Traditional tooth bud gouging in a Ugandan family: a report involving three sisters

It has been reported in the literature that some rural populations of Sub-Saharan and Eastern Africa and other isolated areas around the world, practise gouging or enucleation of primary tooth buds to cure childhood illnesses. The unerupted primary canine tooth bud is believed to be the cause of febrile illness, diarrhoea, and vomiting; prevalent in infants in these areas of the world. Tooth bud gouging has implications for the developing dentition, and is a potential risk to the health and life of the child. Reported prevalence ranges from 22%-90%. From the information in this case report, the practise of tooth bud gouging is no longer confined to rural areas and may well be performed by communities that have emigrated to the UK. The three sisters described, now resident in the UK, suffered tooth gouging in a city clinic in Uganda. The damage caused to the primary and permanent dentition is described and treatment planning and options are suggested for each case to restore structure and function. Appropriate provision of healthcare and education could avoid the potential long-term damage to the health of the child and their developing dentition by the practise of tooth bud gouging, whether it occurs in the developing or developed world.

Evaluation of a new selective medium for methicillin-resistant Staphyloccocus aureus

The aims of this study were to evaluate the performance of a new medium, desferrioxamine oxacillin tellurite egg-yolk mannitol salt agar (DOTEMSA) in detecting methicillin-resistant Staphylococcus aureus (MRSA) and then to compare this medium against the Public Health Laboratory Service (PHLS) recommendation of mannitol salt agar (Oxoid) with oxacillin (OMSA) and Baird-Parker medium with ciprofloxacin (BPC) for the isolation of MRSA. The individual selective agents contained in DOTEMSA were tested against isolates of coagulase-negative staphylococci (CNS) and the medium with all constituents was challenged with various bacteria. Routine screening specimens were plated out on OMSA, BPC and DOTEMSA and the plates were incubated and examined at 24 and 48 h. Tellurite, desferrioxamine and oxacillin each inhibited the majority of CNS isolates; only three (of 103) grew in the presence of all three agents. Sixty-two of 63 isolates of MRSA grew on DOTEMSA and 59 produced lipase. Most other bacteria were inhibited. In all, 184 MRSA isolates were isolated from 540 screening specimens. The sensitivity of OMSA, BPC and DOTEMSA was 42%, 81% and 51% at 24 h, and 60%, 89% and 89% at 48 h. At 48 h, the combination of BPC and DOTEMSA detected 99% of MRSA isolates. Seventy, 49 and one non-MRSA isolates needed investigation for each of the three media respectively. A proposed strategy for MRSA screening would use BPC and DOTEMSA, examining BPC at 24 h and both media at 48 h. Provisional reports could then be issued at 24 h on the basis of rapid agglutination tests to confirm isolates as S. aureus from BPC and at 48 h on the basis of typical colonies from DOTEMSA.

Resolving factor analysis

Bilinear data matrices may be resolved into abstract factors by factor analysis. The underlying chemical processes that generated the data may be deduced from the abstract factors by hard (model fitting) or soft (model-free) analyses. We propose a novel approach that combines the advantages of both hard and soft methods, in that only a few parameters have to be fitted, but the assumptions made about the system are very general and common to a range of possible models: The true chemical factors span the same space as the abstract factors and may be mapped onto the abstract factors by a transformation matrix T, since they are a linear combination of the abstract factors. The difference between the true factors and any other linear combination of the abstract factors is that the true factors conform to known chemical constraints (for instance, nonnegativity of absorbance spectra or monomodality of chromatographic peaks). Thus, by excluding linear combinations of the abstract factors that are not physically possible (assuming a unique solution), we can find the true chemical factors. This is achieved by passing the elements of a transformation matrix to a nonlinear optimization routine, to find the best estimate of T that fits the criteria. The optimization routine usually converges to the correct minimum with random starting parameters, but more difficult problems require starting parameters based on some other method, for instance EFA. We call the new method resolving factor analysis (RFA). The use of RFA is demonstrated with computer-generated kinetic and chromatographic data and with real chromatographic (HPLC) data. RFA produces correct solutions with data sets that are refractory to other methods, for instance, data with an embedded nonconstant baseline.

