Orientation of functional activating regions in the Escherichia coli CRP protein during transcription activation at class II promoters

At class II CRP-dependent promoters the DNA site for CRP overlaps the DNA site for RNA polymerase, covering the -35 region. Transcription activation at class II CRP- dependent promoters requires a contact between an activating region in the upstream subunit of the bound CRP dimer and a contact site in the C-terminal domain of the alpha-subunit of RNA polymerase. Transcription activation is suppressed by amino acid substitutions in the activating region, but activation can be restored by second site substitutions at K52 or E96. These substitutions identify two separate regions on the surface of CRP that appear to be able to interact with RNA polymerase specifically at class II promoters. Using the method of 'oriented heterodimers' we show that these alternative activating regions are functional in the downstream subunit of the bound CRP dimer.

The costs of visits to emergency departments

BACKGROUND

Many visits to emergency departments are for minor medical problems, and these visits are criticized as being expensive and economically inefficient. This study examines the marginal costs (the extra costs for an additional visit) of emergency department visits.

METHODS

Monthly data on the costs of hospital and physicians' services from 1991 through 1993 were obtained from a sample of six community hospitals in Michigan. The data were analyzed with ordinary least-squares regression techniques to determine the ratio of marginal to average costs. Average and marginal costs were then determined for 24,010 visits during 12 randomly selected weeks in 1993. A visit by an individual patient was the unit analysis, and visits were classified as nonurgent, semiurgent, or urgent according to explicit criteria. Costs and charges were determined for all visits and were classified according to the degree of urgency.

RESULTS

For all emergency department visits, the average charge was $383, the average cost was $209, and the marginal cost was $88 (42 percent of the average cost). Thirty-two percent of the visits were classified as nonurgent, 26 percent as semiurgent, and 42 percent as urgent. For nonurgent visits, the average charge was $124, the average cost was $62, and the marginal cost was only $24. For semiurgent visits, the average charge was $312, the average cost was $159, and the marginal cost was $67. For urgent visits, the average charge was $621, the average cost was $351, and the marginal cost was $148.

CONCLUSIONS

The true costs of nonurgent care in the emergency department are relatively low. The potential savings from a diversion of nonurgent visits to private physicians' offices may therefore be much less than is widely believed.

Real time measurements of elongation by a reverse transcriptase using surface plasmon resonance

A rapid direct assay for polymerase-induced elongation along a given template is an obligate requirement for understanding the processivity of polymerization and the mode of action of drugs and inhibitors on this process. Surface plasmon resonance can be used to follow the association and the dissociation rates of a given reverse transcriptase on DNA.RNA and DNA.DNA hybrids immobilized on a biotin-streptavidin surface. The addition of nucleotides complementary to the template strand produces an increase in the local mass, as deduced from an increase in the measured signal, due to elongation of the primer strand that allows an estimation of both the extent and rate of the polymerization process. The terminator drug 3'-deoxy-3'-azidothymidine triphosphate completely abolishes the increase in signal as would be expected from an inhibition of elongation. This technique provides a sensitive assay for the affinities of different polymerases for specific templates and for the effects of terminators of the elongation process.

The future of wellness care

The current restructuring of the US healthcare system will result in a new emphasis on wellness services. Hospitals are challenged to define the wellness role they will play within managed care. This article reports on interviews with wellness experts and hospital CEOs, who reflect on these challenges and define strategic priorities. The interviews highlight the need to understand that this challenge requires a powerful paradigm shift from illness to preventive services, and a major rethinking of how hospitals operate to offer cost-effective preventive services. The interviewees see great opportunity, but also great need for thorough planning, careful design, and implementation. Hospital leaders must understand clearly what wellness means, and how best to position their hospital for strategic advantage. In the final analysis, wellness emerges as an integral strategy in the overall process of managing change.

Quantitative comparison of background rejection, signal-to-noise ratio, and resolution in confocal and full-field laser scanning microscopes

Development of a laser scanning microscope for simultaneous three-dimensional imaging in both a full-field laser scanning mode (FLSM) and a confocal laser scanning mode (CLSM) permits the direct comparison of axial resolution and out-of-focus background rejection as a function of sample thickness for both FLSM and CLSM with varying detector aperture (pinhole) radii. The sample-dependent detector aperture radii that optimize the signal-to-noise ratio (S/N) in the CLSM are experimentally determined. The results verify earlier calculations [Appl. Opt. 33, 603 (1994)]. Using these results, we discuss the practical and theoretical limits on the S/N in the CLSM and compare them with those of a full-field epifluorescence microscope (FEM) that is enhanced by image deconvolution. The specimen volume over which the FLSM exhibits imaging properties that are equivalent to a FEM is calculated in the appendices.

