, if cardiac output is also known. We tested this hypothesis by means of a parameter estimation algorithm applied to simulated arterial pressure signals. The program first estimated three coefficients representing products of passive parameters from the diastolic part of the simulated arterial pressure waveform. Second, it estimated three parameter products pertaining to the ventricular function from the systolic part of the waveform. Third, mean blood flow was entered, enabling the program to compute individual parameters. This program was tested on 200 computer-generated arterial pressure signals, obtained by simulating the model with random but bounded parameters. Correlation between estimated parameters with those actually used in the simulations was excellent. Even though the value of this computer simulation is limited to the simplified model used and requires experimental validation, it demonstrates that the technique is theoretically feasible.

Blood Flow Velocity↗
PubMed1994

Dopachrome tautomerase decreases the binding of indolic melanogenesis intermediates to proteins.

Dopachrome tautomerase (DCT) is a recently characterized enzyme contributing to the control of melanogenesis in mammals. The enzyme catalyzes the rearrangement of L-Dopachrome (L-DC) to 5,6-dihydroxyindole 2-carboxylic acid (DHICA), while the spontaneous rearrangement of L-DC leads to 5,6-dihydroxyindole (DHI). Due to the lower reactivity of DHICA in comparison to DHI, DCT could provide a protective mechanism against the cytotoxicity of decarboxylated indolic melanogenic intermediates by limiting the formation of these highly reactive decarboxylated species within melanocytes. We have followed the binding of radioactive melanogenic precursors to a model protein, bovine serum albumin (BSA). Using L-DC as initial melanin precursor, this binding was decreased by DCT in a concentration-dependent manner. In the presence of tyrosinase, the binding of L-Dopa-derived intermediates to BSA was also decreased by DCT and the percentage of decrease was even higher than using L-DC as initial melanin precursor. SDS-PAGE followed by fluorographic detection of radioactive bands showed the formation of covalent adducts between BSA and melanin precursors, as well as of aggregated forms of this protein. This aggregation was also diminished by DCT. These data indicate that DCT could play a protective role against the cytotoxic action of decarboxylated indoles within mammalian melanocytes.

Animals↗
PubMed1994

Disaster medical assistance teams: providing health care to a community struck by Hurricane Iniki.

STUDY OBJECTIVE: To describe the type of medical care that disaster medical assistance teams (DMATs) provided to a community struck by a major hurricane. STUDY DESIGN: A prospective study describing the use of DMAT field clinics by a population affected by a major hurricane. Data regarding the type of medical care provided to disaster victims and the acuity of each patient's medical condition were abstracted from medical charts at each field clinic. SETTING: Three DMAT field clinics that provided medical care to residents of Kauai, Hawaii, after Hurricane Iniki struck the island on September 11, 1992. RESULTS: From September 16 to 19, 1992, three DMATs provided medical care to 614 people. The patients' average age was 34 years, and 60% were male. The largest treatment categories were injury (40.4%), illness (38.6%), and preventive services (9.0%). Most illnesses and injuries were minor, and 99% of the patients were ambulatory. Only 33 patients (5.4%) were referred to another medical provider. Referrals were generally for procedures not available in DMAT field clinics rather than for life-threatening conditions. CONCLUSION: DMATs sent to assist with the medical needs of a US community struck by a major hurricane should be prepared to deliver basic medical services and primary health care. The need for these medical services will continue beyond the impact phase of a hurricane disaster.

Adolescent↗
PubMed1993

Preparation of purified tyrosinase devoid of dopachrome tautomerase from mammalian malignant melanocytes.

Although tyrosinase has been considered for a long time the only enzyme involved in mammalian melanosynthesis, it has been shown that mouse melanoma melanosomes contain high levels of dopachrome tautomerase (DCT2), an enzyme catalyzing DC tautomerization to DHICA. At least in B16 mouse melanoma, DCT is present in higher catalytic amounts than tyrosinase. Moreover, it can be anticipated that tyrosinase and DCT should be very difficult to resolve by most conventional biochemical techniques because of the structural similarity between these enzymes, as predicted from the sequence of their corresponding cDNAs. It is shown that the presence of DCT can cause serious artifacts when tyrosinase activity is determined by most of the currently available methods, such as the Dopa oxidase and melanin formation assays. We describe a simple and convenient method for the preparation of tyrosinase devoid of DCT. The method takes advantage of the different thermal stability of both enzymes. Heating of crude melanosomal extracts at 60 degrees C for 1 hr results in a complete denaturation of DCT, while tyrosinase activity is recovered almost quantitatively. The resulting tyrosinase preparation is considerably purified and the electrophoretic, immunologic and kinetic characteristics of the enzyme appear unaltered. Because if its high yield and simplicity, the method can be used for the microscale partial purification of DCT-free tyrosinase from mammalian malignant melanocytes grown in culture.

