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Biomedical subjects

J K Glenn

Publications and source records attributed to J K Glenn.

At least 19 recordsLinked to original sources
PubMed2003

Development of an animal-human antibody complex for use as a control in ELISA.

In order to provide the equivalent of a human anti-human protein antibody as positive control in ELISAs, a goat-human antibody complex was created using chemical cross-linking. The resulting hybrid complex had a larger molecular size on HPLC and SDS-PAGE. In ELISA, the goat-human complex bound to human antigen and was detectable by a secondary anti-human conjugate. The method to make the hybrid complex is simple, cost-effective and can be used to make human-like antibodies to many human proteins.

Animals↗
PubMed1991

Rural populations and rural physicians: estimates of critical mass ratios, by specialty.

As physicians and other providers of health care services see their traditional markets erode, an increasingly important element of any provider location decision is the determination of a population base or "critical mass" that can professionally and financially support a given set of health care services. While the size of a local population is not the sole determinant of success, ultimately an adequate population base to support a given spectrum of services must be defined, and providers increasingly need tools for evaluating opportunities in the new economic market. This is especially true in rural areas. An earlier supply and demand model for estimating the critical mass of population needed to support a physician in any one of 25 specialties and subspecialties in urban and suburban areas is adapted to the rural market. The assumptions inherent in the earlier model are examined and the issue of "critical mass" is examined from a rural health care perspective in this paper.

Catchment Area, Health↗
PubMed1990

Manganese regulates expression of manganese peroxidase by Phanerochaete chrysosporium.

The appearance of manganese peroxidase (MnP) activity in nitrogen-limited cultures of Phanerochaete chrysosporium is dependent on the presence of manganese. Cultures grown in the absence of Mn developed normally and produced normal levels of the secondary metabolite veratryl alcohol but produced no MnP activity. Immunoblot analysis indicated that appearance of MnP protein in the extracellular medium was also dependent on the presence of Mn. Intracellular MnP protein was detectable only in cells grown in the presence of Mn. MnP mRNA was detected by Northern (RNA) blot analysis only in cells grown in the presence of Mn. If Mn was added to 4-day-old nitrogen-limited Mn-deficient cultures, extracellular MnP activity appeared after 6 h and reached a maximum after 18 h. Both actinomycin D and cycloheximide inhibited the induction of MnP activity by Mn. These results indicate that Mn, the substrate of the enzyme, is involved in the transcriptional regulation of the MnP gene.

Basidiomycota↗
PubMed1990

Physician referrals from a rural family practice residency clinic: a pilot study.

Primary care physicians see large volumes of unscreened patients in the office setting, and referral to more specialized colleagues is always an option. Discretionary factors may play an important role in the referral decision. In this study, three family physicians retrospectively rated 410 referrals from a rural academic practice for the need for referral based on lack of specialized skills or knowledge by family physicians and the probability of adverse patient outcome. Referrals relating to cancer and pregnancy were rated as less discretionary than other referrals. Specialties receiving the highest proportion of mandatory or probably mandatory referrals were ophthalmology and cardiology. Half of all referrals studied were considered to be elective or possibly elective, although 97 percent of referrals to dermatology were considered elective or probably elective. These findings support the hypothesis that there is considerable clinical discretion in a large proportion of referrals. Hence, imposition of specific criteria for referral in primary care practice (thereby limiting discretion in initiating a referral) could significantly decrease the number of referrals, and consequently decrease the income of subspecialists and tertiary care centers.

Adult↗
PubMed1989

Hospitals and the "ecology" of primary care.

Hospitals should no longer take for granted the expanded network of physicians that directs patients to them. This article offers an integrated examination of that network with special attention to fee-for-service referrals from physicians in primary care to their colleagues in more specialized fields of medicine and surgery. In a competitive environment, understanding the levels of mutual dependence among physicians and the multistage decision chain that brings patients to a specific hospital may become more important than knowing who admits those patients.

Economic Competition↗
PubMed1988

Necessary conditions for supporting a general surgeon in rural areas.