Netropsin and spermine conjugates of a water-soluble quinocarcin analog: analysis of sequence-specific DNA interactions

BACKGROUND

Quinocarcin is the simplest of the bioxalmycin/naphthyridinomycin/tetrazomine/saframycin class of anti-tumor antibiotics, which damage DNA in a process that is inhibited by superoxide dismutase (SOD). The oxazolidine moiety of this class of anti-tumor antibiotics undergoes a redox self-disproportionation reaction of the Cannizzaro type. The reaction is proposed to proceed via an intermediate carbon-centered radical, which then reduces molecular oxygen to give superoxide. We set out to determine whether the DNA-cleavage properties of these anti-tumor antibiotics could be retained in less complex analogs of quinocarcin.

RESULTS

A totally synthetic, water-soluble analog of quinocarcin has been prepared. This analog produced superoxide, but had considerably reduced ability to cleave supercoiled circular DNA compared to quinocarcin or tetrazomine. When conjugated to the DNA-binding molecule spermine, however, it cleaved DNA as effectively as quinocarcin at less than 1/10 the concentration. A conjugate with netropsin displayed selective cleavage around the sequence 5'-d(ATTT)-3'. Molecular modeling of the interaction between the conjugate and DNA, together with the pattern of cleavage, indicates that a non-diffusable oxidant is involved in sequence-selective DNA cleavage. The spermine conjugate displayed weak antimicrobial activity.

CONCLUSIONS

Knowledge of the stereoelectronic requirements for superoxide production by quinocarcin has allowed us to design a structurally less complex analog which has many of the same physical properties, including water solubility, the ability to produce superoxide and the ability to cleave DNA. Covalently attaching known DNA-binding molecules to this analog gave a compound that produced sequence-specific DNA damage. Our results suggest that a mechanism other than superoxide production can mediate DNA damage by the netropsin conjugate.

Benign familial pemphigus--premenstrual exacerbation suppressed by goserelin and oophorectomy

We report the case of premenstrually exacerbated benign familial pemphigus which showed dramatic improvement with subcutaneous goserelin, a gonadotrophin-releasing hormone analogue. Total abdominal hysterectomy and bilateral salpingo-oophorectomy and oestrogen replacement therapy sustained the improvement.

Development of GM-CSF antagonist peptides

Granulocyte/macrophage colony stimulating factor (GM-CSF) is both a hematopoietic growth factor and a cytokine implicated in inflammatory disease. The development of GM-CSF antagonist peptides corresponding to the GM-CSF native sequence should allow their modification into higher affinity analogs, but this is hampered by the low affinity of linear peptides. To adequately evaluate such low affinity peptides, the use of several independent assays should allow specific versus nonspecific inhibitors to be distinguished. In this study, inhibition of GM-CSF-dependent cell growth, inhibition of GM-CSF binding and immunologic cross-reactivity between GM-CSF-derived peptides and native protein by neutralizing antibodies have been used to evaluate peptide analogs with potential bioactivity. The GM-CSF sequence was divided into 6 peptides ranging in size from 15-24 amino acids. Antisera were raised to these peptides in mice and assayed for immunologic cross-reactivity. 4/6 anti-peptide antisera bound GM-CSF on ELISA and 3/6 on immunoprecipitation. Antisera to two of the peptides (corresponding to residues 17-31 and 96-112) inhibited GM-CSF-dependent cellular proliferation in two cell lines, with one peptide derived from residues 17-31 demonstrating inhibition of GM-CSF binding and direct biological inhibitory activity. A peptide that did not elicit native GM-CSF reactive antibodies, corresponding to residues 54-78, was recognized by two neutralizing monoclonal antibodies. It exhibited inhibition of GM-CSF binding and direct biological antagonist activity. These studies implicate two sites in mediating GM-CSF biological activity, and indicate that biological antagonists can be developed based on these sites.