Analysis of pulmonary surfactant by Fourier-transform infrared spectroscopy following exposure to Stachybotrys chartarum (atra) spores

Lung cells are among the first tissues of the body to be exposed to air-borne environmental contaminants. Consequently the function of these cells may be altered before other cells are affected. As gas exchange takes place in the lungs, changes in cellular function may have serious implications for the processes of oxygen uptake and carbon dioxide elimination. In order for these processes to occur, the lung must maintain a high degree of expandability. This latter function is accomplished in part by the pulmonary surfactant which is synthesized and released by alveolar type II cells. Earlier studies have shown that exposure to gas phase materials such as smoke or organic solvents can alter the composition and function of the surfactant. The present study examines the ability of highly toxigenic mold spores to alter surfactant composition. Stachybotrys chartarum spores suspended in saline were instilled into mouse trachea as described earlier. After 24 h, the lungs were lavaged and the different processing stages of surfactant isolated by repeated centrifugation. Intracellular surfactant was isolated from the homogenized lung tissue by centrifugation on a discontinuous sucrose gradient. Samples were extracted into chloroform-methanol, dried and analyzed by Fourier-Transform infrared spectroscopy (FTIR). Exposure to S. chartarum induced an overall reduction of phospholipid among the three surfactant subfractions. The intermediate and spent surfactant fractions in particular were reduced to about half of the values observed in the saline-treated group. The relative distribution of phospholipid was also altered by spore exposure. Within the intracellular surfactant pool, higher levels of phospholipid were detected after spore exposure. In addition, changes were observed in the nature of the phospholipids. In particular strong intramolecular hydrogen bonding, together with other changes, suggested that spore exposure was associated with absence of an acyl chain esterified on the glycerol backbone, resulting in elevated levels of lysophospholipid in the samples. This study shows that mold spores and their products induce changes in regulation of both secretion and synthesis of surfactant, as well as alterations in the pattern of phospholipid targeting to the pulmonary surfactant pools.

Diffuse malignant mesothelioma of the peritoneum following abdominal radiotherapy

Two cases of diffuse malignant mesothelioma of the peritoneum are described in 65 and 54-year-old patients a long time following abdominal radiotherapy treatment for testicular tumour in addition to orchidectomy.

The radiographic localization of impacted maxillary canines: a comparison of methods

This study compared two different radiographic techniques for localization of impacted maxillary canines: vertical parallax (from a panoramic and a maxillary anterior occlusal radiograph) and magnification (from a single panoramic radiograph). The radiographs and the information regarding the impacted canines were obtained retrospectively from records of patients treated in the Day Stay Unit of the Eastman Dental Hospital. The two different radiographic techniques were tested blind and compared for localization of the impacted canine by six examiners. The 'gold standard' used for the radiographic comparisons was the true position of the canine as recorded at operation. The results showed a wide variation between the six examiners in the prediction of the canine position with the two different techniques. Localization with vertical parallax was more successful overall than with magnification, although the difference failed to reach significance. Seventy-six per cent of the impacted canines could be successfully located with vertical parallax and 66 per cent with magnification. Further analysis showed that, while almost 90 per cent of the palatally impacted canines could be correctly detected with both techniques, less than half of the buccal canines could be detected with parallax and only one in 10 buccal canines could be detected with magnification. If a canine is suspected to be buccally placed from its appearance on a panoramic film and cannot be palpated, further views are justified.

The appeal cycle in three cultures: an exploratory comparison of child development

Mother-child behaviors were studied in three cultural groups: Caucasian American (CA), overseas Japanese (JPN), and Chinese Vietnamese (CVN) immigrants. The children were sixteen to twenty-five months old, and the appeal cycle, with its descriptive analytic method, was the research paradigm. Group differences were found in appeal cycle occurrence and phase frequencies. CA mothers promoted independence through encouragement of decision making and toddler-initiated play, and through nonintrusive interactions. Neither JPN nor CVN mothers encouraged independence. JPN mothers were subtly directive; CVN mothers overtly so. Generally, CA toddlers played independently, evincing a beginning capacity for self-regulation. JPN and CVN toddlers reacted to separation by staying close to their mothers, and fewer were observed to play independently than in the CA group. CVN toddlers played independently more frequently than JPN toddlers, but less frequently than CA toddlers. Quantitative measures of dyadic behaviors generally support the descriptive findings, though methodological constraints did not permit comparison of phase sequencing. The findings reflect cultural differences in child development thought to influence psychic structure formation.

