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Biomedical subjects

R Martinez

Publications and source records attributed to R Martinez.

At least 145 records · Page 8Linked to original sources
PubMed1994

Ultrastructural and biochemical changes in alveolar macrophages exposed to nickel hydroxy carbonate.

The aim of this investigation was to assess the cytotoxic effect of nickel hydroxy carbonate (NiHC) on guinea pig alveolar macrophages (AMs) by studying ultrastructural modifications and by determining beta-glucuronidase (BG) and lactate dehydrogenase (LDH) activities, as well as cellular ATP content. The ultrastructural studies revealed phagocytosis of NiHC particles and a general vacuolisation of the cells, especially at high concentrations. X-ray microprobe analyses of these particles demonstrated the presence of Ni, P and Ca which suggests the formation of Ni-P-Ca complexes. In exposed cells, a biphasic change in intracellular ATP concentrations was observed which could indicate 'activation' of AMs at low concentrations and inhibition of energy generation at higher concentrations. As for enzymatic activities, a dose-dependent increase in LDH release was observed except at low doses which increased ATP. There was a good correlation between ATP decrease and LDH release, consistent with a dose-dependent cytotoxic effect of NiHC. However beta-glucuronidase activity remained unchanged at all NiHC concentrations. It has been concluded that NiHC undergoes an intracellular, biological transformation to form Ni-P-Ca. Further investigations are needed to determine the precise nature and importance of these complexes.

Adenosine Triphosphate↗
PubMed1994

Acidic residues in extracellular loops of the human Y1 neuropeptide Y receptor are essential for ligand binding.

To investigate whether negatively charged residues of the human Y1 neuropeptide Y (NPY) receptor are required for ligand binding, a series of mutants were constructed in which aspartic acid and glutamic acid residues present in putative extracellular domains of the Y1 receptor were systematically replaced by alanines. The mutant cDNAs were transiently expressed in HeLa cells using a vaccinia virus-derived expression system, and their ability to bind NPY was evaluated. The level of expression of mutants unable to bind NPY was also tested immunologically. In addition, the ability of the mutant proteins to be recruited to the cell surface was assessed by confocal microscopy. Substitution of aspartic acids and glutamic acids of the N-terminal first extracellular domain had no effect on binding. On the other hand, substitution of acidic residues present in the second, third, and fourth extracellular loops resulted in proteins unable to bind 125I-NPY. These results demonstrate that the extracellular loops of the human Y1 NPY receptor are essential portions of its ligand binding domain.

Amino Acid Sequence↗
PubMed1994

Introducing solution-focused approaches to staff in inpatient psychiatric settings.

The authors describe several approaches to introducing solution-focused ideas to inpatient psychiatric nursing staff and psychiatric nursing students. The approach is intended to show the basic values of this approach in the process of helping participants become acquainted with concepts central to newer models of brief psychotherapy. The format uses humor, small group experiential case examples along with didactic approaches to facilitate new ways of thinking congruent with new models of therapy.

Education, Nursing↗
PubMed1994

Predominance of gram-positive microorganisms as a cause of septicemia in patients with hematological malignancies.

OBJECTIVE: To ascertain the etiology and outcome of episodes of bacteremia and fungemia over a three-year period (1990-1992) in patients with hematological malignancies. DESIGN: Retrospective study. SETTING: Hematology service of a 1,500-bed Spanish university hospital. RESULTS: Of a total of 178 episodes of significant bacteremia or fungemia in 101 patients, 53% affected patients with acute leukemia. Gram-positive microorganisms were found to be the cause in 70% of the monomicrobial episodes. The most frequently isolated microorganism was coagulase-negative Staphylococcus (35%), followed by Staphylococcus aureus (11%). Most blood-stream infections occurred during an episode of neutropenia (59%). A total of 34 patients died during hospitalization; in 14, infection was the cause of death. CONCLUSIONS: A marked increase in the incidence of bacteremias caused by gram-positive microorganisms has been observed in our hospital over the last 10 years, especially in patients with hematological malignancies. The mortality due to bacteremia is similar to that found by other authors in series of bacteremia in hematological patients, and we have not found significant differences in the mortality due to bacteremia between neutropenic and non-neutropenic patients (Infect Control Hosp Epidemiol 1994;15:101-104).

Adolescent↗
PubMed1994

Three-point restraints as a risk factor for chest injury in the elderly.

As the number of drivers over the age of 65 years increases, new trauma patterns are emerging. The use of lap-shoulder restraints, in this population, is beginning to play an important role in new findings about their injuries. Restraint use in motor vehicle crash victims, in relation to average AIS score, ISS, and number of hospital and ICU days, was studied at a level I trauma center. The control group consisted of 100 patients between the ages of 35 and 45 years, who were involved in motor vehicle impacts (MVIs) from January 1990 through January 1992. The study group consisted of 120 patients over the age of 65 years who were involved in MVIs from January 1987 through January 1992. In the control group, restraint use was associated with a lower average AIS score--3.39 versus 7.35 for the unrestrained victims. In addition, the restrained victims spent fewer days in the ICU--0.08 versus 0.30 days for the unrestrained victims; and fewer hospital days--1.08 versus 2.0 days for the unrestrained victims. The general pattern of lower average AIS scores in restrained victims was also seen in the study group. However, in the study group, lap-shoulder belt-restrained patients had higher average AIS scores, in the chest region, than unrestrained patients--0.92 (SE 1.60) versus 0.71 (SE 1.47), respectively. These findings indicate that physicians must be aware of restraint patterns of chest injury in elderly patients. Aggressive triage criteria and vigorous pulmonary toilet, especially in patients with rib fractures, sternal fractures, and pulmonary contusions, should become integral parts of trauma resuscitation protocols in elderly patients.

