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Biomedical subjects

A M Jones

Publications and source records attributed to A M Jones.

At least 163 records · Page 9Linked to original sources
PubMed1989

Domain structure of phytochrome from Avena sativa visualized by electron microscopy.

Highly purified phytochrome from Avena sativa was visualized by electron microscopy after negative staining with uranyl acetate and after rotary shadowing with platinum. The particle shape was variable in both types of specimens, but tripartite structures resembling a 'Y' were consistently observed. The tripartite substructure is composed of three globular domains each having a diameter of 7 to 8 nm and equally spaced in an equilateral triangle. The dimensions of the tripartite particle measured 15 nm between the centers of any two of the three particles. When phytochrome was digested with trypsin in a manner which releases the amino-terminal globular domain from the polypeptide, the tripartite structure was lost and only small globular particles were seen. We propose that the outer particles of this tripartite structure are the amino-terminal domains of the phytochrome dimer, and the central particle comprises the carboxyl domains of the two subunits.

Edible Grain↗
PubMed1989

Practical aspects of establishing a neurosonology laboratory.

The utilization of noninvasive ultrasound techniques to evaluate adult and pediatric patients has become widely accepted in the neurology practice. As utilization increases, however, the need for standardization and technical competence becomes increasingly important. Although efforts to standardize interpretation criteria and technique are currently being addressed on a national basis, day to day operation of the neurosonology laboratory has received little notice. Although specific operational principles will vary according to the scope of the laboratory (neurovascular, pediatric or neuromuscular), several factors are fundamental to the operation of a neurosonology service. After the scope is outlined, personnel requirements, appropriate instrumentation and laboratory space can be appropriately chosen. Once operational, efforts to institute quality control and continuing education requirements must be addressed. Finally, current standards for voluntary certification of technologists and physicians will be reviewed.

Allied Health Personnel↗
PubMed1989

Decay rates of human remains in an arid environment.

The environment of southern Arizona with mild winters and hot, dry summers produces great variability in decay rates of human remains. Summer temperatures, which range well over 38 degrees C (100 degrees F), induce rapid bloating as a result of the accumulation of decompositional gases. However, in certain circumstances, the aridity can lead to extensive mummification, allowing preservation of remains for hundreds of years. A retrospective study of 189 cases, concentrating on remains found on the desert floor or in the surrounding mountains and on remains found within closed structures, outlines the time frame and sequences of the decay process. Remains can retain a fresh appearance for a considerable time in the winter, but the onset of marked decomposition is rapid in the summer months. Bloating of the body usually is present two to seven days following death. Following this, within structures, there is frequently rapid decomposition and skeletonization. With outdoor exposure, remains are more likely to pass through a long period of dehydration of outer tissues, mummification, and reduction of desiccated tissue. Exposure of large portions of the skeleton usually does not occur until four to six months after death. Bleaching and exfoliation of bone--the beginning stages of destruction of the skeletal elements--begins at about nine months' exposure. Insect activity, including that of maggot and beetle varieties, may accelerate decomposition, but this process is greatly affected by location of the body, seasonal weather, and accessibility of the soft tissues. Carnivores and other scavengers also are contributing factors, as are clothing or covering of the body, substrate, elevation, and latitude.

Animals↗
PubMed1987

An unusual atypical gunshot wound. A coin as an intermediate target.

Foreign objects in gunshot wound tracts are common when the bullets have struck intermediate targets. This report describes a coin struck by a 0.45 caliber bullet and propelled into the body of a homicide victim. The report also describes the condition of the victim, found with lime covering her body.

Adult↗
PubMed1987

Suicidal contact gunshot wounds to the head with .38 Special Glaser Safety Slug ammunition.

Glaser Safety Slug TM ammunition is a uniquely designed, essentially prefragmented ammunition. Tests performed by the U.S. Justice Department demonstrated that the ammunition possesses high kinetic energy, high relative incapacitation index (RII) and poses a very low risk to bystanders because of its total loss of kinetic energy in the target. Despite having been manufactured since 1974, no deaths from this ammunition have been previously reported. The authors herein describe the first three reported human deaths.

Adult↗
PubMed1987

An analysis of toxic deaths, 1982 to 1985, Pima County, Arizona.

Toxic deaths in Pima County, Arizona, were studied over a four-year period. The deaths were analyzed according to cause and manner of death, toxic substance, and demographic data. The age group 40 to 49 years had the highest rate of suicide from toxic substances. The accident death rate was highest for ages 20 to 29 years. Carbon monoxide was most often found to be the cause of deaths in this study. The most prevalent drugs were narcotics followed by antidepressants, cocaine, and barbiturates. Comparisons are made with similar studies.

