Prioritizing the Interview in Selecting Resident Applicants: Behavioral Interviews to Determine Goodness of Fit

From our initial screening of applications, we assess that the 10% to 15% of applicants whom we will interview are all academically qualified to complete our residency training program. This initial screening to select applicants to interview includes a personality assessment provided by the personal statement, Dean's letter, and letters of recommendation that, taken together, begin our evaluation of the applicant's cultural fit for our program. While the numerical scoring ranks applicants preinterview, the final ranking into best fit categories is determined solely on the interview day at a consensus conference by faculty and residents. We analyzed data of 819 applicants from 2005 to 2017. Most candidates were US medical graduates (62.5%) with 23.7% international medical graduates, 11.7% Doctors of Osteopathic Medicine (DO), and 2.1% Caribbean medical graduates. Given that personality assessment began with application review, there was excellent correlation between the preinterview composite score and the final categorical ranking in all 4 categories. For most comparisons, higher scores and categorical rankings were associated with applicants subsequently working in academia versus private practice. We found no problem in using our 3-step process employing virtual interviews during the COVID pandemic.

Training the Next Generation of Pathologists: A Novel Residency Program Curriculum at Montefiore Medical Center/Albert Einstein College of Medicine

Pathology residency training is currently a time-intensive process, frequently extending up to 6 years in duration as residents complete 1 or 2 fellowships following graduation. Innovative training curricula may help address the impending changes in the health-care landscape, particularly future shortfalls in pathology staffing and changing health-care models that incorporate more work within interdisciplinary teams. Montefiore has created a novel residency training program aimed at accelerating the acquisition of competency in pathology, preparing residents for independent practice at the completion of residency training, and providing residents with the requisite adaptability and consultative skills to excel wherever they choose to practice. We describe the implementation of this novel pathology residency training curriculum at Montefiore Medical Center/Albert Einstein College of Medicine and the perception of residents in both the old curriculum and the new curriculum.

Report and Recommendations of the Association of Pathology Chairs' Autopsy Working Group

Autopsy has been a foundation of pathology training for many years, but hospital autopsy rates are notoriously low. At the 2014 meeting of the Association of Pathology Chairs, some pathologists suggested removing autopsy from the training curriculum of pathology residents to provide additional months for training in newer disciplines, such as molecular genetics and informatics. At the same time, the American Board of Pathology received complaints that newly hired pathologists recently certified in anatomic pathology are unable to perform an autopsy when called upon to do so. In response to a call to abolish autopsy from pathology training on the one hand and for more rigorous autopsy training on the other, the Association of Pathology Chairs formed the Autopsy Working Group to examine the role of autopsy in pathology residency training. After 2 years of research and deliberation, the Autopsy Working Group recommends the following:Autopsy should remain a component of anatomic pathology training.A training program must have an autopsy service director with defined responsibilities, including accountability to the program director to record every autopsy performed by every resident.Specific entrustable activities should be defined that a resident must master in order to be deemed competent in autopsy practice, as well as criteria for gaining the trust to perform the tasks without direct supervision.Technical standardization of autopsy performance and reporting must be improved.The current minimum number of 50 autopsies should not be reduced until the changes recommended above have been implemented.

Professionalism in Pathology: A Case-Based Approach as a Potential Educational Tool

Context.—Professionalism issues in residency training can be difficult to assess and manage. Generational or role-based differences may also exist between faculty and residents as to what constitutes unprofessional behavior and how to manage it.

Objective.—To examine and compare how faculty and residents would approach the same 5 case scenarios detailing various aspects of unprofessional behavior.

Design.—Five case scenarios highlighting various unprofessional behaviors were presented in a workshop at an annual meeting of pathology department chairs, residency program directors, and undergraduate pathology medical educators (ie, pathologists involved in medical student pathology education). The same cases were presented to a cohort of pathology residents currently in training. A standard set of responses were offered to the participants, polling results were collected electronically, and results were compared.

Results.—Faculty and residents were fairly consistent within their respective groups. In a subset of cases, faculty were more likely to favor working with the individual in the scenario, whereas resident respondents were more likely to favor either no response or a severe response. Generational or role-based differences were also potentially evident.

Conclusions.—Assessing expectations and differences around professionalism for both faculty and residents should be considered as part of any educational and management approach for professionalism. Although a level of generational differences appears to be evident in this study regarding the recognition and management of unprofessional behavior, there was also agreement in some cases. Further exploration into the discrepant responses between faculty and residents may prove useful in developing educational, assessment, and remediation resources.

Training Pathology Residents to Practice 21st Century Medicine: A Proposal

Scientific advances, open information access, and evolving health-care economics are disrupting extant models of health-care delivery. Physicians increasingly practice as team members, accountable to payers and patients, with improved efficiency, value, and quality. This change along with a greater focus on population health affects how systems of care are structured and delivered. Pathologists are not immune to these disruptors and, in fact, may be one of the most affected medical specialties. In the coming decades, it is likely that the number of practicing pathologists will decline, requiring each pathologist to serve more and often sicker patients. The demand for increasingly sophisticated yet broader diagnostic skills will continue to grow. This will require pathologists to acquire appropriate professional training and interpersonal skills. Today’s pathology training programs are ill designed to prepare such practitioners. The time to practice for most pathology trainees is typically 5 to 6 years. Yet, trainees often lack sufficient experience to practice independently and effectively. Many studies have recognized these challenges suggesting that more effective training for this new century can be implemented. Building on the strengths of existing programs, we propose a redesign of pathology residency training that will meet (and encourage) a continuing evolution of American Board of Pathology and Accreditation Council for Graduate Medical Education requirements, reduce the time to readiness for practice, and produce more effective, interactive, and adaptable pathologists. The essence of this new model is clear definition and acquisition of core knowledge and practice skills that span the anatomic and clinical pathology continuum during the first 2 years, assessed by competency-based metrics with emphasis on critical thinking and skill acquisition, followed by individualized modular training with intensively progressive responsibility during the final years of training. We anticipate that implementing some or all aspects of this model will enable residents to attain a higher level of competency within the current time-based constraints of residency training.

Onboarding for Pathology Residency Programs-The Montefiore Experience

Onboarding is a system frequently used in the corporate world as a means of orienting incoming employees to their duties and inculcating the workplace values. The program aims to facilitate transition into new work roles and improve employee retention rates. At Montefiore, we have instituted an onboarding curriculum that is given to new anatomic and clinical pathology residents about a month prior to the start of residency. The program includes an introductory video series of basic histology and a series of anatomic and clinical case studies illustrating basic laboratory principles. This didactic content is tagged to learning objectives and short self-assessment modules. In addition, content related to the work ethos at Montefiore and the role of the core competencies and milestones in residency education are included. Finally, a broader component of the onboarding gives the incoming residents a social welcome to our area, including key information about living in the area surrounding Montefiore. The program has been well received by our residents for whom the content has helped to boost confidence when starting. We feel that the program is helpful in ensuring that all incoming residents start having received the same baseline didactic content. Transmitting this didactic content via onboarding allows our residents to begin the work of learning pathology immediately, rather than spending the first weeks of residency covering remedial content such as basic histology. Such a program may be useful to other pathology residencies, most of whom have residents from a range of backgrounds and whose prior exposure to pathology may be limited.

