Effect of albumin on brushite transformation to hydroxyapatite

Brushite (CaHPO(4) x 2H(2)O) is a precursor to hydroxyapatite [HA, Ca(5)(PO(4))(3)OH]. It has been shown that a modified form of brushite, with potassium substituting for calcium at specific sites, demonstrated accelerated transformation to HA when exposed to nonproteinaceous Hanks' balanced aqueous salt solutions (HBSS). The biocompatibility of a transforming material is related to cellular response to the process, which is initiated by protein adsorption. The effect of adsorbed protein on the kinetics and chemistry of brushite transformation to HA, when exposed to HBSS containing bovine serum albumin (BSA), was examined using Fourier transform IR spectroscopy, X-ray diffraction, and energy dispersive spectrometry techniques. The effect of solution pH was also studied. Results show that, in the presence of a protein-free environment, transformation is faster in buffered medium than in nonbuffered medium. Moreover, curve fitting and second derivatives of the IR spectra show that some bands shift depending on whether the brushite transforms in a buffered or nonbuffered medium. Therefore, variation in pH affects both transformation rate and the associated chemistry. The presence of BSA in either buffered or nonbuffered medium retards the transformation in comparison to the corresponding BSA-free medium. The extent of this retardation increases with the increase in bulk concentration of BSA but does not alter the transformation chemistry. This suggests the retardation on the transformation rate is due to BSA adsorption coverage on the calcium phosphate ceramic. This may be due to the shielding of Ca(2+) and PO(4)(-3) sites, preventing their interaction with the HBSS.

Managed care education in osteopathic medical schools: development of a fourth-year predoctoral healthcare management clerkship

This article describes the current managed care curricula in osteopathic medical schools and summarizes the development and implementation of a healthcare management clerkship for fourth-year osteopathic medical students at Ohio University College of Osteopathic Medicine. Results of a survey of the 19 osteopathic medical schools indicated that only three schools currently have a stand-alone, managed care elective. No schools have required managed care courses, clerkships, or rotations. The remaining osteopathic medical schools have incorporated managed care-related topics into courses in their schools' curricula. To produce physicians fully competent to succeed in the 21st century's managed healthcare environment, medical schools need to affiliate with managed care organizations, integrate more managed care components into their curricula, and develop required or elective stand-alone managed care courses and clerkships. This article describes content to be integrated in a predoctoral managed care clerkship, including goals and objectives. It also describes the components and learning activities of Ohio University College of Osteopathic Medicine's Healthcare Management Clerkship.

Development of a fish in vitro cell culture model to investigate oxidative stress and its modulation by dietary vitamin E

When cultured in Dulbecco's minimal essential medium the established epithelioma papulosum cyprini cell line from carp was found to be vitamin E-deficient due to the very low level of vitamin E in the medium and the foetal calf serum used as supplement. The toxicity of oxidative stressors to this cell line was evaluated by means of the neutral red cytotoxicity assay and it was found that an organic hydroperoxide, t-butylhydroperoxide was extremely cytotoxic and that the redox-cycling agents diquat and menadione were less toxic. When grown under vitamin E supplementation (25 microM), the toxicity of these chemicals was reduced by at least an order of magnitude in concentration demonstrating the protective effect of vitamin E. These data show the importance of vitamin E status for interpretation of in vitro and in vivo data and that this in vitro system is useful for mechanistic studies.

Transformation of modified brushite to hydroxyapatite in aqueous solution: effects of potassium substitution

Brushite (dicalcium phosphate dihydrate, DCPD, CaHPO4 x 2H2O) was deposited electrolytically from calcium dihydrogen phosphate solution with and without potassium chloride (KCl) as a supporting electrolyte. The kinetics of brushite transformation to hydroxyapatite (HA, Ca5(PO4)3OH) in the presence of calcium and protein free, aqueous body fluid (Hank's balanced salt solution, HBSS) was investigated. We present evidence that the deposition of brushite in a KCl-supported electrochemical bath yields a modified brushite where some of the calcium is substituted by potassium. Transformation of both normal (i.e. potassium free) and modified brushite to hydroxyapatite upon exposure to calcium and protein-free aqueous fluid (HBSS) was followed by reflectance Fourier Transform Infrared (FTIR) spectroscopy and X-ray diffraction (XRD) techniques. Changes in the morphology of the coatings were studied using scanning electron microscopy (SEM). Results indicate that modified brushite undergoes faster transformation to hydroxyapatite in HBSS in comparison to normal brushite. Our results show that the presence of potassium ions in the brushite not only favors the formation of different intermediate phases but also alters transformation rates to HA.