Adolescent↗
PubMed1986

Synthesis of phytochrome apoprotein and chromophore are not coupled obligatorily.

G Gardner and HL Gorton (1985 Plant Physiol 77: 540) demonstrated that gabaculine (5-amino-1,3-cyclohexadienylcarboxylic acid) inhibits the initial synthesis and resynthesis of spectrophotometrically detectable phytochrome in pea, maize, and oat. We show that the level of immuno-detectable phytochrome in pea is unaffected by the presence of gabaculine at a concentration that reduces spectrophotometrically detectable phytochrome up to 10-fold. This result indicates that gabaculine inhibits chromophore synthesis without affecting phytochrome apoprotein synthesis and that chromophore-less phytochrome is stable in the cell.

Journal Article↗
PubMed1986

Cocaine-related deaths in Pima County, Arizona, 1982-1984.

A three-year review of toxicology data from medical examiner autopsies in Pima County, Arizona, has demonstrated that cocaine has rapidly become a leading substance of abuse, second only to alcohol in the frequency of drugs detected by toxicologic analysis of all suspicious deaths, motor vehicle accident fatalities, homicides, and suicides. Gastric contents and urine were analyzed by thin-layer chromatography, and nasal swabs, blood, and urine were tested for the combination of cocaine and its metabolite benzoylecgonine by quantitative radioimmunoassay. A total of seventy-two deaths in Pima County from 1982 to 1984 have involved cocaine. Seventy percent of these have occurred in the last fifteen months. Marked variation in the individual response to cocaine compared to the blood concentration of cocaine/metabolite was noted.

Adult↗
PubMed1985

Vestibular activation, smooth pursuit tracking, and psychosis.

Pursuit tracking and vestibular activation procedures were combined in an investigation to determine if smooth pursuit tracking deficits could be related to abnormalities of visual-vestibular interaction in psychiatric patients. In actively psychotic patients, but not in comparison groups of schizophrenic outpatients with remitted symptomatology or normal controls, a significant failure of visual fixation to suppress caloric nystagmus was related to a higher incidence of disordered tracking during both baseline and postirrigation conditions. Other vestibular irregularities including dysrhythmia and reduced fast phase velocity were observed in these same patients. The results are supportive of a central deficit in visual-vestibular interaction that may contribute to pursuit tracking deficits in psychosis.

Adult↗
PubMed1985

The management of metastatic germ cell tumours and the clinical utility of lactate dehydrogenase estimations.

Forty-five patients with metastatic germ cell tumour were treated with chemotherapy. Complete remission was achieved in 63% of all cases and in 65% of patients whose primary tumour arose in the testis or ovary. Surgical resection of abdominal masses persisting after chemotherapy was performed in seven patients, two of whom were found to have persistent tumours. Twenty-seven of the 33 patients with teratoma originating in the gonads remain in complete remission. Total serum LDH activity was elevated in 28 of the patients with measurable disease. The increased LDH was not accompanied by significant alteration in other hepatic enzymes nor were hepatic metastases demonstrable in these patients. Fractionation of the LDH demonstrated that the increased LDH in these patients was located in either iso-enzymes 1 or fractions 1 + 2. Alteration of the serum LDH activity correlated with the response to therapy and warrants further study.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1984

Azido auxins : photolysis in solution and covalent binding to soybean.

The potential of three auxin analogs, 4-, 5-, and 6-azidoindole-3-acetic (4-N(3)IAA, 5-N(3)IAA, and 6-N(3)IAA), as photoaffinity labeling agents for the detection and isolation of auxin receptors was assessed by irradiating these compounds at 365 nm on TLC plates, in solution, and in contact with soybean (Glycine max L. Merr. var. Wayne) hypocotyl. Photolysis on TLC plates produces immobile spots, indicating extremely polar or covalent binding of the photoproducts to the plates. On irradiation in buffer or in buffer containing sucrose, all three compounds decompose at rates that are first order in N(3)IAA to give fluorescent solutions. Photolysis through a Pyrex filter is slower than that through quartz, but the filter prevents tissue damage and allows a given dose of irradiation to photolyze all three N(3)IAAs to the same extent. The effects of photolysis of these compounds in vivo were evaluated with a straight growth assay using etiolated soybean hypocotyl segments. According to this assay, the photoproducts of the N(3)IAAs possess little auxin activity. Irradiation of soybean hypocotyl tissue after 1-hour exposure to 4-N(3)IAA in the dark causes the tissue to grow during 12 hours as much as tissue that is continuously exposed to 4-N(3)IAA in the dark for this period, suggesting that, on photolysis, this auxin analog binds irreversibly to an auxinsensitive site. Although the fluorescence intensity of the photolyzed N(3)IAAs is weak enough to require another method of detecting the bound analog under physiological conditions, the evidence for covalent binding of the N(3)IAAs on photolysis implies that these compounds will be satisfactory photoaffinity labeling agents.