The pathology milestones and the next accreditation system

CONTEXT

In the late 1990s, the Accreditation Council for Graduate Medical Education developed the Outcomes Project and the 6 general competencies with the intent to improve the outcome of graduate medical education in the United States. The competencies were used as the basis for developing learning goals and objectives and tools to evaluate residents' performance. By the mid-2000s the stakeholders in resident education and the general public felt that the Outcomes Project had fallen short of expectations.

OBJECTIVE

To develop a new evaluation method to track trainee progress throughout residency using benchmarks called milestones. A change in leadership at the Accreditation Council for Graduate Medical Education brought a new vision for the accreditation of training programs and a radically different approach to the evaluation of residents.

DATA SOURCES

The Pathology Milestones Working Group reviewed examples of developing milestones in other specialties, the literature, and the Accreditation Council for Graduate Medical Education program requirements for pathology to develop pathology milestones. The pathology milestones are a set of objective descriptors for measuring progress in the development of competency in patient care, procedural skill sets, medical knowledge, practice-based learning and improvement, interpersonal and communication skills, professionalism, and systems-based practice.

CONCLUSIONS

The milestones provide a national standard for evaluation that will be used for the assessment of all residents in Accreditation Council for Graduate Medical Education-accredited pathology training programs.

A team-based approach to autopsy education: integrating anatomic and clinical pathology at the rotation level

CONTEXT

Pathology residency training programs should aim to teach residents to think beyond the compartmentalized data of specific rotations and synthesize data in order to understand the whole clinical picture when interacting with clinicians.

OBJECTIVE

To test a collaborative autopsy procedure at Montefiore Medical Center (Bronx, New York), linking residents and attending physicians from anatomic and clinical pathology in the autopsy process from the initial chart review to the final report. Residents consult with clinical pathology colleagues regarding key clinical laboratory findings during the autopsy. This new procedure serves multiple functions: creating a team-based, mutually beneficial educational experience; actively teaching consultative skills; and facilitating more in-depth analysis of the clinical laboratory findings in autopsies.

DESIGN

An initial trial of the team-based autopsy system was done from November 2010 to December 2012. Residents were then surveyed via questionnaire to evaluate the frequency and perceived usefulness of clinical pathology autopsy consultations.

RESULTS

Senior residents were the most frequent users of clinical pathology autopsy consultation. The most frequently consulted services were microbiology and chemistry. Eighty-nine percent of the residents found the clinical pathology consultation to be useful in arriving at a final diagnosis and clinicopathologic correlation.

CONCLUSION

The team-based autopsy is a novel approach to integration of anatomic and clinical pathology curricula at the rotation level. Residents using this approach develop a more holistic approach to pathology, better preparing them for meaningful consultative interaction with clinicians. This paradigm shift in training positions us to better serve in our increasing role as arbiters of outcomes measures in accountable care organizations.

Anatomic and Clinical Pathology Boot Camps: Filling Pathology-Specific Gaps in Undergraduate Medical Education

Context.—The Liaison Committee on Medical Education began an initiative to change medical education across the United States in the early 2000s. With the explosion in medical science knowledge, the need arose to teach selected fundamental information both in a contextual and in an active learning manner.

Objective.—To identify ways to address gaps in training and knowledge that became apparent following implementation of learner-centered teaching methods, with devotion of more time to Internet-based learning and less emphasis on face-to-face lecture time. There was a dramatic departure from or de-emphasis of many traditional courses, such as embryology, gross anatomy, microscopic anatomy, and pathology, to the integration of these sciences into system-based active learning courses. This change in medical school curricula produces a medical graduate who hopefully thinks differently but certainly lacks subject-specific knowledge for a variety of medical specialties.

Data Sources.—Pathology residency programs have developed “boot camps” for the initial months of residency training both to provide the necessary foundation of pathology-specific medical science and to introduce basic skills and processes required for practice of anatomic pathology and laboratory medicine. The College of American Pathologists Graduate Medical Education Committee sent a questionnaire out on the Program Directors Section Listserv; the results are discussed and 3 boot camp programs are described.

Conclusions.—Boot camps have 2 purposes: (1) to teach or strengthen knowledge required to practice pathology and (2) to introduce basic skills and processes that will be used during the practitioner's career.

Accelerating effects of nonviable Staphylococcus aureus, its cell wall, and cell wall peptidoglycan

We have previously reported that local application of viable Staphylococcus aureus dramatically accelerates wound healing, but viable Staphylococcus epidermidis does not. Because the S. aureus effect occurred in the absence of infection and because the cell walls of the two bacterial species differ, we hypothesized that nonviable S. aureus, its cell wall, and its cell wall component(s) would accelerate healing. Nonviable S. aureus was prepared by chemical and physical means, and its cell wall and peptidoglycan was prepared from heat-killed cultures. In a large number of experiments, nonviable S. aureus (independent of the strain's protein A content), its cell wall, and peptidoglycan when instilled locally at the time of wounding each significantly increased the breaking strength of rat skin incisions (tested both in the fresh state and after formalin fixation). These agents also enhanced subcutaneous polyvinyl alcohol sponge reparative tissue collagen accumulation, generally by a factor of two. Histologic features of treated and control incisions were similar. In contrast, the reparative tissue of treated sponges contained more neutrophils, macrophages, capillaries, and collagen. These experimental data thus confirm our previous studies, as well as our hypothesis, and extend these observations of enhanced wound healing to specific fractions of the bacterial cell wall.

Molecular mechanisms underlying wound healing acceleration by Staphylococcus aureus peptidoglycan

Molecular mechanisms involved in wound healing acceleration by Staphylococcus aureus peptidoglycan were investigated with the use of polyvinyl alcohol sponges implanted under the dorsal skin of rats. Total collagen and RNA content and messenger RNA levels of alpha1(I) and alpha1(III) procollagen, transforming growth factor-beta1, and matrix metalloproteinase-1 were analyzed in saline solution- and S. aureus peptidoglycan-inoculated sponges at 4, 7, 14, and 21 days after implantation. S. aureus peptidoglycan-inoculated sponges on the fourth and seventh post-operative day were surrounded and penetrated by a thick capsule of reparative connective tissue. They were considerably heavier and contained more collagen and total RNA than saline solution-inoculated sponges. Histologically, the S. aureus peptidoglycan-inoculated sponges early on contained a denser infiltrate of polymorphonuclear cells than saline solution-inoculated sponges, and later fibroblasts, macrophages, collagen, and newly formed blood vessels were more abundant in the S. aureus peptidoglycan sponges. Matrix metalloproteinase-1 messenger RNA expression was elevated at 4 days in both sponge types. However, although matrix metalloproteinase-1 mRNA levels decreased to undetectable levels by 14 days in saline solution-inoculated sponges, they remained elevated throughout the 21-day study period in S. aureus peptidoglycan-inoculated sponges. No other significant differences in the parameters analyzed were detected. These results suggest that S. aureus peptidoglycan induces an accelerated but normal wound healing process in which the markedly increased early deposition of connective tissue is rapidly remodeled likely because of a sustained expression of matrix metalloproteinase-1.

