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Biomedical subjects

H A Thompson

Publications and source records attributed to H A Thompson.

At least 19 recordsLinked to original sources
PubMed1991

Electron microscopy of Coxiella burnetii in tissue culture. Induction of cell types as products of developmental cycle.

An in vitro ultrastructural study was carried out on tissue cultures (J774, murine macrophage-like tumour cell line, and BHK-21, baby hamster kidney cell line) persistently infected with C. burnetii to investigate whether the events of cellular differentiation could be visualized. At a given stage of the developmental cycle, a proportion of the cells within the affected phagolysosomes clearly underwent cellular differentiation. The cells initially showed asymmetrical septation, the primary stage of cellular differentiation, and ended with the formation of the differentiated product, a precursor to the small cell. The results verified our initial observation that the events occurring during growth in a phagolysosome represent stages of a complex developmental cycle consisting not only of i) vegetative growth by typical transverse binary fission, but also ii) cellular differentiation.

Animals↗
PubMed1990

Isolated Coxiella burnetii synthesizes DNA during acid activation in the absence of host cells.

Two populations of Coxiella burnetii were isolated from fibroblast tissue cultures and examined for their ability to synthesize DNA when incubated in a defined medium. Both the populations released by mechanical lysis of heavily infected host cells, as well as those recovered from the tissue culture medium, incorporated H3 32PO4 into DNA. Incorporation occurred at pH 4.5 but not at pH 7.0, and proceeded for 12-15 h. When incorporation of [3H]thymidine was studied, only the organisms obtained by mechanical lysis of host cells were active. Those which had been released by natural means into the tissue culture medium, and then recovered for study, did not incorporate precursor thymidine but were extremely active in protein biosynthesis. In mechanically released organisms, thymidine incorporation was inhibited immediately by rifamycin (40 microM) and hydroxyurea (10 mM), but it was not affected by chloramphenicol (310 microM) until 4 h after addition of the drug. Incorporation of H3 32PO4 by both populations of organisms was also inhibited by rifamycin, chloramphenicol and hydroxyurea, but the time sequence of inhibition differed. Southern hybridization utilizing 32P-labelled DNA suggested that both populations synthesized authentic chromosomal DNA sequences, as well as QpH1 plasmid DNA, during acid activation of metabolism.

Blotting, Southern↗
PubMed1990

Directors' and officers' liability.

Charities or business associations frequently ask physicians--due to their status in the community--to serve as directors or officers. Just as frequently, physicians agree to serve in those positions without fully understanding the responsibilities and possible liabilities they are assuming. This article describes the duties of directors and officers and the liabilities associated with the job.

Charities↗
PubMed1990

Restrictive covenants.

Sales of medical practices and physician employment contracts may contain covenants not to compete, also known as restrictive covenants. These covenants prohibit sellers from competing with buyers and employees from competing with former employers for a specified period of time. As a result of a call for legislative action to dispel confusion created by case law regarding these covenants, there now exists a statute dealing with restrictive covenants. This new law abolishes the "common calling" test, a standard for determining the enforceability of covenants not to compete in employment agreements, which the Texas Supreme Court adopted in 1987. Among other remedies, the new law provides procedures for reforming a broad restrictive covenant to one that is reasonable. This article discusses the 1987 Texas Supreme Court case and reviews the new statute.

Practice Management, Medical↗
PubMed1990

From informed consent to informed refusal.

This article traces the development of the informed consent concept, focusing on Texas case law and statutory provisions. We describe the proper use of the Texas Medical Disclosure Panel forms in establishing informed consent and illustrate common problems in proving that informed consent has been obtained. The need for effective physician-patient dialogue and communication is discussed.

Communication↗
PubMed1990

Employment law primer.

All physicians regardless of their practice size will find themselves one day in the uncomfortable situation of dismissing an employee who may threaten legal action because of termination. Knowledge of and adherence to the basics of employment law as outlined in this article may not stop an angry dismissed employee from pursuing legal action. However, it should allow the physician to feel somewhat secure that such action likely will not be successful.

Employee Grievances↗
PubMed1989

Concurrent care coverage by Medicare.

Medicare is a Federal Health Insurance Program administered by the Health Care Financing Administration for the elderly and certain disabled persons. The Texas Medicare carrier disseminates information and develops educational programs for improved understanding. "Concurrent care" exists when services are performed by more than one physician during a period of time for the same patient. Since Medicare does not have specialty designations for endocrinology, oncology, rheumatology, hematology, and infectious disease physicians, an X6 modifier is used for recognition. Services by two physicians of the same specialty or subspecialty rarely warrant coverage, but services by one physician and later care by another physician for an acute episode do warrant coverage. Emergency department codes should be used when care is given in that department and appropriate modifiers should be used by second- and third-opinion consultants in order to avoid the appearance of concurrent care. Diagnosis related to specialty and documentation of acute situations help avoid denial for "not reasonable or necessary" services. Physicians should use the "Waiver of Liability" when concurrent care seems necessary but is not likely to be covered by Medicare.