Thioguanine for refractory psoriasis: a 4-year experience

BACKGROUND

A variety of systemically administered drugs are used to treat psoriasis, including methotrexate, cyclosporine, acitretin, and hydroxyurea. Unfortunately, some patients are unresponsive to these agents. For others, side effects and cumulative toxicity prevent continued use.

OBJECTIVE

Our purpose is to report the results of thioguanine (6-thioguanine) treatment of 21 patients with refractory psoriasis.

METHODS

We conducted a retrospective review of the treatment courses of 21 patients with psoriasis who were treated with thioguanine. Daily dosing and pulse dosing were both used, from 20 mg two times a week to 120 mg daily. All patients had been treated with other systemic therapies, and the majority (86%) had been treated with methotrexate.

RESULTS

Patient outcome (response to treatment relative to baseline) was classified into 3 groups: those with more than 90% improvement, those with between 50% and 90% improvement, and those with less than 50% improvement. Outcome data were based on the patient's subjective rating of disease severity before the start of thioguanine therapy and during the entire treatment course. Of the 18 patients able to be evaluated, 14 of 18 (78%) had dramatic improvement (>90%); 3 of 18 (17%) had lesser improvement (50%-90%); and only 1 of 18 had less than 50% improvement. The mean duration of treatment was 15.5 months. The primary side effect was myelosuppression, mild in 9 of 18 (white blood cell counts ranging from 1600-3700/microL; platelet counts ranging from 90,000-122,000/microL, and hematocrit values ranging from 24%-31%), and severe in 1 of 18 (white blood cell count of 1300/microL, platelet count of 17,000/microL, and hematocrit of 20%).

CONCLUSION

Thioguanine appears to be an effective treatment for patients with severe recalcitrant psoriasis. Myelosuppression is a significant, but easily monitored side effect that can now be more accurately predicted by determining thiopurine methyltransferase levels before starting thioguanine. Further prospective studies are needed to establish criteria, which will maximize efficacy of this drug in the treatment of psoriasis and minimize toxicity.

A prospective follow-up study of ECT outcome in older depressed patients

BACKGROUND

This study examined the relationship between age and outcome of electroconvulsive therapy (ECT).

METHOD

This was a naturalistic, prospective follow-up of 81 consecutive in-patients with primary major depression. ECT outcome was compared for three age groups - under 65, 65-74 and 75 years and over - on the Hamilton Rating Scale for Depression (HRSD), Global Assessment of Functioning scale (GAF) and clinical outcome rating scale. Assessments were performed pre-ECT, immediately post-ECT, 1-3 years later and, for patients suspected of having dementia, 5 years later.

RESULTS

At post-ECT and follow-up, improvement on HRSD and clinical outcome ratings were comparable for patients in the three age groups. Improvements on GAF were also comparable post-ECT, but not between post-ECT and follow-up. At follow-up, 35.7% of the oldest group had dementia. Importantly, patients who did and did not develop dementia were clinically indistinguishable prior to ECT. The number and severity of common adverse events were similar pre- and post-ECT and were not associated with age.

CONCLUSIONS

Depressive outcome and adverse effects of ECT are largely independent of age. Older patients receiving ECT appear to have a higher risk of developing dementia, possibly underpinned by cerebrovascular disease.

Growth cone form, behavior, and interactions in vivo: retinal axon pathfinding as a model

Studies in vitro have revealed a great deal about growth cone behaviors, especially responses to guidance molecules, both positive and negative, and the signaling systems mediating these responses. Little, however, is known about these events as they take place in vivo. With new imaging methods, growth cone behaviors can be chronicled in the complex settings of intact or semi-intact systems. With the retinal projection through the optic chiasm as a model, we examined the hypothesis previously drawn from static material that growth cone form is position-specific: growth cone form in fact reflects specific behaviors, including rate and tempo of extension, that are more or less prominent in different locales in which growth cones are situated. Other studies show that growth cones interact with cells along the pathway, both specialized nonneuronal cells and other neurons, some expressing known guidance molecules. The present challenge is to bridge dynamic imaging with electron microscopy and molecular localization, in order to link growth cone behaviors with cell and molecular interactions in the natural setting in which growth cones extend.

