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Biomedical subjects

J H Salmon

Publications and source records attributed to J H Salmon.

At least 19 recordsLinked to original sources
PubMed2005

Pharmacokinetics and tissue fluid distribution of cephalexin in the horse after oral and i.v. administration.

The purpose of this study was to determine the pharmacokinetics and tissue fluid distribution of cephalexin in the adult horse following oral and i.v. administration. Cephalexin hydrate (10 mg/kg) was administered to horses i.v. and plasma samples were collected. Following a washout period, cephalexin (30 mg/kg) was administered intragastrically. Plasma, interstitial fluid (ISF) aqueous humor, and urine samples were collected. All samples were analyzed by high-pressure liquid chromatography (HPLC). Following i.v. administration, cephalexin had a plasma half-life (t(1/2)) of 2.02 h and volume of distribution [V(d(ss))] of 0.25 L/kg. Following oral administration, the average maximum plasma concentration (C(max)) was 3.47 mug/mL and an apparent half-life (t(1/2)) of 1.64 h. Bioavailability was approximately 5.0%. The AUC(ISF):AUC(plasma) ratio was 80.55% which corresponded to the percentage protein-unbound drug in the plasma (77.07%). The t(1/2) in the ISF was 2.49 h. Cephalexin was not detected in the aqueous humor. The octanol:water partition coefficient was 0.076 +/- 0.025. Cephalexin was concentrated in the urine with an average concentration of 47.59 microg/mL. No adverse events were noted during this study. This study showed that cephalexin at a dose of 30 mg/kg administered orally at 8 h dosage intervals in horses can produce plasma and interstitial fluid drug concentrations that are in a range recommended to treat susceptible gram-positive bacteria (MIC < or = 0.5 microg/mL). Because of the low oral bioavailability of cephalexin in the horse, the effect of chronic dosing on the normal intestinal bacterial flora requires further investigation.

Administration, Oral↗
PubMed1979

Early surgical intervention in posthemorrhagic hydrocephalus.

10 premature infants were found to have posthemorrhagic hydrocephalus (PHH) over a 4-year period. All weighed less than 2,500 g. The diagnosis was established by ventricular puncture and ventriculogram. Ventriculo-peritoneal (V-P) shunt placement was done in each infant soon after establishing the diagnosis, while the cerebrospinal fluid (CSF) was bloody. The mean age of infants at surgery was 21.4 days (range 16-33 days). Shunt obstruction occurred in 3 infants and infection in 1. No other complication was observed. All infants improved markedly in the immediate postoperative period, especially respirator-dependent infants. All survived; preliminary follow-up revealed that 3 were severely retarded and 2 mildly retarded; 5 infants were normal. Our preliminary experience with early V-P shunt procedure in the treatment of PHH has been favorable and follow-up appears encouraging.

Cerebral Hemorrhage↗
PubMed1978

Surgical treatment of hydrocephalus in infancy.

Correction of hydrocephalus by means of a ventriculoperitoneal shunt incorporating a pericranial reservoir is demonstrated in a five-day-old infant. The reservoir affords access to the ventricle and shunt for pressure determinations and for administration of antibiotics should infection occur. The initial shunt is revised at about one year of age to permit intraventricular pressure to rise to adult levels and to provide for growth.

Age Factors↗
PubMed1978

Intraventricular chloramphenicol.

Very high intraventricular chloramphenicol levels can be obtained if the standard systemic dose is supplemented with a small intraventricular dose. Chloramphenicol sodium succinate can be hydrolyzed to the microbiologically active chloramphenicol in the ventricular fluid. Daily injections are ordinarily adequate to maintain a high concentration of antibiotic. Initial dosage should vary with ventricular volume. The brain does not tolerate repeated needle puncture and the use of a ventriculostomy reservoir is recommended.

Animals↗
PubMed1978

The collapsed ventricle: management and prevention.

Acute obstruction of a shunt may occur when the ventricular space becomes slitlike. Four patients with collapsed ventricles were treated by adding a higher pressure valve to the system. The ventricles enlarged and the patients became asymptomatic. Twelve children who had been shunted in the neonatal period had a higher pressure valve added as an elective procedure to prevent ventricular collapse. There were no episodes of shunt obstruction in the subsequent seven to 38 months.

Cerebral Ventricles↗
PubMed1977

Ocular bobbing with superior cerebellar artery aneurysm. Case report.

A teen-age girl became comatose after the sudden onset of headache. Initial angiography did not reveal the site of bleeding. The subsequent onset of ocular bobbing directed attention to the region of the pons. Repeated angiography showed an aneurysm of the superior cerebellar artery. At surgery, the fundus of the aneurysm was adherent to the pons and there was a small hematoma within the pons. Ocular bobbing is rare, but is most commonly seen in association with destructive lesions of the pontine tegmentum, and is a useful localizing sign.