Simultaneous quantification of an anti-inflammatory compound (DuP 697) and a potential metabolite (X6882) in human plasma and urine by high-performance liquid chromatography

A high-performance liquid chromatographic (HPLC) method using fluorescence detection has been developed for the simultaneous analysis of low nanogram concentrations of an anti-inflammatory drug, 5-Bromo-2-(4-fluorophenyl)-3-[4-(methylsulfonyl)phenyl]thiophene (DuP 697), and a potential metabolite (X6882) in human plasma and of DuP 697 in human urine. This assay method used an EM Separations Lichrospher C18 endcapped column. The mobile phase was acetonitrile-water (75:25, v/v). The detection of DuP 697 and X6882 was by fluorescence at excitation and emission wavelengths of 256 and 419 nm, respectively. The chromatographic system could separate DuP 697 from X6882, the external standard (anthracene), and other endogenous substances present in human plasma. In human plasma the limits of quantification for DuP 697 and X6882 were 3 and 20 ng/ml, respectively; the limit of quantification for DuP 697 in human urine was 5 ng/ml. These compounds were shown to be stable in frozen (-20 degrees C) human plasma and urine for at least 9 weeks. The assay described has been used to characterize DuP 697 pharmacokinetics after oral administration in humans.

Inhibition of cytolytic T lymphocyte activity by oxysterols

The objective of this study was to investigate the effects of oxysterols (OS), namely 5 alpha-hydroxy-6-ketocholestanol, 6-ketocholestanol and 25-hydroxycholesterol, on specific cell-mediated cytotoxicity by C57BL/6 spleen cells against P815-X2 (a DBA/2 mastocytoma) target cells. Cytolytic T lymphocytes (CTL) were generated by intraperitoneally injecting C57BL/6 mice with P815-X2 tumor cells 10 d prior to the cytotoxicity experiments. Preincubation of CTL with 10(-5) M 5 alpha-hydroxy-6-ketocholestanol and 6-ketocholestanol for 45 min in lipoprotein-depleted medium resulted in an inhibition of cytolytic activity (73 and 43%, respectively) as measured by 4-h 51Cr release. At a concentration of 5 x 10(-6) M, 5 alpha-hydroxy-6-ketocholestanol inhibited CTL activity by 65%, whereas 6-ketocholestanol did not elicit any inhibition. By contrast, 25-hydroxycholesterol did not inhibit CTL at either concentration, although it is known to be a potent inhibitor of 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, the rate-limiting enzyme in the cholesterol biosynthetic pathway. When CTL were preincubated with OS in lipoprotein-replete medium, there was no inhibition of CTL activity at the respective concentrations. The results suggest that the inhibition of CTL activity upon short-term incubation with OS is not due to the inhibition of cholesterol synthesis, but may be due to the insertion of OS into the plasma membrane to replace cholesterol and alteration of membrane physical properties.

Two-photon molecular excitation provides intrinsic 3-dimensional resolution for laser-based microscopy and microphotochemistry

With the development of sensitive and specific fluorescent indicators, modern laser scanning microscopies enable visualization and measurement of submicron, dynamic processes inside living cells and tissues. Here we describe the working principles of new, nonlinear laser microscopies based on two-photon molecular excitation. In these techniques, a pulsed laser produces peak photon densities high enough that when focused into an appropriate medium, excitation by photon energy combinations can occur. For example, two red photons interacting simultaneously with a fluorescent molecule can excite within it a UV electronic transition, one corresponding to twice the energy of each single photon. Because the amount of two-photon excitation depends on the square of the local illumination intensity, this process exhibits a unique localization to the diffraction-limited spot of the beam focus. Elsewhere along the beam, excitation of background and photodamage is virtually nonexistent. Focal point localization of two-photon excitation lends to all visualization, measurement, and photopharmacology studies an intrinsic, three-dimensional resolution. We describe some preliminary biological applications, specifically, imaging of vital DNA stains in developing cells and embryos, imaging of cellular metabolic activity from NADH autofluorescence, spatially resolved measurements of cytoplasmic calcium ion activity, and optically induced micropharmacology using caged bioeffector molecules.

O2-dependent cleavage of DNA by tetrazomine

A mechanism for the reduction of molecular oxygen that results in the O2-dependent cleavage of both single-stranded and double-stranded DNA by the antitumor antibiotic tetrazomine (1) is presented. The results are discussed in the context of a redox self-disproportionation of the oxazolidine moiety of tetrazomine. Comparisons are made to the structurally analogous natural product quinocarcin (2) in which, like tetrazomine, the oxazolidine moiety is invoked in redox chemistry, which ultimately results in the reduction of molecular oxygen to superoxide.