Electrodeposition of brushite coatings and their transformation to hydroxyapatite in aqueous solutions

In this study we examine the potential for using brushite (dicalcium phosphate dihydrate) as a coating for orthopedic implants. It was found that brushite is transformed into a more stable calcium phosphate (hydroxyapatite), regardless of the aqueous transforming media utilized. The transformation was carried out at room temperature in deionized water, deionized water with added calcium ions, and modified Hank's type solution without calcium and magnesium ions, modified Hank's type solution with calcium and magnesium ions, and modified Hank's type solution with added calcium ions. In several of the transformation systems it was noted that brushite provided an increased amount of calcium ions to the transforming media through solubility. The process was monitored using X-ray diffraction, X-ray photoelectron spectroscopy, and dissolution studies. Scanning electron microscopy and energy dispersive spectroscopy were also utilized for characterization. The brushite coatings can be easily achieved electrolytically on conducting substrates. The process is non line of sight, simple, and inexpensive; and when using an electrolyte that can sustain currents of approximately 100 mA/cm2, the necessary coating can be completed in about 3 min.

The effect of chlorambucil upon lysozyme activity

Chicken egg white lysozyme is progressively inhibited by diazoacetyl-DL-norleucine methyl ester (DANME) and by chlorambucil at concentrations of 3.4 x 10(-3) M and 5 x 10(-3) M respectively over a three-hour time period. DANME inhibits lysozyme activity to the extent of 87%, and chlorambucil inhibits the enzyme to the extent of 93%. N,N',N"-triacetylchitotriose [(NAG)3], which binds to subsites A, B and C of the enzyme protects lysozyme from DANME inhibition to the extent of 40% of the total activity when added to the enzyme at a concentration of 3.6 x 10(-3) M prior to the addition of DANME. (NAG)3 protects the enzyme from inhibition by chlorambucil to the extent of 14% of the total activity when added to the enzyme at a concentration of 5.6 x 10(-3) M prior to the addition of chlorambucil. Since DANME reacts exclusively with carboxyl groups, and since aspartic acid 101 is required for binding the carbohydrate substrate at site A, it is suggested that (NAG)3 may bind reversibly to the active site of the enzyme, thereby protecting aspartic acid 101 from esterification by DANME and subsequent inactivation. Chlorambucil, which may react with carboxyl, amino, imidazole and thiol groups, more likely acts upon a larger number of susceptible sites, thereby causing irreversible alkylation and conformation changes. As a bifunctional alkylating agent, it may also cross-link with two available nucleophiles. The K(m) for lysozyme with M. lysodeikticus as a substrate in wholly aqueous medium was determined to be 0.05 mg/mL. The inhibitor exhibits a partially uncompetitive upon pre-incubation with the enzyme, and a mixed inhibition between competitive and noncompetitive when pre-incubated with the substrate.

A cross-cultural study of reactivation of posttraumatic stress disorder symptoms: American and Cambodian psychophysiological response to viewing traumatic video scenes

A physiological hyperarousal state, which can be reactivated by traumatic stimuli, occurs frequently in patients with posttraumatic stress disorder (PTSD). The goals of this study were to determine whether physiological hyperarousal measured by increased heart rate is a specific response to reminders of a patient's own traumatic events or a more generalized hyperarousal state. Five brief videotape scenes of traumatic events (hurricane, auto accident, Cambodian refugee camp, domestic violence, and Vietnam War) were shown to two patient groups with PTSD (Vietnam veterans and Cambodian refugees) and three control groups (Vietnam veterans, Cambodian refugees, and nonpatient Americans). Observations of subjects' behavior, subjective ratings of distress, and heart rate change were recorded and evaluated. The results indicated that Cambodians with PTSD had the most reactions as measured by behavior and heart rate changes. These tended to occur during all scenes, not just the specific Cambodian scene, indicating a general nonspecific arousal. The Vietnam veterans had the fewest changes implying an inhibition of response. The control groups were intermediate in physiological response. The response in PTSD patients to reactivation scenes is complex and probably relates to type and degree of trauma, as well as to culture.