Age Factors↗
PubMed1994

Circles of care: home care and community support for rural older adults.

Rural dwelling, frail older adults are a vulnerable population owing to the complexity of health problems superimposed upon limited health care resources. Home care facilitates managing complex health needs and is congruent with rural valued independence. An ethnography was conducted to describe rural home care for frail older adults from the perspective of those delivering and receiving services. A major theme identified was "Circles of Care." Grounded in rural culture, the circles assisted the system of formal care to work in harmony with informal care, maintaining independence for vulnerable rural elderly and their families.

Aged↗
PubMed1994

[Epidemiological expression of other sexually transmitted diseases among AIDS patients].

This study was carried out in order to estimate the frequency of other sexually transmitted diseases (STD) among AIDS patients and to identify their epidemiological association and possible relations to the groups most exposed to the virus. The data were collected from the medical case histories and the STD were identified on the basis of data provided by anamnesis, physical examination and laboratory examinations. Of the total of HIV/AIDS patients assisted at the hospital studied (S. Paulo State, Brazil), between January 1986 and January 1992, 207 were included as sample subjects for this survey. Of the patients studied, 88 (42.5%) had some other STD and 119 (57.5%) had no other STD, equivalent to a proportion of 0.7 STD patients-STD to each non-STD patient. The most prevalent STD identified were hepatitis B (33.3%), syphilis (30.3%) and gonorrhoea (12.9%). Concerning the means of transmission by which the patients had probably been infected with HIV, blood transmission was the most prevalent (44.9%); followed by sexual contact (21.3%); sexual/blood (17.9%); in 25.9% it was undetermined. In a particular comparison of sexual and blood transmission and the presence of other STD a statistical difference in those cases that were exposed to sexual transmission was observed.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Rupture of pancreaticoduodenal artery aneurysm in duodenum. Report of a case.

We report the case of a 74 year-old woman presenting a rupture in the duodenum of pancreaticoduodenal artery aneurysm treated with success by an aorto-mesenteric by-pass and ligature of gastroduodenal artery. The pancreaticoduodenal artery is an uncommon aneurysmal localization; surgical treatment of which is often difficult on account of the proximity of the pancreatic parenchyma and arteriography is essential to guide the surgical procedure.

Aged↗
PubMed1994

[Pancreatic-duodenal artery aneurysm ruptured in the digestive tube. Report of a case].

We report the successful treatment of an aneurysm of the pancreatoduodenal artery which ruptured into the duodenum in a 78-year-old patient. The pancreatoduodenal arcades were excluded by aorto-mesenteric bypass and ligature of the gastroduodenal artery. Aneurysm are rarely located in pancreatoduodenal artery. Surgical repair is often difficult due to the close relations with the pancreatic parenchyma. Arteriography is essential to guide the operation.

Aged↗
PubMed1994

Oral administration of heptylphysostigmine in healthy volunteers: a preliminary study.

Heptylphysostigmine (HP) is a reversible cholinesterase (ChE) inhibitor with greater lipophilicity and longer inhibitory action than the parent compound, physostigmine (Phy). Single (0.1-0.6 mg/kg) and multiple 5-day (0.1-0.3 mg/kg) doses of HP were administered to 21 young normal volunteers. The relationship between logarithmic dose (mg/kg) and peak inhibition of red blood cell (RBC) ChE was linear with dose. In one subject given 0.6 mg/kg of HP, concentration in plasma was 0.68 ng/ml at 2 h and gradually declined to below the detection limit by 4 h. Peak plasma and RBC ChE inhibitions of 31.2% and 55.8% were achieved at 2 h for both with a 0.6 mg/kg dose. Chronic studies did not result in any accumulation of ChE inhibition up to 0.2 mg/kg b.i.d., whereas at 0.3 mg/kg b.i.d. 10-15% RBC ChE inhibition was maintained. Higher levels of ChE inhibition can be achieved with HP than with its parent compound, Phy. Red blood cell ChE inhibition recovered more slowly than plasma even though the maximum inhibition was similar for both enzymes.

Administration, Oral↗
PubMed1994

The impact of ethgender on self-esteem among adolescents.

This study examined the impact of ethgender, the combination of race and gender, on global and public domain aspects of adolescent self-esteem. Using the Rosenberg Self-Esteem Scale and a 3-item index, differences were observed among 10 ethgenders. Black and Hispanic males had the highest levels of global self-esteem, and Asian and Native American Females had the lowest. On public domain components white and black males had the highest scores, and Asian and Native American females had the lowest. Females (except blacks) had lower levels of both global and public domain self-esteem than did males.

Adolescent↗
PubMed1993

High affinity VEGF binding and developmental expression suggest Flk-1 as a major regulator of vasculogenesis and angiogenesis.

Examination of flk-1 receptor tyrosine kinase mRNA expression by in situ hybridization analysis revealed specific association with endothelial cells at all stages of mouse development, including the blood islands in the yolk sac of day 8.5-10.5 embryos, in which the early progenitors of this lineage originate. flk-1 transcripts were abundant in proliferating endothelial cells of vascular sprouts and branching vessels of embryonic and early postnatal brain, but were drastically reduced in adult brain, where proliferation has ceased. Identification of the angiogenic mitogen, vascular endothelial growth factor (VEGF), as the high affinity ligand of Flk-1 and correlation of the temporal and spatial expression pattern of Flk-1 and VEGF suggest a major role of this ligand-receptor signaling system in vasculogenesis and angiogenesis.

Amino Acid Sequence↗