Animals↗
PubMed1992

Regulation of the final phase of mammalian melanogenesis. The role of dopachrome tautomerase and the ratio between 5,6-dihydroxyindole-2-carboxylic acid and 5,6-dihydroxyindole.

The regulation of the final steps of the melanogenesis pathway, after L-2-carboxy-2,3-dihydroindole-5,6-quinone (dopachrome) formation, is studied. It is shown that both tyrosinase and dopachrome tautomerase are involved in the process. In vivo, it seems that tyrosinase is involved in the regulation of the amount of melanin formed, whereas dopachrome tautomerase is mainly involved in the size, structure and composition of melanin, by regulating to the incorporation of 5,6-dihydroxyindole-2-carboxylic acid (DHICA) into the polymer. Moreover, using L-3,4-dihydroxyphenylalanine (dopa) and related compounds, it was shown that the presence of dopachrome tautomerase mediates an initial acceleration of melanogenesis since L-dopachrome is rapidly transformed to DHICA, but that melanin formation is inhibited because of the stability of this carboxylated indole compared to 5,6-dihydroxyindole (DHI), its decarboxylated counterpart obtained by spontaneous decarboxylation of L-dopachrome. Using L-dopa methyl ester as a precursor of melanogenesis, it is shown that this carboxylated indole does not polymerize in the absence of DHI, even in the presence of tyrosinase. However, it is incorporated into the polymer in the presence of both tyrosinase and DHI. Thus, this study suggests that DHI is essential for melanin formation, and the rate of polymerization depends on the ratio between DHICA and DHI in the medium. In the melanosome, this ratio should be regulated by the ratio between the activities of dopachrome tautomerase and tyrosinase.

Animals↗
PubMed1991

[Immunohistochemical expression of the carcinoembryonic antigen in gallbladder cancer].

Immunohistochemical techniques using monoclonal antibodies were used to investigate the carcinoembryonic antigen (CEA) in gallbladders from 26 patients with gallbladder cancer and 26 patients without cancer, including normal mucosa, areas of pyloric metaplasia and areas identified by the presence of "clear cells". All carcinomas were strongly positive for CEA but 61% of noncancerous samples were also positive. However, only 1 of the last samples was strongly positive. According to histologic type the positivity for CEA in noncancerous samples was 6/11 in normal mucosa, 6/8 in samples with intestinal metaplasia and 1/8 in samples with pyloric metaplasia (p less than 0.05). Thus a negative reaction for CEA is 100% specific for absence of cancer. If mild reactions are disregarded, a strong reaction for CEA is 81% specific for cancer.

Antibodies, Monoclonal↗
PubMed1989

[Gastric cancer in the IX Region of Chile: an analysis of 233 cases].

Gastric cancer is the leading cause of mortality from malignancy in Chile. Different reports indicate a high incidence of well differentiated forms of this tumor. Among 233 endoscopically diagnosed lesions in patients from the Ninth Region of Chile, we found a high incidence of poorly differentiated tumors and a relatively high incidence of signet-ring cell carcinoma. The incidence of inoperable lesions was high.

Adult↗
PubMed1989

[Gallbladder pathology in Temuco, IX Region].

We reviewed the histological (light microscopy) findings in 1553 biopsies obtained after surgery for gallbladder disease and correlated these with demographic characteristics of patients. Cancer of the gallbladder was present in 6.1%. Women prevailed in all age and disease groups, especially in mapuches (11:1). Both for neoplastic and nonneoplastic disease the proportion of patients with mapuche surnames was lower than expected for the population in the area. 52% of neoplastic lesions were not macroscopically apparent. Seven tumors involved only the mucous layer and 2 were intraepithelial. Only 2 tumors were well differentiated. The liver was the organ most frequently invaded by gallbladder cancer.

Adolescent↗
PubMed1986

Medical care at the 1982 US Festival.

The 1982 US Festival, a three-day outdoor rock music festival, attracted close to 410,000 people. Through a private contractor, a group of physicians participated in the design, administration, and implementation of medical care for this event. Basic ambulatory care was provided by a multitiered approach, using emergency medical technicians, registered nurses, medical health counselors, and physicians. A total of 2,623 encounters required examination and evaluation by health professionals. Thirty-eight percent (1,014 cases) involved minor surgical trauma. Extreme environmental conditions, including temperatures exceeding 114 F, high winds, and unusually high dust concentrations, were thought to be responsible for 361 (13.6%) cases of reactive airway disease and 184 (7%) cases of heat exhaustion. There were 91 transports, of which 12 were classified as major casualties; there were no deaths.

Ambulances↗