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Biomedical subjects

M L Clark

Publications and source records attributed to M L Clark.

At least 109 records · Page 6Linked to original sources
PubMed1980

Comparison of the absorption of two protein hydrolysates and their effects on water and electrolyte movements in the human jejunum.

Because of the generally more rapid amino acid absorption and lower osmotic pressure of small peptides compared with free amino acids, it has been suggested that 'elemental' diets should contain both small peptides and free amino acids as the nitrogen source. While studying protein hydrolysates intended for use in such diets we observed surprising differences in the absorption of amino acids, water, and Na+ during jejunal perfusion of partial enzymic hydrolysates of two proteins (lactalbumin and fish) which contained high and approximately equal amounts of their constituent amino acids in the form of small peptides. Total alpha amino nitrogen (alpha NH2N) absorption from the lactalbumin hydrolysate was greater, and individual amino acid absorption more even, than from equinitrogenous solutions of the fish protein hydrolysate, or from mixture of free amino acids simulating either hydrolysate. Net water and Na+ absorption occurred during perfusion of the lactalbumin hydrolysate, whereas net water and Na+ secretion occurred during perfusion of the fish protein hydrolysate. These differences were significant (P < 0.05 or less). As the differences between the hydrolysates are so marked, we conclude that it is unwise to assume that all protein hydrolysates are equally suitable for use in patients.

Adult↗
PubMed1980

Self-induced water intoxication in schizophrenic patients.

The authors report on 21 cases of self-induced water intoxication and cite 25 others in the literature. Three of their patients demonstrated at least temporary inappropriate antidiuretic hormone secretion, 3 were receiving a diuretic, and the other 15 appeared to have "pure" water intoxication. Fifteen patients were receiving a psychotropic medication. Self-induced water intoxication appears to be more common in schizophrenic patients than is generally realized and should be suspected in any schizophrenic patient who develops convulsions or coma. Hyperdopaminergic CNS activity may be involved, and the authors suggest a possible mechanism similar to that for tardive dyskinesia.

Adult↗
PubMed1979

Retrograde spread of hydrocortisone containing foam given intrarectally in ulcerative colitis.

A method is described of estimating retrograde spread through the colon of a 10% hydrocortisone acetate foam by labelling the foam with technetium-99m sulphur colloid and observing spread after intrarectal administration by serial gamma-camera pictures. The recommended 51 ml dose of foam reached the mid-sigmoid colon in all of the nine patients who had active ulcerative colitis. Furthermore, in seven the foam reached the proximal sigmoid colon. Foam spread less extensively in five patients with quiescent disease than in those with active disease. Increasing the volume of enema to 50 ml did not improve retrograde spread through the colon. These results suggest that 10% hydrocortisone foam may be useful in treating patients with distal ulcerative colitis that is not necessarily limited to the rectum.

Administration, Topical↗
PubMed1979

Effect of enzymes on rotavirus infectivity.

The infectivity of a bovine rotavirus was enhanced 140-, 8-, and 3-fold, respectively, by trypsin, protease, and lactase. Ficin, carboxypeptidases A and B, lysozyme, and beta-galactosidase had little effect on the infectivity. Chymotrypsin caused a threefold decrease in the infectivity. Trypsin acts directly on the rotavirus and not on the host cell.

Animals↗
PubMed1978

Quantitative determination of amitriptyline in blood.

An assay was developed and standardized for amitriptyline and its hydroxylated tertiary amine metabolites in blood and other biological tissues. This method is capable of determining 5--15 ng of these compounds/ml and is based on reacting the drug as base with 9-bromomethylacridine to form a quaternary product which, on photolysis, yields fluorescence in a stoichiometric fashion. The precision of the method is usually around +/-5%.

Amitriptyline↗
PubMed1978

Absorption of glucose and maltose in congenital glucose-galactose malabsorption.