Loss of a general surgeon in a rural community cna alter the referral patterns, the image and utilization of the local hospital, and even the market share of local primary care physicians. Prior research has not defined the necessary and/or sufficient conditions for a rural county to be able to support a local general surgeon. Based upon empirical analysis of 96 rural Missouri counties and the limited literature available on rural surgeons and physician referral rates, a first approximation of those conditions are offered. We conclude that a rural county with a hospital, a population base of more than 15,000 people, and at least 11 potential referring physicians has sufficient conditions to enable it to support a local general surgeon. Among those rural Missouri counties not meeting the above conditions but having a general surgeon in 1984, we estimate that 8 to 10 potential referring physicians appear to be the minimum necessary condition for supporting a rural general surgeon through patient referral. From those conclusions, we argue that any rural hospital currently without a surgeon should re-examine its situation. To prepare for a competitive future, such a hospital should take every opportunity to expand the referral base necessary to support a full-time local surgeon rather than place long-term reliance upon itinerant general surgeons.

Catchment Area, Health↗
PubMed1988

The development of clinical independence: resident-attending physician interactions in an ambulatory setting.

Interactional analysis data from 949 resident-attending physician interactions about the care of 2,975 ambulatory patients were analyzed to test the hypothesis that consultation rates and behaviors would demonstrate a progressive increase in clinical independence and assertiveness. Consultation rates for first-, second-, and third-year residents were 48, 28, and 26 percent, respectively. The mean durations of consultations were 7.7, 6.9, and 6.1 minutes, respectively. Attending physicians visited 20, 12, and 13 percent of the patients of first-year, second-year, and third-year residents. The more senior residents displayed fewer of most types of interactional behaviors, suggesting a more focused discussion. Senior residents showed a progressive increase in initiating interactions of all types, demonstrating a kind of clinical independence and educational assertiveness that progressed through three years. There is a growing consensus that teaching in ambulatory medical practices will become widespread, but little information directs educational efforts in these settings. The findings suggest that clinical independence in the ambulatory setting is progressive and that measurements of consultation rates and behaviors expand knowledge about education in ambulatory care.

Ambulatory Care Facilities↗
PubMed1987

Physician referrals in a competitive environment. An estimate of the economic impact of a referral.

Beyond offering optimum care for individual patients, physician referrals have a cumulative economic impact on many components of the broader medical care system. This article offers an approximation of the magnitude of that impact. By retrospectively reviewing financial records associated with 225 referrals from fee-for-service, rural family practice sites to university-based specialist colleagues, we found that the average referral generated $2944 in combined hospital charges and professional fees within a six-month period after referral. Almost half (110/225, or 49%) of those referrals resulted in a hospital admission and 72% of all revenue associated with referral accrued to the hospital. A second and more detailed study of 97 referrals showed that only 18% of total revenue resulting from referrals accrued to the physician to which the patient was initially referred. We argue that control over volume and destination of referrals, historically the referring physician's prerogative, is susceptible to change in our rapidly restructuring medical care system. In the future, no economic entity that benefits from physician referrals should take for granted those referrals or their impact.

Fees and Charges↗
PubMed1987

Cyclical variation in number of visits and major diagnoses at a rural family practice clinic.

Many physicians have noted time-related variations in the numbers of patients and types of diagnoses seen in their practices. These variations may be weekly, monthly, or seasonal. A powerful analytical technique used in electronics, economics, and the life-sciences to detect cyclic variation (time-series analysis) was applied to total visits and major diagnoses at a rural clinic to identify and describe the existence of time-related variations. Significant cycles were found in total visits and most diagnostic categories, with cycles longer than four months being the most prominent. Physician availability was highly correlated with variations in all visit categories tested, including injury visits. However, little variation was found in the use of referral. These findings may have implications for medical training, epidemiologic surveillance, and health resource planning. This method should be considered to be a standard technique for study of time-related variables.

Family Practice↗
PubMed1986

Mn(II) oxidation is the principal function of the extracellular Mn-peroxidase from Phanerochaete chrysosporium.