Innervation and mast cells of the rat exorbital lacrimal gland: the effects of age

The distribution of nerves and mast cells was studied in the lacrimal glands of 3-5-, 14- and 24-month-old rats, using light microscopic histochemical and immunohistochemical techniques. In 14-month and, to a greater extent, in 24-month-old rats there were signs of chronic inflammation and patchy destruction of acinar, ductal and vascular tissue. The glands of the three different age groups contained acetylcholinesterase (AChE), vasoactive intestinal polypeptide (VIP)-, neuropeptide Y (NPY)-, calcitonin gene-related peptide (CGRP)-, tyrosine hydroxylase-, substance P- and the phosphoprotein B-50-immunoreactive nerves. B-50-immunoreactive nerves were distributed around acini, blood vessels and ducts, in a similar manner to VIP and AChE. Substance P- and CGRP-immunoreactive nerves were sparsely distributed in interlobular connective tissue and around ducts and blood vessels. Tyrosine hydroxylase- and NPY-containing nerves were found around blood vessels. The 3-5- and 14-month-old rats had a similar pattern of innervation, however, by 24 months there was a reduction in the number and intensity of immunoreactive nerves. The loss of nerves was particularly associated with damage to the gland. Mast cells were also found in the lacrimal, mostly associated with neurovascular tissue. These could be histochemically labelled with alcian blue/safranin or toluidine blue and were immunohistochemically labelled with histamine and serotonin. Substance P-, CGRP-, VIP- and NPY-immunoreactive nerves were found apposed to mast cells. A large increase in mast cells was observed in 24-month compared to 3-5-month-old rats and these were found throughout the acinar tissue. These results show that a decrease in innervation and also chronic inflammation, with mast cell infiltration, occurs in aged rats. These findings may be contributing factors to reduced tear output in aging.

Sudden death caused by giant cell myocarditis following coronary artery bypass

An unusual case of idiopathic giant cell myocarditis (GCM) is described. The patient had a 5-year history of stable and unstable angina, poorly controlled by medical treatment. He underwent a successful coronary artery bypass, but 2 months later died suddenly at home. A coroner's autopsy revealed isolated GCM. This newly described possible association between the surgery and the condition is discussed and the pertinent literature is reviewed. We suggest that the list of causes of GCM in postoperative patients should also include foreign-body reaction. Our findings support the view that myocarditis occasionally masquerades as fatal acute myocardial infarction.

Some effects of zona pellucida glycoproteins and sulfated polymers on the autoactivation of boar sperm proacrosin and activity of beta-acrosin

The effects of zona pellucida glycoproteins, sulfated polymers and non-sulfated polymers on the activation kinetics of boar sperm proacrosin to beta-acrosin have been investigated. The aim has been to understand more about the behaviour and function of this protein after it has been released from the acrosome at the time of fertilization. Purified proacrosin was allowed to autoactivate at pH 8.0 in the presence of different concentrations of homologous zona glycoproteins, sulfated polymers (fucoidan, chondroitin sulfates A, B and C, dextran sulfate, polyvinylsulfate and heparin) and non-sulfated polymers (dextran, polyvinylphosphate and hyaluronic acid). Enzyme activity was measured against N-benzoyl-L-arginine p-nitroanalide substrate and changes in molecular mass of the protein monitored by SDS-PAGE. Results show that zona pellucida glycoproteins, fucoidan, dextran sulfate and polyvinylsulfate all potentiate the conversion of proacrosin to beta-acrosin but subsequently inhibit its amidase activity. Dextran, polyvinylphosphate, chondroitin sulfates A, B and C and glucose-6-sulfate, on the other hand, either have no effect on autoactivation and beta-acrosin activity, or enhance it slightly. SDS-PAGE analysis confirmed these observations and further indicated that binding of sulfated polymers to proacrosin inhibited staining by Coomassie Blue. These results are consistent with the hypothesis that binding of zona pellucida glycoproteins and sulfated compounds to proacrosin/acrosin is stereospecific and that contact activation onto soluble 'surfaces' causes conformational changes that are responsible for potentiation or inhibition of activation. The implications of these findings for sperm binding and penetration of the zona pellucida are discussed.(ABSTRACT TRUNCATED AT 250 WORDS)

Health care reform and emergency department services

EDs are the access of last resort for many Americans, and cost-driven reform initiatives that restrict ED utilization could deter people from seeking necessary and timely medical services. The experience in Canada under universal coverage suggests that major reform could lead to a substantial increase in ED utilization, especially in view of the relative shortage of primary care physicians in the United States. Many hospitals could face short-term overcrowding problems that compromise the quality of care provided in EDs, and rural hospital EDs face specific and unique problems relative to competition and cost efficiency. Integration of emergency services into comprehensive health delivery systems under the concept of managed competition is essential to ensure access and cost-effective delivery of services. The hospital ED may well serve as an important focal point in the development of alternative physician-hospital relationships.

