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Biomedical subjects

G F Johnson

Publications and source records attributed to G F Johnson.

At least 73 records · Page 4Linked to original sources
PubMed1983

Craniofacial malformation among endemic cretins in Ecuador.

Nearly 6% of the inhabitants of two villages in Ecuador are deaf-mute and mentally retarded cretins. These communities are situated in the Andean highlands where environmental and dietary stores of iodine are extremely scarce. Endemic goiter and cretinism are widespread, and 10% of the cretins are additionally burdened with dwarfism and facial dysmorphia. Those with obvious involvement of the skeletal system were selected in order to study the extent of craniofacial malformation. Their appearance is characterized by midface hypoplasia, a broad nose with a depressed bridge, and a conspicuous circumoral prominence. Radiographic evaluation demonstrates a vertical displacement of the cranial base with an associated upward tilt of the midface. The flattened frontal bone, reduced frontal sinus pneumatization, and diminutive nasal bones collectively create a backward sloping face. The defect in the craniofacial skeleton of these Ecuadorian cretins is characteristic, and it readily sets them apart from the dysmorphism of those cretins with myxedema.

Adolescent↗
PubMed1982

Acceleration of the body clearance of phenobarbital by oral activated charcoal.

We investigated the effect of multiple oral doses of activated charcoal on the pharmacokinetics of intravenously administered phenobarbital in a randomized crossover trial. Six healthy men volunteered to take 200 mg of phenobarbital sodium per 70 kg of body weight intravenously on two separate occasions. On one occasion, each subject received oral activated charcoal (180 g) in divided doses over three days after the infusion of phenobarbital. Serum levels of phenobarbital were measured in all subjects up to 96 hours after the infusion, and urinary excretion of phenobarbital was measured in two subjects 24 to 96 hours after the infusion. A pharmacokinetic analysis showed that the charcoal decreased the serum half-life of phenobarbital form 110 +/- 8 to 45 +/- 6 hours (S.E.M.) (P less than 0.01), increased the total body clearance of phenobarbital from 4.4 +/- 0.2 to 12.0 +/- 1.6 ml per kilogram per hour (P less than 0.01), and increased the nonrenal clearance from 52 to 80 per cent of the total body clearance. We conclude that oral administration of activated charcoal enhances the nonrenal clearance of phenobarbital.

Administration, Oral↗
PubMed1982

Chronic active hepatitis in Doberman pinschers.

Eleven Doberman Pinschers were affected with a disease that had clinical signs, serum biochemical abnormalities, and histologic features of chronic active hepatitis. Intrahepatic cholestasis and accumulations excess hepatic copper were prominent features. Most of the dogs deteriorated within weeks to months, and 6 died within 9 months after the 1st signs of disease were noticed.

Animals↗
PubMed1982

Syndactyly type V.

We report a mother and three of her four children with type V syndactyly. All the patients had metacarpal 4-5 fusion. The other hand anomalies consisted of abnormal origin of the fifth fingers, anomalies of digits 4 and 5, brachydactyly, syndactyly, camptodactyly, absent distal interphalangeal creases, and unusual palmar dermatoglyphics. Anomalies of the feet consisted of varus deviation of the metatarsals, valgus deviation of the toes, hyperplasia of the first ray, and hypoplasia of the third to fifth rays. None of the patients had metatarsal fusions. The anomalies were similar in the mother and her two older sons far less severe in her daughter. This daughter also had a congenital anomaly of the urinary tract. Anomalous and/or defective muscle and tendon insertions were demonstrated in one patient during an operation. Syndactyly V is transmitted as an autosomal dominant trait.

Abnormalities, Multiple↗
PubMed1982

Pharmacokinetics of standard (lithicarb) and sustained-release (Priadel) lithium carbonate preparations in patients.

Equivalent oral dosages (800 mg, 21.6 mmol) of a standard (Lithicarb) and a sustained-release (Priadel) lithium carbonate preparation were administered to six patients receiving lithium maintenance treatment using a randomized cross-over design. There were no significant differences in the two preparations for 24 hour plasma level curves, 24 hour bioavailability, peak plasma concentrations (Cmax), time to peak plasma concentrations (Tmax) or urinary excretion rates. These results are in agreement with a previous study using Priadel in healthy volunteers, and indicate that Priadel is a delayed-release, rather than a true sustained-release preparation. In order to maintain therapeutic plasma levels and to minimise adverse effects that may occur with high plasma lithium levels, Priadel needs to be administered in divided dosages rather than as a single daily dose.

Administration, Oral↗
PubMed1982

An enzymic, reaction-rate assay for serum creatinine with a centrifugal analyzer.

