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Biomedical subjects

D Adams

Publications and source records attributed to D Adams.

At least 235 records · Page 13Linked to original sources

Uptake and subcellular compartmentation of gibberellin a(1) applied to leaves of barley and cowpea.

The uptake and subcellular accumulation of gibberellin A(1) (GA(1)) by leaves and protoplasts of barley (cv. Numar) and cowpea (cv. Blackeye pea No. 5) were investigated.Uptake of GA(1) by cowpea leaves is optimal at pH 5.8 and occurs by a saturable, probably carrier-mediated process having a half-maximal velocity at 10 to 20 micromolar. Uptake by both barley and cowpea leaves is inhibited by low temperature (+4 C) and the metabolic inhibitors 2,4-dinitrophenol and azide and is stimulated by ATP. Mesophyll protoplasts isolated from leaves fed radioactive GA(1) retain 20 to 80% of the radioactivity incorporated by excised leaves.The subcellular localization of the [(3)H]GA was determined by lysing protoplasts and separating subcellular organelles by density gradient centrifugation. Less than 5% of the incorporated [(3)H]GA was found associated with chloroplasts, mitochondria, nuclei, or other organelles or membranes with densities in sucrose gradients greater than 1.15 grams per cubic centimeter. Fifty to 100% of the [(3)H]GA was found in vacuoles. Isolated vacuoles were judged to be free of contamination by cytoplasm using phosphoenolpyruvate carboxylase as a marker enzyme. Osmotic breakage of vacuoles or protoplasts released > 95% of the [(3)H]GA, suggesting that GA is associated with the vacuolar sap rather than with the tonoplast membrane.

Journal Article↗

Viral antibody titres in HBs antigen-positive and -negative chronic active hepatitis.

A comparative study of antibody titres to nine common viruses has been carried out in hepatitis B surface (HBs) antigen-positive and -negative chronic active liver disease. The results show that increased titres of antibody to morbilli virus by complement fixation and to rubella by haemagglutination inhibition are found in HBs antigen-negative but not in HBs antigen-positive chronic active liver disease. There was a significant association of increased morbilli but not of rubella virus antibody titres with the presence of high-titre nuclear antibodies (ANA) but no association with smooth-muscle antibody or the presence of HLA-B8.

Adolescent↗

The impact of psychiatric intervention on patients with uncontrolled seizures.

There is much evidence that emotional stess can trigger both neurogenic and hysterical seizures in susceptible patients. We reviewed out experience with 37 patients whose seizures appeared to be precipitated at times by emotional stress and had not been controlled by anticonvulsant medication alone. Approximately 70 per cent of patients demonstrated substantial improvement in seizure control after psychiatric treatment and maintained this improvement during follow-up. The findings of this study suggest that patient characteristics associated with better prognosis include normal intelligence, partial (as opposed to generalized) neurogenic seizures, a diagnosis of hysterical seizures, a less severely abnormal EEG, and being hypnotizable. After psychiatric treatment, 32 per cent of patients had their anticonvulsant medication reduced and another 16 per cent had it discontinued.

Adolescent↗

HLA antigens in chronic relapsing idiopathic inflammatory polyneuropathy.

Observations are reported on 14 patients with a clinical diagnosis of recurrent or chronic relapsing idiopathic inflammatory polyneuropathy of Guillain-Barré type. The results suggest the possibility of a disease susceptibility gene for this disorder associated with the HLA-A1, -B8, -DRw3, and -Dw3 haplotype.

Chronic Disease↗

Carbon fiber-reinforced carbon as a potential implant material.

A carbon fiber-reinforced carbon is being evaluated as a promising implant material. In a unidirectional composite, high strengths (1200 MN/m2 longitudinal flexural strength) and high modulus (140 GN/m2 flexural modulus) may be obtained with an interlaminar shear strength of 18 MN/m2. Alternatively, layers of fibers may be laid in two directions to give more isotopic properties. The compatibility of the material with bone has been studied by implanting specimens in holes drilled in rat femora. For a period of up to 8 weeks, a thin layer of fibrous tissue bridged the gap between bone and implant; but this tissue mineralizes and by 10 weeks, bone can be observed adjacent to the implant, giving firm fixation. Potential applications include endosseous dental implants where a greater strength in the neck than that provided by unreinforced carbon would be advantageous.

Animals↗

Nitrous oxide pollution levels in oral surgery offices.

Nitrous oxide pollutant levels, surveyed in oral surgery offices in Southern California, were lower than previously reported. These evaluations were related to rebreathed gas samples obtained from the operator and assistants, and appear to correlate well with exposure to nitrous oxide contamination. The lower levels in the hallway were tenfold less than those previously reported. Better air-conditioning in these offices and better airway control could be responsible, in part, for the difference.

Air Pollutants↗

A histochemical method for the detection of metals in tissues, with reference to the use of surgical implants.

This report describes a method for the detection of metals in tissues that is suitable for a routine pathology laboratory. The method has been developed specifically for the examination of soft tissues taken at biopsy from the site of surgical implants. It involves the mineralization of organic matter in sections by sodium metasilicate and the conversion of the metals to sulphates by sulphuric acid, which are then stained by appropriate solutions. The method is described with particular reference to titanium and cobalt.

Animals↗

[Experimental reproduction of a secondary pacemaker center for alimentary motivation].

In chronic experiments on rabbits the possibility of artificial modeling of motivational feeding pacemaker's function by different limbic-reticular structures was investigated. It was shown that simultaneous stimulation of the lateral hypothalamic "feeding" centre with various structures of the limbic-reticular complex makes secondary pacemaker of feeding motivation in the midbrain reticular formation only.

Animals↗

Aseptic osteomyelitis and necrosis of the mandibular condylar head after intracapsular fracture.

Aseptic osteomyelitis and necrosis of the mandibular condylar head is a rare complication which may occur several months after an untreated intracapsular fracture. Clinical symptoms are pain in the temporomandibular joint on the affected side and limitation of opening of the mouth. Radiographically, the condylar head is characteristically eroded and irregular. Treatment consists of surgical removal of the necrotic condylar head and débridement of the area, which are performed via a preauricular approach.

Adult↗