Adolescent↗
PubMed1977

A ventriculo-peritoneal shunt for hemorrhagic or high protein fluid.

A ventriculoperitoneal shunt may be a more satisfactory method of treating hydrocephalus than periodic needle aspiration or external drainage. A shunt that can be used when the ventricular fluid is hemorrhagic or has a high protein content is described. Only two of 12 patients required revision for shunt obstruction in the two months after surgery.

Cerebrospinal Fluid Proteins↗
PubMed1977

The fontogram: a noninvasive intracranial pressure monitor.

The applanation transducer was used to measure intracranial pressure (ICP) through the intact fontanel. The method is painless, rapid, and accurate. The pressures recorded with this fontogram were correlated with direct measurements of ICP. The correlation coefficient of the 21 paired determinations was .98--a very good correlation. Fontanel pressure was determined in 35 normal newborn infants. The mean pressure was 7.37 mm Hg with an SD of +/- 1.45 (range, 3.5 to 9.5 mm Hg). Three clinical cases are presented to illustrate the usefulness of this apparatus in the detection of increased ICP and in monitoring the effectiveness of treatment.

Brain Edema↗
PubMed1975

Salmonella meningitis.

Three cases of salmonella meningitis in infants were successfully treated with a combination of intraventricular and systemic antibiotics after standard treatment had failed. The intraventricular antibiotics were administered through a subcutaneously implanted ventriculostomy reservoir. The ventricular fluid cultures were positive in all cases. The organisms in the ventricle may periodically reinoculate the subarachnoid space and add to the difficulty in curing salmonella meningitis. Details of the prolonged treatment (29-59 days) and the antibiotic levels obtained are presented. No local reservoir complications were encountered. All three patients were developing normally 10 to 18 months following treatment including two who required a shunt procedure for nonabsorptive hydrocephalus.

Ampicillin↗
PubMed1971

Effect of intracranial hypotension on cerebral blood flow.

Intracranial hypotension increases cerebral blood flow. In dogs the average increase in cortical blood flow was 30 ml./100 g/min (47%) when the intracranial pressure was lowered acutely from 100 to 40 mm CSF. Permanent intracranial hypotension was established in seven demented patients using a ventriculoatrial shunt. The mean post shunt pressure was 50 mm CSF. In this group, the cerebral vascular resistance decreased 32%, the cortical blood flow increased 37%, and the relative weight of functional grey matter increased 44%. The systemic blood pressure was 8% lower. The increase in cerebral blood flow is the result of an increase in the pressure differential between the precapillary arterioles and the veins. In addition, the vessels dilate in response to the decreased external pressure. This increase in cerebral blood flow may be the mechanism for improvement in patients with normal pressure hydrocephalus who are shunted.

Adult↗
PubMed1971

Cable parameters, sodium, potassium, chloride, and water content, and potassium efflux in isolated external intercostal muscle of normal volunteers and patients with myotonia congenita.

In isolated fiber bundles of external intercostal muscle from each of 13 normal volunteers and each of 6 patients with myotonia congenita, some or all of the following were measured: concentrations of Na(+), K(+), and Cl(-), extracellular volume, water content, K(+) efflux, fiber size, fiber cable parameters, and fiber resting potentials. Muscle from patients with myotonia congenita differed significantly (0.001 <P< 0.025) with respect to the following mean values (myotonia congenita vs. normal): the membrane resistance was greater (5729 vs. 2619 omega.cm(2)), the internal resistivity was less (75.0 vs. 123.2 omega.cm), the water content was less (788.2 vs. 808.2 ml/kg wet weight), and the mean resting potential was greater (68 vs. 61 mv).NO SIGNIFICANT DIFFERENCES WERE FOUND WITH RESPECT TO THE FOLLOWING VARIABLES: K(+) content (73.5 vs. 66.7 mEq/kg wet weight) and the calculated intracellular K(+) concentration (215 vs. 191 mEq/liter fiber water), fiber capacitance (5.90 vs. 5.15 muf/cm(2)), Na(+) content (97.7 vs. 94.1 mEq/kg wet weight), Cl(-) content (79.0 vs. 74.7 mEq/kg wet weight), mannitol extracellular volume (45.1 vs. 46.6 cc/100 g wet weight), and K(+) efflux (23.2 vs. 21.5 moles x 10(-12) cm(-2).sec(-1)). These abnormalities of skeletal muscle in human myotonia congenita are like those of skeletal muscle in goats with hereditary myotonia. We tentatively conclude that a decreased Cl(-) permeability accounts for some of the abnormal electrical properties of skeletal muscle in myotonia congenita.

Action Potentials↗