The anatomy of an OPTI: Part 2. The CORE system. Ohio Osteopathic Hospital Association. Ohio Association of Osteopathic Medical Directors. Ohio Osteopathic Association

In July 1995, the American Osteopathic Association (AOA) Board of Trustees passed new regulations regarding the accreditation of osteopathic graduate medical education (GME) by establishing the Osteopathic Postdoctoral Training Institutions (OPTI) system. This system must be phased in by July 1999. The principal changes resulting from the OPTI system include establishing requirements for college cosponsorship of GME programs and for the number of residency programs, interns, and residents to be trained by the OPTI. In essence, OPTI is an osteopathic acronym for consortium. Each OPTI must include at least one college of osteopathic medicine (COM) and one AOA-accredited hospital. The OPTIs will be subject to interval AOA inspections and will be required to demonstrate a governing system, mission statement, organizational structure, and the presence of faculty development programs. The first article in this two-part series, published in the October JAOA, provided a general blueprint for OPTI building and presented both positive and negative issues germane to the formation of OPTIs. Part 2 reinforces the considerations outlined in Part 1 by describing the formation of a large OPTI--the Ohio University College of Osteopathic Medicine (OU-COM) Centers of Osteopathic Regional Education (CORE) system. Key features are described, including the mission statement, organizational structure, committee system, governance, GME programs, operations, and budget.

Anatomy of an OPTI: Part I. Form, function, and relationships

In July 1995, the American Osteopathic Association (AOA) Board of Trustees passed new regulations for the accreditation of osteopathic graduate medical education (GME) programs by establishing the Osteopathic Postdoctoral Training Institutions (OPTI) system, to be implemented over 4 years. The resulting changes include requirements for college cosponsorship of GME programs and the establishment of standards for the minimum number of residency programs, interns, and residents. The OPTIs will be subject to AOA inspections at least every 5 years. Proponents of the OPTI system claim it will strengthen the profession by promoting educational collaboration, raising academic standards, and requiring appropriate resources to support osteopathic medical education. Opponents fear that it will be too resource intensive, create an additional layer of unnecessary bureaucracy, and have a negative impact on small colleges, hospitals, and states. Despite the controversy, a process for applying for OPTI status has been developed by the AOA, and a number of hospitals and colleges are already developing OPTIs. This article, the first in a two-part series, identifies issues and barriers to be considered in the formation of OPTIs and articulates principles underlying successful collaborations. In Part 2 these issues, principles, and barriers will be reinforced by describing the process used to form a large OPTI--the Ohio University College of Osteopathic Medicine (OU-COM) Centers for Osteopathic Regional Education (CORE) System.

The efficacy of local anaesthetics administered by general dental practitioners

AIM

To obtain empirical evidence for the efficacy of local anaesthesia in dentistry.

DESIGN

Retrospective analysis of serial administrations of local anaesthesia.

METHODS

Dentist and patient evaluations of the success of differing techniques (infiltration and block) of anaesthesia in a variety of general practice procedures. Results were analysed for correlation between dentist and patient using a 5-point scale.

RESULTS

Complete data were analysed for 331 administrations. In the hands of experienced dentists over 93% of operations were assessed by both dentist and patient as comfortable or completely comfortable. Dentists were generally able to judge patient comfort (P < 0.001). Administrations requiring repeat injections were less comfortable. Dentists judged infiltration administrations more comfortable than block administrations (P < 0.001), but patient judgements of comfort failed to distinguish between differing techniques at the P < 0.05 level.

CONCLUSIONS

Some variations in success rate exist between dentists the most dental procedures under local anaesthetic in general practice were assessed as being comfortable or better by both dentists and patients.

Videokeratography database of normal human corneas

AIM

To form a database of videokeratography patterns and quantitative indices describing normal human corneas using the absolute scale.