A new high frequency polymorphism in the HER-2/neu oncogene in normal tissue and breast tumors

The HER-2/neu (erbB-2) oncogene, if amplified and/or overexpressed in breast and ovarian cancers, is associated with a poor prognosis. Employing direct DNA sequencing, we have discovered and sequenced an 80 base pair intron from human placenta which contains an A to G polymorphism. This polymorphism lends itself to restriction fragment length polymorphism analysis of the PCR product spanning this intron. All three genotypes, homozygous A, heterozygous, and homozygous G appear in normal control populations and breast tumors. Also, no difference was seen between the polymorphic form found in five breast cancers and the corresponding normal tissue.

Specificity of binding of zona pellucida glycoproteins to sperm proacrosin and related proteins

A major regulatory site for species specificity of fertilization in mammals lies at the level of sperm binding to the zona pellucida. This implies a high degree of complementarity between gamete receptor molecules. One putative receptor molecule on spermatozoa is proacrosin/acrosin which binds to zona pellucida glycoproteins (ZPGPs) non-enzymically and with high affinity. The mechanism of recognition involves polysulphate groups in a particular stereochemical orientation and it has been suggested that this may contribute to species specificity of sperm-egg binding. In the present work this hypothesis has been tested by challenging 125I-labelled ZPGPs from pig, cow, and hamster eggs to recognize heterologous sperm proacrosins as well as a variety of sequence-related and unrelated proteins. Results show that pig and cow 125I-ZPGPs bind readily to boar, ram, and bull proacrosin but do not recognize guinea-pig proacrosin or any of the polysulphate binding proteins from rat, hamster, or mouse spermatozoa. Hamster 125I-ZPGPs also recognise boar, ram, and bull proacrosin as well as a range of unidentified proteins in pH3 extracts of hamster, rat, and mouse spermatozoa. The binding of ZPGPs to a variety of proteins not related to proacrosin is strongest to those with a high content of basic residues (i.e., pI > 8.5), although the secondary folding of the target protein is of major importance as boar proacrosin (pI 6.75) has the highest binding capacity of all proteins tested. Cross-reaction of ZPGP probes was not observed to guinea-pig proacrosin, suggesting that in this species the conformation of the protein is different to other sperm proacrosins.(ABSTRACT TRUNCATED AT 250 WORDS)

Health policy and quality: an ethical dilemma

Emergency medicine is on the front line of many important health issues, such as access for the poor and uninsured, the AIDS epidemic, and domestic violence. Virtually all key policy issues relating to emergency medicine deal with the concept of quality. During the 1970s, quality issues dealt with issues of value. Interest in quality is now vested in the tradeoff between cost containment activities and preserving access to health care. Key definitions of efficacy, effectiveness, and efficiency are provided. A policy approach to quality definition and assessment is suggested based upon the concepts of continuous quality improvement. The role of emergency physicians in health policy and the future of emergency medicine are discussed.

Malignant melanoma of penis and male urethra. Is it a difficult tumor to diagnose?

Two cases of malignant melanoma of the penis and male urethra are presented in which the diagnosis was difficult to make clinically and histopathologically. Our findings support the general opinion that melanomas at this site have a poor prognosis.

Histopathology: its role in the diagnosis of a child with intussusception

Spontaneous expulsion of a small portion of the intestinal mucosa per rectum, in an infant, associated with ileocolic intussusception is an extremely rare condition. This appears to be the first report of such a clinical presentation. The initial diagnosis was raised by the histopathologist following examination of the eliminated piece of tissue. Subsequent barium enema and laparotomy confirmed the diagnosis and the ileocolic intussusception was successfully reduced. This unusual presentation, together with a review of the pertinent literature, is discussed. Our findings indicate that both the clinicians and histopathologists should be aware of this phenomenon and stress the importance of the histological examination of any unusual faecal matter. This may prove to be a simple, quick and cheap method of investigation of this condition.

Tobacco and alcohol use among Australian secondary school students in 1990

OBJECTIVE

To obtain up-to-date prevalence estimates of tobacco smoking and alcohol drinking among Australian secondary students, and to compare these estimates with those obtained from similar studies conducted in 1984 and 1987.

DESIGN

Data were collected from 24,892 secondary students aged 12 to 17 years from all Australian States and the Northern Territory. A stratified two-stage sample design was used. First, a random sample of schools was selected and second, for each school a sample of 80 students was randomly selected from predetermined year levels. A total of 351 schools participated in the survey. Students completed an anonymous, self-administered questionnaire on their smoking and drinking behaviours.

