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Biomedical subjects

R Martinez

Publications and source records attributed to R Martinez.

At least 235 records · Page 13Linked to original sources
PubMed1989

Severe metabolic acidosis after acute naproxen sodium ingestion.

Naproxen, a nonsteroidal anti-inflammatory drug (NSAID), is a propionic acid derivative that possesses analgesic and antipyretic properties through inhibition of prostaglandin synthesis. The propionic acids have been considered the least toxic of the NSAIDs, and one, ibuprofen, is currently available as an over-the-counter medication. Though acidosis has been reported with ibuprofen, no such occurrence has been reported for naproxen sodium. We report the case of a 15-year-old girl who presented with severe metabolic acidosis and seizures that rapidly followed naproxen sodium ingestion. Serum bicarbonate levels returned to normal 12 hours after admission and correlated with the known pharmacokinetics of naproxen. The pharmacokinetics of naproxen and treatment of its overdose, and possible mechanisms of metabolic acidosis are reviewed.

Acidosis↗
PubMed1989

Evolutionary expression of the neuronal form of the src protein in the brain.

The protooncogene src encodes two proteins, designated pp60c-src+ and pp60c-src.pp60c-src+ is expressed only in neurons, whereas pp60c-src is expressed in neuronal and nonneuronal cells. pp60c-src+ differs from pp60c-src in that it contains an insert of 6 amino acids. To study the evolutionary conservation of the 6-amino acid insert, the expression of pp60c-src+ in the brain of animals from different classes was assayed by using pp60c-src+-specific antibodies raised against a synthetic peptide corresponding to the insert. pp60c-src+ was detected only in the brain of mammals, birds, and reptiles, but not amphibians and fish, whereas pp60c-src was present in the brain of all animals tested, including lobster (invertebrate). These findings indicate that pp60c-src+ may play a role in events associated with higher brain function, such as neuronal plasticity.

Amino Acid Sequence↗
PubMed1989

Tattoos of the Marielitos.

Tattoos on Cuban refugees, particularly those who entered the United States during the Mariel Boatlift of 1980, have been associated with both criminal activity and religious affiliations. In an effort to understand better the significance and meanings of these tattoos, a series of interviews (initially informal, followed by a formal survey instrument) were conducted. Examples of the various tattoos were gleaned from the files of the Dade County Medical Examiner Department. In general, tattoos on Cuban refugees signify prior incarceration in Cuban prisons, usually do not reflect criminal specialization, and often reflect affiliation to Afro-Caribbean cults (especially Santeria, Palo Mayombe, and the Abakua Secret Society). In addition, many tattoos reflect the values and attitudes of Cuban jail subculture.

Cuba↗
PubMed1989

Subependymoma of the cervical spinal cord.

A case of subependymoma of the spinal cord in the cervical region is presented. Our experience with this patient and the seven cases of spinal cord subependymoma previously reported show that this tumor predominates in the cervical region and in males (3:1). Although radical removal is considered the rational goal of treatment, larger experience is necessary to know both the rate of growth and prognosis of subependymomas when these tumors arise within the spinal cord.

Female↗
PubMed1988

Effect of serum on the intracellular pH of BALB/c-3T3 cells: serum deprivation causes changes in sensitivity of cells to serum.

One of the earliest responses of quiescent mammalian cells to the addition of serum is an increase in intracellular pH (pHin). This pHin change is generally believed to be due to an increased activity of Na+/H+ exchange. A number of investigators have observed steady-state differences in pHin between cells in the presence and absence of serum. However, no one has examined differences in pHin regulation that may exist between cells chronically exposed to, or deprived of serum. In this study, we investigated the effects of serum deprivation to identify those components of pHin regulation that were associated with quiescence. To do this, we examined pHin in cells growing chronically in 10% serum as well as in cells that were either acutely (1.5-2 hr) or chronically (48 hr) deprived of serum. Intracellular pH was monitored using the fluorescence of intracellularly loaded pyranine dye. Our results indicate that the resting pHin values of chronically or acutely serum-deprived cells were not significantly different from each other yet, in both cases, were lower than those observed in cells exposed to 10% serum. Furthermore, we observed significant increases in pHin of both acutely or chronically serum-deprived cells in response to the addition of serum at various concentrations, in the presence of 24 mM bicarbonate. Chronically serum-deprived cells had slightly smaller responses and were more sensitive to lower concentrations of serum than were acutely deprived cells. Therefore, our data suggest that long-term serum deprivation affects the magnitude and sensitivity of pHin to serum stimulation and causes the loss of some form of pHin regulatory mechanism(s).

Animals↗
PubMed1988

Intracellular acidification inhibits the proliferative response in BALB/c-3T3 cells.

One of the earliest events to occur upon the addition of serum to quiescent cells is an increase in the intracellular pH (pHin). The relationship between this pH change and proliferation is not known. In the present study, we investigate the consequences of acidifying the cytosol using the weak acid, 5', 5"-dimethyl oxazolidine 2,4-dione (DMO). At a concentration of 50 mM, DMO inhibits the serum-induced increases in pHin, DNA synthesis, and cell number. This concentration of DMO is shown not to inhibit the steady-state rate of mitochondrial respiration and not to inhibit DNA synthesis in a pH-independent fashion. The effects of DMO treatments are also shown to be reversible, indicating that this compound is not cytotoxic. These observations indicate that DMO inhibits cell proliferation by lowering intracellular pH. One important event that must occur prior to the initiation of DNA synthesis is an elevated rate of protein synthesis. The rate of protein synthesis in situ is extremely pH sensitive. Addition of 50 mM DMO to serum-stimulated cultures reduces the rate of leucine incorporation to unstimulated levels. These observations suggest that cytoplasmic acidification may inhibit proliferation through its effects on protein synthesis.

Animals↗
PubMed1988

Distortion of body image in the obese: a sensory phenomenon.

Body weight in 42 obese and normal weight subjects was measured using a video TV monitor. Tasks included a continuous task where subjects manipulated the width of their body image on TV, and a discrete task, where they judged the accuracy of their TV image which was presented as either normal, too heavy, or too thin. Subjects rated their full body, body regions which included face, waist, and thighs, and two inanimate control objects. Results from the continuous task revealed that obese subjects overestimated body size more than normals. There was also a significant difference in the ratings of the four body regions, with all regions overestimated. Judgements were more accurate for body regions and control objects on ascending trials where the subjects had to increase the width of the image. No differences were obtained between obese and normals on judgements of the control objects. On the discrete discrimination task, a signal detection analysis revealed sensory sensitivity differences between obese and normal weight subjects. Obese subjects were poorer at detecting size distortions of the body regions. The thin/normal discrimination was more difficult than the heavy/normal discrimination. No response criterion differences were found between obese and control subjects, although subjects adopted a more strict criterion with the thin/normal discriminations. Implications of these findings for clinical intervention in eating disorders are discussed.

Adult↗
PubMed1988

Physiological responses of obese subjects to external stimuli.

Physiological arousal was measured in 11 obese and 11 normal-weight subjects during presentation of emotive, food, and neutral stimuli. No differential arousal (heart rate, temperature, GSR, and EMG on frontalis muscle) between the groups was obtained for any of the three types of stimuli. Discrepancies between the present findings and earlier results are discussed.

Adolescent↗