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Biomedical subjects

A C Jones

Publications and source records attributed to A C Jones.

At least 73 records · Page 4Linked to original sources
PubMed1997

Myers-Briggs Type Indicator and dental school performance.

The Myers-Briggs Type Indicator (MBTI) was administered to 256 dental students, representing four classes, at the University of Florida College of Dentistry. The results of this psychological instrument were then correlated with overall dental school performance based on results from the National Dental Board Examinations Part I and II (NB-I, NB-II), yearly class rank, and specific academic difficulties as measured by the Student Performance Evaluation Committee. Introverted students were found to display a significantly increased performance on NB-I (p = .038) and NB-II (p = .044). They were also found, however, to demonstrate a progressively lower class rank over the four-year period than extroverted students and were more likely to experience major academic difficulties as well. Judging and sensing individuals were found to earn a higher class rank over the four-year period than perceiving and intuitive students, respectively. Perceiving students were found to exhibit major difficulties or were placed on probation more often than judging individuals. These results may prove useful in counseling students to recognize potential problems before they commence their dental education or to anticipate and address specific weaknesses during the course of their education.

Achievement↗
PubMed1996

Investigation of porphyrins and metalloporphyrins using two-step laser mass spectrometry.

Laser desorption time-of-flight mass spectrometry with laser postionization at 193 nm has been used to study a series of selected porphyrins and metalloporphyrins. Molecular ions are predominantly formed under soft ionization conditions, with extensive fragmentation of the peripheral substituents being observed under hard ionization conditions. Cu-octaethylporphyrin is found to exhibit anomalous demetallation at this ionization wavelength. At high ionization laser fluences it is also possible to observe extensive fragmentation of the porphyrin macrocycle. Much of the observed fragmentation can be understood with reference to previous studies using electron impact (EI) ionization. The stability of the porphyrin nucleus allows the fragmentation of the side chains to be examined. As in earlier EI studies dehydration products are observed in the mass spectra of hematoporphyrin IX. These products are shown to be thermally induced during infrared laser desorption, rather than fragments arising from photoionisation. The flexibility of this two-step laser mass spectrometric approach has allowed the analysis of chlorophyll a directly from an organic matrix. The data obtained suggest that information concerning the interaction between adsorbate and substrate can be extracted.

Chlorophyll↗
PubMed1996

Human papillomavirus-associated oral epithelial dysplasia (koilocytic dysplasia): an entity of unknown biologic potential.

Intraepithelial neoplasia of the female genital tract has long been associated with human papillomavirus infection. To date, there have been no previously published studies of oral dysplasia that have identified light microscopic features predictive of the presence of human papillomavirus. We identified a variant of oral epithelial dysplasia, koilocytic dysplasia, that exhibited light microscopic features suggestive of HPV infection. To determine if these microscopic features were specifically correlated with human papillomavirus infection, DNA in situ hybridization for human papillomavirus 6/11, 16/18, and 31/33/51 was performed on 31 lesions diagnosed histologically as koilocytic dysplasia. Seventeen matched control cases of conventional oral epithelial dysplasia were also analyzed for human papillomavirus. Human papillomavirus DNA was detected significantly more often (p < 0.001) in koilocytic dysplasia (80.6%) than conventional oral epithelial dysplasia (0.0%). Positive cases of koilocytic dysplasia contained either intermediate-risk (31/33/51) or high-risk (16/18) human papillomavirus types whether or not they contained low-risk human papillomavirus types (6/11). The histologic and clinical presentation of koilocytic dysplasia was unique. Lesions demonstrated koilocytes and other microscopic characteristics of human papillomavirus infection, as well as features of conventional epithelial dysplasia. A striking male predominance was noted, as was a relatively young average age of presentation (39.0 years). On the basis of our preliminary analysis, we conclude that oral koilocytic dysplasia represents a unique pathologic entity and that the presence of human papillomavirus can be predicted on light microscopy with at least 80% accuracy. The clinical significance and potential for malignant transformation of koilocytic dysplasia remain to be investigated.