Staphylococcus aureus peptidoglycan ameliorates cyclophosphamide-induced impairment of wound healing

Cyclophosphamide given systemically to rats leads to impaired wound healing, characterized by decreases in the inflammatory reaction, fibroplasia, neovascularization, reparative collagen accumulation, and wound breaking strength. In contrast, the local application of Staphylococcus aureus peptidoglycan at the time of wounding increases all of these processes in normal rats. Accordingly, we hypothesized that inoculation of S. aureus peptidoglycan into wounds of cyclophosphamide-treated rats would ameliorate the otherwise impaired healing. Dorsal bilateral skin incisions and subcutaneous implantation of polyvinyl alcohol sponges (two on each side) were performed on male Sprague-Dawley rats receiving either saline or cyclophosphamide (24 mg/kg) intraperitoneally at the time of operation, on postoperative days 1, 2, 3, 4 (for rats killed on postoperative day 7), and also on day 8 (for rats killed on postoperative day 14). The incisions on one side were inoculated at the time of closure with 0.2 ml of saline solution, and the incisions on the other side with 6 mg S. aureus peptidoglycan in 0.2 ml saline solution (860 microg/cm incision). The sponges were instilled with 0.1 ml saline solution on the saline solution-instilled incision side or with S. aureus peptidoglycan 0.5 mg/sponge) in 0.1 ml saline solution on the other side. In control rats receiving saline solution intraperitoneally, incisions treated with S. aureus peptidoglycan were significantly stronger than saline solution-treated incisions by a factor of 1.8 at 1 week (p < 0.001); at 2 weeks the increase was small and not significant. Cardiac blood leukocytes and platelets fell markedly (90%) in cyclophosphamide- treated rats, and there was a decrease in wound breaking strength of their saline-treated incisions at both 7 and 14 days compared with saline solution-treated incisions of control rats. S. aureus peptidoglycan treatment of the wounds completely prevented this effect at 7 days, and partially at 14 days. Polyvinyl alcohol sponge reparative tissue hydroxyproline, 7 days after surgery, was decreased in cyclophosphamide-treated rats; this was completely prevented by S. aureus peptidoglycan treatment of the sponges. Histologically, the inflammatory response to the wounding, influx of macrophages and fibroblasts, angiogenesis, and collagen accumulation were all reduced at day 7 and 14 after surgery in the sponge reparative tissue of cyclophosphamide- treated rats; this was prevented by S. aureus peptidoglycan treatment of the sponges. In conclusion, a single local application of S. aureus peptidoglycan ameliorates cyclophosphamide-impaired wound healing.

Single local instillation of nonviable Staphylococcus aureus or its peptidoglycan ameliorates glucocorticoid-induced impaired wound healing

An excess in glucocorticoid steroids, either from endogenous or exogenous sources, has been shown to inhibit wound repair. Key to this impairment is a diminution of the inflammatory response to wounding, fibroplasia, capillary formation, reparative tissue collagen accumulation, and wound breaking strength. Because a single local application at operation of nonviable Staphylococcus aureus or its peptidoglycan increases all of these processes in normal rats, we hypothesized that nonviable S. aureus and S. aureus peptidoglycan would each ameliorate glucocorticoid-induced impaired healing. Sprague-Dawley male rats aseptically received two 7 cm paravertebral skin incisions and underwent subcutaneous implantation of polyvinyl alcohol sponges. Two glucocorticoids were used: hydrocortisone, 8 mg intramuscularly, daily beginning 1 day before operation and continuing during the postoperative period; or a single dose of a long-acting preparation of methylprednisolone, 6 or 8 mg intramuscularly, on the day before operation. Controls received intramuscular injections of saline solution at the same respective times. At the time of the operation, one incision and the polyvinyl alcohol sponges on one side of the animal were instilled with saline solution while the incision and sponges on the opposite side were instilled with nonviable S. aureus (hydrocortisone study) or S. aureus peptidoglycan (two methylprednisolone studies). The data showed that, at postoperative day 7, the single local application at wounding of nonviable S. aureus or S. aureus peptidoglycan increased wound breaking strength in the control rats by factors of 1.6 in the hydrocortisone experiment and 1.4 and 1.6 in the methylprednisolone studies. These treatments prevented (in hydrocortisone-treated rats) or mitigated (in methylprednisolone-treated rats) the glucocorticoid-induced decrease in wound breaking strength. In addition, these treatments prevented the glucocorticoid-induced decreases in the inflammatory (largely mononuclear cells) response to wounding and in the accumulation within the polyvinyl alcohol sponge of reparative tissue fibroblasts, capillaries, and collagen.

Effects of desialylation of ovine submaxillary gland mucin (OSM) on humoral and cellular immune responses to Tn and sialylated Tn

Resected carcinoma patients were immunized 3-5 times with ovine submaxillary gland mucin (OSM) containing predominantly sialylated Tn (sTn), completely desialylated ovine submaxillary gland mucin (dOSM) containing predominantly Tn, or 50% desialylated OSM containing Tn and sTn plus bacillus Calmette-Guerin (BCG) as an immunologic adjuvant. Pre- and postimmunization sera were quantified by ELISA, whole-cell ELISA, and immune stain dot blots. Fifteen of 17 patients produced IgG antibody titers from 40 to 5120 times more reactive with OSM and dOSM postimmunization. More importantly, these IgG antibodies reacted with LS-174T, a human colon carcinoma cell line. Significant DTH-like responses (1-17 cm) were observed in 15 of 17 patients; the strength of these responses was dependent on the presence or absence of sialic acid. Biopsies of these DTH-like reactions revealed infiltration with some CD8+ lymphocytes and mast cells. These results suggest that a single 9-carbon sugar can affect cellular immune responses to mucin antigens. It is thought that these large erythematous, nonindurated cellular reactions are antibody-mediated Arthus-like reactions. OSM, and especially dOSM, were also found to inhibit lymphocyte proliferation.

Evaluation of DNA adduction of AZT in peripheral blood leukocytes of HIV-infected individuals by (32)P-post-labeling thin-layer chromatography: a feasibility study

3'-Azido-3'-deoxythymidine (AZT, Zidovudine) has been effectively used for HIV infection treatment. It inhibits virus reproduction through viral reverse transcriptase inhibition. However, the side effects of this anti-retroviral drug might be cumulative, particularly in its effects on the patients' DNA. As a nucleoside analogue, AZT might incorporate into hosts' DNA, and then form DNA adducts. This may result in potential long-term risks of mutagenesis in AIDS patients who received therapy. In this feasibility study, a (32)P-post-labeling thin-layer chromatography (TLC) assay is successfully used to measure AZT-DNA analogue and adducts formed in peripheral blood leukocytes of AZT treated patients. There are DNA analogue/adducts measured in all four AZT treated patients' DNA specimens. This assay is reliable with the significant coefficient of correlation in both intra-assay (r = 0.8761, P = 0.0001) and inter-assay (r = 0.8761, P = 0.0001).