The manganese peroxidase (MnP), from the lignin-degrading fungus Phanerochaete chrysosporium, an H2O2-dependent heme enzyme, oxidizes a variety of organic compounds but only in the presence of Mn(II). The homogeneous enzyme rapidly oxidizes Mn(II) to Mn(III) with a pH optimum of 5.0; the latter was detected by the characteristic spectrum of its lactate complex. In the presence of H2O2 the enzyme oxidizes Mn(II) significantly faster than it oxidizes all other substrates. Addition of 1 M equivalent of H2O2 to the native enzyme in 20 mM Na-succinate, pH 4.5, yields MnP compound II, characterized by a Soret maximum at 416 nm. Subsequent addition of 1 M equivalent of Mn(II) to the compound II form of the enzyme results in its rapid reduction to the native Fe3+ species. Mn(III)-lactate oxidizes all of the compounds which are oxidized by the enzymatic system. The relative rates of oxidation of various substrates by the enzymatic and chemical systems are similar. In addition, when separated from the polymeric dye Poly B by a semipermeable membrane, the enzyme in the presence of Mn(II)-lactate and H2O2 oxidizes the substrate. All of these results indicate that the enzyme oxidizes Mn(II) to Mn(III) and that the Mn(III) complexed to lactate or other alpha-hydroxy acids acts as an obligatory oxidation intermediate in the oxidation of various dyes and lignin model compounds. In the absence of exogenous H2O2, the Mn-peroxidase oxidized NADH to NAD+, generating H2O2 in the process. The H2O2 generated by the oxidation of NADH could be utilized by the enzyme to oxidize a variety of other substrates.

Basidiomycota↗
PubMed1985

Purification and characterization of an extracellular Mn(II)-dependent peroxidase from the lignin-degrading basidiomycete, Phanerochaete chrysosporium.

A Mn(II)-dependent peroxidase found in the extracellular medium of ligninolytic cultures of the white rot fungus, Phanerochaete chrysosporium, was purified by DEAE-Sepharose ion-exchange chromatography, Blue Agarose chromatography, and gel filtration on Sephadex G-100. Sodium dodecyl sulfate-gel electrophoresis indicated that the homogeneous protein has an Mr of 46,000. The absorption spectrum of the enzyme indicates the presence of a heme prosthetic group. The pyridine hemochrome absorption spectrum indicates that the enzyme contained one molecule of heme as iron protoporphyrin IX. The absorption maximum of the native enzyme (406 nm) shifted to 433 nm in the reduced enzyme and to 423 nm in the reduced-CO complex. Both CN- and N-3 readily bind to the native enzyme, indicating an available coordination site and that the heme iron is high spin. The absorption spectrum of the H2O2 enzyme complex, maximum at 420 nm, is similar to that of horseradish peroxidase compound II. P. chrysosporium peroxidase activity is dependent on Mn(II), with maximal activity attained above 100 microM. The enzyme is also stimulated to varying degrees by alpha-hydroxy acids (e.g., malic, lactic) and protein (e.g., gelatin, albumin). The peroxidase is capable of oxidizing NADH and a wide variety of dyes, including Poly B-411 and Poly R-481. Several of the substrates (indigo trisulfonate, NADH, Poly B-411, variamine blue RT salt, and Poly R-481) are oxidized by this Mn(II)-dependent peroxidase at considerably faster rates than those catalyzed by horseradish peroxidase. The enzyme rapidly oxidizes Mn(II) to Mn(III); the latter was detected by the characteristic absorption spectrum of its pyrophosphate complex. Inhibition of the oxidation of the substrate diammonium 2,2-azino-bis(3-ethyl-6-benzothiazolinesulfonate) (ABTS) by Na-pyrophosphate suggests that Mn(III) plays a role in the enzyme mechanism.

Basidiomycota↗
PubMed1984

Purification and characterization of an extracellular H2O2-requiring diarylpropane oxygenase from the white rot basidiomycete, Phanerochaete chrysosporium.

An H2O2-requiring oxygenase found in the extracellular medium of ligninolytic cultures of the white rot fungus Phanerochaete chrysosporium was purified by DEAE-Sepharose ion-exchange chromatography and gel filtration on Sephadex G-100. Sodium dodecyl sulfate (SDS)-disc gel electrophoresis indicated that the purified protein was homogeneous. The Mr of the enzyme as determined by gel filtration and SDS-polyacrylamide gel electrophoresis was 41,000. The absorption spectrum of the enzyme indicated the presence of a heme prosthetic group. The absorption maximum of the native enzyme (407 nm) shifted to 435 nm in the reduced enzyme and to 420 nm in the reduced-CO complex. The pyridine hemochrome absorption spectrum indicated that the enzyme contained one molecule of heme as iron protoporphyrin IX. Both CN- and N-3 bound readily to the native enzyme, indicating an available coordination site and that the heme iron was high spin. The purified enzyme generated ethylene from 2-keto-4-thiomethyl butyric acid, and oxidized a variety of lignin model compounds, including the diarylpropane, 1-(3'4'-diethoxyphenyl)1,3-dihydroxy-2-(4"-methoxyphenyl)propane (I); a beta-ether dimer, 1-(4'-ethoxy-3'-methoxyphenyl)glycerol-beta-guaiacyl ether (V); an olefin, 1-(4'-ethoxy-3'-methoxyphenyl)-1,2 propene (III); and a diol, 1-(4'-ethoxy-3'-methoxyphenyl)-1,2-propane diol (IV). The products found were equivalent to the metabolic products previously isolated from intact ligninolytic cultures.