Aged↗
PubMed1989

Blood transfusions and Jehovah's Witnesses.

Jehovah's Witnesses believe that a human must not sustain his life with another creature's blood, and they recognize no distinction "between taking blood into the mouth and taking it into the blood vessels." It is their deep-seated religious conviction that Jehovah will turn his back on anyone who receives blood transfusions (1). Thus, Jehovah's Witnesses regularly refuse transfusions for themselves and their children because they believe the procedure creates a risk of losing eternal salvation. Legally, such refusals are based on the constitutional grounds that the transfusion is an invasion of the right of privacy and a violation of the individual's freedom of religious practice. When courts review these refusals they focus on state interests that outweigh the individual's rights. With an eye toward providing guidance to Texas physicians in dealing with such refusals, this article reviews case law on the subject of blood transfusions and Jehovah's Witnesses.

Blood Transfusion↗
PubMed1989

Consent requirements for treatment of minors.

The American Academy of Family Physicians, the American Academy of Pediatrics, the American College of Obstetricians and Gynecologists, the Nurses Association of the American College of Obstetricians and Gynecologists, and the National Medical Association recently released guidelines aimed at protecting the privacy of adolescent patients. The organizations stated that, in many cases, young people will not confide in health professionals if the young people feel that these discussions will be reported to their parents. Ultimately, the organizations said, health risks to adolescents are so impelling that legal barriers and deference to parental involvement should not stand in the way of needed health care. In Texas there is a statute regarding consent for medical treatment of minors, which responds to the above organizations' concerns about confidentially treating children for substance abuse, sexually transmitted diseases, and suicide prevention. However, the statute is silent in regard to medical treatment involving prescription contraceptives. By negative inference, the statute would preclude a minor on her own from making a decision about abortion. This article examines Texas statutes dealing with consent for medical treatment for minors and discusses US Supreme Court decisions on a minor's rights to abortions and contraceptives.

Abortion, Spontaneous↗
PubMed1987

Effects of temperature upon the cell-free translation system from Coxiella burnetii.

The rate and extent of coliphage Q beta RNA translation by cell-free extracts prepared from Coxiella burnetii were studied. When translations were conducted at temperatures elevated above 37 degrees C, both polypeptide elongation and frequency of initiation were by comparison increased. The ratios of products synthesized from the polycistronic phage mRNA also changed upon increases in translation temperature, especially at 45 degrees C. Although the organism is a moderate acidophile, initiation of protein synthesis in extracts did not occur below pH 6.2, and was superior when the pH was 6.8-7.2. The results are discussed in context with the known physiological characteristics of this obligate intracellular bacterium.

Animals↗
PubMed1977

Studies on native ribosomal subunits from rat liver. Purification and characterization of a ribosome dissociation factor.

A population of free, native ribosomal 40S subunits, that do not react with 60S subunits to form 80S ribosomes, has been identified in the postmicrosomal fraction of rat liver homogenates. A protein (IF-3) has been purified from high salt (0.88 M KCI) extracts of native 40S subunits by gradient centrifugation and by ammonium sulfate fractionation; it prevents the reassociation of subunits and to a limited extent dissociates ribosomes to subunits. The activity is measured by ultracentrifugation of the reaction products on linear sucrose gradients, or with an assay developed in this laboratory that couples dissociation with the 60S-specific peptidyltransferase reaction; the latter procedure measures the amount of 60S subunits released from ribosomes or remaining in incubations in the presence of IF-3. Dissociation factor activity is recovered from most of the particles that are resolved by zonal centrifugation of the total "native subunits" obtained from the postmicrosomal fraction; the highest concentration of IF-3, however, appears to be associated with native 40S subunits. The purified dissociation factor IF-3 is composed of about ten polypeptides and the molecular weight is estimated to be between 500 000 and 700 000, on the basis of glycerol and cesium chloride gradient centrifugation. When purified 40S subunits react with IF-3 or when 80S ribosomes are dissociated by IF-3, a product is formed which is dependent on the concentration of the protein factor and has the characteristics of a 40SIF-3 complex; centrifugation of the complex on sucrose and cesium chloride gradients suggests that the complex consists of 1 equiv of each of the two components. Although dissociation factor IF-3 appears to react in a specific manner with free or ribosome-associated 40S subunits, the reaction with subunits differs in several respects from that with ribosomes. The dissociation factor also appears to interact with 60S subunits but multiple complexes are formed, some with more than 1 IF-3 equiv per 60S particle. The IF-3 converts 40S dimers (55S particles) to the 40S-IF-3 complex and dissociates free, native 80S particles present in the postmicrosomal fraction, but it does not affect polysome-associated ribosomes engaged in protein synthesis.

Animals↗