METHODS

Both eyes of 195 normal subjects were examined with a TMS-1 videokeratoscope. Videokeratographs were divided into 10 categories based on a classification scheme devised from the absolute scale and analysed with 10 quantitative indices devised to describe phenotypic features of keratoconus videokeratographs. Correlations were sought between videokeratograph patterns and quantitative indices. Additionally, data were analysed for differences in age, sex, and ethnicity.

RESULTS

For symmetric videokeratography patterns, analysis in the absolute scale was similar to a previous study done in the normalised scale. In the asymmetric categories, analyses differed markedly. Using the absolute scale and our classification scheme more variation in normal videokeratography patterns could be appreciated. There was good correlation between quantitative indices and videokeratography patterns. Neither videokeratography patterns nor indices differed significantly between sex, ethnic groups, or age using two way analysis of variance.

CONCLUSIONS

Pattern analysis of videokeratographs in the absolute scale using, a standard classification scheme, may be more useful in trying to determine whether a cornea is normal or represents subtle early disease than analysis in the normalised scale. Quantitative indices could remove the subjectivity from the decision making process thus facilitating universal reproducibility of videokeratography data interpretation.

Hydroxyapatite/metal composite coatings formed by electrocodeposition

Early bone infusion by cementless fixation of composite orthopedic and dental implants consisting of metallic substrates and bioceramics is well documented. Calcium phosphate ceramics in general and hydroxyapatite (HA) in particular have been the most popular of the bioceramics used for coating metals. Here, a non-line of sight coating procedure by electrocodeposition is reported for mechanically fixing HA particles in a metal matrix. Analyses of the coating showed excellent adhesion to the substrate and no structural transformation in either crystallinity or stoichiometry. Adhesion and surface coverage of HA depended upon the particle size. As a demonstration of the coating procedure's non-line of sight applicability, it was successfully used to coat titanium rods sintered with small titanium spheres.

A comparative study of family functioning among Vietnamese and Cambodian refugees

This study was designed to determine the extent of family problems among a clinic population of Cambodian and Vietnamese refugees, and to identify similarities and differences between the two groups. All 107 patients with adolescent children from a total clinic population of 298 were interviewed using a semistructured questionnaire, results were tabulated, and statistical methods were applied. The types of problems with children described by parents were classified into the dimensions of communication, personal behaviors, school performance, social behaviors, and antisocial behaviors. There were significantly more problems described by Vietnamese parents as compared with Cambodian parents. Vietnamese parents reported significantly more dissatisfaction with life in the United States. For both ethnic groups, parents' relationships with their adolescent children were a major source of concern and had a major impact on parents' perceptions of their own health. Yet, there were important ethnic differences between these refugee groups in how patients perceived their problems.

Ceroid granulomas in the female genital system

Three cases of ceroid granulomas of the female genital system are presented, involving the cervix in two and lesions in the ovaries and bowel serosa in the other. Ceroid granulomas are unusual and interesting lesions formed when suitable substrates accumulate within macrophages to such an extent that a relative lack of biological antioxidants results and auto-oxidation and conversion to ceroid is favoured. This may occur in the setting of haemorrhage and necrosis, whether from tumour necrosis or associated with endometriosis. Other sources of lipids and lipoproteins include bile, meconium and vernix caseosa.

Weekly and yearly rhythms in plasma fibrinogen in hospitalized male military veterans

The variation in plasma fibrinogen level demonstrating prominent circaseptan and circannual cycles is clinically relevant. There is a correlation between increasing level of fibrinogen and other hemostatic factors and risk of myocardial infarction and sudden death. The circaseptan and circannual cycles in fibrinogen concentration described in this study may help to explain further the variation in frequency of coronary events. Furthermore, the recent demonstration of a circadian pattern in the efficacy of tissue plasminogen activator, with peak efficacy occurring at 2000 hours--10 hours after the peak incidence of myocardial infarction--implies that further patterns to coronary artery syndromes may be predicted and the treatment efficacy may rely on demonstrated circaseptan and circannual cycles of these events.

