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Biomedical subjects

I Miller

Publications and source records attributed to I Miller.

At least 91 records · Page 5Linked to original sources
PubMed1980

Calorimetric investigation of the complex phase behavior of glucocerebroside dispersions.

The thermotropic behavior of aqueous dispersions of glucocerebroside from Gaucher's spleen has been investigated by different scanning calorimetry. These results indicate that glucocerebroside undergoes two distinct phase transitions centered at 47 and 83 degrees C, respectively. The high-temperature transition is associated with the main gel-liquid crystalline transition and has an enthalpy change of 13.6 kcal/mol of lipid; this transition is not rapidly reversible and the liquid crystalline phase supercools to a metastable gel phase. The low-temperature transition is exothermic with an enthalpy change of -6.3 kcal/mol and involves a transformation of the metastable gel phase to a more highly ordered gel conformation, without involving changes in the conformational state of the hydrocarbon chains. The behavior of these transitions as a function of the amount of water suggests that the origin of the metastability is related to a hydration-dehydration process of the cerebroside molecule. Experiments with synthetic-D-erythro-N-palmitoylglucocerebroside revealed the same thermotropic behavior. These glucocerebroside transitions are irreversible and together define a unidirectional cycle in which each state of the molecule can only be reached by completing the entire cycle.

Calorimetry, Differential Scanning↗
PubMed1977

A comparison of osteotomy and joint replacement in the surgical treatment of the arthritic knee.

The relatively small numbers of knees compared in this study make it impossible to draw conclusions with great confidence. On the other hand we believe that the quality of our comparison has been improved by our effort to match the groups of knees under study. Our results lead to the controversial conclusion that, at least in RA and in elderly patients with OA, ICLH arthroplasty is preferable to osteotomy regardless of the pathology and preoperative deformity and that osteotomy should not be used as a temporizing procedure before ICLH arthroplasty. We are unable to say whether or not similar conclusions would apply to other forms of arthroplasty but we suspect that they would. Certainly joint replacement is now widely preferred to osteotomy at the hip and it is difficult to see why the knee should be different. It should not be concluded from these results that replacemnt is to be preferred to osteotomy for the mildly damaged knee. It does however appear that if osteotomy fails (for technical or other reasons), it may then be difficult to obtain a satisfactory result even by replacement. Thus if a patient with a mildly damaged knee is not to be disabled irreparably, it may be better to avoid osteotomy until the day comes when the causes of failure after this operation can be predicted preoperatively and prevented. The data presented here suggest (as do those in many other studies) that one step in this direction is to confine osteotomy to the varus OA knee. Even in this group the surgeon should, we believe, do his utmost to avoid surgery altogether until the parents' disability is unacceptable. In summary therefore, we now advance the view that if the arthritic knee is sufficiently disabling to require major surgery, it should be replaced. If the disability is less severe, the joint should be treated conservatively.

Adult↗
PubMed1977

A contemporary review of incidence and detection of enterotoxigenic E. coli strains in human diarrheal diseases.

Methodical possibilities for detection of enterotoxic strains of E. coli and the frequency of appearence of these strains in infants and adults suffering from diarrheal diseases are reviewed. Our own study, using the ligated rabbit intestinal loop, revealed 6.8% incidence of enterotoxin producing strains among the classical enteropathogenic serotypes of E. coli, isolated from stools of infants with mild diarrhoea. The model of mice intestinal loop was not found to be suitable for detection of enterotoxin of E. coli strains. The most sensitive model seems to be the intestine of precolostral piglet; however this model is not suitable for routine tests.

Acute Disease↗
PubMed1976

Release and elimination of 14C-fluphenazine enanthate and decanoate esters administered in sesame oil to dogs.

The rates of release of 14C-fluphenazine enanthate and 14C-fluphenazine decanoate were compared in two groups of five male dogs. Each dog was given a single dose (2 mg/kg im) of either the enanthate or decanoate ester in sesame oil. The times required to attain maximum concentrations of radioactivity in plasma were 3.8 +/- 0.5 days (+/-SE) for the enanthate ester and 10.6 +/- 1.1 days for the decanoate ester (p less than 0.001); maximum concentrations of radioactivity in the plasma at these times were 16.7 +/- 1.1 and 11.1 +/- 1.2 ng/ml, respectively (p less than 0.01). However, 35 days after dosing, the concentrations of radioactivity in plasma were greater for the decanoate ester than for the enanthate ester. The times required for 50% of the dose to be excreted in the urine and feces were 7.8 +/- 0.5 days for the enanthate ester and 22.6 +/- 4.4 days for the decanoate ester (p less than 0.05). The total amounts excreted in 35 days were 85.4 +/- 1.8 and 68.8 +/- 6.6% of the dose for the enanthate and decanoate esters, respectively; the average half-times for the rates of release of radioactivity from depot and body, as calculated from the data for total excretion, were 5.55 days for the enanthate ester and 15.4 days for the decanoate ester. Thirty-five days after dosing, the amount of the dose present in the injection site was 4.6 +/- 1.6% for the enanthate ester and 18.6 +/- 5.7% for the decanoate ester. Two groups of six dogs each were protected against the emetic effects of apomorphine more than twice as long by the decanoate ester than by the enanthate ester after the subcutaneous administration of single 8-mg/kg doses of either drug in sesame oil (p less than 0.05). Based on measurements of total radioactivity, it was concluded that the decanoate ester was released from the depot at less than one-half the rate of the enanthate ester.

Animals↗
PubMed1975

Lateral diffusion of cholesterol in monolayers.

The surface diffusion coefficient of cholesterol in cholesterol monolayers has been measured as a function of cholesterol surface concentration. Two different radiochemical methods, one integral and the other differential, were developed which gave comparable results. In the integral method two cholesterol monolayers, one of which is radioactive, are isolated on inert hydrophilic supports and then brought into contact. After some time the supports are separated and the radioactivity of the supports is measured. The differential method is an autoradiographic experiment. Two cholesterol monolayers, one of which is radioactive, are separated by means of a thin barrier. Upon removal of the barrier and at later times, an autoradiographic plate is brought to within a fraction of a mm from the aqueous surface and exposed. The plates are developed and analysed. The data show that the cholesterol surface diffusion coefficient in the dilute monolayers is approximately 10(-6)cm2/s and is nearly independent of surface concentration up to a concentration corresponding to an area of 40 A2/molecule. As the monolayer becomes compressed beyond this surface concentration, the diffusion coefficient decreases ubruptly with the deeply decreasing surface tension to about 10(-7) cm2/s, when a fully condensed surface layer of 38 A2/molecule is reached. This diffusion coefficient is of the same order of magnitude as the diffusion coefficients measured in lipid bilayers and in membranes.

Cholesterol↗
PubMed1975

The role of immune pig colostrum, serum and immunoglobulins IgG, IgM, and IgA, in local intestinal immunity against enterotoxic strain in Escherichia coli O55 in germfree piglets.

The protective effect of pig immune colostrum, serum and immunoglobulins IgG, IgM and IgA against the enterotoxic strain of Escherichia coli O55, was studied in newborn germfree piglets. This strain produced accumulation of fluid and dilatation of intestine when injected into the ligated ileal segment of germfree piglets, which is considered to be the typical effect of enterotoxins. Erosion of the intestinal epithelium and penetration of bacteria into the submucosa were also observed. Immune serum, colostrum and all the immunoglobulin classes used produced a local protective effect, IgA being most effective. The mechanism of protection conferred by these immunoglobulins is discussed with respect to the possible pathogenic action of enterotoxic Escherichia coli O55 in the intestinal tract of immunologically virgin germfree piglets.

Animals↗