Biomedical subjects
Publications and source records attributed to A Kane.
Clindamycin penetrated extremely well into inflamed (19) and normal (one) appendices. Average levels in appendiceal tissue taken 26 to 300 minutes after a single intravenous dose were 154% of the simultaneous serum concentration.
Tissue residues from 3 SSPE brains extracted at neutral pH were thoroughly washed with phosphate-buffered saline and further extracted at acidic pH. The low-pH extracts had significant measles antibody titers, and their measles-specific IgG content ranged from 40 to 60% of total IgG. Agarose-gel electrophoretic analysis of the extracts showed oligoclonal IgG bands, most of which disappeared after suitable absorption with measles virus, demonstrating the presence of restricted measles antibody population. Ouchterlony analysis showed a reaction of identity between bound IgG and IgG extracted at neutral pH. Thus IgG extracted at low and neutral pHs is remarkably similar.
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We compared the ocular penetration of labeled with radioactive carbon gentamicin in squirrel monkeys after subconjunctival and retrobulbar administration. In both normal and infected (Staphylococcus aureus endophthalmitis) eyes, high concentrations of drug were achieved in the sclera and choroid-retina by both routes, while corneal levels were markedly higher after subconjunctival injection than after retrobulbar injection. Regional variations in concentration were evident in these tissues; the highest levels were clustered about the site of injection. Aqueous humor concentrations were lowest in the group with normal eyes treated by the retrobulbar route; vitreous humor levels were extremely low in normal eyes injected subconjunctivally. These data differ from those in rabbits, especially with regard to penetration of the vitreous humor of normal eyes. Interspecies differences were less marked in inflamed eyes. The two species were similar in demonstrating maximum access to the cornea and aqueous humor with subconjunctival injection, and equivalence of the two routes in penetrating the vitreous humor of the inflamed eyes.
We subconjunctivally, injected gentamicin, in a dose of 10 mg, into normal and inflamed (Staphylococcus aureus endophthalmitis) rabbit eyes in which the nasolarcrimal ducts had been blocked. We retrieved approximately 10% of the dose of drug in the tears, the majority in the first 30 minutes. The difference in lacrimal excretion of the drug between normal and inflamed eyes was not significant. Higher concentrations of gentamicin found in the ocular tissues of normal eyes than inflamed eyes cannot be attributed to loss in the tears.
Forty tissue samples, primarily of skin and bone, were obtained from 29 patients undergoing excision of decubitus ulcers after intravenous injection of 600 mg of clindamycin. Antibiotic concentrations exceeded 2.5 mug/g in 80% of the samples. In 50% of the instances, tissue levels were greater than those simultaneously present in the serum.
Chloramphenicol (D-threo-2-dichloroacetamido-1-p-nitrophenylpropane-1,3-diol) added to blood samples did not alter the observed shift in the red cell osmotic fragility curves as the samples were aged in vitro for 24 hours at 37 degrees C. Nor was the normal rate of loss of 2,3-diphosphoglycerate, ATP, or glutathione from the red cells affected by the presence of chloramphenicol over the same period. Consequently, this bacteriostatic agent can be added to blood samples taken under non-sterile conditions, such as from the heel of an infant, in order to preserve them from the effects of microbial contamination. In this way red cell osmotic fragility results can be obtained on non-sterile samples after their incubation at 37 degrees C for 24 hours. A miniaturisation of the standard osmotic fragility procedure is described, which allows results to be produced from the small, non-sterile samples obtained by heel-prick of infants.
Trephined disks of tissue (6 mm diameter) from fresh rabbit eyes were immersed overnight in solutions of radioactive carbon (14C)-dicloxacillin or gentamicin, then assayed by one of two methods: agar-diffusion bioassay, using filter-paper disks immersed in known concentrations of antibiotic as standards, or radioactive assay. The bioassay underestimated the concentrations of antibiotic in sclera and iris by 38 to 72%, and slightly overestimated those in the cornea. A corrected bioassay was calculated, based on the differences in fluid mass between tissue specimens and filter-paper disks; this value was within 20% of the radioactive assay in 18 of 24 experiments with dicloxacillin, and in 14 of 24 with gentamicin. There was evidence of pronounced binding of gentamicin to ocular tissues (iris greater than sclera greater than cornea); this appeared to be a saturable and reversible phenomenon. Less marked binding of dicloxacillin to iris and sclera was noted. The results indicated that, depending on the degree of accuracy required, the corrected trephine-disk agar-diffusion bioassay provides a reasonable estimate of the antibiotic content of ocular tissues.
