Biomedical subjects

H Trujillo

Publications and source records attributed to H Trujillo.

36 records · Page 2Linked to original sources

PubMed1981

Safety and efficacy of netilmicin in neonates with serious systemic infections.

Twenty-five hospitalized neonates, each with two or more serious symptomatic infections, were given netilmicin by intramuscular injection. The antibiotic was administered usually at 1.5 or 3.0 mg/kg twice a day (q 12 hr) for 7 to 13 days. At the end of therapy the signs and symptoms of infection were completely resolved in twenty-four of the twenty-five patients and markedly improved in the remaining one. Thirty-five causative organisms were isolated from 30 of the 59 infection sites; after netilmicin therapy 31 causative organisms were completely eliminated and 4 were markedly reduced in number. One of the babies had a slight increase in serum creatinine level, possibly related to therapy, and a mild transient rash which was doubtfully related to netilmicin. None of the other neonates had adverse reactions.

Bacterial Infections↗

PubMed1981

Cefadroxil monohydrate versus erythromycin in paediatric patients.

Cefadroxil monohydrate, an oral cephalosporin with a long half-life, was compared to erythromycin estolate for efficacy in treating upper respiratory tract infections in children. The study was carried out on forty patients, twenty receiving cefadroxil and twenty receiving erythromycin. Each drug was dosed at 50 mg/kg/day and was given every 12 hours in two equally divided doses. The complete cure rate was 95% for the cefadroxil group and 80% for the erythromycin group. Two patients originally in the erythromycin test group showed no improvement either bacteriologically or clinically after 3 days of treatment. It was found that these patients harboured S. aureus which had become resistant to erythromycin during the course of therapy. Both patients were shifted to cefadroxil treatment and achieved complete cures. Two patients in the erythromycin group and one in the cefadroxil group were diagnosed as having scarlet fever. All three responded clinically, yet cultures from the two treated with erythromycin showed persistence of bacteria while the one treated with cefadroxil proved to be cured both clinically and bacteriologically.

Cefadroxil↗

PubMed1980

Mathematical models of synaptic plasticity: I. Posttetanic potentiation.

A mathematical model of post-tetanic potentiation is proposed. The model uses differential equations and is based upon physiological postulates of the electrical, metabolic, and neuroendocrine activities that are related to synaptic connectivity. These activities may modify some important parameters in synaptic function. In the proposed model these parameters are restricted to the presynapse in view of the physiological evidence indicating that posttetanic potentiation is probably due to presynaptic mechanisms. The model takes into consideration the size of the transmitter pool available for release, the mobilization of transmitter from and to this pool, and the fraction of transmitter released. Based upon the above postulates, we have simulated different phases of the phenomenon of posttetanic potentiation, and we have presented the results of several preparations in which this event has been studied. This work represents a successful attempt to reproduce the dynamics of posttetanic potentiation based upon physiological results with a mathematical model.

Calcium↗

PubMed1980

Mathematical model of synaptic plasticity: II. Habituation.

A mathematical model of the phenomenon of habituation as a homosynaptic depression of the amount of transmitter release is proposed. The model is based on the physiological studies of habituation in invertebrates and in the spinal cord of vertebrates, where a single synapse has been isolated and some of the physiological mechanisms of this process have been elucidated. The model simulates the following properties of habituation: (1) reduced amount of transmitter release attributed to a repetitive stimulus through changes in the membrane permeability to Ca2+ ions; (2) spontaneous recovery by rest; (3) the amplitude and frequency dependence of habituation; (4) modulation of habituation: sensitization, through an increase in membrane Ca2+ permeability, and presynaptic inhibition, through a reduced depolarization of the physiological stimulus; (5) long-term habituation attributed to repetitive trials of habituation and spontaneous recovery.

Animals↗

PubMed1980

Mathematical model of synaptic plasticity: III. Heterosynaptic changes.

A mathematical model, using differential equations, of heterosynaptic plasticity is proposed. The model is based on physiological studies of invertebrates in which nonspecific conditioning, such as sensitization and heterosynaptic inhibition, starts to be elucidated and behavioral studies of classical and instrumental conditioning, which we postulate to have the same mechanisms as those found in nonspecific conditioning. The model permits us to simulate the following heterosynaptic changes: sensitization, heterosynaptic inhibition, classical and instrumental conditioning--including short- and long-term memory--extinction and recuperation--spontaneously and by stimulation.

Animals↗

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↗

PubMed1977

Serum levels and urinary concentrations of kanamicin, bekanamicin and amikacin (BB-K8) in diabetic children and a control group.

Serum levels of kanamicin, bekanamicin, and amikacin were studied, after a single intramuscular dose of each antibiotic, in three groups of diabetic children, with their respective normal controls, paired by age, weight and sex. Lower serum levels were observed with kanamicin and bekanamicin in diabetic children compared to their controls. The difference in low serum levels was less noticeable with amikacin.

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 in newborn infants: comparative pharmacology with kanamycin and clinical efficacy in 45 neonates with bacterial diseases.

The pharmacokinetic properties of amikacin (BBK8) were similar to those of kanamycin in newborn infants. Peak serum concentrations of both drugs were in the range of 15 to 25 mug/ml with the exception of kanamycin in babies weighing greater than 2,000 g at birth where peak levels were 12.5 to 15 mug/ml. Volumes of distribution, plasma clearances, and serum half-life values were comparable for the two drugs. The clinical and bacteriological responses to amikacin therapy were assessed in 45 neonates with bacterial diseases. A case fatality rate of 26% was observed in infants with septicemia and/or meningitis, whereas no deaths occurred among 22 infants with urinary tract and mucocutaneous infections. Cultures from infected sites were sterile within 72 h of initiating amikacin therapy in 47% of the infants, continued positive for greater than 72 h in 31%, and were not reevaluated during therapy in 22%. The clinical response was judged to be satisfactory in 92% of the surviving infants. The efficacy of amikacin was comparable to that of kanamycin or gentamicin in neonatal bacterial diseases.

Amikacin↗

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↗

PubMed1974