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Biomedical subjects

J L Grant

Publications and source records attributed to J L Grant.

16 recordsLinked to original sources
PubMed1995

Association of molybdopterin guanine dinucleotide with Escherichia coli dimethyl sulfoxide reductase: effect of tungstate and a mob mutation.

We have identified the organic component of the molybdenum cofactor in Escherichia coli dimethyl sulfoxide reductase (DmsABC) to be molybdopterin (MPT) guanine dinucleotide (MGD) and have studied the effects of tungstate and a mob mutation on cofactor (Mo-MGD) insertion. Tungstate severely inhibits anaerobic growth of E. coli on a glycerol-dimethyl sulfoxide minimal medium, and this inhibition is partially overcome by overexpression of DmsABC. Isolation and characterization of an oxidized derivative of MGD (form A) from DmsABC overexpressed in cells grown in the presence of molybdate or tungstate indicate that tungstate inhibits insertion of Mo-MGD. No electron paramagnetic resonance evidence for the assembly of tungsten into DmsABC was found between Eh = -450 mV and Eh = +200 mV. The E. coli mob locus is responsible for the addition of a guanine nucleotide to molybdo-MPT (Mo-MPT) to form Mo-MGD. DmsABC does not bind Mo-MPT or Mo-MGD in a mob mutant, indicating that nucleotide addition must precede cofactor insertion. No electron paramagnetic resonance evidence for the assembly of molybdenum into DmsABC in a mob mutant was found between Eh = -450 mV and Eh = +200 mV. These data support a model for Mo-MGD biosynthesis and assembly into DmsABC in which both metal chelation and nucleotide addition to MPT precede cofactor insertion.

Electron Spin Resonance Spectroscopy↗
PubMed1994

The developing cerebral surface. Preliminary report on the patterns of sulcal and gyral maturation--anatomy, ultrasound, and magnetic resonance imaging.

This literature review provides data on the temporal sequence in which gyri, sulci, and fissures first become apparent on anatomic specimens of the developing brain surface. Ultrasonic display of these anatomic features lags behind the initial appearance of the features by a variable interval, greater in early gestation and diminishing in late gestation. MR imaging, especially three-dimensional surface rendering, displays the degree of surface maturation to advantage. Different publications have provided variable estimates of the time course of surface maturation, leading to discordance in the date tabulated. None-the-less, the overall sequence is clear and the surface features are useful in assessing the degree of fetal-neonatal maturity by ultrasonography and by MR imaging.

Brain↗
PubMed1983

A pinhole method for measuring chest wall compliance.

We describe a method of measuring chest wall compliance (Cw) that readily detects whether respiratory muscles are relaxed. The method simulates a normal slow sigh, with the subject exhaling through a needle valve. Cw is calculated from the slope of the volume-esophageal pressure line. With relaxed subjects, repeated measurements yield similar slopes. When subjects cannot relax, the volume-pressure line is irregular and variable. In 26 subjects who could relax, Cw averaged 0.208 +/- 0.05 (SD) l/cmH2O.

Adult↗
PubMed1981

Hypoventilation.

Explore the source record for details and available documents.

Humans↗
PubMed1981

The epizootiology of nematode parasites of sheep in a high-rainfall area of Zimbabwe.

Fifty-two untreated lambs from a contaminated flock were slaughtered at regular intervals throughout the year, and their gastro-intestinal tracts were examined for the presence of nematode parasites. Haemonchus contortus and Oesophagostomum columbianum were found to be of major importance. The incidence of Haemonchus rose to a peak and remained at a high level throughout the winter through the fourth larval stages of the parasite predominated at this stage. Oesophagostomum columbianum was recovered in numbers unusually high for this species, the incidence of which remained at a relatively high level from March until October. The minor genera recovered were Trichostrongylus spp., Cooperia spp., Strongyloides papillosus and Trichuris ovis.

Animals↗
PubMed1980

Microsurgical relationships of the anterior inferior cerebellar artery and the facial-vestibulocochlear nerve complex.

The relationship of the anterior inferior cerebellar artery (AICA) to the facial (7th) and vestibulocochlear (8th) nerves was studied using 3x to 20x magnification in 50 cerebellopontine angles (CPAs) from 25 adult cadavers. The AICA originated from the basilar artery as a single (72% of the CPAs), duplicate (26%), or triplicate (2%) artery. Each of the 50 CPAs had one or more arterial trunks that coursed in close proximity to the 7th and 8th cranial nerves and thus were said to be nerve-related. The nerve-related arterial trunks were divided into three segments based on their relationship to the nerves and meatus: the premeatal, meatal, and postmeatal segments. The meatal segment projected to the meatus or into the canal in 64% of the CPAs. In relation to the nerves, the premeatal segment was most commonly anteroinferior, the meatal segment was inferior, and the postmeatal segment was posteroinferior. The nerve-related branches of the AICA gave rise to internal auditory arteries in 100% of the 50 CPAs, recurrent perforating arteries in 82%, and the subarcuate artery in 72%. The internal auditory and recurrent perforating arteries arose most commonly from the premeatal segment, and the subarcuate artery arose most commonly from the postmeatal segment. There were one to four internal auditory arteries per CPA, zero to three recurrent perforating arteries, and zero or one subarcuate artery. The effects of occlusion of the nerve-related arteries and their involvement in conditions treated by neurosurgeons are reviewed.

Adult↗
PubMed1980

Bronchial adenoma resection with relief of hypoxic pulmonary vasoconstriction.

Experimental airway obstruction is known to cause reflex pulmonary artery constriction, but clinical documentation of reversible bronchial obstruction and vasoconstriction is rare. A soft bronchial adenoma obstructed the left main bronchus, and scans showed minimal ventilation and perfusion on the left. Gas aspirated from beyond the tumor was hypoxic. The adenoma was removed and the lung left intact by means of a skin graft in the bronchial wall. Four months later, pulmonary function was normal, and both ventilation and perfusion of the left lung were normal. Reflex pulmonary vasoconstriction resulting from alveolar hypoxia minimizes systemic hypoxemia and also minimizes alveolar tissue hypoxia in the lung itself. The reflex is seen most frequently in perfusion scans in patients with chronic airways disease. This case in important in that it documents reversal of vasoconstriction after ventilation was restored.

Adenoma↗
PubMed1979

Use of biofeedback in weaning paralyzed patients from respirators.

Two paralyzed patients who were being treated with mechanical respirators and in whom weaning with intermittent mandatory ventilation failed were treated with regular sessions of biofeedback. Their respiratory volumes were displayed to them on oscilloscopes at bedside. A plastic (Plexiglas) template was placed on the face of the oscilloscope with two horizontal strips of adhesive tape affixed to it; the patient had to achieve a certain tidal volume (TV) to push the tracing outside the space between the horizontal lines. During each session the highest TV achieved determined the target TV to be maintained during the next session. The application of treatment coincided with improved ventilation; both patients were eventually weaned.

Biofeedback, Psychology↗
PubMed1975

Chronic binodal block with Wenckebach phenomenon.

Coexistent sino-atrial and atrioventricular block with Wenckebach phenomenon is an extremely unusual cardiac arrhythmia. Observations on the natural history of sinus node dysfunction are rare. For over six years our elderly patient has been followed without symptoms but with increasing severity of atrio-ventricular block.

Aged↗