We compared the penetration of radioactive carbon (14C) labeled-gentamicin into ocular tissues and fluids of albino rabbit eyes after subconjunctival (anterior subtenon's) and retrobulbar (posterior subtenon's) injections. In both normal and infected (Staphylococcus aureus endophthalmitis) eyes, higher levels of drug were produced with subconjunctival rather than with retrobullar admininistration in cornea, sclera, choroid and retina (as a unit), and iris; levels in the aqueous and vitreous humors of infected eyes were similar with the two routes of injection. Marked regional variations in the concentrations of gentamicin were noted in cornea, sclera, and choroid-retina after subconjunctival therapy. The pattern of these variations suggests that subconjunctival antibiotic penetrates the eye by direct diffusion. The low levels of drug after retrobulblar injection may be due to systemic absorption through the highly vascular orbital plexus of the rabbit.
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Synthetic melanin (100 to 1,000 mug/ml) markedly inhibited the in vitro activity of aminoglycosides and tetracyclines but did not affect the activity of betalactam antibiotics, erythromycin, or clindamycin.
Cellulose acetate and agarose gel electrophoresis of pH 7.4 brain extracts from three patients with subacute sclerosing panencephalitis (SSPE) revealed two to three homogeneous bands in the gamma-globulin region. The IgG concentration in the brain extracts ranged from 6 to 8.5% of the total protein. The IgG was isolated by passing each brain extract twice through gel filtration on Sephadex G-200 column. The Sephadex-isolated IgG preparations, at a concentration of 1 mg/ml, had hemagglutination inhibition (HI) titers ranging from 512 to 800, complement fixation (CF) titers of 64 to 100, and neutralizing titers of 400 to 1024 when tested against envelope, nucleocapsids, and while measles virus, respectively. These IgG preparations were further separated into several fractions by isoelectric focusing (IEF) technique and the reactivities of these eluted fractions were examined against differnt specific measles virus components and against whole virus. The results showed that both slow and fast moving homogeneous IgG had high HI and neutralizing titers. However, CF antibodies were present only in specific IEF-eluted fractions and their profiles differed somewhat from one brain to another. The IgG fractions reacted with both kappa-and gamma-chain antisera, but the reactivity varied from one brain to another. When the polyacrylamide gel electrophoretic (PAGE) patterns of heavy (H) and light (L) chains of SSPE IgG were compared to those of IgG from controls, the H chain patterns of both groups were identical whereas the SSPE brain IgG demonstrated two distinct bands in L chain as compared to a single diffuse band observed in controls. These latter results, in addition to homogeneous bands and selective CF antibody activity in IEF eluted IgG fractions from SSPE brain, fulfill some of the criteria of monoclonality.
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Selective mutism is a disorder which can cause severe social and academic impairment, and for which a wide variety of treatment approaches have been used, with varying degrees of success. Selective mutism can be conceptualized as the lack of generalization of a class of operant responses (e.g. audible and comprehensible verbalizations) across environmental contexts. The rehabilitation hospital setting, in which the patient is seen daily by multiple people in multiple settings, is particularly well-suited for implementing a systematic behavioural intervention to establish verbal behaviour and simultaneously reinforce its generalization. Data are presented on a 7-year-old female admitted to a rehabilitation hospital following orthopaedic surgery, who met the DSM-IV diagnostic criterion for selective mutism. Additional medical diagnoses included cerebral palsy, microcephaly, and mild mental retardation. A behavioural programme was developed and implemented to reinforce differentially first any communication, then verbal communication across staff and settings. Results were evaluated using a modified multiple baseline across settings design, and demonstrate that verbal, written, and tangible reinforcement effectively increased verbal behaviour where it previously rarely occurred. Results are discussed in terms of the relationship between selective mutism, social phobia and related disorders. The theoretical roles of behavioural phenomena (discriminative stimuli, stimulus generalization) in the development and treatment of these disorders are discussed.
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