Adult↗
PubMed1996

Fetal peripheral blood mononuclear cell proliferative responses to mitogenic and allergenic stimuli during gestation.

Blood samples were obtained from fetuses and premature babies (n = 51) (15-34 weeks gestation) to determine at what stage the fetal immune system was able to produce a positive proliferative response to common allergens. Peripheral blood mononuclear cells (PBMC) were stimulated with the mitogen, phytohaemagglutinin (PHA), and the allergens, house dust mite, cat fur, birch tree pollen, beta-lactoglobulin, ovalbumin and bee venom (mellitin). Results were expressed as ratios of stimulated to unstimulated 3H thymidine incorporation, and as percent positive responders. There was an increase in proliferation ratio which correlated with increasing gestational age for PHA (p < 0.0001), cat fur (p = 0.042), birch pollen (p = 0.022) and beta-lactoglobulin (p = 0.006). The point in gestation when cells from some individuals began responding to the allergens with a ratio of 2.0 was at approximately 22 weeks. PBMC proliferative response ratios were higher from samples from babies > 22 weeks gestation compared to < 22 weeks for the mitogen and all allergens, except mellitin. There was also a greater proportion of positive responders from samples > 22 weeks compared to < 22 weeks for the mitogen and all allergens, except mellitin. Maternal exposure to birch pollen, which has a discrete season, was assessed to determine whether exposure had occurred at 22 weeks gestation or beyond. Results showed a higher proliferative response in infant cells stimulated with birch pollen (p = 0.005) and higher proportion of positive responders (p = 0.01) in the group of babies whose mothers had been exposed to birch pollen beyond 22 weeks, compared to those whose mothers had not been so exposed. These results suggest that in utero fetal exposure to an allergen from around 22 weeks gestation may result in primary sensitisation to that allergen, leading to positive proliferative responses, at birth.

Adult↗
PubMed1996

Indispensable amino acid deficiency and increased seizure susceptibility in rats.

Repeated subthreshold stimulation of limbic brain areas increases seizure susceptibility in experimental models of epilepsy. In addition, acute dietary indispensable amino acid (IAA) deficiency activates the anterior piriform cortex (APC), a seizure-prone limbic brain area in the rat. Based on these two findings, we hypothesized that activation of the APC by chronic exposure to IAA-deficient diets might increase seizure susceptibility. Several nonessential amino acid neurotransmitters are important in seizures, but deficiencies of nontransmitter IAAs have not been well studied in seizure models. In four trials, we made injections of pentylenetetrazole intraperitoneally or of bicuculline into the APC in histidine-, isoleucine-, or threonine-deficient rats and controls. Increased susceptibility to seizures in the deficient animals was observed as increased severity of the seizures, decreased threshold for the dose of the chemostimulant and time to seizure, or a combination thereof. Pair-fed controls showed that this effect was not due to an energy deficit. This novel but robust finding suggests that IAA deficiency may increase vulnerability to seizures by repeated activation of the APC.

Amino Acids↗
PubMed1996

Ontogeny of circulating leucocytes in the fetal guinea pig.

The ontogeny of leucocytes in the fetal guinea pig was investigated. The total leucocyte concentration increased between days 40 and 56, but thereafter was unchanged at term (day 68). T and B lymphocytes were detected on day 56 and at term, and while T cell concentrations remained constant between day 56 and term, the concentration of B cells decreased. The ratio of CD4+ to CD8+ T cells increased from 0.9 on day 56 to 3.0 at term. All fetal cell concentrations were significantly lower as compared with adult animals. The fetal peripheral blood mononuclear cell proliferative responses to mitogenic stimulation increased from day 40 to 56, but tended to decrease between day 56 and term. The fetal proliferative responses were significantly lower as compared with adults. Comparison of these data with previous analyses of the pattern of human fetal lymphocyte development indicated that, although there were similarities, such as the timing of the first appearance of circulating lymphocytes, there were also differences, for example the changes which occur between birth and adulthood, between the two species. This suggests that the guinea pig may have a limited use as a model of some aspects of the ontogeny of the human immune system.

