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Biomedical subjects

A Uribe

Publications and source records attributed to A Uribe.

At least 91 records · Page 5Linked to original sources
PubMed1979

Amikacin concentration in the cerebrospinal fluid of children with acute bacterial meningitis.

Penetration of the aminoglycoside, amikacin, into the cerebrospinal fluid (CSF) of twenty children with acute bacterial meningitis was studied at various times after intramuscular administration and at various stages of therapy. Six of the patients were evaluated during therapy with amikacin at 7.5 mg/kg (intramuscularly) every 12 hours plus ampicillin every 6 hours at 300 mg/kg/day (intravenously); thirteen of the remaining fourteen patients were treated with ampicillin alone, but were given a single intramuscular dose of 7.5 mg/kg of amikacin for evaluation of CSF concentration. Amikacin concentration in CSF with respect to time after administration followed essentially the same pattern as in serum. A minimum concentration of 2 microgram/ml was found in 76% of the CSF samples obtained between 0.5 and 7 hours after administration. A mean amikacin serum/CSF ratio of 3:1 was demonstrated up to 7 hours after dose in all patients who underwent clinical improvement. Patient response was predictable by a correlation of in vitro MIC values with in vivo CSF concentration in three of the six patients who received amikacin therapy.

Acute Disease↗
PubMed1978

Amikacin in gram-negative paediatric infections.

Amikacin was used in the treatment of various Gram-negative infections in sixty-six children ranging in age from two days to thirteen years. Over 72% of the infections treated were classified as severe and the remainder were moderate. Among infections in which the site of origin was the urinary or gastro-intestinal tract, amikacin achieved thirty-eight (95%) complete or partial cures in forty patients. In respiratory tract infections, amikacin completely or partially cured six (75%) out of eight patients. The remaining eighteen infections involved skin, soft tissue and other miscellaneous categories in which amikacin therapy resulted in seventeen (94%) complete or partial cures. Overall, amikacin achieved fifty-four complete cures and seven clinical or bacteriological cures in sixty-six patients, which represents an 82% complete cure rate and 10% partial cure rate for all the patients in the study.

Adolescent↗
PubMed1976

Clinical and laboratory studies with amikacin in newborns, infants, and children.

Thirty (86%) of 35 infants and older children with proven gram-negative sepsis had a complete clinical remission after treatment with amikacin. In 27 (82%) of 33 infectious episodes for which bacteriologic results were available before and after treatment, the organism was eradicated. The dosage of amikacin was either 7.5 mg/kg or 15 mg/kg given intramuscularly at 12-hr intervals. No adverse clinical effects or laboratory abnormalities were observed during treatment, which lasted from five to 14 days. All bacteria were sensitive to amikacin when tested by the disk diffusion method, and all but a single strain of Pseudomonas were sensitive when tested by the agar dilution method. Assays of serum and urine demonstrated adequate levels of amikacin after single intramuscular injections of 3.75 or 7.5 mg/kg; simultaneous assays of serum and cerebrospinal fluid in two cases demonstrated comparable concentrations of drug suggestive of a high degree of penetration into the cerebrospinal fluid in two cases demonstrated comparable concentrations of drug suggestive of a high degree of penetration into the cerebrospinal fluid during infection. Serial measurements of amikacin in serum from 0.5 to 12 hr after administration of single doses of 7.5 mg of drug/kg to six newborns revealed no significant differences in the concentrations achieved with intramuscular or intravenous administration of the drug.

Adolescent↗
PubMed1976

Amikacin (BBK8) in infections due to gram-negative organisms in children over the age of one month.