DNA biomarkers antecede semiquantitative anthracycline cardiomyopathy

Adriamycin (ADM, or doxorubicin hydrochloride) is an effective antineoplastic agent whose use is restricted by its well-described, dose-dependent cardiotoxicity. This study measures ADM DNA adduct formation by 32P-radiolabeling DNA, enzymatically digesting radiolabeled DNA, separating the formed adducts on two-dimensional thinlayer chromatography (2D-TLC), and quantitating the adducts with autoradiography and densitometry. Thirty-six male Sprague-Dawley rats are randomized to receive ADM at varying intraperitoneal (i.p.) injection concentrations: 0.9% saline i.p. controls, 4 mg/kg ADM i.p., and 6 mg/kg ADM i.p. Myocardial and pulmonary tissues are harvested 48 hours after i.p. injection for autoradiographic and histopathologic analyses. The results indicate differences in the amount and type of adduct formation as a function of ADM concentration. Increased partial depurination of dGMP and dAMP occurs with increasing ADM concentration at equal incubation times. This depurination correlates with the emergence of new adducts HM-dUMP, 8-OH-dGMP, HM-dCMP, and Me-dCMP. The quantification of these adducts can potentially represent an early marker of ADM cardiotoxicity and thereby optimize the efficacy of individual chemotherapy regimens while minimizing adverse effects.

Cisplatin DNA adduct detection and depurination measured by 32P DNA radiolabeling and two-dimensional thin-layer chromatography: a time and concentration study

Platinum-based chemotherapies cause the formation of DNA adducts and have profound effects on DNA. This study measured cis-diamminedichloroplatinum II (cisplatin) DNA adducts by 32P-radiolabeling DNA, enzymatically digesting radiolabeled DNA, separating the formed adducts on two-dimensional thin-layer chromatography, and quantitating the adducts with autoradiography and densitometry. HeLa DNA was incubated with cisplatin at varying concentrations (6.25-325 nM) and times (0 min to 72 hr). Cisplatin rapidly depurinated dGMP and dAMP (90%, 15-min incubation with 325 nM cisplatin). Partial depurination of dGMP (15%) and dAMP (25%) occurred with lower cisplatin concentrations at equal incubation times. A minimum of four new adducts, with relatively rapid migratory patterns, were detected at high cisplatin concentrations with short incubation times. These results indicate that the depurination of DNA correlates with DNA adduct formation and that the quantification of these adducts may be applicable to monitoring tumor and host cell response to cisplatin chemotherapy.

Environmental ethics

The U.S. Environmental Protection Agency (EPA) held the first meeting on environmental ethics sponsored by the Scientific Advisory Panel and Board on 10-11 December 1998 in Arlington, Virginia (1). The report from the meeting will more completely inform scientists and the community of current issues. This editorial should serve as an initial brief of this meeting [which was held on the fiftieth anniversary of the Declaration of Human Rights (adopted by the United Nations on 10 December 1948)].

Variation in the deoxynucleotide composition between organic and nonorganic strawberries

The differences in xenobiotic chemical content between organic and nonorganic products can be chemically measured. In this study, the deoxynucleotide composition of strawberry samples is used to demonstrate chromatographic methods of quantifying the differences between pesticide- and toxic-exposed strawberries. The samples were analyzed by (32)P labeling and two-dimensional thin-layer chromatography. This technique is sensitive for detecting rare (1/10(10)) deoxynucleotide adducts and analogues (minor bases) in DNA. The results indicate differences in the amount and type of adduct formation between organic and nonorganic strawberry samples and within different parts of the same type of sample. The elucidation of the content and effects of pesticides and toxics in foods is critical in differentiating organic from common produce. It can also aid the agricultural industry in improving the application of chemicals in pest management. Furthermore, it helps to enhance the understanding of long-term epidemiology in nutrition research, especially in susceptible populations. These findings are of particular application in the pediatric population, where dietary habits are restricted to specific food groups.

Single local instillation of Staphylococcus aureus peptidoglycan prevents diabetes-induced impaired wound healing

Diabetes-induced impaired wound healing is characterized by inhibition of the inflammatory response to wounding, macrophage infiltration, angiogenesis, fibroplasia, reparative collagen accumulation, and wound breaking strength. Because all of these processes are accelerated in normal rats by a single local application at operation of Staphylococcus aureus peptidoglycan, we hypothesized that S. aureus peptidoglycan would prevent diabetes-induced impaired wound healing, despite persistent, untreated hyperglycemia, polydipsia, glycosuria, and polyuria. Sprague- Dawley male rats were divided into two groups. One group received an intraperitoneal injection of streptozotocin (65 mg/kg) in citrate solution; the other group received an intraperitoneal injection of an equivalent volume of citrate solution. Seventeen days after the injections, the diabetic and control rats received aseptically two 5.5-cm paravertebral incisions and subcutaneous implantation of six polyvinyl alcohol sponges, three on each side. On one side, each sponge contained 0.5 mg S. aureus peptidoglycan in 50 microliter saline solution, and the incision was inoculated along its length with 4.7 mg S. aureus peptidoglycan in 157 microliter saline solution (860 microgram/S. aureus peptidoglycan/cm incision); on the other side, the same respective volumes of saline were used. During the preoperative and postoperative periods, diabetic rats lost a small amount of weight (2%), were hyperglycemic (363 +/- 10 mg/100 ml blood), polydipsic, glycosuric, and polyuric, whereas the controls gained weight (25%) and were normoglycemic (104 +/- 5 mg/100 ml blood); these differences were significantly different (p <.001 in each case). In controls, S. aureus peptidoglycan inoculation increased wound breaking strength (by a factor of 2.0) and hydroxyproline content (by a factor of 1.4; p <.001 in each case); in diabetics, there were significant decreases in wound breaking strength (by a factor of 1.7) and hydroxyproline content (by a factor of 1.3) of saline solution-inoculated incisions and sponges compared with the wound breaking strength and hydroxyproline content of saline solution-inoculated incisions and sponges in controls (p <.02 and p <.001, respectively). These decreases were completely prevented when the incisions and polyvinyl alcohol sponges had been inoculated at operation with S. aureus peptidoglycan; S. aureus peptidoglycan inoculation in the diabetic rats increased wound breaking strength by a factor of 2.2 and sponge reparative tissue hydroxyproline by a factor of 1.6 (p <.001 in each case). Thus, diabetes-induced impaired wound healing was prevented completely by a single local instillation at operation of S. aureus peptidoglycan, despite persistent, untreated hyperglycemia, polydipsia, polyuria, and glycosuria.

The immunohistological diagnosis of E. coli O157:H7 colitis: possible association with colonic ischemia

OBJECTIVE

E. coli O157:H7 may cause hemorrhagic colitis resembling ischemic colitis. Diagnosis is usually made by finding sorbitol-negative colonies on MacConkey agar that react with O157 and H7 antisera. Most ischemic colitis is idiopathic, but some may be caused by E. coli O157:H7, inasmuch as this organism can produce fibrin thrombi in colon vasculature. The objectives of this study were to determine whether E. coli O157:H7 infection can be diagnosed retrospectively from paraffin blocks of colon sections and whether an association exists between E. coli O157:H7 infection and colonic ischemia.

METHODS

Paraffin-embedded sections of normal colon (n = 2) and various colitides [ischemic (n = 11), E. coli O157:H7 (n = 2), IBD (n = 8) and pseudomembranous (n = 3)] were used. Sections were deparaffinized, rehydrated, incubated with 3% peroxide in methanol, rinsed, and incubated with peroxidase-labeled antibody isolated from goats immunized with whole E. coli O157:H7. Sections were stained with peroxidase chromagen reagent and counterstained with hematoxylin. Coarse, granular, orange-brown staining was considered positive. To determine the localization of the chromagen deposits, three cases that stained positive, including one of the culture-proved E. coli O157:H7 colitis and two of colonic ischemia, were processed for electron microscopy.