RESULTS

The prevalence of current smoking (defined as having smoked at least one cigarette in the week preceding the survey) was found to increase with age to reach a peak of 25% among 16-year-old boys and 29% among girls aged 15 years. From the age of 13, smoking was more prevalent among girls than boys. Among current smokers, boys were heavier smokers than were girls. Unlike smoking, drinking was slightly more prevalent among boys than girls; boys were heavier drinkers. The proportion consuming at least one alcoholic drink in the week before the survey rose with age to a peak of 51% of boys and 46% of girls aged 17 years. Comparisons with data obtained from a similar survey conducted in 1987 showed that there had been a decrease in the proportion of 12 to 15 year olds smoking. The prevalence of drinking among both 12 to 15 year olds and 16 to 17 year olds was significantly lower in 1990 than 1987.

CONCLUSIONS

While the continuing downward trends in smoking and drinking among younger students is encouraging, the results show that there are still large numbers of students smoking and drinking.

National health reform and emergency medicine

I accept the responsibility of the office of President of ACEP today with great pride--not in myself at having achieved this prestigious office, but rather in the specialty of emergency medicine. I am honored to have the privilege and pleasure of your association and support, and I am immensely proud of being an emergency physician. I have presented these ideas and challenges in a spirit of enthusiasm and optimism for emergency medicine and ACEP. Innovation, courage, and determination are our heritage and will hopefully forever be our legacy. Emergency physicians truly are on the leading edge of the great issues of our society. I believe the time has come for us to assume a leadership position in medicine that reflects the dedication, compassion, and pioneering spirit on which this specialty was founded nearly 25 years ago--and which is so evident in this room today. Please join me in this exciting and worthwhile endeavor.

New outpatient treatment of recurrent patellar dislocations

From December 1987 through February 1991, outpatient arthroscopic procedures were done on patients experiencing recurrent dislocations of the patella. A modified Emslie-Trillat procedure was used. Twenty-four patients (27 knees) were available for follow-up. Using the criteria of Cox, excellent results were found in 78% (21 knees), whereas 18% (5 knees) were rated as good. Only 4% (1 knee) was considered fair, and none were rated poor. Most patients (96%) showed improvement. No patient suffered a postoperative dislocation. Based upon the findings of this study, it is concluded that this procedure is an effective method of treatment for patients having recurrent dislocations of the patella.

Public policy and quality assurance

The definition of quality varies widely among different key players in the American health care system. It is important for physicians and other providers to have an understanding of the public policy approach to quality assessment and assurance. Policy analysts use a number of techniques and methods in an attempt to define and balance the interests of individual patients with that of society as a whole. Benefit-cost, cost-effectiveness, and evaluation synthesis methods are used by public policy makers to arrive at rational consideration of the implications of allocation of scarce health care resources. Emergency medicine is on the forefront of many key policy decisions relative to the health care system. As the nation's health safety net, emergency medicine plays an integral and pivotal role in the definition, structure, and function of the health care system. In this regard, it is essential that emergency physicians and emergency medicine organizations play an active and formative role in the rapidly changing health care environment. Understanding conceptual approaches to the public policy approach to the health care system is an important endeavor for leadership in emergency medicine.

Actinomycosis associated with pilonidal sinus of the penis

We report a case of actinomycosis associated with a penile pilonidal sinus. This association does not appear to have been described previously. We recommend the submission of biopsies of unusual lumps in the genital region (fresh biopsies for bacteriological examination and fixed biopsies for histomorphological assessment).

Impalpable breast lesions: marking of surgical specimens for pathology

A simple method is described to indicate the abnormal area in breast biopsy specimens excised following mammographic localization of impalpable lesions. A hypodermic needle is inserted into the specimen through the abnormality immediately following specimen radiography, removing the need to radiograph individual tissue slices. The technique has proved successful in 121 out of 122 specimens.

Inhibition of NK cell-mediated cytotoxicity by oxysterols

Some of the oxidation products of cholesterol (oxysterols) have profound effects on plasma membrane structure and function. The present studies were undertaken to determine the effects of oxysterols on NK cell-mediated cytotoxicity. When mouse spleen cells were preincubated with certain oxysterols, NK cell cytotoxicity was inhibited without loss of effector cell viability. The strongest inhibition was observed with oxysterols that are oxidized at the C-5, C-6, or C-7 positions of the sterol nucleus. Among these, 7 beta-hydroxycholesterol caused more inhibition than 7 alpha-hydroxycholesterol suggesting that the spatial orientation of the hydroxyl group in the beta-position results in a greater perturbation in plasma membrane structure than that oriented in the alpha-position. In contrast, oxysterols that are oxidized at the C-20 and C-25 positions that are located on the C-17 acyl chain had little or no inhibitory effect, suggesting that oxidation in the cholesterol nucleus which is situated closer to the phospholipid headgroups at the lipid bilayer-aqueous interface results in a more profound effect on the plasma membrane physical structure. These results suggest that the lytic function of NK cell is sensitive to alterations in the physical state of its plasma membrane induced by oxysterols.