Acetaldehyde-modified lysozyme function: its potential implication in the promotion of infection in alcoholics

Incubation of lysozyme with acetaldehyde (0.44 M) at room temperature for 2 h produces a 62% inhibition of enzymic activity. Because the active site cleft contains tryptophyls, asparagine, glutamine, and an arginine residue, and because acetaldehyde reacts with indoles, amides, and guanidines, it is suggested that these sites are likely ones for alkylation. The epsilon-amino groups of lysines on the surface of the molecule are also susceptible to covalent modification. Total acetylation of lysozyme has been reported to inactivate the enzyme. These results suggest the possibility that inactivation of a fraction of the lysozyme activity by acetaldehyde may decrease the effectiveness of the enzyme in chronic alcoholics, thereby leading to an increased potential for susceptibility to bacterial infection.

Analysis of apatite deposits on substrates

Calcium phosphate coatings, important for medical implant applications can occur in several different phases. Because of differences in properties of these phases it is imperative to be able to identify their presence in a substrate's coating. In this study we characterized hydroxy apatite (HA) surfaces applied by four different coating procedures. Included were plasma sprayed, sputtered, a composite, and a composite overlayed with plasma sprayed. It was found that a combination of reflectance infrared and Raman spectroscopy could be utilized to make an in situ characterization of the calcium phosphate phases. It was shown that plasma sprayed and sputtered coatings of HA lost OH and thus decreased in crystallinity, while composite coatings remained unchanged from the original HA powder.

Periodontal microflora of HIV positive subjects with gingivitis or adult periodontitis

The subgingival microflora of 39 HIV+ subjects with gingivitis or adult periodontitis was cultured quantitatively anaerobically for bacteria, spirochetes, and mycoplasma and aerobically for yeasts. Isolates were characterized by conventional biochemical tests, polyacrylamide gel electrophoresis of soluble proteins, cellular fatty acid profiles, immunofluorescence, and immunodiffusion. In general, the same types of bacteria were isolated from the subgingival crevice of HIV+ subjects as we previously had isolated from the subgingival crevice of non-HIV subjects. A statistically significant difference was found between the composition of the flora of HIV+ subjects with adult periodontitis (AP) and concurrent studies of a non-HIV+ AP population. Mycoplasma salivarium was significantly elevated in the HIV+ subjects examined. Yeasts were isolated from only 10% of the samples and from 13% of the HIV-positive subjects at 0.05 to 0.0002% of the total cultivable count when present.

Increased activity of 6-phosphogluconate dehydrogenase and glucose-6-phosphate dehydrogenase in purified cell suspensions and single cells from the uterine cervix in cervical intraepithelial neoplasia

The activities of 6-phosphogluconate dehydrogenase and glucose-6-phosphate dehydrogenase have been measured in squamous epithelial cells of the uterine cervix from normal patients and cases of cervical intraepithelial neoplasia (CIN). A biochemical cycling method, which uses only simple equipment and is suited to routine use and to automation, was applied to cells separated by gradient centrifugation. In addition, cells were examined cytochemically, and the intensity of staining in the cytoplasm of single whole cells was measured using computerised microcytospectrophotometry. Twenty per cent of cells in samples from normal patients (n=61) showed staining intensities above an extinction of 0.15 at 540 nm, compared to 71% of cases of CIN 1 (n=14), 91% of cases of CIN 2 (n=11) and 67% of cases of CIN 3 (n=15). The cytochemical data do not allow definitive distinctions to be made between different grades of CIN whereas the biochemical assay applied to cell lysates shows convincing differences between normal samples and cases of CIN. There are no false negatives for CIN 3 (n=14) and CIN 2 (n=10) and 11% false negatives for CIN 1 (n=9) and 14% of false positives for normal cases (n=21). The results of this preliminary study with reference to automation are discussed [corrected].

Periodontal health in 200 HIV-positive patients

Two hundred HIV-positive subjects were surveyed to determine their periodontal health status. Particular attention was given to the occurrence of a severe and rapidly progressing form of periodontal disease designated "HIV-associated periodontitis", which has been reported as being unique to AIDS patients. Among the subjects comprising the cohort, 85 subjects had good gingival health, 59 subjects exhibited gingivitis, 49 cases of adult periodontitis were observed, 5 subjects presented with advance adult periodontitis, and 2 cases of necrotizing ulcerative periodontitis (NUP) were found within the group. The periodontitis of the patients in this survey did not have unique or pathognomonic characteristics which could set their periodontal disease apart from the periodontal disease seen in HIV negative population.