RESULTS

Both cases (100%) of E. coli O157:H7 colitis and three of 11 (27.3%) cases of ischemic colitis stained positive by light microscopy. In one culture-proved case, electron microscopy demonstrated staining of bacillary structures; in two cases of colonic ischemia, extensive deposits of chromagen material were present that were associated neither with inflammatory cells nor with bacterial forms.

CONCLUSIONS

Immunoperoxidase staining of archival sections may be used to diagnose E. coli O157:H7 infection. An etiological role for this organism is possible in some cases of colonic ischemia.

DNA damage by gliotoxin from Aspergillus fumigatus. An occupational and environmental propagule: adduct detection as measured by 32P DNA radiolabelling and two-dimensional thin-layer chromatography

Gliotoxin is produced by the fungus Aspergillus fumigatus. Aspergillus is widespread in the environment and this ubiquitous nature results in disease and co-carcinogenesis to be distributed world-wide. Gliotoxin contains an epipolythiodioxopiperazine (ETP) ring that is believed to be involved in redox reactions. The reactive oxygen species produced interact with DNA to form hydroxylated and other altered DNA products. To measure DNA adduct formation, we used 32P radiolabelling and, after enzymatic DNA digestion, separated adducts in two dimensions using thin-layer chromatography (2D-TLC), with ultimate autoradiography and densitometry. HeLa DNA was incubated with 0.1 mmol l-1 and 0.3 mmol l-1 of gliotoxin (and necessary redox agents) for 1 and 20 h. We found an increase in 6-hydro-5,6-dihydroxythymidine (thymine glycol) monophosphate [d(TG)MP] from 0.0% to 30.4%, an increase in 8-hydroxy-2'-deoxyguanidine monophosphate [8(OH)dGMP] from 0.0% to 4.2%, an increase in deoxynucleotide diphosphate (dNDP) from zero adducts to six DNA adducts, as well as an increase of other as yet unidentified adducts. Also, time exposure may have a greater effect than concentration based on a 20-h incubation with 0.3 mmol l-1 gliotoxin that completely obliterates the pyrimidines deoxythymidine 3'-monophosphate (dTMP) and deoxycytidine 3'-monophosphate (dCMP).

Nonviable Staphylococcus aureus and its peptidoglycan stimulate macrophage recruitment, angiogenesis, fibroplasia, and collagen accumulation in wounded rats

We have previously shown that local application at the time of operation of Staphylococcus aureus, nonviable S. aureus, its cell wall, or S. aureus peptidoglycan accelerates wound healing. We hypothesized that this effect is due to both direct and indirect mechanisms, among which is an increase in the inflammatory response to wounding, resulting in an increase in macrophages, angiogenesis, and fibroblasts. Twenty-seven Sprague-Dawley male rats were anesthetized, and two 7-cm paravertebral skin incisions were made. Four polyvinyl alcohol sponges, two on each side, containing either 100 microliter of isotonic saline or 0.5 mg of nonviable S. aureus or S. aureus peptidoglycan in 100-microliter saline were implanted subcutaneously. Nonviable S. aureus or S. aureus peptidoglycan (860 microgram/cm incision) in 200-microliter saline were inoculated into the incisions at closure. The rats ate a commercial rat chow and drank tap water ad libitum throughout. After days 3 and 7 postwounding, rats were euthanized, and tissues were examined for immunohistochemical features of reparative tissue using ED-1, Factor VIII, and vimentin antibodies, markers for monocyte/macrophages, endothelial cells, and mesenchymal cells (including fibroblasts), respectively. Incisions treated with nonviable S. aureus or S. aureus peptidoglycan showed more macrophages along and deep in the wound tract 7 days postoperatively. Nonviable S. aureus or S. aureus peptidoglycan-treated sponges were surrounded and penetrated by much larger capsules of reparative tissue than saline-treated sponges at both 3 and 7 days. Neutrophil influx was much greater in nonviable S. aureus or S. aureus peptidoglycan-treated sponges, especially in central regions, and there were many more ED-1-stained macrophages in distinct geographic locations, specifically, the more peripheral-cortical areas. Some clustering of macrophages occurred around areas of invasion by reparative tissue into the surrounding subcutaneous fat and within the interstices of the sponges at the interface between reparative tissue and acute inflammatory cells. In contrast, saline-treated sponge reparative tissue had significantly fewer macrophages, much thinner and flimsy reparative tissue, with proportionately fewer macrophages clustering centrally. There were many more mesenchymal cells (notably fibroblasts) and new blood vessels and much more reparative collagen in the nonviable S. aureus or S. aureus peptidoglycan-treated sponges. We conclude that local application of nonviable S. aureus or S. aureus peptidoglycan at wounding induces an increased number and alteration in location of macrophages, increased influx (or proliferation) of mesenchymal cells (notably fibroblasts), and increased angiogenesis and reparative collagen accumulation, as well as increasing the overall acute inflammatory response to wounding.

Interstrain variation in the deoxynucleotide composition of Cryptococcus neoformans: nucleotide composition of Cryptococcus neoformans

The deoxynucleotide (dNMP) composition of ten strains of C. neoformans was analysed by 32P-labelling and two-dimensional thin-layer chromatography. This technique is very sensitive for detecting rare deoxynucleotide adducts and analogues (minor bases) in DNA. The results indicate considerable variation among strains in DNA nucleotide composition.

In vivo determination of 5-bromo-2'-deoxyuridine incorporation into DNA tumor tissue by a new 32P-postlabelling thin-layer chromatographic method

The halopyrimidine 5-bromo-2'-deoxyuridine (BUDR) can serve as one of many indicators of tumor malignity, complementary to histologic grade. We have developed a thin-layer chromatographic (TLC) technique that can assess tumor DNA base composition and analogue (BUDR) incorporation which vies with immunochemistry for BUDR. This requires post-labeling DNA by nick-translation and radioactive 5'-phosphorylation of representative 32P-alpha-dNMPs (deoxynucleotide monophosphates). Subsequent 3'-monophosphate digest exchanges a radioactive 32PO4 for the neighboring cold nucleotide. Separation in two dimensional PEI-cellulose TLC is carried out in acetic acid, (NH4)2SO4, and (NH4)HSO4. TLC of dNMPs was applied to control HeLa DNA, and HeLa cells receiving BUDR. BUDR is detected in 10(6) HeLa cells after 12-72 h incubations. Findings in HeLa DNA demonstrate normal TLC retention factors for all 32P-dNMPs. Two dimensional R(F) (x,y axes in cm) demonstrate: dAMP=1.4, 9.4; dCMP=10.0, 13.5; dGMP=4.6, 4.4; dTMP=9.0, 7.4; and BUDRMP 6.4, 6.6. This technique quantifies BUDR--which parallels tumor S phase, and serves as an indicator of labelling index (LI).

