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Biomedical subjects

A J Dietrich

Publications and source records attributed to A J Dietrich.

At least 19 recordsLinked to original sources
PubMed1999

CART: a controlled algebraic reconstruction technique for electron microscope tomography of embedded, sectioned specimen.

Reconstruction of thick, embedded, sectioned material has to cope with the restricted tilt view of the electron microscope, with information not stemming from the object of interest in the projections, with aberrations of the objective lens and with a distorted relationship between the projected densities in the micrographs and the specimen mass densities due to incoherent electron interactions within the specimen. Micrograph densities over a full tilt-range show in general an averaged mass increase which is more than should be expected from the cosine dependency of the tilt-angles of the projections. The hereby presented reconstruction technique finds a solution for the under-determined system by a controlled algebraic iteration procedure. For this solution the procedure stabilises the region of interest by dynamically scaling the input data during the procedure. A model for the electron transport through thick specimens is proposed and microscope projection simulations are carried out to test the algorithms.

Algorithms↗
PubMed1998

SCP2: a major protein component of the axial elements of synaptonemal complexes of the rat.

In the axial elements of synaptonemal complexes (SCs) of the rat, major protein components have been identified, with relative electrophoretic mobilities (M rs) of 30 000-33 000 and 190 000. Using monoclonal anti-SC antibodies, we isolated cDNA fragments which encode the 190 000 M r component of rat SCs. The translation product predicted from the nucleotide sequence of the cDNA, called SCP2 (for synaptonemal complex protein 2), is a basic protein (pI = 8.0) with a molecular mass of 173 kDa. At the C-terminus, a stretch of approximately 50 amino acid residues is predicted to be capable of forming coiled-coil structures. SCP2 contains two clusters of S/T-P motifs, which are common in DNA-binding proteins. These clusters flank the central, most basic part of the protein (pI = 9.5). Three of the S/T-P motifs are potential target sites for p34(cdc2) protein kinase. In addition, SCP2 has eight potential cAMP/cGMP-dependent protein kinase target sites. The gene encoding SCP2 is transcribed specifically in the testis, in meiotic prophase cells. At the amino acid sequence and secondary structural level, SCP2 shows some similarity to the Red1 protein, which is involved in meiotic recombination and the assembly of axial elements of SCs in yeast. We speculate that SCP2 is a DNA-binding protein involved in the structural organization of meiotic prophase chromosomes.

Amino Acid Sequence↗
PubMed1998

Localization of SCP2 and SCP3 protein molecules within synaptonemal complexes of the rat.

SCP2 and SCP3 are major protein components of the lateral elements (LEs) of synaptonemal complexes (SCs) of the rat, with Mrs of 173, 000 and 30,000. We performed a detailed immunocytochemical comparison of the localization of SCP2 and SCP3 within SCs at the electron microscopic level. The ultrastructural localization of SCP2 and SCP3 was analyzed by immunogold labeling of two types of preparations, namely surface-spread spermatocytes and ultrathin sections of Lowicryl-embedded testicular tissue of the rat. For each of the antisera used, the distribution of immunogold label over SCs in surface-spread spermatocytes differed significantly from the distribution of label on sections. We attributed this difference to artifacts caused by the surface-spreading technique, and therefore we relied on sections for the precise localization of epitopes. On sections, the distribution of label obtained with two antisera against nonoverlapping, widely separated fragments of SCP2 did not differ significantly. There was a small but significant difference between the labeling pattern obtained with an anti-SCP3 serum and the pattern obtained with either of the two antisera against fragments of SCP2; although for all three antisera the peak of the immunogold label coincided with the center of the LE, the distributions of label obtained with the antisera against fragments of SCP2 were asymmetrical, with a shoulder at the inner side of the LE, whereas the distribution of label obtained with anti-SCP3 serum was symmetrical. Furthermore, we observed fuzzy connections between the LEs that were labeled by anti-SCP2 but not anti-SCP3 antibodies. It is possible that labeling of these fuzzy bridges caused the shoulder in the gold label distributions obtained with anti-SCP2 antibodies.

Animals↗
PubMed1998

A community-based randomized trial encouraging sun protection for children.