HLA-DR-promiscuous T cell epitopes from Plasmodium falciparum pre-erythrocytic-stage antigens restricted by multiple HLA class II alleles

Previously, we identified and established the antigenicity of 17 CD8+ T cell epitopes from five P. falciparum Ags that are restricted by multiple common HLA class I alleles. Here, we report the identification of 11 peptides from the same Ags, cicumsporozoite protein, sporozoite surface protein 2, exported protein-1, and liver-stage Ag-1, that bind between at least five and up to 11 different HLA-DR molecules representative of the most common HLA-DR Ags worldwide. These peptides recall lymphoproliferative and cytokine responses in immune individuals experimentally immunized with radiation-attenuated Plasmodium falciparum sporozoites (irradiated sporozoites) or semi-immune individuals naturally exposed to malaria in Irian Jaya or Kenya. We establish that all peptides are recognized by individuals of each of the three populations, and that the frequency and magnitude of helper T lymphocyte responses to each peptide is influenced by the intensity of exposure to P. falciparum sporozoites. Mean frequencies of lymphoproliferative responses are 53.2% (irradiated sporozoites) vs 22.4% (Kenyan) vs 5.8% (Javanese), and mean frequencies of IFN-gamma responses are 66.3% (irradiated sporozoites) vs 27.3% (Kenyan) vs 8. 7% (Javanese). The identification of HLA class II degenerate T cell epitopes from P. falciparum validates our predictive strategy in a biologically relevant system and supports the potential for developing a broadly efficacious epitope-based vaccine against malaria focused on a limited number of peptide specificities.

Feasibility of implementing health promotion interventions to improve health-related quality of life

Survivors of childhood cancer are a growing and vulnerable population. Cure rates for pediatric cancers now exceed 60% and, by the year 2000, an estimated 1 of every 1,000 young adults will be a cancer survivor. Because this population is at increased risk for late medical and neoplastic complications that impact adversely on health-related quality of life, it is important to investigate methods to promote risk reduction by motivating survivors to practice health-promoting behaviors. With this background, we initiated a prospective, randomized, controlled feasibility study in which survivors attending a long-term follow-up clinic were randomized to receive standard care or standard care plus an educational intervention. Our objectives were to determine if the intervention would improve the survivors' knowledge about their cancer treatment and risks of late effects and increase their practice of health-protective behaviors. Since July 1995, 272 of 318 families (86%) approached about the study agreed to participate. Of these, 266 are evaluable for assessment of baseline knowledge and health behaviors. Demographic features, baseline knowledge, health perceptions and health behaviors did not differ among randomized groups. Assessment of the intervention's efficacy at changing health behaviors of survivors randomized to the intervention group will be available when the 1-year follow-up evaluations are completed for the study cohort. Our preliminary experience with this pilot study supports the feasibility of educational intervention research in a specialty clinic dedicated to monitoring long-term childhood cancer survivors. Int. J. Cancer Suppl. 12:138-142, 1999.

Transport and health: en route to a healthier Australia?

We have been slow to recognize the impact that decisions about transport, land use and infrastructure have on health. Apart from encouraging a sedentary lifestyle, reliance on motor vehicle transport has a range of adverse health effects (traffic accidents, air and noise pollution, and greenhouse gas emissions). Physical activity equivalent to 30 minutes (in total) of brisk walking on all, or most, days of the week provides preventive and protective benefits for a wide range of health conditions (including cardiovascular disease, diabetes, depression and osteoporosis). "Active transport"--walking, cycling and/or using public transport instead of car travel--could have dual health benefits by providing physical activity and reducing the adverse health effects of motor vehicle transport. Doctors, medical administrators and health advocates can encourage the use of "active transport", and influence community-based programs and policy development about land use planning and travel demand management.