Contrasting effects of identical nutrients given parenterally or enterally after 70% hepatectomy: bacterial translocation

High mortality occurs in rats with 70% hepatectomy fed intravenous (IV) total parenteral nutrition (TPN; 13.9% glucose, 4.17% amino acids, 1.46% fat, electrolytes, trace minerals, and vitamins providing 216 kcal.kg-1.d-1) but not when the identical nutrients are given at the same rate enterally (gastrostomy). We hypothesized that a difference in bacterial translocation (BT) was a contributing factor to this phenomenon. Forty-five male Sprague-Dawley rats (300-360 g) were divided into five groups and underwent the following: control (no operation), sham (intraperitoneal [IP] pentobarbital anesthesia, central venous and gastrostomy catheters, laparotomy, sham hepatectomy), standard oral feeding (SOF), TPN (IV nutrients), and total enteral nutrition (TEN; gastrostomy). The SOF, TPN, and TEN groups had IP pentobarbital anesthesia, central venous and gastrostomy catheters, and 70% hepatectomy. Postoperatively, control and SOF (both catheters plugged) rats ate a commercial rat chow and drank tap water ad libitum pre- and postoperatively. The sham, TPN, and TEN groups were given the identical infusate composition as above, but the nutrient concentrations were cut in half (110 kcal/kg) and three-quarters (165 kcal/kg) on postoperative days 1 and 2, respectively. At the end of postoperative day 2, all rats were euthanized. BT to mesenteric lymph nodes (MLNs), liver, spleen, and lungs was significantly higher in the TPN rats compared with all other groups, except that BT to the MLNs was similar in the TPN and TEN groups. Bacteremia was found only in the TPN rats. BT in TPN rats with 70% hepatectomy was significantly greater 48 h after operation than in those fed the identical nutrients enterally at the same rate; this correlates with the previously reported significantly greater mortality in rats with 70% hepatectomy receiving TPN.

The formation and measurement of DNA neuroadduction in alcoholism. Case report

We present a case report of an intoxicated alcoholic driver who sustained fatal motor vehicle injuries. We subsequently quantified ethanol-derived acetaldehyde (ACE) DNA products in his brain, which may represent a major contributor to clinical alcoholic use and complications. Further, ACE DNA neuroadducts may indicate chronic exposure to alcohol, as demonstrated by 32P-prelabeled DNA and two-dimensional thin-layer chromatography. ACE and other unknown neuroadducts were evident in the histologically normal frontal, parietal, and caudate lobes. DNA neuroadduct formation was extensive and similar in three separate brain regions with normal histology. Contributing neuroadduction by chronic drug abuse is also possible, though the deceased's terminal acute blood screens for recent drug abuse were negative. The mechanism of alcohol neurotoxicity remains unknown, but biochemical nonenzymatic changes of DNA at the nucleic acid level (adduct formation) can alter gene function and stability. DNA neuroadduct detection may represent an important determinant in quantifying neurotoxicity from drug abuse or alcoholism in the absence of history, the presence of negative blood, tissue, and urine assays for recent drug and alcohol use, and the absence of neuropathology.

Ectopic expression of reg protein: A marker of colorectal mucosa at risk for neoplasia

Pancreatic regenerating gene (reg I) messenger RNA is overexpressed within the pancreas following injury and resection. Its level of expression corresponds to the level of cellular dedifferentiation. Human reg I has been localized to chromosome 2p12, and ectopic expression of its mRNA has been found within colorectal tumors. We postulated that colorectal production of reg I might either be a marker for the presence of cancer or define mucosa at risk for development of neoplasia. Using a monoclonal antibody to reg I, regenerating gene protein was histochemically mapped in 56 cases of documented colorectal adenocarcinoma. In sections of colon from normal control subjects no reg I protein was noted, whereas 58.9% of the specimens from cancer patients stained positive for reg I. Although a correlation was noted between reg I staining and Dukes' stage, there was no correlation with histologic grade or 5-year patient survival. In 39 of 55 cancer specimens the transition zone (interface) between the neoplasm and normal mucosa was visualized; 100% of the transition zones contained cells that stained strongly positive for reg I. We conclude that reg I protein is ectopically expressed in colorectal mucosa at the transition zone of colorectal cancer, and occasionally within the tumor itself. Although ectopic reg I expression in colorectal epithelia is not a marker for the presence of carcinoma, it may be a sensitive marker for mucosa at risk for development of neoplasia.

Morphologic pattern of tenascin as a diagnostic biomarker in colon cancer

BACKGROUND

Immunohistochemical methods were used to study the pattern of expression of tenascin (TN) in invasive colon cancer and its relation to prognosis.

METHODS

Sixty patients (29 males, 31 females) with a mean age of 77 years were studied. TN expression was evaluated by immunohistochemistry using paraffin-embedded tissue sections, TN expression levels were correlated with patient age, tumor stage, and survival.

RESULTS

TN positivity varied from trace to 4+. Staining patterns were as follows: in well-differentiated cancer, TN fibers form thick bands around invading tumor glands. In poorly differentiated cancer, TN fibers had an interstitial pattern surrounding individual tumor cells. Using Cox's proportional hazard regression method, survival was significantly related to TN score (P < 0.0001) and stage of disease (P < 0.05). No significant relationship was found between survival and age (P = 0.375).

CONCLUSION

Patients with more TN expression had better long-term survival than patients with no or weak TN expression. Pathologic and clinical entities in colon cancer have distinct immunohistochemical TN matrix patterns that may correlate with predictive value and long-term survival.

Traumatic pancreatitis: method and effects of i.v. fluids and Sandostatin

Somatostatin and its analogs are used clinically to treat patients with pancreatitis. To evaluate the effects of i.v. Sandostatin (SNST) on rats with trauma-induced acute pancreatitis, 130 male Sprague-Dawley rats (300-350 g) underwent celiotomy, controlled direct pancreas contusion, and central i.v. line insertion under ip sodium pentobarbital anesthesia. The rats were divided randomly into control (IA, IIA, and IIIA) and SNST-treated (IB, IIB, and IIIB) groups. The basic infusion solution contained 4.8% glucose, vitamins, and electrolytes. For groups IA and IB, the infusion rate was 24 ml/kg/day, while it was 240 ml/kg/day for groups IIA, IIB, IIIA, and IIIB. SNST administration was 6 micrograms/kg/hr i.v. for groups IB and IIB during the first postoperative day, while group IIIB received 6 micrograms/kg/hr i.v. for 4 days. Surviving rats were euthanized after 4 days. All survivors and nonsurvivors were autopsied. In all groups, severity of pancreatitis, fat necrosis, and ascites were greater in the nonsurvivors (P < 0.005 in each case). Mortality rates were consistently lower in the SNST groups: IA (76%) vs IB (52%), IIA (71%) vs IIB (50%), and IIIA (63%) vs IIIB (50%). Because individual group mortality rates were not affected by volume of infusate given or length of time SNST was administered, the results of all control and all SNST rats were combined; there was a statistically significant lower mortality in the SNST-treated rats (51 vs 71%, P < 0.04).

CONCLUSION

Intravenous administration of Sandostatin to rats following induction of severe acute traumatic pancreatitis significantly ameliorates the course of the disease.

Microglial nodule encephalitis: limited CNS infection despite disseminated systemic cryptococcosis

A 28-year-old patient with AIDS was found at autopsy to have disseminated cryptococcal infection involving the lungs, spleen, lymph nodes, kidneys, gastrointestinal tract, thyroid, bone marrow, and liver. Despite widespread organ dissemination the patient did not have clinical or pathological evidence of meningitis. Microscopic examination of the brain showed cryptococci limited to the brainstem and basal ganglia; microglial nodules with multinucleate giant cells, a histological hallmark of HIV-1 encephalitis, were shown to contain Cryptococcus neoformans. This feature may suggest a form of synergism between HIV-1 and Cryptococcus neoformans. This case demonstrates an unusual form of cryptococcal neurotropism with limited CNS involvement.

