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Biomedical subjects

J Jacobson

Publications and source records attributed to J Jacobson.

At least 127 records · Page 7Linked to original sources
PubMed1986

Pharmacokinetics of mezlocillin in patients with hepatobiliary dysfunction.

The pharmacokinetics of mezlocillin were investigated in 26 patients with alcoholic liver disease. Serum concentrations of mezlocillin were measured following intravenous administration of 3 g doses over 30 min. The mean peak serum concentration (+/- standard deviation) of mezlocillin at the end of infusion was 138.8 +/- 55.7 mg/l and the mean terminal half-life (T 1/2 beta) was 2.10 +/- 0.9 h. The 24 h urinary recovery of mezlocillin was 35.4 +/- 12.4% of the administered dose. Serum clearance was found to be inversely correlated with alkaline phosphatase and with total bilirubin. The T 1/2 beta was related to the following clinical measurements: age, SGOT and prothrombin time. This relationship suggests it may be prudent to adjust the dosage and the dosage interval of mezlocillin in patients with hepatobiliary dysfunction.

Adult↗
PubMed1986

Spontaneous diabetes mellitus in the Bio-Breeding/Worcester rat. Evidence in vitro for natural killer cell lysis of islet cells.

We sought direct evidence for anti-islet cellular cytotoxicity in diabetic Bio-Breeding/Worcester (BB/W) rats by comparing the effects of splenic lymphoid cells from BB/W diabetic (D), diabetes-prone (DP), and diabetes-resistant (DR) rats on the release of 51Cr from damaged islet cells in vitro. D and DP splenic lymphoid cells were cytotoxic to major histocompatibility complex (MHC)-compatible Wistar-Furth (WF) rat islet cells and also to MHC-incompatible Lewis rat islet cells and a rat islet cell line (RIN 5F), whereas WF and Lewis rat spleen cells and a rat pituitary cell line (GH3) were not lysed by lymphoid cells from D or DP rats. The cytotoxic cells were identified as natural killer (NK) cells since NK-sensitive cells (G1-TC and YAC-1 cell lines) were lysed by D and DP spleen cells, YAC-1 cells competed for the lysis of RIN islet cells by D spleen cells, lysis of RIN cells was increased by using D spleen cells from the low density fraction (large lymphocytes/monocytes) of a Percoll density gradient, and incubation of D spleen cells with an antiserum to NK cells (anti-asialo GM1 serum) and complement decreased monoclonal antibody-defined subsets containing NK cells (W3/13+ OX19- and OX8+), and this was accompanied by similar decreases in cytotoxicity to YAC-1, RIN, and WF islet cells. These studies demonstrate that NK cell activity is increased in BB/W diabetic and DP rats, and that islet cells can serve as targets for these NK cells. The findings suggest that NK cells may participate in the islet-directed cellular cytotoxic response leading to beta cell destruction and diabetes.

Animals↗
PubMed1985

Incidence of hearing loss in high risk and intensive care nursery infants.

The incidence of hearing impairment in high risk infants is summarized for five programs which use brainstem electric response audiometry (BERA) to detect hearing loss in this population. Programs are compared with respect to the following variables which may affect reported incidence figures: population characteristics, stimulus and recording parameters, criteria for failure on the initial BERA test, and follow-up protocols. Between 10-30% of these infants fail an initial BERA test, with initial failure rate largely dependent on the failure criteria used. Approximately 10% will continue to show some degree of hearing impairment on follow-up tests at 2-5 months of age. Between 2-4% will have a moderate to profound bilateral sensorineural hearing loss requiring amplification and habilitation.

Acoustic Stimulation↗
PubMed1984

Measurement of adsorption isotherms by liquid chromatography.

Adsorption behavior on silica-bound hydrocarbonaceous sorbents used in high-performance liquid chromatography was investigated by frontal chromatography and elution on a plateau, and procedures were developed for data collection, analysis and correlation. Isotherms of selected compounds were measured, including several of biological relevance. The relative merits of various dynamic methods of isotherm measurement were compared and illustrated by experimental findings. The frontal analysis technique was determined to be more accurate and convenient than other methods. A miniaturized liquid chromatographic system was constructed to measure isotherms with milligram quantities of material by frontal development. The performance of this apparatus compared favorably with that of equipment which has dimensions usual in high-performance liquid chromatography and requires orders of magnitude greater amounts of a substance for isotherm measurement. Thus the miniaturized system is eminently suited for applications when the substance of interest is in short supply, as is the case with many biological substances. The effects of operating parameters on adsorption behavior were investigated, both to optimize the procedure, and to further explore the fundamental of the process.

Adsorption↗
PubMed1983

Pharmacokinetics of amdinocillin in healthy adults.

The pharmacokinetics of amdinocillin (mecillinam) were determined in 10 healthy volunteers. Single doses of 10 and 15 mg/kg of body weight were administered intravenously and intramuscularly in a crossover study. Plasma concentrations of amdinocillin were determined by microbiological assay. Mean peak plasma concentrations were 49 and 87 micrograms/ml after intravenous doses of 10 and 15 mg/kg, respectively. The terminal half-life value of 0.89 h was similar for both doses. After intramuscular injections, the mean concentration of drug in plasma was 26.2 micrograms/ml for the 10-mg/kg dose and 29.6 micrograms/ml for the 15-mg/kg dose, with terminal half-lives of 0.96 and 0.86 h, respectively. The mean apparent volumes of distribution at steady state were 18 and 16 liters/100 kg for the intravenous doses of 10 and 15 mg/kg, respectively. Drug concentrations in plasma at 4 h were above the minimal inhibitory concentrations for gram-negative organisms categorized as susceptible to this drug.

