Biomedical subjects
Publications and source records attributed to S M Johnson.
The carotid endarterectomy procedure has provided an invaluable option in the management of patients with symptomatic atherosclerotic carotid artery disease. The criteria for surgical interventions vary from different institutions as well as the mortality and morbidity, but, for a select patient population, it is a viable alternative to conservative medical management.
Thirteen immunoglobulin-secreting mycoplasma-free human cell lines were treated with increasing concentrations of lymphoblastoid interferon-alpha (IFN-alpha) in order to study the activity of their CD73 ecto-5'-nucleotidase (5'N), their rate of growth and their immunoglobulin (Ig) production. Although IFN-alpha did not immediately affect the activity of the 5'N on the cell plasma membranes, the class of Ig secreted by the cell lines determined whether culturing the cells in the presence of IFN-alpha gave a small increase in the 5'N enzyme activity (IgM), or had no effect (IgE), or showed a marked decrease in activity (IgG). The 5'N activity of two IgG4-secreting clones was more suppressed by IFN-alpha than that of the four IgG1-secreting clones. The clone with the highest 5'N was killed by IFN-alpha. A high 5'N activity inhibited the growth rate of the cells, since the rate of growth of the three IgG-producing lines with high 5'N was increased when their 5'N was inhibited by increasing concentrations of IFN-alpha. The growth rate of three other Ig-producing lines was uninhibited by up to 10(5) U/ml IFN-alpha, whereas the rest were partially or strongly inhibited. Excluding the clone which died, 10/11 lines or cultures increased their Ig/cell by a mean of 25% at 100 U/ml IFN-alpha; their total Ig production also increased despite any growth inhibition. One IgG-secreting clone decreased its Ig production at 100 U/ml IFN-alpha by 11%. The Ig/cell of 4/5 of the cell lines increased with IFN-alpha concentrations up to at least 10(4) U/ml. The increase in Ig/cell was not related to the class of Ig, the growth rate of the cells or the amount of 5'N.
This paper outlines the advances made in the field of marital therapy in the last decade. The present status of clinical intervention, empirical research and theoretical conceptualization is reviewed. In addition, the challenges the field now faces are outlined, and proposals made for future directions, which would enable marital intervention to become a more comprehensive and systematic endeavor.
This study examined whether the inhibitory actions of opioids in the guinea-pig ileum were influenced by agents which mimic or elevate intracellular cyclic adenosine 3',5'-monophosphate (cyclic AMP) levels. In longitudinal muscle-myenteric plexus preparations, the mu agonist, [D-Ala2,NMePhe4,Gly-ol5]enkephalin (DAGO) and the kappa agonist, dynorphin A-(1-13) depressed contractions of the longitudinal muscle evoked by electrical stimulation of myenteric neurons. Mean IC50 values were 19 and 2.8 nM for DAGO and dynorphin, respectively. Neither forskolin, cholera toxin nor dibutyryl cyclic AMP affected significantly the IC50s for the opioid agonists. The experiments suggest that mu and kappa agonists inhibit excitatory cholinergic transmission to the longitudinal muscle by intracellular effector mechanisms that do not involve cyclic AMP.
To investigate the role of cyclic adenosine-3'5'-monophosphate on the inhibitory actions of opioids in guinea-pig ileum, we made intracellular recordings from the two electrophysiologically defined classes of neurons (S and AH) in the myenteric plexus. The selective opioid mu agonist (D-Ala2,N-Me-Phe4,Gly5-ol)-enkephalin caused a membrane hyperpolarization in 34 out of 67 S neurons but did not affect the membrane potential of AH neurons. The mean amplitude (+/- S.E.M.) of the hyperpolarization was 8.2 +/- 0.8 mV. Forskolin, which activates adenylate cyclase and increases intracellular cyclic adenosine-3',5'-monophosphate levels, caused a membrane depolarization in AH neurons (9.4 +/- 1.9 mV) but did not alter the resting membrane potential of S neurons. Similarly, neither the phosphodiesterase inhibitor, isobutylmethylxanthine, nor the membrane permeable analogue of cyclic adenosine-3',5'-monophosphate, dibutyryl cyclic adenosine-3'-5'-monophosphate, altered the resting membrane properties of S neurons. Furthermore, none of these agents affected significantly the amplitude of the hyperpolarization of S neurons by (D-Ala2,N-Me-Phe4,Gly5-ol)-enkephalin. The experiments indicate that changes in intracellular cyclic adenosine-3',5'-monophosphate are not important in the processes that link occupation of mu receptors to the opening of potassium channels on myenteric neurons.