OBJECTIVE: We evaluated the impact of an intervention promoting sun protection behavior among children 2 to 11 years of age through schools and day care centers, primary care practices, and recreation areas. METHODS: Ten towns in New Hampshire were paired, then assigned randomly to intervention or control status. The multicomponent SunSafe intervention was provided to children and caregivers through primary care practices, day care centers, schools, and beach recreation areas. Training support and materials were provided by the SunSafe project, but project staff had no direct contact with children or parents in providing the intervention. All intervention components promoted the same message: avoid the sun between 11 AM and 3 PM, cover up using hats and protective clothing, use sun block with a sun protection factor >/=15, and encourage sun protection among family and friends. The impact of the intervention was determined by observing children's sun protection behavior at the beach during baseline compared with 1 year later. The primary outcomes of interest were changes in the proportion of children per town using at least some sun protection and changes in the proportion of children fully protected. Children were clustered by town, with the town thus being the unit of analysis. The primary care practice component included one practice meeting for clinicians and staff at which project staff presented background on skin cancer and how to promote its prevention; a sun protection office system manual based on our previous work, which provided specific direction on how to share responsibility among office staff and clinicians in carrying out routines that promote sun protection; and educational posters, pamphlets, and self-adhesive reminder notes designed to enhance sun protection counseling. SunSafe removable tattoos and stickers were offered to children at well-child and illness visits during the summer months. Schools each received three project staff visits: a brief visit with the principal to describe the intervention and to answer questions; an in-service program to educate teachers about skin cancer and to introduce curricular materials; and help with one parent outreach program. Larger day care centers each received one project staff visit. An additional six smaller day care centers received curricular materials through the mail but no visits. Two similar sets of curricular materials were used, one for grade schools and the other for preschools and day care centers. Both emphasized the importance of sun protection rather than the danger of skin cancer. Materials emphasized dynamic activities modeled after the "Slip, Slop, Slap" and "SunSmart" programs and included new material developed to suit regional needs. Both manuals offered structured plans but also provided a variety of activities from which teachers could choose. Teachers agreed to devote a minimum of two class periods to these materials. For recreation areas, lifeguards in each of the intervention communities attended an in-service meeting, during which background about skin cancer prevention was presented by project staff. The project also provided displays about the ultraviolet (UV) light index and about sun protection to be posted at each beach. Subsequently, project staff called beach staff in each community each morning with the predicted UV index for the day to post on the display. Educational pamphlets about the UV index and free sun-block samples were available to beachgoers through the lifeguards. One brief follow-up visit by project staff was made to each beach area to provide reinforcement. RESULTS: We observed 1930 children. Use of some sunscreen on at least one body area increased in all 5 intervention towns compared with paired control towns. In intervention towns, this mean proportion increased from 0.56 of those observed at baseline to 0.76 of those observed postintervention, with a minimal increase among control town children. (ABSTRACT TRUNCATED

Child↗
PubMed1998

Variations in approaching the diagnosis of depression: a guided focus group study.

BACKGROUND: Primary care physicians are often held to the same standard of performance as mental health specialists, yet they face special challenges in recognizing and treating depression. The purpose of this study was to explore the range of approaches to diagnose depression. METHODS: A purposeful sample of 21 primary care physicians in three US cities participated. A semistructured series of questions and clinical cases stimulated discussions about recognizing and managing major and minor depression. The focus groups were videotaped, and data were analyzed by two independent reviewers using the classic method of content analysis. RESULTS: Primary care providers have three major ways of approaching the diagnosis of depression: a biomedical exclusionary approach, where investigation of all physical complaints occurs first; a mental health approach, where psychosocial aspects of a presentation are pursued first; and a synergistic approach, where physical and mental health complaints are addressed simultaneously. Physicians move freely across all approaches depending on patient cues. CONCLUSIONS: Physicians' approaches to depression vary depending on patient characteristics and cues. Through a better understanding of current practices, future researchers can identify the optimal clinical approaches to match the characteristics and cues of specific patients. This study informed the development of a larger objective study of primary care physician performance.

Adult↗
PubMed1998

Commentary: compasses to help navigate the terrain on mental health classification.

OBJECTIVE: To study current patterns of panic disorder (PD) recognition and management by primary care physicians (PCPs). METHOD: We administered a vignette describing a female PD patient to 189 PCPs. RESULTS: Three-quarters of respondents believed that PD was at least 50 percent probable, and the mean PD likelihood rating was 63 percent. Diagnostic suspicion was significantly higher for PD than for other anxiety disorders, major depressive disorder, and cardiac disorders. Medication was rated as significantly more necessary than medical testing and mental health referral. A benzodiazepine was suggested by 78 percent of respondents, while 35 percent suggested a serotonin reuptake inhibitor (SRI). Under half rated the patient as requiring medical testing, mostly for hyperthyroidism (70%) and/or cardiovascular disorder (62%), and half felt that the patient required mental health referral. CONCLUSIONS: The data suggest that most PCPs are able to recognize PD. However, they may be excessively inclined to prescribe benzodiazepines rather than more appropriate medications.

