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Biomedical subjects

J M Goodman

Publications and source records attributed to J M Goodman.

At least 109 records · Page 6Linked to original sources

Confirmation of brain death with portable isotope angiography: a review of 204 consecutive cases.

Intravenous isotope angiography is a rapid, safe, and specific bedside test for confirming brain death by demonstrating the lack of critical cerebral perfusion that occurs in this condition, regardless of etiology. A review of 204 consecutive cases of suspected brain death studied with isotope angiography has reaffirmed our confidence in the specificity of the technique and has convinced us to make less stringent our radiographic criteria for confirming brain death by this method. A technically satisfactory single flow study that shows arrest of the carotid circulation at the base of the skull and absence of the intracranial arterial circulation may be considered confirmatory of a carefully established clinical diagnosis of brain death, even though there may be some visualization of the intracranial venous sinuses. Arbitrary waiting periods, withdrawal of sedative drugs, and electrophysiological studies are not needed when this technique is used.

Adolescent↗

Alcohol oxidase assembles post-translationally into the peroxisome of Candida boidinii.

Candida yeasts rapidly form peroxisomes of simple function and composition when grown on methanol. Because the induction is both massive and rapid, this system may be useful for a detailed dissection of peroxisomal biogenesis. We report procedures to express peroxisomal proteins in cells and spheroplasts of Candida boidinii to stabilize peroxisomes in a lysate of spheroplasts and to obtain an enriched peroxisomal fraction. With these techniques we have been able to study the assembly of alcohol oxidase, a homo-octomeric flavoprotein, into the organelle in vivo. The primary translation product of alcohol oxidase comigrates on sodium dodecyl sulfate-polyacrylamide gels with the mature subunit. Pulse-chase experiments indicate that the newly synthesized monomer of alcohol oxidase has a half-life of about 20 min in intact cells and 13 min in spheroplasts before conversion to octomer. The monomer first appears in a high speed supernatant of a lysate of spheroplasts and then chases into a purified peroxisomal fraction before or during its octomerization. There is no detectable intermediary organelle involved in this process.

Alcohol Oxidoreductases↗

Sequence of the leader peptidase gene of Escherichia coli and the orientation of leader peptidase in the bacterial envelope.

The nucleotide sequence of the leader peptidase structural gene from Escherichia coli has been determined. The gene codes for a protein of 323 amino acid residues with a calculated Mr = 35,994, in agreement with the apparent molecular weight of leader peptidase (37,000) determined from gel electrophoresis in sodium dodecyl sulfate. In addition, the amino acid composition predicted from the DNA sequence matches that of the purified enzyme. Leader peptidase synthesized in a cell-free transcription-translation system and isolated from cell membranes have identical apparent molecular weights on sodium dodecyl sulfate-polyacrylamide gels. The presence of methionine and cysteine in the NH2-terminal tryptic peptide shows that no more than three amino acid residues have been removed from the primary translation product predicted from the DNA sequence. These results indicate that leader peptidase is synthesized and assembled into the membrane without proteolytic removal of a leader peptide. Leader peptidase is shown to be largely found in the inner membrane of overproducing strains. The majority of the polypeptide chain is exposed on the outer surface of the inner membrane. It is anchored by a membrane-spanning segment near the NH2 terminus. This orientation agrees with the functional orientation of leader peptidase observed in artificial membrane vesicles.

Amino Acid Sequence↗

Membrane assembly: posttranslational insertion of M13 procoat protein into E. coli membranes and its proteolytic conversion to coat protein in vitro.

The major coat protein (gene 8 product) of bacteriophage M13 is an integral membrane protein during infection of host cells. It is synthesized as a larger precursor (procoat) with a leader sequence of 23 amino acids at its amino terminus. In vivo studies have shown that procoat only inserts into the host-cell plasma membrane after its synthesis is completed. We now demonstrate that procoat can post-translationally insert into inverted cytoplasmic membrane vesicles from E. coli and can be processed proteolytically to yield coat protein. Procoat changes from an assembly-competent substrate to an incompetent (denatured) form within minutes after its synthesis; much of the procoat that accumulates during an hour of in vitro synthesis is therefore denatured. These studies emphasize the importance of stringent criteria for the demonstration of obligate cotranslational assembly.

Cell Membrane↗

Procoat, the precursor of M13 coat protein, requires an electrochemical potential for membrane insertion.

The coat protein of coliphage M13 spans the host cell cytoplasmic membrane prior to its assembly into extruding virus. It is made as a soluble cytoplasmic precursor, termed "procoat," with 23 extra amino acid residues at the NH2 terminus. Procoat binds to the cell membrane and is converted proteolytically to coat protein. When the electrochemical gradient of an infected cell is rapidly dissipated by uncouplers, procoat still binds to the plasma membrane but is not converted to coat. We report here that membrane-bound procoat is only detected at the inner face of the cytoplasmic membrane and that uncouplers prevent it from integrating into a transmembrane conformation.

Coliphages↗

Compartmentalization of the cerebral ventricles as a sequela of neonatal meningitis.

Thirteen infants with compartmentalization of the lateral ventricles diagnosed by air encephalography, computerized tomography, or autopsy are reported. In each case, the body of one or both lateral ventricles was completely divided by a membrane posterior to the foramen of Monro. Recognition of this entity is important from both therapeutic and prognostic standpoints.

Brain Diseases↗

Confirmation of brain death at bedside by isotope angiography.

Documentation of the absence of cerebral circulation is useful as a confirmatory test of brain death. Intravenous isotope angiography performed at the bedside with a mobile gamma camera is a safe, convenient, rapid, reliable, and easily understood method of proving the absence of cerebral blood flow that occurs in brain death.

Brain Death↗

Provisional splinting in advanced periodontal disease. Case report.

This case report describes an approach to treatment for a patient with severe bone loss resulting from advanced periodontal diseae. A provisional splint was constructed in conjunction with suitable periodontal therapy. The purpose was to allow time for evaluation prior to deciding whether to commit the patient to permanent stabilization.

Adult↗

Barbiturate intoxication. Morbidity and mortality.

The complications encountered in caring for 185 patients intoxicated with barbiturates were reviewed. The population consisted of 142 patients with long-acting barbiturate concentrations of 8 mg per 100 ml or greater, 20 patients with short-acting barbiturate concentrations of 3 mg per 100 ml or greater and 23 consecutive patients with short-acting barbiturate intoxication referred for monitoring. Pneumonia was the major cause of morbidity and mortality and correlated best with the initial depth of coma and the use of an endotracheal tube in treatment. Cardiovascular instability manifested by pulmonary edema was the next leading cause of morbidity and mortality and correlated best with the initial depth of coma and the quantity of intravenous fluid administered. In retrospect, use of eliminative measures such as dialysis would probably not have altered the outcome in most of the patients who died and attempts at forced diuresis may have contributed to several deaths. Particular emphasis should be placed on the problems of sepsis and fluid therapy in the management of these patients.

Adolescent↗