This study investigated whether knowledge and attitudes of Malay college students regarding smoking can be positively influenced by educational intervention. The experiment included a pretest to assess the students knowledge and attitudes regarding smoking, a lecture on the health risks associated with smoking, and a posttest given six weeks later to assess whether any changes had occurred. A profile of the typical Malay student smoker was also elicited. Twenty-seven percent of the study population were smokers. Of the men in the sample, 44% were smokers, while less than 4% of the women were smokers. T-tests indicated that knowledge of the health risks associated with smoking was significantly improved for most groups, while attitudes towards smoking were essentially unchanged.
The stability of ranitidine in concentrations of 0.5, 1.0, and 2.0 mg/mL in admixtures with commonly used i.v. fluids was studied. The admixture vehicles were 0.9% sodium chloride, 5% dextrose, 10% dextrose, 5% dextrose and 0.45% sodium chloride, and 5% dextrose with lactated Ringer's (DLR) injections in polyvinyl chloride bags. Three bags were prepared for each test solution and stored under each of the following conditions: seven days at room temperature (23 +/- 1 degrees C) in normal laboratory lighting, 30 days at 4 degrees C, and 60 days at -20 degrees C followed by either seven days at room temperature (in light) or 14 days at 4 degrees C. Ranitidine content was determined by high-performance liquid chromatography at several intervals. Color, clarity, and pH were also examined. Ranitidine concentrations remained greater than or equal to 90% of initial concentrations under all storage conditions except in the frozen DLR admixtures. Drug loss in the DLR admixtures was greatest at the lower ranitidine concentrations. The only visual changes were yellow color in the thawed DLR admixtures and those containing ranitidine 2.0 mg/mL in 5% dextrose and 0.45% sodium chloride. Slight increases in the pH of some admixtures were noted. Ranitidine is stable for seven days at room temperature and 30 days at 4 degrees C at all concentrations and in all vehicles studied. At the studied concentrations, the drug is stable in admixtures frozen for 60 days and stored for seven days at room temperature or 14 days refrigerated, except in DLR admixtures; these admixtures should not be stored frozen.
The stability of ranitidine at low concentration (0.05 mg/mL) in five intravenous infusion solutions (0.9% sodium chloride, 5% dextrose, 10% dextrose, 5% dextrose with 0.45% sodium chloride, and 5% dextrose with lactated Ringer's injections) was studied. Admixtures were stored for seven days at room temperature in 150-mL and 1-L polyvinyl chloride infusion bags. Ranitidine stability in 0.9% sodium chloride injection and in 5% dextrose injection was also examined for up to 28 days, and these data were compared with data obtained at higher ranitidine concentrations (0.5-2.0 mg/mL). At intervals during the storage periods, color, clarity, and solution pH were examined and ranitidine content was determined by a stability-indicating high-performance liquid chromatographic assay. Ranitidine content remained greater than 90% of the initial concentration for more than 48 hours in all infusion fluids except 5% dextrose with lactated Ringer's injection. No visual changes or appreciable changes in pH were observed for any of the solutions. At the dilute concentration, ranitidine was markedly more stable after eight hours in 0.9% sodium chloride injection than in 5% dextrose injection. In 0.9% sodium chloride injection, ranitidine concentrations remained above 95% for up to 28 days, but drug concentrations in 5% dextrose injection fell below 90% after seven days. Stability in 5% dextrose injection improved as ranitidine concentrations increased from 0.05 to 2.0 mg/mL. Ranitidine (0.05 mg/mL) is stable for at least 48 hours at room temperature in all infusion fluids tested except 5% dextrose with lactated Ringer's injection.
We have become increasingly aware of sexual abuse in our society, and yet the majority of teens who were sexually abused as children enter adolescence carrying the secret of their abuse. Such hidden abuse may have devastating effects on the development of personal identity, self-esteem, attitudes, behaviors, and interpersonal relationships that may persist and set a pattern for a troubled adulthood. This article details how children cope with a sexually abusive situation, the long-term effects of unresolved sexual abuse, and diagnostic criteria to differentiate a hidden history of sexual abuse from other trauma and conditions. Focus is on recognizing and assessing "legitimate" symptoms that may be conscious or unconscious cries for help by victims of previous sexual abuse. Correct diagnosis is essential to appropriate intervention to lessen possible further psychologic damage during adolescence.
We retrospectively reviewed the charts of 47 patients who had had penetrating keratoplasty and intraocular lens exchange with fixation of a posterior chamber lens to the ciliary sulcus. Follow-up ranged from 5 to 30 months (mean, 13 months). The corneal grafts remained clear in 46 eyes. The average visual acuity of patients followed for more than 12 months was 20/60. Complications have been minor. Because of complications associated with anterior chamber lenses and these findings, we now utilize this technique in all patients who require penetrating keratoplasty and intraocular lens insertion without posterior capsule support.