Humans↗
PubMed1998

Referrals for depression by primary care physicians. A pilot study.

BACKGROUND: Communication between primary care physicians (PCPs) and mental health providers (MHPs) is integral to the management of depressive disorders. Our study investigated referrals from PCPs to MHPs in a rural research network. METHODS: From April 1997 to September 1997, 5 family physicians tracked 6 weeks of referrals for depression and non-mental health problems and assessed the outcomes of these referrals after 3 months. The referrals were characterized by the nature and extent of communication between the PCP and the MHP and by the effectiveness of the consultation. RESULTS: Sixty-seven patients (44 with non-mental health disorders and 23 with depressive disorders) were identified and followed. Analysis of the initial referral process showed that the referring physicians felt a greater sense of urgency for the referrals for depression. Written evidence of the referral in the patient's chart at the 3-month survey was more common for non-mental health disorders. CONCLUSIONS: This pilot study demonstrates that there are communication barriers between PCPs and their mental health colleagues. Enhanced communication might improve satisfaction with the referral process. The details of the referral process need further study.

Communication↗
PubMed1997

Using follow-up support with grand rounds CME in community hospitals.

PURPOSE: To determine the proportion of regional primary care physicians who would attend grand rounds on preventive services and their interest in and use of free follow-up enabling and reinforcing assistance to implement changes in their practice routines. METHOD: From January to July 1992 grand rounds on early detection of cancer were offered by Dartmouth Medical School at 38 acute care community hospitals in New Hampshire and Vermont. The target audience of 679 family physicians and general internists was identified through state medical society and hospital attending lists. The hour-long grand rounds program described preventive service guidelines and an office system that promoted their implementation. Follow-up practice support with planning, office staff training, and materials were offered to augment the effects of the grand rounds. Attendance was determined by sign-in documents. In addition, all attendees were asked to complete a survey regarding practice and personal characteristics and interest in follow-up assistance. Statistical comparisons were made using chi square and Fisher's exact tests. RESULTS: In all, 261 family medicine physicians and general internists (38.4%) attended. Certain categories of physicians were more likely to have attended: internists, those younger than 55 years, and physicians on the staffs of hospitals located in small towns. Assistance was requested by 70.1% of the attendees; many requested more than one type of assistance. Physicians from hospitals in smaller towns were more likely to show interest in follow-up assistance and use it when offered. CONCLUSION: Many of the grand rounds attendees were receptive to follow-up assistance that could improve the preventive services they provided. Most hospitals offer grand rounds, and many organizations have interest in and resources for helping physicians provide high-quality care. Future research should establish the best linkage to the actual care provided in practices and explore the relevance of similar approaches to clinical areas beyond prevention.

Attitude of Health Personnel↗
PubMed1997

Solar protection of children at the beach.

BACKGROUND: Excessive sun exposure during childhood has been associated with subsequent development of skin cancers. Children have been advised to avoid sun exposure, use protective clothing, and apply sunscreen lotions, but how completely these recommendations are followed has not been studied. OBJECTIVE: To determine the extent of sun protection among children visiting lake beaches, the methods used, and the characteristics associated with more protection. DESIGN: Direct observations of children were linked with concurrent care giver/parent interviews. SUBJECTS/SETTING: A total of 871 children 2 to 9 years of age and their parents/care givers at freshwater beaches in 10 small New Hampshire towns during July and August 1995. OUTCOME MEASURES: Protection of the head, torso, and legs according to method used (hats, shirts, pants, sunscreen, or shade). RESULTS: Fifty-four percent of children were protected by at least one method for all three body surface regions, although 17% had no protection for any region. Sunscreen was used either alone or in combination with clothing for at least one region in 79%. Hats were used by 3%, shirts by 22%, and pants to the knee by 49%. Only 12% of observed children were in the shade. The region that was protected most often was the legs for boys (due to swim suit styles) followed by the torso for both sexes. The region most often unprotected was the legs for girls followed closely by the face for both boys and girls. Girls were significantly more likely to have no protection (31.2% female vs 7% male, chi2 83.3) due to better leg protection from swim trunks to the knees popular with boys. Full protection of all three regions was more common for children younger than 5 (odds ratio [OR] = 1.8, 95% confidence interval, [CI] 1.3-2.5), for children perceived to usually or always burn (OR = 2.0, 95% CI 1.4-2.7), for children whose parents had more than a high school education (OR = 1.8, 95% CI 1.3-2.5), and if the parents indicated receiving sun protection information from a school or clinician during the previous year (OR = 1.7, 95% CI 1.2-2.3). Approximately 51.6% of parents recalled receiving childhood solar protection advice in the past year from either their physician, a nurse, or a school/day care setting. CONCLUSIONS: Sunscreen provided the most common form of solar protection. Hats and shade were used rarely, and shirts were also underused. Although the sun protection of these children visiting the beach was substantial, nearly half were still not fully protected. Clinician advice within the past year was associated with better protection. Clinicians could increase their influence by providing more specific counseling about how to achieve full protection. Use of multiple methods of protection rather than just sunscreen and full protection rather than protection for just one or two body regions should be emphasized. It is helpful to remind families to protect the regions most frequently omitted from protection: girls' legs and boys' and girls' faces. Advice can be enhanced with patient education materials such as included in the "Slip" (on a shirt), "Slop" (on sunscreen), and "Slap" (on a hat) program developed in Australia and available through the American Cancer Society.