Preliminary studies on the vascular anatomy of the equine superficial digital flexor tendon

The vascular and microvascular anatomy of normal equine superficial digital flexor tendons was studied by dissection of vinyl-perfused specimens and by microangiography on high detail film. The presence of an extensive intratendinous vascular latticework was confirmed, and a 'nutrient artery' described closely associated with the accessory ligament of the superficial digital flexor tendon (proximal check ligament). Circumferential stripping of the paratenon from the tendon to eliminate afferent vessels was performed bilaterally in three horses and unilaterally in a fourth, followed by a treadmill training regimen. No resulting intratendinous lesions could be documented on gross post mortem and histological examination at three, 10, or 35 days post operatively. There was mild paratendinous proliferation in all instances. In one horse, four intratendinous ligatures were placed within the medial and lateral borders of the contralateral tendon to isolate further from its blood supply a 10 cm segment. Gross lesions at 35 days post operatively included a marked paratendinous response involving the entire 10 cm segment, and a darkened, soft focus within the core of the tendon. Histopathology and electron microscopy demonstrated focal degeneration. It was concluded that the blood supply of the normal equine superficial digital flexor tendon is primarily intratendinous, rather than paratendinous as previously thought. The lesions in one horse similar to those in naturally occurring tendinitis supported a vascular aetiology of the disease, and set the groundwork for studies aimed at the development of a clinically relevant tendinitis model.

To lead or lag?

Health care policy is the hottest of all emerging issues. Although the largest foundations have changed to meet the challenge, one question remains: should health funders advocate as well as explore solutions?

Giardia lamblia and Cryptosporidium infections in child day-care centers in Fulton County, Georgia

Risk factors for the introduction, spread and persistence of Cryptosporidium and Giardia lamblia infections in child day-care centers are not well understood. In 1989 and 1990 stool specimens were obtained from 292 diapered children attending 17 randomly selected day-care centers in Fulton County, GA; 8 (2.7%) children in 2 centers were infected with Cryptosporidium and 21 (7.2%) children in 7 centers were infected with Giardia. In 1986 the prevalence of Cryptosporidium and Giardia in these same centers had been 0.4 and 11.0%, respectively; the prevalence of Cryptosporidium, but not Giardia, increased significantly (P = 0.04) between 1986 and 1989 to 1990. Risk factors for Giardia infection included day-care attendance for greater than 3 months, the presence of toddlers in the classroom and the presence of other children in the household. Day-care centers with a Giardia-positive child in 1986 were not more likely to have an infected child in 1989 to 1990. Cryptosporidium, like Giardia, may be endemic in day-care centers in Fulton County.

Use of pooled formalin-preserved fecal specimens to detect Giardia lamblia

Three formalin-preserved fecal specimens from the same child attending a child-care center were pooled and compared with the three separate individual specimens by a single microscopic examination of concentration sediment for Giardia lamblia. The sensitivity of the pooled system was 100% when two or more individual specimens were positive and 88% when only one individual specimen was positive. The organism density in a single specimen was not a factor of whether the pool of specimens was positive or negative. Nearly half of the pools that contained positive specimens had only one of three specimens with positive results, reinforcing the need for multiple stool examinations when diagnosing G. lamblia infections.

Determination of the capacity of ram epididymal and ejaculated sperm to undergo the acrosome reaction and penetrate ova