Thirty children over the age of one month were treated with amikacin (BBK8), a new aminoglycoside derived from kanamycin A, with three intramuscular dosage schedules. Each group consisted of ten patients. The first received 7-5 mg/kg/12 hours, the second 7-5 mg/kg/24 hours and the third, 3-75 mg/kg/12 hours. The infections and the bacteria were similar in all three groups: pyelonephritis, abscesses of soft tissues, infected wounds, septicaemia, superinfected empyema, gastro-enteritis, chronic otitis media; the bacteria were E. coli, Klebsiella, Pseudomonas and Salmonella. A were sensitive by the Kirby-Bauer method, although two were resistant by dilution in Petri dish. Of the thirty patients, twenty four (80%) were cured. The schedule of 3-75 mg/kg/12 hours was as effective as the schedule of 7-5 mg/kg/12 hours for infections such as pyelonephritis, superficial abscesses, contaminated wounds, gastro-enteritis and sepsis. The cases with infections localized in rather unaccessible sites required double the dose and strict drainage and cleanliness. Plasma levels with the administration of 3-75 mg/kg fluctuated between 8-3 and 12-6 mcg/ml; with 7-5 mg/kg they fluctuated between 8-6 and 13-1. The minimum inhibitory level (MIL) for the majority of the bacteria was 1-25 mcg/ml. No toxic reactions were observed.

Adolescent↗
PubMed1976

Effectiveness of two new cephalosporins, cephazolin and cephapirin, administered intermittently in acute and chronic osteomyelitis in children.

Ten patients were treated, most of pre-school age, with acute osteomyelitis, produced by Staphylococcus aureus and Salmonella, having evolved for approximately one week, with sodium cephazolin at doses of 60 mg/kg/day intramuscularly in two daily injections for the first seven days and then in a single dose every twenty-four hours for four to seven weeks. Nine of ten patients were asymptomatic six months after this treatment. The patient who manifested chronic signs at the end of six weeks of therapy continued to be treated with three weekly injections of the same drug at an equal dose until the completion of six months, at the end of which he was asymptomatic. Ten patients with chronic osteomyelitis having evolved for two months to five years, due to penicillin-resistant Staphylococcus aureus, were treated with cephapirin at the dose of 30 mg/kg in one daily injection intramuscularly for three to four weeks and then the same dose on Mondays, Wednesdays and Fridays until the completion of six months. Eight patients who required it were sequestrectomized. Seven of the ten patients improve and remained asymptomatic for the same period of observation. The three patients who did not show marked clinical improvement did exhibit an appreciable radiological recovery. We have presented these regimens of treatment with a view of encouraging research into the intermittent administration of bactericidal antibiotics for pyogenic infections; in spite of the good results, we do not dare to recommend them in daily practice.

Acute Disease↗
PubMedDate not supplied

Characterization of the F1F0-ATPase and the tightly-bound ATPase activities in submitochondrial particles from human term placenta.

In a previous study we demonstrated the existence of a tightly-bound ATPase in the human placental mitochondria (Martínez et al., 1993). The current study characterizes the ATP hydrolysis produced by the F1F0-ATPase and the tightly-bound ATPase in submitochondrial particles from the human term placenta. Both enzymes were not differentiated by pH. Inhibitors were necessary to distinguish the activity of each enzyme. The kinetic of the total ATP hydrolysis fitted into a model of two enzymes. During the characterization, it was observed that the tightly-bound ATPase activity was partially inhibited by vanadate and Mg2+, whereas the F1F0-ATPase was totally inhibited by Mg2+. Different nucleotides were hydrolyzed by the tightly-bound ATPase; the F1F0-ATPase hydrolyzed exclusively ATP. Glucose-6-phosphate, p-nitrophenylphosphate, or pyrophosphate were not hydrolyzed by the F1F0-ATPase, although some hydrolysis was observed with the tightly-bound ATPase. It is concluded that the tightly-bound ATPase activity corresponded to a 5'-nucelotidase, and that the human placental mitochondria could participate in the metabolism of nucleotides.

Adenosine Triphosphate↗
PubMedDate not supplied

A novel ATP-diphosphohydrolase from human term placental mitochondria.