Overexpression of NGF within the heart of transgenic mice causes hyperinnervation, cardiac enlargement, and hyperplasia of ectopic cells

Nerve growth factor (NGF) supports the survival of developing sympathetic and a subpopulation of sensory neurons. In the adult it participates in maintenance of the neurotransmitter phenotype of responsive neurons. The amount of NGF synthesized by a given target tissue determines its final innervation density; those developing neurons that fail to receive sufficient NGF undergo apoptosis. In order to examine the ramifications of this principle in the context of a specific target organ, a transgenic mouse model was developed in which NGF expression was increased in developing and adult cardiac tissue by placing a NGF minigene under the transcriptional control of the cardiac-specific alpha-myosin heavy chain promoter. Transgenic mice developed cardiac enlargement secondary to both an increase in myocardial mass and the presence of an abundant ectopic cell population. Immunohistochemical analyses with the neural marker S-100 revealed staining of a subpopulation of ectopic cells, suggesting their derivation from the neural crest. Whereas immunostaining for the neuronal-specific protein neuron-specific enolase demonstrated labeling of another subpopulation of ectopic cells within the heart. Measurements of cardiac tissue catecholamine levels revealed a marked elevation in transgenic mice, consistent with sympathetic hyperinnervation. Analysis of mediastinal sympathetic ganglia revealed increases in both the size and the number of neurons. In this model, increased expression of NGF produced hyperinnervation of the heart, pathological cardiac growth, and the recruitment and/or expansion of an ectopic, neural crest-derived cell type.

Contrasting effects of identical nutrients given parenterally or enterally after 70% hepatectomy

Based on clinical observations, we hypothesized that prolonged parenteral nutrition (in contrast to enteral nutrition) is detrimental after major hepatic resection. Male Sprague-Dawley rats (300 to 380 g) anesthetized with intraperitoneal sodium pentobarbital had 70% hepatic resection and jugular vein and gastrostomy catheterizations using aseptic techniques and were divided randomly into three groups: (1) total parenteral nutrition (TPN) (nutrients via central vein), (2) total enteral nutrition (TEN) (identical nutrients via gastrostomy), and (3) standard oral feeding (SOF) (chow and water ad libitum). Unused catheters were plugged. In the first set of experiments (n = 42), nutrient intake was formulated to approximate the nutritional intake of normal rats, 216 kcal/kg/d. Infusate was 15% glucose, 4.5% amino acids, electrolytes, trace minerals, vitamins, and 20% fat emulsion given half-strength the first day, three-fourths strength the second day, and full strength thereafter. On postoperative day 7, surviving rats were killed. Mortality prior to day 7 was very high (68%) in the TPN group and low in the TEN (9%) and SOF (9%) groups (p < 0.005). Among survivors, the serum albumin level was lowest (p < 0.002) and serum bilirubin level (p < 0.025) and wet weight of regenerated liver (p < 0.002) highest in the TPN group. However, the livers in TPN rats appeared pale and were found to be abnormal histologically with markedly diminished glycogen and amphophylic hepatocyte cytoplasm, and their spleens were enlarged (by a factor of two). The high mortality of TPN rats was seen whether the fat emulsion was given as a bolus daily, continuously as part of the infusate, or not included as part of the TPN regimen. In the next series (n = 70), nutrient concentrations, volumes, and rates of infusion were varied. There was a high correlation between caloric (r2 = 0.831, p < 0.0006), glucose (r2 = 0.598, p < 0.02), and amino acid (r2 = 0.619, p < 0.03) intakes and mortality in the TPN group: at 140 kcal/kg/d, none died; at 178 kcal/kg/d, 50% to 62% died; and at 230 kcal/kg/d, 80% died. No TEN rat died. In conclusion, 70% hepatectomized rats fed enterally with nutrients approximating the intake of normal rats do well and survive. In sharp contrast, mortality is very high when identical nutrients are infused parenterally. By reducing the levels of nutrients given parenterally, survival improves significantly.

Ozonation of DNA forms adducts: a 32P-DNA labeling and thin-layer chromatography technique to measure DNA environmental biomarkers

Little direct documented evidence of ozone's genotoxicity exists. Deoxyribonucleic acid (DNA) adducts are produced by environmental toxic agents, including ozone. We have described a modified thin-layer chromatography (TLC) technique that can assess adduct formation as a biomarker of ozone injury. This requires 32P-labeling DNA, digestion of deoxynucleotides (dNMPs), and separation in two-dimensional PEI-cellulose TLC. We have applied this technique to control DNAs, to control DNA in solution exposed to acute ambient ozone, and to control DNA exposed to acute bubbled-through ozone (2 ppm for 24 h). We detected stable DNA adducts, including hydroxymethyluracil (HMU), thymine glycol (TG), 8-hydroxyguanine (8-OHG), and demonstrated, as yet, unidentified adducts that may serve as a "fingerprint" pattern of DNA adduction. This technique quantifies low-molecular-mass DNA adducts, both in vivo and in vitro, with potential applications to environmental toxicology.

Lactate turnover at rest and during submaximal exercise in patients with heart failure

Systemic and lower limb skeletal muscle lactate metabolism was studied in 10 men with congestive heart failure by use of a primed continuous intravenous infusion of L-(+)-[U-14C]lactate. Arterial and deep femoral venous blood samples were obtained at rest and during 30 min of submaximal exercise. Systemic lactate metabolic turnover rate (Rd) was determined using Steele's isotopic steady-state equation (Rd = isotopic infusion rate/arterial specific activity). Plasma lactate concentrations in the artery and deep femoral vein did not change significantly from resting values during exercise (1.11 +/- 0.13 vs. 1.26 +/- 0.12 and 1.27 +/- 0.12 vs. 1.30 +/- 0.12 mM, respectively), whereas Rd increased from 22.5 +/- 1.8 to 41.6 +/- 4.8 mumol.kg-1.min-1 (P < 0.005). Rd did not significantly correlate with arterial lactate concentration during rest or exercise. Because of simultaneous uptake and release of lactate in skeletal muscle, arterial and deep femoral venous lactate concentrations are not closely related to either systemic or lower limb skeletal muscle lactate metabolism in patients with congestive heart failure.

Assay of deoxy-deazapurines in DNA by 3'-phosphorylation and two-dimensional thin-layer chromatography

Deoxy-deazapurines (deaza-dNMPs) are incorporated into cellular DNA after administration of anti-neoplastic, anti-viral, or anti-parasitic chemotherapy. Deaza-dNMPs are stable purine analogues and can be detected via 32P-labeling cold DNA. Assay of analogue incorporation and normal base composition is carried out by radiolabeling DNA with all four deoxynucleotides (dNMPs) through nick translation. 3'-Monophosphate digest radiolabels representative dNMPs and deaza-dNMPs. Separation occurs in two-dimensional polyethyleneimine-cellulose thin-layer chromatography, which resolves all dNMPs. The technique was applied to human placental and calf thymus DNA, control and altered calf thymus DNA with cold stoichiometric replacement of deaza-dNMPs to include deoxy-deazaadenosine, deoxy-deazaguanosine, and deoxy-deazainosine. Scintillation detection and densitometry both accurately reflect dNMP content. This technique easily and quickly quantifies the low-molecular-mass deaza-dNMP analogues in DNA. Deaza-dNMP uptake into DNA may reflect clinical chemotherapeutic efficacy and host toxicity. The assay may therefore serve as an early biochemical dosimeter of drug effect and resistance.