An understanding of epididymal maturation of sperm requires descriptions of changes in membrane properties and their relation to changes in cell function. While sperm membranes have been studied in some detail in rams, few reports address associated functional changes. This report provides such data by evaluating (a) the time course of sperm acrosome reaction (AR) induction for cells from each epididymal region; (b) the capacity of epididymal sperm to penetrate ova; (c) differences in physiological AR and general sperm degeneration; and (d) acrosin release of epididymal sperm. Ram epididymal (caput, corpus, and proximal and distal cauda) and ejaculated (EJ) sperm were incubated in vitro to assess their capacity to undergo an AR. Light microscopy revealed that in sperm populations which had traversed the proximal cauda epididymidis, greater than or equal to 50% exhibited an endogenous AR in less time (less than 17 h) than did sperm isolated from more proximal regions of the epididymis (22-greater than 50 h). Heparin added to sperm did not stimulate the AR in epididymal or EJ sperm, whereas addition of a calcium ionophore (A23187) increased AR rates for cauda and EJ sperm, but not caput or corpus sperm. A second experiment evaluating percent AR, percent motile cells, and percent hamster ova penetrated revealed that sperm isolated from regions proximal to the cauda epididymidis failed to penetrate ova. When cauda or EJ sperm exhibited motility greater than 5% and AR greater than 24%, penetration of hamster eggs occurred. Comparisons of acrosomal integrity by electron or light microscopy were not different for sperm at any stage of epididymal maturation, suggesting that minimal nonspecific membrane changes occur and that light microscopy is valid for evaluating the acrosomal status of ram spermatozoa. Acrosin activity (sperm bound and dissociated) also was measured. Both total activity and release of acrosin from sperm to the medium during an 8-h incubation was greater for mature than for immature sperm. Results from these experiments are discussed in relation to the changes that must occur in sperm as they acquire the capacity to undergo an AR and penetrate hamster ova.

Evaluation of a commercially available enzyme-linked immunosorbent assay for Giardia lamblia antigen in stool

The lack of a quick, simple, and inexpensive diagnostic test has limited the ability of public health officials to rapidly assess and control outbreaks of Giardia lamblia in child day-care centers. We evaluated the performance of a commercially available enzyme-linked immunosorbent assay (ELISA) for the detection of a G. lamblia-associated antigen in stool. Stool specimens were collected from the diapers of 426 children attending 20 day-care centers, fixed in 10% Formalin and polyvinyl alcohol, and examined by microscopy by Formalin concentration and trichrome staining techniques. Specimens were also tested visually and spectrophotometrically by ELISA. Of 99 tests positive by microscopy, 93 were visually positive by ELISA (sensitivity, 93.9%). Of 534 tests negative for G. lamblia by microscopy, 32 (6.0%) were ELISA positive. However, on the basis of examination of multiple specimens from the same child, none of these could be considered false-positive ELISAs; the specificity of the ELISA was therefore 100%. The sensitivity of both microscopy and ELISA improved as the number of specimens per child increased. An optical density value of greater than 0.040 was 98.0% sensitive and 100% specific for G. lamblia. This ELISA, which appeared to be more sensitive for G. lamblia than did microscopic examination of stool, should be useful as an epidemiologic tool, particularly in day-care settings, and may also have a role in confirming clinical diagnoses of giardiasis.

Radiation-induced augmentation of host resistance to histocompatible tumor in mice. Detection of a graft antitumor effect of syngeneic bone marrow transplantation

Lethally irradiated and syngeneic bone marrow-reconstituted (C57BL/6JxDBA/2J) F1 female mice demonstrated prolonged survival following challenge with the DBA/2 mastocytoma P815-X2 compared with non-irradiated littermate controls. This radiation-induced augmentation of host resistance to P815-X2 was not abolished by the adoptive transfer of normal syngeneic spleen cells. In addition, this phenomenon was not detectable in adult thymectomized recipients, suggesting the requirement for an intact host thymus. This effect was also absent in syngeneic F1 male recipients. We suggest that lethal irradiation and marrow reconstitution may result in activation of a nonspecific immune effector mechanism against tumor cells--and, as such, may serve as a model to explore the graft-antitumor effect of bone marrow transplantation.

Phase I clinical trial with floxuridine and high-dose continuous infusion of leucovorin calcium

Sixty-two patients with metastatic disease were treated with continuous infusion folinic acid (leucovorin calcium; Lv) and 2-deoxy-5-fluorouridine (floxuridine; FUDR). Lv was given by constant intravenous (IV) infusion at 500 mg/m2/d, days 1 to 6, while FUDR was given by IV push, days 2 to 6, at 3:00 PM daily with doses ranging from 294 to 1,214 mg/m2/d. This program was well tolerated with dose-limiting toxicities of diarrhea and stomatitis, while hematologic toxicity was minimal. Eighty-two percent of the assessable patients (46 of 56) had failed at least one chemotherapy regimen. One complete remission lasting 9 months and 10 partial remissions ranging from 5 to 10 months were observed in this heavily pretreated patient population for an overall response rate of 20%. These data suggest that the combination therapy with Lv and FUDR may have clinical use. Because of differing patient sensitivity to this drug combination, the recommended dose of FUDR for the initial therapy cycle is 500 mg/m2/d, days 2 to 6, with subsequent escalation to 900 mg/m2/d in those patients without extreme sensitivity. Phase II studies are now in progress with these doses.