An intestinal perfusion technique has been used to study absorption of glucose from free glucose and the disacchairde maltose in a patient with congenital glucose-galactose malabsorption. Minimal absorption of glucose occurred from high luminal concentrations of either free glucose (100 mmole/liter) or maltose (50 mmole/liter). Glucose diffused into the intestinal lumen during perfusion of a 2 mmole/liter glucose solution. These observations offer no support for nutritionally important glucose absorption in congenital glucose-galactose malabsorption by either passive diffusion or via a "disaccharidase-related" transport system.

Biological Transport↗
PubMed1977

Effect of glycylglycine on absorption from human jejunum of an amino acid mixture simulating casein and a partial enzymic hydrolysate of casein containing small peptides.

1. A jejunal perfusion technique has been used in normal volunteer subjects to study jejunal absorption of amino acid residues from a partial enzymic hydrolysate of casein in which about 50% of the amino acids existed as small peptides, and also from an equivalent mixture of free amino acids. 2. The effect of a high concentration of the dipeptide glycylglycine on the absorption of amino acid residues from these preparations was studied to quantify the importance of mucosal uptake of intact peptides during absorption of the partial hydrolysate of casein. 3. The results were unexpected. Glycylglycine significantly inhibited absorption of several amino acid residues (aspartic acid + asparagine, serine, glutamic acid + glutamine, proline, alanine, phenylalanine, threonine and isoleucine) from the free amino acid mixture, whereas it significantly inhibited the absorption of only two (serine, glutamin acid + glutamine) from the peptide-containing partial casein hydrolysate. 4. The effect of glycylglycine on absorption of amino acids from the mixture of free amino acids was apparently due to inhibition of amino acid uptake by free glycine liberated from the dipeptide during perfusion. The reason for the failure of glycylglycine to cause extensive inhibition of absorption from the partial hydrolysate is not clear. It may be due to glycylglycine being only a weak inhibitor of peptide uptake, but the possibility that some peptides are taken up by a system unavailable to glycylglycine has to be considered.

Adult↗
PubMed1977

Effect of sodium chenodeoxycholate on oxalate absorption from the excluded human colon--a mechanism for 'enteric' hyperoxaluria.

A perfusion technique has been used to study the effect of sodium chenodeoxycholate (5 mmol 1-1) on absorption of oxalate (2 mmol 1-1) from the surgically excluded colon in two patients with chronic liver disease. Colonic absorption of oxalate increased at least fivefold when sodium chenodeoxycholate was incorporated in the perfusion solutions. This observation may explain enteric hyperoxaluria after ileal resection and in some other gastrointestinal disorders.

Adult↗
PubMed1977

Evaluation of two dose levels of loxapine succinate in chronic schizophrenia.

In a double-blind, placebo controlled design in chronic schizophrenic inpatients using 50 mg. and 100 mg. LOX, an attempt was made to replicate the findings of a previous study and to establish the dose-level and duration of treatment optimal for this kind of patient. Multiple regression analysis adjusting for dose, age, duration of illness, and baseline values indicated that 100 mg. LOX was an effective dose as previously shown. In contrast to the previous study, significant response effects were found by the 4th week. In addition, the dose was linearly related to response on nearly all the variables. The principal side effects were drowsiness and extrapyramidal signs.

Adult↗
PubMed1977

Butaclamol in newly admitted chronic schizophrenic patients: a modified fixed-dose dose-range design.

In a double-blind placebo controlled study of newly admitted chronic schizophrenics, an attempt was made to further evaluate the safety, acceptability, and effectiveness of BT in doses of 10, 20, and 40 mg. Significant dose related responses occurred on several behavioral variables by the first week of treatment. Maximum clinical response appeared to be at the 20-40 mg. dose level. Extrapyramidal signs occurred at all doses, but with greater severity at higher doses. Excessive daytime drowsiness occurred in all groups but with longer duration and greater intensity in the 20 mg. group. Rebound insomnia occurred after the abrupt withdrawal of BT at all dose levels suggesting the desirability of further study of its hypnotic properties.

Adolescent↗