Biomedical subjects
R F Harris
Publications and source records attributed to R F Harris.
Enumeration and Characterization of Bacterial Colonists of a Submersed Aquatic Plant, Eurasian Watermilfoil (Myriophyllum spicatum L.).
A simple procedure for enumerating and grouping the bacterial colonists of Eurasian watermilfoil (Myriophyllum spicatum L.) is described. Colony characteristics of bacteria associated with M. spicatum were better defined and more stable on nutrient-poor, diluted nutrient broth agar than on high-nutrient media. Acinetobacter, Cytophaga, Flavobacterium, Moraxella, Pseudomonas and/or Alcaligenes, and Vibrio/Aeromonas spp., as well as two highly fastidious unidentified bacterial groups (gram-negative rods and gram-negative cocci), were associated with cultured watermilfoil during January, February, May, June, July, and August 1988. In Lake Wingra (Madison, Wis.), Micrococcus spp. and enterobacters were also associated with Eurasian watermilfoil during July, August, and October 1987.
Models of the mind: their role in the clinical teaching of psychoanalytic psychotherapy.
In acquiring psychoanalytic ideas, psychotherapy trainees are often hampered by preconceptions about what constitutes a psychoanalytic perspective. These preconceptions can even constitute unarticulated models of pathogenesis and cure, which organize how trainees assimilate a supervisor's suggestions. We have identified two such models: the "passive-learning" model and the "cathartic" model. Realizing that trainees are operating under one of these models can help the supervisor to understand many of their errors. A traditional model emphasizing conflict and compromise formation addresses the deficiencies of these models and provides an initial framework for a psychoanalytic understanding of psychopathology and change. Certain guidelines for technique arise from this model: understanding rather than trying to change behavior, attending to the patient's emotional set, and using the therapist's emotional set. We describe one resident's use of the compromise-formation model to overcome an impasse in his treatment of a patient, and discuss some implications for clinical supervision.
Turn around or pull the plug? Lessons in hospital diversification.
Diversification has reached a crossroad. Ventures that are profitable or break even are likely to continue as such. For those which are not, management can divest through sale or liquidation or choose the "turnaround" route, which entails carefully and objectively appraising each diversification activity or entity. The initial step in a turnaround is to review the original strategic diversification objectives to determine if they remain valid. Next is a strategic overview and appraisal of the system's diversification activities. Specific, measurable objectives and action plans are necessary to guide the turnaround process. But even with the best turnaround plan, managers must anticipate the possibility of failure by establishing a "pull-the-plug" threshold. This is the point at which a venture's operating losses exceed the value of profits. Experience with successful turnarounds shows that corporate managers must consider the following steps: (1) the specialized skills and experience of the diversification activities' managers, (2) market-based volume and revenue projections, (3) downsizing space allocations, sharing space, or adding new services, (4) ways to keep from drowning in overhead, (5) appropriate organizational controls, (6) ways to improve patient access, (7) employee incentives, (8) use of equity capital, (9) effective management information systems, and (10) "sticking to the knitting."
Spore Yield and Microcycle Conidiation of Colletotrichum gloeosporioides in Liquid Culture.
The effect of V8 juice concentration (5 to 40%, vol/vol), spore inoculum density (10 and 10 spores per ml), and liquid batch or fed-batch culture condition on mycelium and spore production by Colletotrichum gloeosporioides was evaluated. The amount of mycelium produced, the time required for initiation of sporulation following attainment of maximum mycelium, and the time for attainment of maximum spore concentration increased with increasing V8 juice concentration in batch culture. Cultures containing V8 juice at >10% achieved a similar spore density (apparent spore-carrying capacity) of about 0.8 mg of spores per ml (1 x 10 to 2 x 10 spores per ml) independent of inoculum density and V8 juice concentration. The relative spore yield decreased from a high of 64% of the total biomass for the low-inoculum 5% V8 culture, through 13% for the analogous 40% V8 culture, to a low of 2% for the high-inoculum 27% V8 culture. Fed-batch cultures were used to establish conditions of high spore density and low substrate availability but high substrate flux. The rate of addition of V8 juice was adjusted to approximate the rate of substrate utilization by the (increasing) biomass. The final spore concentration was about four times higher (3.0 mg of spores per ml) than the apparent spore-carrying capacity in batch culture. This high spore yield was obtained at the expense of greatly reduced mycelium, resulting in a high relative spore yield (62% of the total biomass). Microcycle conidiation occurred in the fed-batch but not batch systems. These data indicate that substrate-limited, fed-batch culture can be used to increase the amount and efficiency of spore production by C. gloeosporioides by maintaining microcycle conidiation conditions favoring allocation of nutrients to spore rather than mycelium production.