This report describes an ATP-diphosphohydrolase activity associated with the inner membrane of human term placental mitochondria. An enriched fraction containing 30 per cent of the total protein and 80 per cent of the total ATP-diphosphohydrolase activity was obtained from submitochondrial particles. ATP-diphosphohydrolase activity was characterized in this fraction. The enzyme had a pH optimum of 8 and catalysed the hydrolysis of triphospho- and diphosphonucleosides other than ATP or ADP. Pyrophosphate was also hydrolysed, but AMP or other monoester phosphates were not. The activity of ATP-diphosphohydrolase was dependent on Mg(2 + ), Ca(2 + )or Mn(2 + )and the enzyme substrate was the cation-nucleotide complex. An excess of free cation produced inhibition.ATP-diphosphohydrolase activity was stimulated at micromolar concentrations of calcium or magnesium in the presence of La-PPi. Negative cooperativity kinetics was observed with all substrates tested. The V(max)ranged from 150 to 300nmol of Pi released/mg/min. The [S](0.5)for nucleotides was 1-10m m and 182m m for PPi. The enzyme was inhibited by orthovanadate, but not by l -phenylalanine, oligomycin, sodium azide, P(1),P(5)-di(adenosine-5')pentaphosphate or sodium fluoride.The experimental evidence showing absence of inhibition by sodium azide and sodium fluoride, hydrolysis of pyrophosphate but not of monoester phosphates, and negative cooperativity suggested that this enzyme was a novel ATP-diphosphohydrolase.

Apyrase↗
PubMedDate not supplied

[Coronary angioplasty in the treatment of symptomatic myocardial ischemia with one vessel disease].

Our group initiated a program of coronary angioplasty (CA) in patients with symptomatic one vessel disease, or multivascular lesions with a critical "culprit" stenosis. In a 16 month period we have performed CA of 28 lesions in 25 patients (20 men) with a mean age of 54 +/- 10 years. Stable angina was diagnosed in 14 patients, unstable angina in 7, and post-myocardial infarction residual angina or stenosis in 4 patients treated with streptokinase. Successful dilatation was obtained in 23 (82.1%) of 28 stenotic segments, reducing the stenosis from 90 +/- 8% (range 70-100) to 9 +/- 12% (range 0-30; p less than 0.00001). In 4 cases with total occlusion, dilatation was not obtained, and in one case the procedure was complicated by fatal brain embolism. There were 4 complications due to coronary occlusion or spasm, all of them resolved during CA without sequelae. The 20 cases with primary success have been followed during an average of 8.6 months. In three cases (15%) restenosis was detected; two of them underwent surgery, and CA was repeated successfully in the other. Disappearance of myocardial ischemia was confirmed in 14 patients, and functional improvement in the other three. In conclusion, CA is an effective and relatively safe therapeutic alternative in different clinical forms of coronary heart disease with a single vessel stenosis, or in selected cases of multivascular lesions with a critical stenosis.

Adult↗
PubMedDate not supplied

DNA synthesis in the gastroduodenal mucosa during acute and chronic stress in the rat.

We investigated the effects of acute and chronic stress on the DNA synthesis of the gastroduodenal mucosa of the rat using two different methods of physical stress at various time intervals. Acute stress was produced in the rats being briefly plunged or swimming for two hours (water temperature 37 degrees C). "Sham - transported" rats were used as controls. The results indicate that in the stomach the DNA synthesis was substantially reduced during acute stress in both groups tested (when compared to controls). The DNA synthesis was also reduced in experimental rats after one and two weeks of stress (as compared to day one). By four and eight weeks, the rate of DNA synthesis in the gastric mucosa had significantly increased in the stressed animals. Controls demonstrated significantly lower DNA values following two to eight weeks of stress (as compared to day one). From the outset, the DNA replication values were 2.5 to 3 times higher in the duodenal mucosa than in the gastric mucosa. Following two weeks of stress, the duodenal mucosa of both test groups showed significantly lower DNA values than controls, but significantly higher values after four weeks of stress. By eight weeks, the duodenal mucosa in all rats had reached the same values as that of day one. This was considered a sign of "adaptation to stress" in the duodenal mucosa. The above results suggest that the fluctuations of DNA replication may be connected to compensatory mechanisms aimed at adjusting the gastroduodenal mucosa to protracted stress situations.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