Biomedical subjects
Publications and source records attributed to M J Jackson.
An automated ion-selective electrode system has been used to measure ionised calcium in bile from patients undergoing cholecystectomy for gallstones. Ionised calcium ranged from 0.63 to 1.73 mmol/l for a range of total calcium concentrations of 1.35 to 10.93 mmol/l. The correlation coefficient for ionised calcium regressed on total calcium was highly significant (r = 0.97). The slope of the line was 0.126 and the intercept 0.443.
An overview of the field of maxillofacial prosthetics has been presented. Current advances in the field have been discussed in brief. Soliciting the expertise of the prosthodontist preoperatively can greatly augment the total therapy of the head and neck cancer patient.
A national health program is inevitable if medical care costs continue to soar as they have in recent years. Those of us treating patients with cancer of the head and neck are aware that the costs are high, but many are not aware of the actual figures involved. In this study, five typical head and neck cancer patients were selected, and the costs incurred by these patients were calcualted. Both direct and indirect medical expenses were considered and are presented. In addition, we report the representative costs of various treatment modalities. An awareness of medical care costs plus appropriate consideration of them in the planning and administration of treatment may help to reduce health care expenses. If we do not control these costs, the government undoubtedly will.
Tracings were made on three patients using a modified pantographic device. The tracings were made on glass flags with wax, etched, and superimposed. The effects of body position and modification were investigated. From this research project the following can be concluded: 1. A precise method has been developed which permits superimposition of pantographic tracings for analysis. 2. There is a significant difference in reproducibility between medicated and nonmedicated subjects. 3. The percentage coincidence of border tracings increases significantly when the patient is pantographed while under the influence of medication (Valium). 4. The angulation of the body does not appear to be significant for reproducing border tracings. 5. There appears to be no significant difference in the reproducibility of the border tracings relative to time (1, 1 1/2, 2, and 2 1/2 hours) after medication. 6. The lateral side shift of the jaw cannot always be reproduced accurately. 7. The neuromusculature appears to be the overriding factor governing border movements.
The athymic nude mouse is a useful animal model for assaying the neoplastic growth potential in vivo of animal cells transformed in vitro. Despite the demonstrated absence of thymus-dependent immunological functions, however, the nude mouse has now been shown to reject transplants of certain highly malignant heterologous tumors. In addition, a few transformed mammalian cell lines that exhibit all or most of the cellular phenotypes usually associated with malignancy fail to grow as tumors when injected into nude mice. In a continuing study to identify the in vitro phenotypes associated with tumor-forming ability in vivo, we investigated the role of cellular susceptibility to the naturally occurring, thymus-independent lymphocytes (natural killer or NK cells) in determining tumor induction by animal cells in nude mice. A representative collection of animal cells (ranging from normal human diploid cell strains to highly tumorigenic clonal cell lines, either transformed in vitro or derived from experimental tumors) was tested to see if the ability of cells to form tumors is consistently correlated with their susceptibility to NK cell-mediated lysis measured in vitro with splenic leukocytes from nude mice. If the physiological role of the NK cells in vivo were to recognize, and possibly to destroy, incipient tumor cells in situ, a direct association between cellular tumorigenicity and susceptibility to NK activity, might be expected. If, on the other hand, the formation of growing tumors by animal cells in nude mice depended on their ability to escape the cytolytic activity of NK cells, cellular tumorigenicity would be associated with cellular resistance to NK cells. Results obtained in this study failed to confirm either of these associations. Thus, cellular suscepbibility to NK cells, at least as determined by direct cytotoxicity assay in vitro, is not a useful predictive indicator of cellular tumorigenicity in nude mice.
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A study has been made of the steady-state fluxes of barbituric acid, six of its substituted derivatives, and 5,5-dimethyloxazolidinedione (DMO) across the wall of rat jejunum in vitro. For each of the compounds tested the mucosal (M) to serosal (S) flux was significantly larger than the S to M flux. Both M to S and S to M fluxes increased linearly with concentration, and the transport of one acid was not influenced by the presence of a tenfold greater concentration of a second heterocyclic acid. The fluxes decreased as the pH of the incubation saline was increased, but neither the M to S, nor the S to M fluxes could be described in terms of simple nonionic diffusion. It was found that the relation between the flux ratios of the transported acids and their pKalpha values could be described by an equation derived from consideration of the transport of a weak acid in a series three compartment system, and it has been concluded that the three compartment system provides a good working hypothesis for the mechanism of heterocyclic acid transport across rat jejunum. It was found that the best fit of the theoretical curve to the experimental data was obtained when the ratio of permeabilities to the ionized and nonionized forms of a weak acid at one of the barriers was assigned the value 5 X 10(-1). It is suggested that this value may be characteristic of a noncellular restriction to diffusion, such as a layer of connective tissue, and substantiates previous suggestions that the intermediate compartment of the intestinal three compartment system is a component of the sub-epithelial extracellular space.