Postprandial hypoglycemia in islet beta cell hyperplasia with adenomatosis of the pancreas

Organic hyperinsulinism causing hypoglycemia in adults is caused by insulinoma, islet hyperplasia, or a combination of adenomata and hyperplasia. We present a patient with long-standing symptoms of postprandial hypoglycemia occurring within 15 minutes of meals in the absence of fasting hypoglycemic symptoms. An intravenous glucagon stimulation test resulted in a rise of plasma insulin from 194 to 21,883 pmol/L at 7.5 minutes. Blood glucose simultaneously rose from 4.9 to 5.9 mmol/L. A glucose tolerance test revealed an exuberant insulin response. A euglycemic hyperinsulinemic clamp demonstrated incomplete suppression of plasma C-peptide. At surgery, three nodules were found and a 50-60% distal pancreatectomy was performed. The pancreas revealed a combination of multiple beta-cell islet adenomata and islet hyperplasia with no evidence of nesidioblastosis. The coexistence of islet adenomata with hyperplasia must be considered in the differential diagnosis of postprandial hypoglycemia.

Enzymatic shot-gun 5'-phosphorylation and 3'-sister phosphate exchange: a two-dimensional thin-layer chromatographic technique to measure DNA deoxynucleotide modification

DNA adducts occur through environmental, therapeutic, dietary, oxygen stress, and aging processes. A modified thin-layer chromatographic (TLC) technique can asses base composition and adduct formation. This requires labeling DNA by "shot-gun" 5'-phosphorylation of representative 32P-alpha-deoxyribonucleotide monophosphates. Subsequent 3'-monophosphate digest "sister exchanges" a radioactive 32PO4(2-) to the neighboring cold nucleotide. Separation in two-dimensional polyethyleneimine-cellulose TLC is carried out in acetic acid, (NH4)2SO4, and (NH4)HSO4. The technique was applied to control DNA, cold substitution of dUMP, methylation, depurination, and pBR322. This technique quantifies low-molecular-mass adducts and DNA integrity both in vivo and in vitro.

Determination of plasma lactic acid concentration and specific activity using high-performance liquid chromatography

Assessment of lactate metabolism is of particular interest during exercise and in disease states such as diabetes, shock, and absorptive abnormalities of short-chain fatty acids by the colon. We describe an analytical method that introduces radio-active tracers and high-performance liquid chromatography (HPLC) to simultaneously analyze concentrations and specific activities (SAs) of plasma lactate. The HPLC conditions included separation on a reversed-phase column (octadecylsilane) and an isocratic buffer (30% acetonitrile in water). [3H]Acetate served as an internal standard. Lactate and acetate were extracted from plasma samples with diethyl ether following a pH adjustment to less than 1.0 and back-extracted into a hydrophilic phase with sodium carbonate (2 mM, pH greater than 10.0). Lactate is detected in the ultraviolet range (242 and 320 nm) by derivatization with alpha-bromoacetophenone. Control plasma samples were studied after an overnight fast for precision and analytical recovery. Calibration curves were linear in the range 0.18-6.0 mM (r = 0.92). The precision was 3% and the analytical recovery was 87%. The detection limit of the method was 36 pmol. Determination of lactate metabolism was performed in a patient with chronic congestive heart failure who was administered primed-continuous L-[U-14C]lactate (10 microCi bolus and 0.3 microCi/min continuously) during a 60-min rest period. Mean arterial lactate concentration and SA were 1.69 +/- 0.2 mM and 253.8 +/- 22 dpm/mumol, respectively. Systemic lactate turnover was 25.65 mumol/kg per min. Lactic acid systemic turnover, organ uptake and release rates can be accurately determined by isocratic HPLC.

The spleen in the spleen syndrome: the association of splenoma with hematopoietic and neoplastic disease--compendium of cases since 1864

Splenomas have been described as benign congenital growths. We report six cases of splenomas, all in males. Three had hairy cell leukemia, one had Hodgkin's disease, and one had myeloid metaplasia. Average splenic weight was 1629 gm, and all had multiple splenomas (average diameter 1.89 cm). Splenomas bulged above the cut splenic surface, were pseudoencapsulated, and showed involvement of the underlying disease. A re-evaluation of 105 prior cases are adult (86%; age: 49), with 56% associated with neoplastic disease or hematologic abnormalities. Average spleen weight was 626 gm, and 22% contained multiple splenomas. We conclude that splenomas are most likely an acquired proliferative process strongly associated with neoplastic disease or hematologic abnormalities. Splenomas can also be congenital growths (hamartoma; 26% of the series), which are of little importance.

Chondrocyte mediated cartilage degradation: regulation by prostaglandin E2, cyclic AMP and interferon alpha

Local responses to cytokines and their induced products play a critical role in outcome in the arthritic joint. Using a bovine nasal cartilage culture model, chondrocyte mediated breakdown was stimulated by lipopolysaccharides or tumor necrosis factor. Cartilage breakdown was inhibited in a dose dependent manner by prostaglandin E2, cyclic AMP enhancement and interferon alpha. The possible regulatory roles played by these agents in cytokine activated cartilage breakdown suggest potential therapeutic strategies in human arthritis.

Antibody to interleukin 1 inhibits the cartilage degradative and thymocyte proliferative actions of rheumatoid synovial culture medium

Cartilage breakdown in rheumatoid arthritis results from (a) lytic action by synovial enzymes, and (b) release of synovial catabolin, now believed to be a form of interleukin 1 (IL-1), causing chondrocytes to degrade their matrix. Rheumatoid synovial culture media were tested for their ability to stimulate cartilage degradation (proteoglycan release from bovine nasal cartilage discs) and thymocyte proliferation (3H-thymidine incorporation) in the absence or presence of anti-IL-1. Degradation of living cartilage, stimulated 2-fold by synovial culture media, was inhibited up to 80% by anti-IL-1. Residual breakdown in living cartilage and synovial culture media induced breakdown in dead cultures were of similar magnitude, and both were unaffected by antibody treatment. Proteoglycan products released from synovial culture media treated cartilage were of smaller average molecular weight (Sepharose CL-2B), and such size reduction was inhibited by anti-IL-1 treatment. Synovial culture media that stimulated cartilage degradation also stimulated thymocyte proliferation; the latter was fully suppressible by anti-IL-1. One of 8 synovial culture media contained an inhibitor(s) of thymocyte proliferation, removable by dialysis. We conclude (1) rheumatoid synovial catabolin activity is due to a form of IL-1. (2) A minor nonsuppressible component of synovial culture media stimulated breakdown, identical in living and killed cartilage, is due to passive transfer of enzymic activity. (3) Cultured rheumatoid synovium releases both IL-1 and an inhibitor(s) of IL-1 action.