Animals↗
PubMed1996

Peripheral blood mononuclear cell proliferative responses in the first year of life in babies born to allergic parents.

BACKGROUND: Raised peripheral blood mononuclear cells (PBMCs) proliferative responses to food allergens have been demonstrated in children with established atopic dermatitis. OBJECTIVE: In this report we investigate the PBMC proliferative responses to inhalant and food allergens from babies at birth, 6 months and 1 year of age, born to atopic and non-atopic parents. METHODS: PBMCs, separated by density gradient centrifugation, were cultured for 6 days with autologous plasma and a range of allergens (house dust mite [HDM], cat, grass pollen, tree pollen, betalactoglobulin and ovalbumin). Proliferative responses were measured by the uptake of [3H] thymidine added for the final 18 h of culture. RESULTS: At birth, infants born to atopic parents who developed allergic disease by 1 year of age had significantly more positive responses (stimulation index > or = 2 with a value of > or = 1000 cpm above background) to HDM (P = 0.0097), betalactoglobulin (P = 0.0166) and ovalbumin (P = 0.0035) than newborns who did not develop allergy. Infants who developed allergy also had significantly more positive responses to HDM (P = 0.03) and ovalbumin (P = 0.0057) than babies, born to non-atopic parents, who did not develop allergies. At 6 months of age a significant fall in response to HDM (P = 0.003) and cat fur extract (P = 0.006) was seen in infants who developed allergic disease by 1 year of age. A similar pattern was seen for proliferative responses to betalactoglobulin and ovalbumin (P = 0.0006, P = 0.004). Conversely, proliferations to grass and tree pollen extracts increased at 6 months (P = 0.04, P = NS) and 1 year (P = NS, P = 0.01) compared with birth which was significant for infants who did not develop allergic disease. CONCLUSION: Proliferative responses to seasonal allergens increased over the first year of life whilst those to perennial allergens, both inhalant and food, fell. This suggests either the induction of a systemic immune tolerance by perennial exposure to antigens or movement of sensitized cells to target organs where allergen exposure occurs. This process may be independent of the development allergic disease.

Aging↗
PubMed1996

Clinical audit and effective change in leg ulcer services.

An audit of clinical leg ulcer services was undertaken in South Bedfordshire and was followed by a process of implementation using research-based methods; a re-audit was conducted 18 months later. Using an adaptation of the Riverside model, patients were referred to community leg ulcer clinics. They were assessed using Doppler ultrasound; those with ABPI > 0.8 were treated using a high-compression four-layer bandage system. Those with ABPI 0.6-0.8 were treated using reduced compression, and those with ABPI < 0.6 were sent to their GP for referral for specialist opinion. In October 1993, the average cost of consumables for each patient was 8.53 pounds, and this rose to 10.14 pounds in May 1995. However, patients treated in community clinics had a reduced cost of consumables of 7.91 pounds compared with 10.78 pounds for patients treated at home. There was also a corresponding reduction in weekly treatments and an overall reduction in nursing time to treat patients. In 111 patients (134 limbs) treated by high compression in the community clinics, cumulative percentage healing was 54% after 12 weeks and 68% after 24 weeks. Although these results were lower than those achieved in the Riverside project, much of the difference can be explained by the different patient populations and ulcer duration. The results support a system of care which offers rationalisation of service, staff training and research-based effective assessment and treatment.

Aged↗
PubMed1995

The establishment of two cell lines from a mouse uterine cervical carcinoma (U14) and their metastatic phenotype changes.