Journal Article↗
PubMed1984

Azido auxins: quantitative binding data in maize.

The binding constants of three auxin analogs, 4-, 5-, and 6-azidoindole-3-acetic acid (4-, 5-, and 6-N(3)IAA), and of the photoproducts of 5-N(3)IAA to the naphthalene-1-acetic acid (NAA) binding sites of Zea mays L. WF9 x BR38 were determined to evaluate the potential of these analogs as photoaffinity labeling agents. We have found that 4- and 5-N(3)IAA bind to these sites with affinities similar to that of IAA, while 6-N(3)IAA and the photoproducts of 5-N(3)IAA bind less tightly. This binding is fully reversible in the dark. Binding of 5-N(3)IAA becomes covalent and irreversible upon UV irradiation, as evidenced by a 30% loss in NAA binding at sites pretreated with 5-N(3)IAA and UV irradiation, then washed extensively. IAA or NAA, included with this 5-N(3)IAA pretreatment, can protect the sites from blockage, whereas benzoic acid and tryptophan are unable to protect the site, indicating that 5-N(3)IAA specifically labels the auxin sites.

Journal Article↗
PubMed1984

Azido auxins : photoaffinity labeling of auxin-binding proteins in maize coleoptile with tritiated 5-azidoindole-3-acetic Acid.

Tritiated 5-azidoindole-3-acetic acid (5-N(3)-[7-(3)H]IAA), a photoaffinity labeling agent, was used to photolabel proteins of a crude microsomal preparation from maize (Zea mays L., Bear Hybrid, WF9 x BR38) coleoptile. Approximately 50% of the bound radioactivity was solubilized in 5 molar urea containing Triton X-100, and the extract was fractionated using a variety of techniques. High performance liquid chromatography demonstrated that, although many membrane proteins incorporated tritiated label, only a few showed reduced incorporation in the presence of excess indole-3-acetic acid. By contrast, no detectable reduction in incorporation was observed in the presence of excess naphthalene-1-acetic acid. Results from isoelectric focusing gel electrophoresis indicate that the proteins that showed reduced incorporation of photolyzed 5-N(3)-[7-(3)H]IAA in the presence of IAA fell into two main groups: one which focuses between pH 5.2 and 5.7 (pI 4.8-5.3) and another around pH 6.2 (pI 5.8). In sodium dodecylsulfate polyacrylamide gel electrophoresis, the proteins migrated as four bands with apparent molecular weights of 60, 49, 45, and 37 kilodaltons. The auxin-transport inhibitor, 2,3,5-triiodobenzoic acid, competes for the labeling by 5-N(3)-[7-(3)H]IAA, suggesting that some of these proteins may be involved in auxin transport.

Journal Article↗
PubMed1984

Campylobacter laridis causing bacteremia in an immunosuppressed patient.

An unusual species, Campylobacter laridis , belonging to the group of nalidixic acid resistant thermophilic Campylobacter species, was isolated from the blood of a 71-year-old man with multiple myeloma, hyperviscosity syndrome, and renal failure. The organism was first recognized in the laboratory by gram-stain reaction and resistance to nalidixic acid. The organism differs from C. jejuni and C. coli by its resistance to nalidixic acid, whereas anaerobic growth in the presence of trimethylamine N-oxide hydrochloride differentiates this organism from other Campylobacter species. Biochemical characterization and DNA homology studies confirmed the identity of this species as being C. laridis . To our knowledge, this is the first recorded case of bacteremia due to C. laridis in humans.

Aged↗
PubMed1984

Outcome after peritoneo-jugular shunting of pancreatic ascites.

Three patients with pancreatic ascites documented by ascitic fluid protein greater than 2.5 g/dl and elevated amylase in their peritoneal fluid were treated by peritoneo-jugular shunting (PJS). Patient 1 was so treated inadvertently; Patient 2 had resolving amylase levels but increasing amounts of ascites; Patient 3 had clear, active pancreatic ascites. None incurred untoward effects from this procedure. Ventilatory compromise from reduced diaphragmatic excursion was ameliorated in all patients. Two patients required no further therapy. The third patient was greatly improved in preparation for definitive surgical therapy for a leaking pancreatic pseudocyst. The infusion of enzyme-rich fluids into the circulation may be responsible for certain systemic effects of pancreatitis. Coagulation defects are a known complication of PJS for the ascites of Laennec's cirrhosis. There was no evidence of histamine-mediated cardiovascular collapse, exacerbation of respiratory failure, or coagulation defects in these patients. We conclude that these complications are not the inevitable results of PJS of pancreatic ascites.

Adult↗