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In this time series design study we investigated the effects of conversation on intracranial pressure (ICP). Two conversation types were used, and continuous measurements of ICP were recorded. Type 1 conversation was an emotionally referenced conversation that reflected an actual nursing report on the patient's current condition. Type 2 conversation was a predetermined dialogue unrelated to the patient. Two hypotheses were tested to determine the existence of differences between the ICP measurements at baseline and the ICP measurements during any conversation, and differences between the ICP measurements recorded during type 1 conversation and during type 2 conversation. Eight subjects served as their own control. T tests were performed between the mean scores of the minimum, maximum, and average ICP measurements before, during, and after both conversations. The hypotheses were not supported by the findings. There was, however, a statistically significant decrease in ICP when minimum ICP measurements before type 2 conversations were compared with measurements recorded during type 2 conversation. The data also demonstrated a wide variation of individual patient responses. The results of the current study suggest that the direction of influence from conversation on the ICP is individual and may be influenced greatly by the patient's level of consciousness.
In preparations of guinea-pig ileum comprising the circular muscle and the axonal processes of myenteric neurons, electrical stimulation evoked contractions of the circular muscle which were abolished by tetrodotoxin and by hyoscine, indicating that they resulted from action potential-mediated release of acetylcholine. The selective mu opioid agonist, (D-Ala2-N-Me-Phe4-Gly5-ol)-enkephalin (DAGO), and the selective kappa opioid agonist, trans-(+/-)-3,4-dichloro-N-(2-(1-pyrrolidinyl) cyclohexyl) benzeneacetamide, U-50488H, caused concentration-dependent and naloxone-reversible inhibitions of nerve-mediated contractions. The experiments indicate that opioid mu and kappa receptors are present on the axonal processes of cholinergic excitatory motor neurons supplying the circular muscle of the guinea-pig ileum.
In this study, the phrenic motor nucleus of adult guinea pigs was characterized following retrograde transport of horseradish peroxidase. The phrenic motor nucleus was localized to cervical sections C4-C7 in the ventromedial portion of the ventral horn. We further analyzed the internal organization of the phrenic motor nucleus by calculating the spatial interval distribution for the labeled motor neurons and their dorsally projecting dendrites which extended perpendicular to the longitudinal axis of the nucleus. Although the phrenic motor neurons were not clustered, the dendrites occurred in bundles with a mean longitudinal distance between bundles of 165 micron (range, 40-350 micron).
Enzyme-linked immunosorbent assay (ELISA) comparative studies are described in which 10 Blastomyces dermatitidis antigenic preparations from human, dog, and soil strains were used for the detection of rabbit serum antibodies directed against B. dermatitidis killed yeast cells of human and dog origin as well as detection of antibodies in human serum samples. Reactive reagents were produced from all 10 strains, but two antigens (K-Le and T-043324) demonstrated exceptional sensitivity with moderate cross-reactivity with histoplasmosis specimens. Additionally, these reagents were able to detect anti-B. dermatitidis antibodies produced in rabbits in response to human (H-100) or dog (T-042976) strains in a comparable manner. These data suggest that a single antigenic reagent might be suitable for ELISA detection of B. dermatitidis antibodies in different species with blastomycosis.
We assessed the efficacy of silver oxide coating of the indwelling urethral catheter and catheter adapter, and instillation of trichloroisocyanuric acid into the urinary drainage bag in the prevention of catheter-associated bacteriuria in a prospective and randomized study of 74 patients. Bacteriuria was documented in 29 of the 74 patients (39 per cent). There was a significant difference between the attack rates, with 11 of 41 patients (27 per cent) in the test group and 18 of 33 (55 per cent) in the control group having bacteriuria (p equals 0.02) after a median time to bacteriuria of 36 and 8 days, respectively (p equals 0.01). Urethral meatal colonization was implicated as the source of bladder bacteriuria in 12 of 18 patients (67 per cent) in the control group and 5 of 11 (45 per cent) in the test group. Trichloroisocyanuric acid significantly reduced drainage bag contamination but bag contamination with the same microorganism responsible for bacteriuria preceded infection in only 2 of the 29 patients (7 per cent), 1 in each group. Patients who received systemic antimicrobial agents acquired bacteriuria less frequently than those who did not. The apparent protective effect of systemic antimicrobials was strongest during the first 4 days of catheterization. The data indicate that episodes of bacteriuria arising from the urethral meatus are common among catheterized patients and that the antimicrobial catheter is effective in reducing the incidence of catheter-associated bacteriuria.
A 4-way crossover study was done to determine the pharmacokinetic and palatability characteristics of ibuprofen 800 mg tablets when given as a solution in various beverages. When compared to the tablet itself, no significant difference was noted for any variable measured for an orange juice solution. A delay in time-to-peak concentration (Tmax) was noted for a dilute cherry syrup solution. Changes in Tmax, peak concentration achieved and area-under-the-curve were noted with a Coca-Cola solution. The authors conclude Coca-Cola to be clearly inappropriate for this method, a dilute cherry syrup solution slightly better and orange juice to be the preferred option.
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