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Biomedical subjects

J E Walker

Publications and source records attributed to J E Walker.

18 recordsLinked to original sources
PubMed1979

Lorazepam in status epilepticus.

Lorazepam, a dichloro-3-hydroxy-1,4-benzodiazepine, has been shown to be a potent anticonvulsant in animal models of epilsepsy and has minimal depressant effects on respiration and circulation in humans. The effects of this compound were studied in status epilepticus. Twenty-five patients were given intravenous lorazepam during status epilepticus of varying cause. Four or 8 mg of the drug controlled status in 22 of the 25 patients. Although single seizures recurred in 5 of the 22 patients, none experienced recurrence of status during a prolonged follow-up period. Transient respiratory arrest occurred in 1 patient, but no other significant complications were observed. Studies of plasma drug levels suggest that most patients attain good seizure control at concentrations between 30 and 100 ng per milliliter. Clinical observations indicate that repetitive injections are not required for continuing control of seizures in patients whose seizures are initially controlled. Lorazepam appears to be an effective and safe drug for treatment of status epilepticus, with a duration of control longer than that achieved with diazepam.

Adolescent↗
PubMed1979

Chasing Crohn's.

The importance of Crohn's disease in oral pathology is briefly discussed. A series of experiments using immunofluorescent tracing techniques is described which culminates in the identification of a Crohn's-specific circulating antibody which reacts with autologous oral mucosa in vitro. It is suggested that this forms the basis of a diagnostic test.

Adult↗
PubMed1979

Lymphoblastic transformation in response to viral antigens in multiple sclerosis.

The blastogenic response of lymphocytes to pokeweed mitogen and a battery of viral antigens was studied in healthy individuals, patients with multiple sclerosis (MS), and patients with other neurologic disorders. The multiple sclerosis patients exhibited a diminished response to pokeweed mitogen and to mumps, parainfluenza, and poliomyelitis I antigens when compared with healthy individuals. However, there was no significant difference between the multiple sclerosis patients and the neurologic control group, except that the MS patients had a better response to measles antigen. The three groups did not differ with regard to herpes antigen. Blocking factors were found in the autologous plasma of all three groups with approximately equal frequency, but were not responsible for the decreased responses noted. A significant inverse correlation was found between disease severity and the blastogenic response to pokeweed mitogen and herpes, parainfluenza, and measles antigens. These findings indicate that the decreased cell-mediated immune response in some MS patients is not specific for any of the viruses tested, and is probably a nonspecific effect of chronic disease. Patients with the relapsing-remitting form of the disease had a higher response to measles antigen and a lower response to pokeweed mitogen than patients with the chronic progressive form of the disease, suggesting that these variants differ immunologically as well as clinically.

Adult↗
PubMed1978

Possible diagnostic test for Crohn's disease by use of buccal mucosa.

Immunofluorescent tracing was used on buccal mucosa from patients with Crohn's disease to investigate some of its immunological characteristics, and to compare these with those of mucosa from controls. Normal buccal mucosa from patients with Crohn's disease, incubated with its own serum then stained for deposited antibody by the fluorescent technique, showed a positive reaction, not observed in buccal mucosa from normal persons or patients with ulcerative colitis. These observations could provide the basis of a diagnostic test.

Adult↗
PubMed1978

Serum albumin domain secondary structure prediction.

A new method has been used to predict probability profiles for helix, beta-sheet and bend structures along the entire sequence and derive an averaged profile for the three homologous domains. The results are correlated with the disulphide bridge pattern, the distribution of hydrophobic sites and points where albumin is cleaved by enzymes.

Amino Acid Sequence↗
PubMed1978

Uptake and release of norepinephrine by slices of rat cerebral cortex: effect of agents that increase cyclic AMP levels.

Cerebral cortical slices from rats were incubated in physiologic saline, and the uptake, release, and K+-stimulated release of norepinephrine were measured. Dibutyryl cyclic AMP, the phosphodiesterase inhibitors aminophylline and papaverine, and adenosine (which stimulates adenyl cyclase) all caused a variable increase in uptake of norepinephrine at concentrations ranging from 10(-7) to 10(-4) M. Prostaglandins E1 and E2 appeared to have no effect on uptake, but this may be because the alcohol required to dissolve them had an inhibitory effect on uptake. None of these compounds appeared to affect basal or K+-stimulated release of norepinephrine. These agents therefore seem to have an effect opposite to that of the tricyclic antidepressants (which inhibit uptake of norepinephrine). Since norepinephrine's postsynaptic effects are usually inhibitory in the cortex, the stimulatory effect of the drugs tested on the presynaptic uptake of norepinephrine may explain the stimulant and epileptogenic effects of these drugs.

Adenosine↗
PubMed1977

Sequence and structure of D-glyceraldehyde 3-phosphate dehydrogenase from Bacillus stearothermophilus.

The glyceraldehyde 3-phosphate dehydogenase holoenzyme of Bacillus stearothermophilus possesses precise 222 symmetry: in this respect it differs from the reported structure of the lobster muscle enzyme. Pairs of active sites are linked through a flexible polypeptide loop which probably mediates the structural changes giving rise to cooperative effects. Three additional salt bridges made by each subunit to others would make a major contribution to thermostability of the tetramer.

Allosteric Regulation↗
PubMed1977

Postoperative jaw pain--floctafenine versus dihydrocodeine.

A double-blind single dose trial was made of floctafenine 200 mg versus dihydrocodeine 30 mg in 100 patients complaining of jaw pain following oral surgery under general anaesthesia. There was no statistical difference between the two analgesics for the whole group, but dihydrocodeine was better for the relief of more severe pain.

Adolescent↗
PubMed1975

Tumor rejection in experimental animals treated with radioprotective thiols.

In experimental animals, a systemic treatment with thiols of the mercaptoalkylamine type has affected all of five solid tumors so far investigated. (Three of the tumors were transplanted into the strain of origin.) There was either inhibition of growth or "oncodieresis," i.e., a necrosis and sloughing of tumors conducive to full recovery and repair. Mercaptoalkylamines and derivatives of the type used in our experiments are known to bind to cellular sites by a two-point attachment involving both thiol and amino groups. One of these compounds, cysteamine, was active in its native, unsubstituted form, but did not bring about oncodieresis when either the amino or thiol group, or both, were alkylated. Mercaptopropylamine, the 3-carbon homolog of cysteamine, was less active. Cystamine, a disulfide dimer of cysteamine that has no free reactive sulfhydryl, did not induce any reaction. Thioglycerol, lacking a terminal amino group, had only negligible activity. Rejection was much more striking when treatment was started on the day of inoculation than when started 7 days later. Male mice rejected better than females. Results were inferior when tow of the agents were given simultaneously or together with other radioprotectants, such as L-cysteine, glutathione, dimethyl sulfoxide, or reserpine. Tumor rejection was enhanced when the phosphorylated thioyls, S-2-(3-aminopropylamino)ethylphosphorothioic acid or S-(2-ethylguanidine)phosphorothioci acid, were given simultaneously with the radioprotective serotonin, but there was no synergy of serotonin with the nonphosphorylated compounds S-2-aminoethylisothiouronium bromide or cysteamine. Serotonin alone did not affect the tumors.

Animals↗