Colonization of a Submersed Aquatic Plant, Eurasian Water Milfoil (Myriophyllum spicatum), by Fungi under Controlled Conditions.
A laboratory assay to assess colonization of a submersed aquatic plant, Eurasian water milfoil (Myriophyllum spicatum), by fungi was developed and used to evaluate the colonization potential of Colletotrichum gloeosporioides, Acremonium curvulum, Cladosporium herbarum, Aureobasidium pullulans, a Paecilomyces sp., and an unidentified sterile, septate fungus. Stem segments of plants were first immersed in suspensions of fungal propagules for 24 h and then washed to remove all but the tightly attached component of the population. Inoculation was followed by two growth cycles of 3 days each. At the start of each cycle, washed plants were transferred to a mineral salts medium to provide an opportunity for the attached fungal populations to grow. After each growth period, plants were again washed, and fungal populations in the medium (nonattached), loosely attached and tightly attached to the plant, and within the plant (endophytic) were assayed by dilution plating. The fungi differed in the extent to which they attached to water milfoil and in their ability to grow in association with it. There were relatively few significant differences among the tightly attached fungal populations after 24 h, but growth of the better colonizers led to a greater number of significant differences after 4 and 7 days. In addition, the better colonizers showed sustained regrowth of loosely and nonattached fungal propagules in the face of intermittent removal by washing. A milfoil pathogen, C. gloeosporioides, was the only endophytic colonizer; it was also among the best epiphytic colonizers but was not demonstrably better than A. curvulum, a fungus commonly found as an epiphyte on watermilfoil. The yeastlike hyphomycete Aureobasidium pullulans was the only fungus that consistently failed to establish an increasing population on the plant.
Sources of variability in the measurement of fungal spore yields.
VARIABILITY IN THE PRODUCTION OF FUNGAL SPORES AND IN THE MEASUREMENT OF SPORE YIELDS WAS INVESTIGATED IN FOUR SPECIES OF FUNGI: Colletotrichum gloeosporioides, Colletotrichum coccodes, Colletotrichum phomoides, and Acremonium strictum. When the fungi were grown on solid medium in microplates and spore yields were measured by counting the subsamples with a hemacytometer, the variability among hemacytometer squares was always the largest source of variation, accounting for 51 to 91% of the total variation. Variability among replicate cultures and results of repeat experiments were generally also significant. The effect of square-to-square variability on the precision of spore yield measurement was minimized by counting a moderate number (ca. 30) of squares per culture. Culture-to-culture variability limited the practical precision of spore production measurements to a 95% confidence interval of approximately the mean +/- 25%. We provide guidelines for determining the number of replicate cultures required to attain this or other degrees of precision. Particle counter-derived spore counts and counts based on spore weights were much less variable than were hemacytometer counts, but they did not improve spore production estimates very much because of culture-to-culture variability. Results obtained by both of these methods differed from those obtained with a hemacytometer; particle counter measurements required a correction for spore pairs, while the relationship between spore weights and spore counts changed as the cultures aged.
Tax Reform Act of 1986: implications and trends.
The Tax Reform Act of 1986 contains several changes that substantially reduce economic flexibility for not-for-profit hospitals and healthcare systems. These changes, involving limited partnerships, investment tax credit, depreciation, and income deferral plans, among other items, carry several implications. Tax-motivated joint ventures will no longer be attractive to physician investors, donations to hospitals are expected to decline by up to 15 percent, and flexibility in attracting and retaining high-caliber employees is reduced. Efforts to reduce the federal budget deficit and renewed scrutiny of unrelated business income further jeopardize economic flexibility. Another threat is intensified Internal Revenue Service scrutiny of Form 990, which is filed by all not-for-profit organizations with $25,000 or more in annual gross receipts, and Form 990T, which is used to report unrelated business income. Measures to protect facilities' economic flexibility include careful return preparation, alternative recruitment tactics, objective opinions, refusal of high-risk deals, and outside appraisals.
Microplate assay for colletotrichum spore production.
A simple microplate method was devised to assay spore production by Colletotrichum gloeosporioides by growing the fungus on 1 ml of solid media in the wells of tissue culture plates. Growth and sporulation on microplates were compared at days 4 and 8 with growth and sporulation in 100-ml liquid batch cultures that involved 11 common media. Spore production per unit volume of medium was the same for solid and liquid forms of the media. Qualitative assessment of mycelial growth measured on microplates agreed with that of growth measured in liquid cultures. The microplate assay indicated that V8 juice was the best medium and that an organic content of about 6 mg/ml was optimal for high sporulation and low mycelium production. The assay provides a convenient, rapid, and inexpensive means of screening media for the production of fungal conidia in large numbers, to be used, for example, in biological control programs.