A retrospective study of unerupted maxillary incisors associated with supernumerary teeth

We retrospectively reviewed the clinical records and radiographs of 100 patients who had had supernumerary teeth removed. Their mean (SD) age was 9 years 3 months (2). The 100 patients had a total of 127 unerupted maxillary incisors associated with supernumerary teeth. The supernumerary tooth was removed without exposure of the permanent tooth more often among the 79 younger children (aged 10 years or less) (SND=3.52, P<0.01), and when the incisors were less mature (Cvek classification 1, 2, and 3) (SND=5.27, P<0.01). Of these incisors with immature roots that were treated conservatively, 60 (72%) erupted and 24 (28%) required further operation. Of the mature incisors treated conservatively, 10 (63%) required further operation. In this study, almost three-quarters of immature incisors erupted spontaneously after removal of the associated supernumerary teeth. Over half of the mature teeth required further operation. Mature teeth should be exposed with or without bonding at the time of removal of the supernumerary teeth.

Developmental regulation of spine motility in the mammalian central nervous system

The function of dendritic spines, postsynaptic sites of excitatory input in the mammalian central nervous system (CNS), is still not well understood. Although changes in spine morphology may mediate synaptic plasticity, the extent of basal spine motility and its regulation and function remains controversial. We investigated spine motility in three principal neurons of the mouse CNS: cerebellar Purkinje cells, and cortical and hippocampal pyramidal neurons. Motility was assayed with time-lapse imaging by using two-photon microscopy of green fluorescent protein-labeled neurons in acute and cultured slices. In all three cell types, dendritic protrusions (filopodia and spines) were highly dynamic, exhibiting a diversity of morphological rearrangements over short (<1-min) time courses. The incidence of spine motility declined during postnatal maturation, but dynamic changes were still apparent in many spines in late-postnatal neurons. Although blockade or induction of neuronal activity did not affect spine motility, disruption of actin polymerization did. We hypothesize that this basal motility of dendritic protrusions is intrinsic to the neuron and underlies the heightened plasticity found in developing CNS.

Health professionals' perspectives on service delivery in two Northern Ireland communities

This research builds on the findings of an ethnographic study of health inequalities in two small, rural communities in Northern Ireland. Through further analysis of existing data, this second study aimed to explore health professionals' perspectives on issues of service delivery relevant to government policy on primary care. Anthropological fieldwork was conducted for two consecutive 4-month periods during 1995 and 1996 in one predominantly Catholic and one predominantly Protestant town. To preserve confidentiality, the locations have been given the pseudonyms, respectively, of Ballymacross and Hunterstown. Research tools included fieldwork journals and a fieldwork diary, meetings with key informants, tape-recorded interviews, group discussions, participant observation and use of secondary material such as census data, local newspapers and community health profiles. Interviews with 15 health workers revealed that there was not a coherent approach to achieving health gain, little collaborative enterprise and minimal interaction between the different professional groups. The National Health Service (NHS)-employed primary care professionals, more than local community workers, appeared to be demoralized, exhausted and suspicious of the business-orientated health service. In this respect, the primary care-led NHS appeared not to be working. It is concluded that a shared health agenda should be developed by NHS-employed primary care professionals and local community workers to create a health-inducing environment at community level. This needs to be complemented by the establishment of formal mechanisms for inter-agency working at local, professional and government levels.

A nasopalatine cyst in an 8-year-old child

The nasopalatine cyst (NPC) was first described in 1914 and it is considered the most common non-odontogenic cyst. Most studies show a higher incidence of NPC among males than females, with a male/female ratio of 1.7:1. The majority of the cases described in people in their fifth decade involve Afro-Caribbeans, while those in their sixth decade are mainly caucasians. These cysts are normally asymptomatic, unless they are infected. The most commonly reported clinical symptom is swelling in the anterior part of the palate. The treatment of choice is enucleation. Even though it has been stated that NPCs may occur at any age no reports have been made on children less than 9 years old. Some reports support a predisposition in young Afro-Caribbeans, where NPCs appear to be more aggressive, larger and symptomatic. We present a case of a NPC in an 8-year-old caucasian female.