Adult↗
PubMed1996

Organization of SCP1 protein molecules within synaptonemal complexes of the rat.

SCP1, a major protein component of synaptonemal complexes (SCs), is probably a constituent of the transverse filaments (TFs). The protein consists of three domains: a short, proline-rich N-terminal part, a stretch of 700 amino acid residues capable of forming an amphipathic alpha-helix, and a C-terminal domain of 240 amino acid residues which is capable of binding to DNA. To analyze the orientation of SCP1 molecules within SCs, we elicited polyclonal antibodies against three non-overlapping fragments of SCP1, which comprise, respectively, the N-terminus, the C-terminus, and a fragment from the middle of the SCP1 molecule. Using these antibodies, we performed immunoelectron microscopy on SCs in two types of preparations, namely, surface-spread spermatocytes and ultrathin sections of Lowicryl-embedded testicular tissue of the rat. For each of the three antibodies used, the distribution of immunogold label on surface-spread spermatocytes differed significantly from the distribution of label on sections. Masking of SCP1 epitopes within the lateral elements (LEs) and the central element (CE) of SCs in surface-spread preparations and the influence of the surface morphology of the spreads on the labeling pattern were considered as possible explanations for these differences. We therefore relied on the results from sections for the localization of epitopes. On the basis of the distributions of immunogold label in Lowicryl sections and the predicted secondary structure and dimensions of SCP1 molecules, we present the following model: the C-terminus of SCP1 molecules lies in the inner half of the LE, the molecules protrude from the LE through the central region into the CE, and end up with their N-terminus between the center of the CE and the opposite LE, so that the N-termini of SCP1 molecules from opposite LEs overlap. The model has several implications for the assembly of SCs and the possible functions of SCP1.

Animals↗
PubMed1996

Three-point repositioning of axes: three-dimensional alignment procedure for electron microscope tomography using three markers.

A description is given of a new procedure to align series of tilted graphs, made with an electron microscope, for computer tomographic purposes. The procedure uses the coordinates of three projected markers to calculate parameters needed for the reconstruction. To that end the procedure computes the direction of the tilt-axis, the translation and rotation parameters, the tilt-angle of every micrograph, and the spatial coordinates of the individual markers with their centre of gravity as origin of the coordinate system. A searching technique, based on cross-correlation, is described to locate accurately the micrographs markers.

Animals↗
PubMed1996

An office system for organizing preventive services: a report by the American Cancer Society Advisory Group on Preventive Health Care Reminder Systems.

Despite increasing recognition of the importance of preventive services, such services are not provided in primary care practice as often as recommended. One of the most important reasons is the lack of a systematic, organized approach within practices. The American Cancer Society Ad Hoc Advisory Group on Preventive Health Care Reminder Systems reviewed evidence-based reports and expert opinion to summarize current knowledge about office systems for clinical preventive services. This article describes the process of developing an office system for preventive care, beginning with writing a practice policy, auditing charts for baseline performance, developing and implementing a plan for efficient delivery of preventive care, involving office staff, and monitoring progress. Strategies for dissemination of this approach to a wide range of primary care practices may involve professional medical organizations and managed care companies.

Ambulatory Care Information Systems↗
PubMed1996

Physician preventive care philosophy and the five year durability of a preventive services office system.