Plasma zinc, copper, and amino acid levels have been measured in a group of autistic children. All three variables were found to be normal. These findings are in disagreement with the previously reported results of some other workers but if confirmed would indicate that autism cannot simply be attributed to a disorder of zinc metabolism.
Comatose patients may develop a neuropathologic chewing reflex that results in self-inflicted oral trauma. Loss of coordination between the tongue and chewing cycle leads to maceration of the tongue and infection. The use of a tongue-depressing stent can keep the tongue from acting as a bolus and prevent perpetuation of the reflex chewing cycle and resultant self-injury.
The determinants of weak electrolyte influx into everted segments of rat small intestine have been studied. Preliminary experiments showed that the observed influxes could be described as unidirectional, diffusional fluxes of the nonionized compound uncomplicated by a parallel ionic component. It is shown that the determinants of weak electrolyte influx in this situation may be described in terms of the resistance of the unstirred layer to movement from the bulk phase to the cell surface, the degree of ionization of the weak electrolyte at the cell surface, and the cellular permeability to the nonionized weak electrolyte. Quantitative considerations indicated that the unstirred layer was totally rate-limiting in the cases of some poorly ionized, or highly permeant compounds, but the unstirred layer was not totally rate limiting for most of the compounds studied. Calculation of cellular permeabilities for the nonionized forms of weak electrolytes required assumptions to be made concerning the pH value in the surface fluid layer. A uniform set of permeability data including both weak acids and weak bases was obtained only when it was assumed that the pH in the surface fluid layer was equal to that in the bulk phase, and it was concluded that these studies do not support the concept of a microclimate of distinctive pH at the epithelial surface as a determinant of weak electrolyte transport.
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The oxygen consumption of rat small intestine in vitro is influenced by the anions, chloride and bicarbonate, as well as by sodium.
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1. A study has been made of factors influencing release of amylase from dispersed pancreatic acinar cells. 2. In the basal, unstimulated, condition cells released 2-3% of the total amylase present in 30 min. 3. The rate of amylase release was stimulated 50-70% by C-terminal octapeptide of cholecystokinin (CCK-OP, maximally effective concentration, 3 X 10(-10) M); carbamylcholine (maximally effective concentration, 10(-5 M); secretin (maximally effective concentration greater than 10(-6) M); vasoactive intestinal peptide (VIP, maximally effective concentration, 10(-8) M); and adenosine 3':5' monophosphate (cyclic AMP) and guanosine 3':5' monophosphate (cyclic GMP) as well as their dibutyryl derivatives (maximally effective concentrations, 10(-3) M). 4. The responses to CCK-OP or carbamylcholine were potentiated by secretin, VIP or dibutyryl cyclic AMP. 5. The responses to secretin or VIP were potentiated by CCK-OP, carbamylcholine, or dibutyryl cyclic GMP. 6. There appear to be two pathways for the regulation of amylase release from pancreatic acinar cells: one pathway can be stimulated by cholecystokinin or cholinergic agonists, and the response to these stimuli is mediated by cyclic GMP; the other pathway can be stimulated by secretin or VIP, and the response to these stimuli is mediated by cyclic AMP.
A 25-year-old patient with acrodermatitis enteropathica who had been treated with di-iodohydroxyquinoline for 20 years was changed to zinc sulphate therapy and studied under full metabolic balance control for zinc, calcium, magnesium, and inorganic phosphorus. The results obtained indicate that there is only a small overall deficit of body zinc stores in this disease and that the function of di-iodohydroxyquinoline is to increase the amount of zinc absorbed and retained by the body.
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The jejunal and ileal regions of rat small intestine in vitro exhibit different patterns of weak-electrolyte transport and acid-base metabolism. The jejunal pattern of weak-electrolyte transport is net transport of weak acids M yields S and of weak bases S yields M (M, mucosal; S, serosal), and the pattern of acid-base metabolism is luminal acidification and serosal alkalinization. In the absence of sodium or in the presence of metabolic inhibitors, weak-electrolyte transport and serosal alkalinization are inhibited, but luminal acidification is not inhibited. The ileal pattern of weak-electrolyte transport is the opposite of that of the jejunum and may be associated with the presence of a luminal alkalinization process observed in this region. In the absence of chloride the ileal patterns of weak-electrolyte transport and acid-base metabolism become similar to those of the jejunum. It is suggested that these observations support a previously proposed model for weak-electrolyte transport in the intestine consisting of a series three-compartment system in which the pH of the intermediate compartment is greater than that of the bulk phases.