We describe a procedure for specific, rapid, kinetic determination of creatinine, in which a manual coupled-enzyme micro-scale assay is adapted to a centrifugal analyzer. The creatinine reaction is ultimately linked to NADH utilization, which is measured by the absorbance change at 340 nm. This procedure requires 15 microL of serum and the standard curve is linear to a creatinine concentration of 200 mg/L. A four-point kinetic algorithm allows the dynamic range of the assay to be extended without sacrificing sensitivity, and makes a separate serum blank unnecessary. The within-run precision (CV) for samples with a creatinine concentration of 11 and 52 mg/L was 5.6 and 2.4%, respectively; day-to-day CV for a creatinine concentration of 11 mg/L was 7.7% (n = 21). We compared this procedure with a kinetic Jaffé procedure, with excellent agreement (r = 0.996; y = 0.96x + 2.4 mg/L). Bilirubin, non-esterified fatty acids, and ketone bodies do not affect creatinine determinations by this method; thus the method is especially useful for monitoring the renal function of diabetics.

Creatinine↗
PubMed1982

Single-stage automated assay for heparin.

We have developed a single-stage assay for heparin, using reagents modified from the two-stage Dade Protopath heparin synthetic substrate assay. The single-stage assay involves simultaneous mixing of a plasma sample, an antithrombin III source, alpha-thrombin, and the alpha-thrombin fluorogenic substrate. The synthetic substrate, antithrombin III, and heparin-antithrombin III complex compete for the alpha-thrombin active site. The alpha-thrombin is inactivated by the heparin-antithrombin complex while substrate is being hydrolyzed, so that total product formation decreases with heparin concentration. Day-to-day CV was 9.3% at a heparin concentration of 246 USP units/L. Comparison of results of the single-stage heparin assay with those of a two-stage esterolytic assay yielded the linear regression equation: esterolytic = 0.834 (single-stage)--7 USP units/L (r = 0.94, n = 47). Bilirubin interfered with the single-stage assay, resulting in an apparent increase in sample heparin concentration. The single-stage heparin assay can be automated for centrifugal analyzers capable of double-reagent addition and fluorometric detection, substantially decreasing reagent requirements and therefore costs.

Centrifugation↗
PubMed1981

The tetracyclic antidepressant mianserin: evaluation of its blockade of presynaptic alpha-adrenoceptors in a self-stimulation model using clonidine.

It has been suggested that the tetracyclic antidepressant mianserin may be an antagonist at inhibitory presynaptic alpha-adrenoceptors. If mianserin exerted a selective antagonist effect it should produce effects that are essentially opposite to those of a selective agonist such as clonidine. This hypothesis was investigated in a shuttle-box self-stimulation model previously shown to be sensitive to alpha-adrenergic drugs. In this model a presynaptic alpha-adrenoceptor antagonist would be expected to enhance self-stimulation and to reverse the inhibitory effects of clonidine. Mianserin (2.5-4.0 mg/kg) did not enhance self-stimulation, but instead produced a selective inhibition of reward. Further, mianserin did not reverse the inhibitory effects of clonidine on self-stimulation. These data suggest that if mianserin is an antagonist of the presynaptic alpha-adrenoceptors it is not a selective antagonist. It is possible that the presynaptic alpha-adrenoceptor antagonism may be effects on postsynaptic alpha-adrenoceptors and/or on a presynaptic noradrenaline reuptake mechanism.

Adrenergic alpha-Antagonists↗
PubMed1981

The Gordon syndrome: autosomal dominant cleft palate, camptodactyly, and club feet.

The triad of a camptodactyly, club feet, and cleft palate, called the Gordon syndrome, is a rare autosomal dominant trait with variable expressivity, known from only three previously described families. Here we report the condition in a mother and her daughter. They also had several previously undescribed anomalies, which suggests that the Gordon syndrome is a more complex malformation syndrome than previously suspected.

Abnormalities, Multiple↗
PubMed1981

A linkage study of manic-depressive disorder with HLA antigens, blood groups, serum proteins and red cell enzymes.

Families with a two-generational history of affective disorder and well and ill sibs were selected from a population of bipolar manic-depressive patients and typed for HLA antigens, blood groups, serum proteins and red cell enzymes. Segregation of specific HLA alleles was not associated with affective illness across family pedigrees. Further, no significant associations were found between affective disorder and ABO, Rh, MNSs blood groups or Hp, EsD, C3, Gc or PGM. Using the lod score method of Morton (1955) for determining linkage, these data indicated that close linkage is unlikely for affective disorder and HLA alleles, haptoglobin, Rh factor, or ABO blood groups.

Adolescent↗
PubMed1981

Canine hepatocellular carcinoma.

In a study of 110 primary hepatic neoplasms in dogs, 55 hepatocellular carcinomas and two combined hepatocellular and cholangiocarcinomas were diagnosed. These neoplasms were classified into the following 11 groups based on histo-architectural pattern: trabecular, peliod, cobblestone, peritheliomatous, anaplastic, pseudoglandular, pleomorphic, scirrhous, clear cell, solid, and combined hepatocellular and cholangiocarcinoma. The neoplastic hepatocytes varied from almost normal to highly anaplastic spindle cells. Pleomorphic and giant cells were common in some groups, rare or absent in others. Metastasis was found in 61% (35 of 57), in contrast to a much higher percent in man, indicating the possibility of a different pathogenesis in the dog.

Adenoma, Bile Duct↗