This paper studies the heterogeneity of metastatic potential of murine cervical carcinoma (U14). Two cell lines, P11-90 and L10-90, were established from a pulmonary metastatic substrain (U14AP11) and a lymphatic metastatic substrain (U14AL10), which were selected from U14 in vivo after 11 and 10 passages, respectively. The biologic differences between the two cell lines are as follows. (1) The cells of the P11-90 line grow more rapidly compared with the L10-90 line. From the 40th passage the medium pH was different. (2) The median number of chromosomes in P11-90 and L10-90 was 72 and 64, respectively; the rates of gap aberration were 88% and 78%, respectively. (3) The number of T lymphocytes and T helper lymphocytes in the peripheral blood from hosts with P11-90 were higher than that of hosts transplanted with L10-90, but the number of B lymphocytes in the latter was larger than that in the former. (4) The metastatic potential of each cell line partially decreased compared to the relative tumor substrain, but their organ preference still remained and the transplant locations, axillary or footpad, had a prominent influence on their metastatic behavior. To observe the effects of metastatic target organs on the metastatic phenotypes of tumor cells, as well as to explore a method for the establishment and maintenance of the metastatic organ preference of tumor cells, conditioned medium (CM) from pulmonary or lymphatic node diploid cells was added to the culture medium of P11-90 and L10-90. Two sublines, P + P11-90 and Ln + L10-90, were thus established. Using stereological methods we found that the majority of P + P11-90 cells became larger and their nuclei also increased in size compared with their parental lines, but the majority of Ln + L10-90 cells became smaller in size, though the nuclei were enlarged. The pulmonary metastatic rate and lymphatic metastatic rate of P + P11-90, as well as the lymphatic metastatic rate of Ln + L10-90, were restored dramatically. The results suggest that by taking advantage of the interaction between tumor cells and the CM of host cells the metastatic potential of tumor cell lines can be maintained in vitro. Our work may offer an experimental model for the manipulation of metastasis of cell lines coming from the same parent strain but with different metastatic potentials.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1995

Intra-articular hyaluronic acid compared to intra-articular triamcinolone hexacetonide in inflammatory knee osteoarthritis.

The aim of this study was to determine the comparative efficacy and safety of intra-articular (i/a) triamcinolone. hexacetonide (TH) and i/a hyaluronic acid (HA) in inflammatory knee osteoarthritis. A randomized double-blind comparative trail was carried out in a rheumatology outpatient department. There were 63 patients (24 male, 39 female, mean age 70.5 years) with bilateral symptomatic knee osteoarthritis with effusion. Each was given five HA injections at weekly intervals; or 20 mg TH followed by four placebo (saline) injections. Patients were examined weekly during the treatment period and then at monthly intervals for a further 6 months. Assessment included recording of: visual analog scores (VAS) for pain; duration of stiffness; range of movement; joint effusion; local heat; synovial thickening; joint-line and periarticular tenderness. The principal outcome measure was pain on a self-selected activity assessed by Vas. The two groups were comparable at entry and no significant differences between the groups developed at any time during the treatment period. However, there was a high drop-out rate and intention to treat analysis failed to demonstrate statistically significant differences between the groups. In patients remaining in the study, significantly less pain was experienced by the HA group during the 6 month follow-up period. Other parameters showed a similar trend in favor of experienced by the HA group during the 6 month follow-up period. Other parameters showed a similar trend in favor of HA. We could not, however, demonstrate significant differences between the placebo and active treatments. HA may therefore be a useful additional therapy for symptomatic knee osteoarthritis and may have a long duration of action.

Aged↗
PubMed1994

Percutaneous and mucous membrane exposure protocol in a southeastern dental school.

A southeastern dental educational institution formalized a Percutaneous and Mucous Membrane Exposure Protocol in 1990. This article outlines the development, implementation, and administration of the protocol including risk assessment and rationale for testing health care workers and source persons. Pretest and posttest counseling for HIV testing is also discussed.

AIDS Serodiagnosis↗
PubMed1994

Multinucleate cell angiohistiocytoma of the upper lip.

Multinucleate cell angiohistiocytoma is a rare benign fibrohistiocytic vascular tumor with distinctive histologic features. It appears clinically as small, slow-growing, grouped reddish-brown to purple papules and nodules that may be mistaken for other vascular proliferative or reactive conditions. Multinucleate cell angiohistiocytoma tends to occur more frequently in women, to favor the extremities, and to appear as multiple lesions. We report a case of solitary multinucleate cell angiohistiocytoma that appeared as a nodule on the upper lip of a man but that otherwise demonstrated characteristic histologic and immunohistochemical features. Greater awareness of this uncommon benign lesion will facilitate diagnosis and appropriate management.

Adult↗