Microcycle Conidiation and Spore-Carrying Capacity of Colletotrichum gloeosporioides on Solid Media.
The effect of spore inoculum density, medium concentration, and temperature on slime-spot formation, spore yield, and mycelium production by Colletotrichum gloeosporioides on agar media were studied with a simple microplate assay. A steady-state spore yield (spore-carrying capacity) independent of inoculum density was reached only on media that supported good fungal growth and sporulation. The spore-carrying capacity was reached earlier, the denser the inoculum. On standard mycological media a high inoculum density (2.5 x 10 spores per ml) resulted in a slimy mass of conidia forming a slime spot, a phenomenon associated with greatly reduced mycelium formation and indicative of microcycle conidiation. In contrast, for a similar inoculum density, enhanced mycelial growth preceded sporulation and overrode slime-spot formation on highly concentrated media; a very low medium concentration resulted in much less mycelium, but spore production was also decreased. Exposure to suboptimal growth temperatures of 36 to 48 degrees C for up to 8 days did not induce microcycle conidiation from inocula that did not form a slime spot at 28 degrees C.
Nursing home site for rabies clinic.
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Effects of parent loss: interaction with family size and sibling order.
The authors studied the effect of parent loss during the first 18 years of life and its interactions with family size and sibling order in a nonpsychiatric population of 247 men. Groups defined by loss type, family size, and sibling order were compared using MMPI scale scores. The results strongly suggest that parent loss and family size and their interaction have an important impact on adult personality traits as measured by MMPI scores. The strong adverse impact of intermittent loss and temporary loss in large families (much greater than that of permanent loss) is a crucial finding not previously noted in the literature.
A case of congenital urethral duplication cyst and its embryological significance.
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Strategic financial planning: mandate for survival.
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The congenital varicella syndrome.
Two children, aged 18 months and 3 years, with the congenital varicella syndrome are described. Neuropathic bladder and lax abdominal wall musculature were present in one case. In the other, paralysis and marked hypoplasia of one arm, and an ipsilateral Horner's syndrome, were the main abnormalities. Extensive skin scarring corresponding to a dermatome distribution was present in both children. This constellation of abnormalities, which may best be explained on the basis of a developmental radiculopathy, emphasises the neuropathic effects on the fetus of varicella zoster (VZ) infection in early pregnancy.
Determination of the carbon-bound electron composition of microbial cells and metabolites by dichromate oxidation.
The applicability of the silver sulfate-acid dichromate oxidation (chemical oxygen demand) method for determining the carbon-bound electron compositions of microbial cells, substrates, and metabolic by-products was evaluated. An approach for approximating the carbon-bound electron composition of microbial cells from CHN data is also presented. Ten aliphatic and aromatic carboxylic acids, 17 amino acids, and 8 sugars generally gave 96 to 101% (mainly >/=98%) recovery with 0.0625 N dichromate (digestion mixture of 10 ml of sample-10 ml of 0.25 N dichromate-20 ml of Ag(2)SO(4)-amended concentrated H(2)SO(4)). Recoveries of nicotinic acid (5%) and methionine (65%) were incomplete; arginine (125%) and two purine and three pyrimidine bases (105 to 120%) were overestimated. The validity of 0.0625 N dichromate for determining the carbon-bound electron composition of bacterial cells was supported by theoretical analysis of the carbon-bound electron composition of hypothetical bacterial cell material (defined monomer composition) and by the compatibility of elemental and dichromate oxidation-derived carbon-bound electron compositions of typical bacterial cells.
Detection of ototoxicity from drugs applied topically to the middle ear space.
This paper summarizes data obtained from two separate studies done in our laboratory. Both studies were done to investigate the possibility that drugs commonly applied to the middle ear space could be the cause of sensori-neural hearing loss. The two drugs that were felt to be the most likely candidates for the studies were neomycin and polymyxin B. In the neomycin study, the various drug concentrations were administered three times a day for four weeks. In the polymyxin B study, the administration was three times a day for two weeks. Cochlear function was evaluated electrophysiologically and by examination of surface preparations of the organ Corti. The data show that both neomycin and polymyxin B can, in concentrations similar to those found in commercially available otic drops, induce cochlear damage when they are applied to the middle ear space of guinea pigs. The degree of damage produced is related. In the case of neomycin, it was shown that the effect worsens as the duration of the dosage administration is extended...
Maternal phenylketonuria: a family with seven mentally retarded siblings.
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