Basidiomycota↗
PubMed1984

Teaching behaviors in the attending-resident interaction.

A total of 949 interactions between residents and attending physicians in the ambulatory care center were analyzed in terms of defined categories of teaching behavior by using direct observation and the interactional analysis technique of educational research. Results showed that an interaction reflects team problem solving as the predominant teaching mode with the interaction being for the most part directed at the problems of the current patient. Hypothetical situations that broadened the discussion occurred in less than 20 percent of the interactions, and the attending physician rather than the resident virtually always initiated those teaching opportunities. Questioning and verbal expressions of positive, reinforcing behavior were used less often than might have been expected. Problems and opportunities in superimposing teaching goals upon an ambulatory clinical setting are explored in the discussion.

Ambulatory Care Facilities↗
PubMed1983

An extracellular H2O2-requiring enzyme preparation involved in lignin biodegradation by the white rot basidiomycete Phanerochaete chrysosporium.

An H2O2-requiring enzyme system was found in the extracellular medium of ligninolytic cultures of Phanerochaete chrysosporium. The enzyme system generated ethylene from 2-keto-4-thiomethyl butyric acid (KTBA), and oxidized a variety of lignin model compounds including the diarylpropane 1-(4'-ethoxy-3'-methoxyphenyl) 1,3-dihydroxy-2-(4"-methoxyphenyl)propane (I), a beta-ether dimer 1-(4'-ethoxy-3'-methoxyphenyl)glycerol-beta-guaiacyl ether (IV) and an olefin 1-(4'-ethoxy-3'-methoxyphenyl)1,2-propene (VI). The products found were equivalent to the metabolic products previously isolated from intact ligninolytic cultures. In addition, the enzyme system partially degraded 14C-ring labeled lignin. The enzyme was not found in high nitrogen (N) cultures, nor in cultures of a ligninolytic mutant strain which is incapable of metabolizing lignin.

Basidiomycota↗
PubMed1983

Decolorization of Several Polymeric Dyes by the Lignin-Degrading Basidiomycete Phanerochaete chrysosporium.

The polymeric dyes Poly B-411, Poly R-481, and Poly Y-606 were examined as possible alternatives to the radiolabeled lignin previously used as a substrate in lignin biodegradation assays. Like lignin degradation, the decolorization of these dyes by the white rot basidiomycete Phanerochaete chrysosporium occurred during secondary metabolism, was suppressed in cultures grown in the presence of high levels of nitrogen, and was strongly dependent on the oxygen concentration in the cultures. A variety of inhibitors of lignin degradation, including thiourea, azide, and 4'-O-methylisoeugenol, also inhibited dye decolorization. A pleiotropic mutant of P. chrysosporium, 104-2, lacking phenol oxidase and ligninolytic activity was also not able to decolorize the polymeric dyes, whereas a phenotypic revertant strain, 424-2, regained this capacity. All of these results suggest that the ligninolytic degradation activity of the fungus was responsible for the decolorization of these dyes.

Journal Article↗
PubMed1983

Continuity of care in the referral process: an analysis of family physicians' expectations of consultants.

A total of 497 referrals from a rural family practice training center are analyzed from the perspective of the referring physicians' expectations for continuing care of the referred patient. Those expectations were stated explicitly at the time of referral within three mutually exclusive categories. Referral expectations are partitioned by diagnostic groups and by specialty of the consultant. Analysis suggests that the referring physicians' expectations for continuing care of the referred patient vary significantly depending upon the specialty of the consultant.

Continuity of Patient Care↗