Adult↗
PubMed1983

Crossover study of the pharmacokinetics of ceftriaxone administered intravenously or intramuscularly to healthy volunteers.

The pharmacokinetics of ceftriaxone were investigated in six healthy adults. One-gram doses were administered either intramuscularly or intravenously in a crossover design study. Mean peak ceftriaxone concentrations in plasma of 79.2 and 123.2 micrograms/ml were achieved with intramuscular injection and intravenous infusion, respectively, with plasma half-lives of 5.4 and 5.8 h. The urinary recovery of ceftriaxone in the first 24 h was 37% after intravenous infusion and 25% after intramuscular injection.

Adult↗
PubMed1983

Transient ischemic attacks with external carotid artery stenosis and a normal internal carotid artery.

Transient ischemic attacks have been attributed to emboli from the external carotid artery in patients with complete occlusion of the internal carotid artery. We report a patient with an external carotid stenosis and normal internal carotid who developed ipsilateral transient ischemic attacks. Real time B-mode ultrasonography demonstrated that the plaque obstructing the external carotid artery extended into the carotid sinus. This may have served as a source of emboli into the internal carotid circulation.

Aged↗
PubMed1983

Naproxen in the treatment of OC-resistant primary dysmenorrhea. A double-blind cross-over study.

The efficacy of oral contraceptives (OC) in the treatment of primary dysmenorrhea in controlled studies varies from 50 to 80%. The addition of a prostaglandin synthetase inhibitor, naproxen, was found to afford pain relief to a further 70% of women with OC-resistant dysmenorrhea in a double-blind cross-over study comprising 39 patients. This effect was shown to be statistically significant at p = 0.0005. Our recommendation is that low-dose OCs should be the first choice as contraceptive agents for women with dysmenorrhea and that a prostaglandin synthetase inhibitor should be given when OCs are ineffective.

Adolescent↗
PubMed1979

Prostaglandin synthetase inhibitors and dysmenorrhea. A survey and personal clinical experience.

A survey of earlier published studies on treatment of dysmenorrhea with prostaglandin synthetase inhibitors is given and personal clinical experiences are presented. The time when treatment should start in relation to the onset of bleeding is also discussed. A survey of studies published in English and Scandinavian literature yielded 532 patients. Pain relief was experienced in 64 to 100 per cent of the patients in these studies. The incidence of side-effects has generally been low but in a few studies a high incidence was reported. In the current study 34 patients with prinary dysmenorrhea completed the douule-blind, placebo controlled study on naproxen. The patients were treated for two cycles, 16 with naproxen and 18 with placebo. The mean relief score indicated a "slight to good" pain relief in the naproxen group and "no alleviation" in the placebo group. The difference is statistically significant (p = 0.003). Supplementary medication was much more used in the placebo group compared to the naproxen group (p = 0.01). In the placebo group no change whatsoever was demonstrated in alleviation of interference with every-day life, whereas there was a statistically significant improvement in the naproxen group. No major side-effect was registered. Thus none of the subjects withdrew from the study.

Adolescent↗
PubMed1977

Regional cerebral blood flow with intracranial mass lesions. Part I: Local alterations in cerebral blood flow.

Focal changes in the cat cerebral blood flow were studied by the technique of H2 polarography. Areas studied included the caudate nuclei, thalami and midbrain. A unilateral mass effect was created by inflation of an epidural balloon. A rapid decrease in regional cerebral blood flow was noted ipsilateral to the mass at very small balloon volumes. This was followed closely by contralateral supratentorial decrease in regional cerebral blood flow. The normal midbrain blood flow was found to be preserved until total decompensation (herniation) occurred.

Animals↗
PubMed1977

Regional cerebral blood flow with intracranial mass lesions. Part II: Autoregulation in localized mass lesion.

Autoregulation of regional cerebral blood flow was evaluated in cats. In normal baseline situations autoregulation was invariably present. Concomitant to an enlarging mass, supratentorial loss of this protective mechanism was seen both ipsilateral and contralateral to the mass. There was relative preservation of midbrain autoregulation until very high balloon volumes were reached. There was no acute regulation upon balloon deflation.

Animals↗
PubMed1976

Naloxone blockade of morphine analgesia: a dose-effect study of duration and magnitude.

The purpose of the experiment was to determine the minimal dose of naloxone needed to block the analgesic effect of morphine as measured by the foot-shock titration procedure in the rat. Various groups of rats received, subcutaneously, various doses of naloxone hydrochloride, from 0.03 to 2.0 mg/kg, 15 minutes before receiving 10 mg/kg of morphine sulfate. The results indicate that 1.0 mg/kg of naloxone is the minimum dose necessary to provide full blockade of the measured morphine effect for up to 5 hours after the morphine administration. Partial blockade was evident at doses much smaller than 1.0 mg/kg of naloxone. A dose of 0.125 mg/kg of naloxone completely blocked the onset of a measurable effect from 10 mg/kg of morphine for 60 minutes in six out of the seven animals tested at that dose. The results provide a clear dose-effect relationship for both magnitude and duration of naloxone blockade of the analgesic effect of morphine.

Animals↗