A group of 30 community physicians who practiced in northeastern United States and who participated in the Cancer Prevention in Community Practice project in 1988 were interviewed five years later. The aim of the interviews was to assess the long-term impact of the preventive services office system which had been introduced by the project. The qualitative analysis of interviews revealed three distinct physician philosophies about the provision of preventive services: a Request Only focus, responding to specific patient inquiries about prevention but taking no initiative to recommend indicated services; a Health Maintenance Visit focus, providing indicated services only during visits specifically scheduled for preventive care; and an Opportunistic Prevention focus, providing indicated preventive services at every chance. Physicians demonstrated these philosophies in their overall view of disease prevention, perceived obstacles to delivery of preventive care, as well as in their continued use of flow sheets and their impression of the value of the Cancer Prevention in Community Practice project. The long-term impact of the office system was the most apparent in the Opportunistic Prevention group. We conclude that the durability of a preventive services office system is influenced by a physician's preventive care philosophy.

Adult↗
PubMed1995

A change in the phosphorylation pattern of the 30000-33000 Mr synaptonemal complex proteins of the rat between early and mid-pachytene.

The lateral elements (LEs) of synaptonemal complexes (SCs) of the rat contain major components with relative electrophoretic mobilities (Mr s) of 30000-33000, which are the products of a single gene. After one-dimensional separation of SC proteins on polyacrylamide-SDS gels, these components show up as two major bands, whereas upon two-dimensional electrophoresis they are resolved in at least 24 spots, which focus at pH 6.5 to 9.5. In this paper we show that these spots represent phosphorylation variants. For the analysis of the phosphorylation of the 30000- to 33000-Mr SC components during progression through meiotic prophase, we developed a procedure for isolation of fractions of testicular cells of the rat that are enriched in separate stages of meiotic prophase. Analysis of the 30000- to 33000-Mr SC components in these fractions by two-dimensional electrophoresis and immunoblotting showed that phosphorylated variants of the 30000- to 33000-Mr SC proteins occur throughout meiotic prophase. However, the extent of phosphorylation changes between early and mid-pachytene, when one phosphate group is probably added to each of the variants.

Animals↗
PubMed1995

A standardized-patient assessment of a continuing medical education program to improve physicians' cancer-control clinical skills.

BACKGROUND: Although continuing medical education (CME) has long been used to inform physicians and teach specific skills, its efficacy in many areas is not well established. This randomized controlled trial assessed the effects of differing educational techniques on the cancer-control skills of 57 physicians. METHOD: The CME program was part of the Cancer Prevention in Community Practice Project in Hanover, New Hampshire, and was implemented in 1988. The program used several methods in its presentation, including interactive small-group discussion, role playing, videotaped clinical encounters, lecture presentations, and trigger tapes. Measurements included cross-sectional observations made by unannounced standardized patients (SPs) who, one year after the CME program, assessed 25 physicians who had participated in the program and 32 physicians who had not. To measure consistency in the SPs' performances and accuracy in assessing the physicians' performances, most interactions were audiotaped using a hidden microphone. Pearson chi-square, Fisher exact two-tailed test, and kappa coefficients were used for analysis. RESULTS: Significantly higher ratings were found for the CME physicians in two areas: breast cancer risk-factor determination (determined maternal history: 80% versus 52%, p = .03; determined age at first period: 16% versus 0%, p = .02), and smoking cessation counseling (providing written material: 32% versus 9%, p = .03). The CME physicians were rated higher on all 19 study variables in the target areas of early detection of breast cancer and smoking cessation. The results show that the physicians' performance were better in those areas where the CME program had used performance-based learning, such as role playing or viewing and discussing a videotaped role-play encounter. CONCLUSION: The educational techniques that rehearsed or portrayed clinical applications seem to have increased the physicians' performances of cancer-control clinical activities. The standardized-patient instrument seems to be particularly useful in evaluating interventions that address specific skills training.

Adult↗
PubMed1994

Changing office routines to enhance preventive care. The preventive GAPS approach.

While family physicians aspire to provide their patients with the best possible preventive care, the services actually provided sometimes fall short of this ideal. Enhancing the provision of preventive care may require changes in office operations. Through working with more than 200 community practices in the Cancer Prevention in Community Practice Project, we have developed the Preventive GAPS Approach, which can help physicians and their practice staff to enhance their preventive care. The approach is based on teamwork among clinicians, staff, and patients; routines that encourage opportunistic provision of indicated preventive care; and flexibility, which allows physicians and their staffs to tailor their improvement strategy and the pace of change to their own unique situation. The approach includes the following four-step method (or GAPS): goal setting regarding preventive care; assessment of existing routines that support preventive care and of the current level of attainment of preventive goals; planning to modify existing routines that support preventive care; and starting and maintaining the improved preventive care office system.

Community Health Planning↗