Guide to practice or 'load of rubbish'? The influence of care plans on nursing practice in five clinical areas in Northern Ireland

A nursing care plan is a written, structured plan of action for patient care. There is strong evidence that care plans are viewed negatively by nurses and poorly implemented, with little evidence to suggest that they have any positive effect on quality of care or patient outcomes. The project reported in this paper aimed to investigate how nursing care plans were being used in five clinical areas, and to assess their influence on nursing practice. An exploratory, predominantly qualitative research design was selected utilizing participant observation, focus groups and diaries. In four of the five clinical areas, the 'activities of daily living' section of care plans had no apparent positive influence on nursing practice which was driven by other factors and sources of information. Care plans in the remaining ward were clinically led and locally owned, and in this setting they operated as an important guide to practice. It is concluded that a reinvention of the nursing care plan is needed without the constraint of a nursing model as its necessary foundation. New and imaginative plans of action for patient care should be encouraged, developed at ward level and tailored to the demands of the clinical area. These should contain a minimum of documentation and integrate with nursing practice.

Consensual partnering in Australia: a review and 1991 census profile

"This paper is the first part of a two-part examination of consensual partnering in Australia. It reviews the Australian literature on consensual partnering, summarizing evidence of its proliferation since the mid-1960s and also the findings of investigations into its nature and the personal attributes that predispose some people more than others to adopt it. It then discusses the shortcomings of Australian census data as a source for studying consensual unions, before using data from the 1991 Census to present the first elements in a comprehensive profile of the cohabiting population. These cover the basic demography of consensual partnering: the ages, marital statuses and family type distributions of those involved."

Group psychotherapy for women molested in childhood: psychological and somatic symptoms and medical visits

Molested women who completed a series of 16 weekly group psychotherapy sessions conducted by social workers improved substantially regarding various aspects of psychological functioning, including self-image, coping techniques, relationship issues, and mothering. In addition, there was significant improvement in all psychological symptom scales and all global indices of symptomatic distress measured by the SCL-90-R. Furthermore, the improvement was present immediately after therapy and, with the exception of the hostility score, persisted 1 year later. Although the somatization score was reduced, the number of visits for physical symptoms did not change. The patients studied manifested characteristics typical of previously surveyed women with a history of childhood abuse, including a frequent history of major surgery (Drossman et al., 1996; Longstreth & Wolde-Tsadik, 1993; Springs & Friedrich, 1992) and, in some, a previous problem with alcohol (Springs & Friedrich, 1992; Walker et al., 1995) or drugs (Longstreth & Wolde-Tsadik, 1993; Miller & McCluskey-Fawcett, 1993; Springs & Friedrich, 1992). Also, nearly one half of the subjects had irritable bowel syndrome, the prototypical functional bowel disorder (Drossman et al., 1995; Longstreth & Wolde-Tsadik, 1993; Scarinci et al., 1994; Walker et al., 1995). Most of their baseline SCL-90-R scores were > 1 SD above the nonpatient norms. A problem inherent in assessing the long-term benefit of this study and other group psychotherapy studies is the tendency for some patients to continue similar or different forms of therapy after completing the group sessions. More than one half of patients received subsequent therapy that could have influenced their status at 1-year follow-up. However, most of the symptom dimensions and all global indices were similar 1 year posttherapy in the women who did not receive more treatment as compared to results in the women who did. Patients who received additional therapy had higher somatization scores before, immediately after, and 1 year posttherapy; scores in the other group increased 1 year posttherapy. Although the indications for subsequent therapy were not surveyed, there was an association between additional psychological care seeking and somatization. Furthermore, improvement in psychological status reflected by the phobic-anxiety score immediately posttherapy may have contributed to the decision of some patients to seek subsequent therapy. In the group without additional treatment, the loss of some of the initial somatization improvement at 1 year may have contributed to the lack of reduction in medical care visits in the combined groups. We speculate that provision of additional therapy to more patients might have had a long-term effect on somatization and reduced medical visits. We obtained complete psychological data and nearly complete medical-visit data on our patients, and our survey included 1-year follow-up. Our survey did not meet rigorous methodological standards for an outcome study, however. We surveyed only a small number of patients and did not collect similar data on an untreated control group. It was not possible to distinguish health care visits for organic versus functional disorders, but such a distinction may be artificial, because psychological factors may influence health care seeking for "organic" illness. Because our measurements came from a subset of our patients who were willing to complete the survey questionnaires, we do not know how generalizable the findings are. There is increasing awareness among health care professionals that childhood sexual abuse is common and that it may have serious and long-term psychological and medical sequelae. Our data suggest that group psychotherapy by social workers for women victims may have long-lasting psychological and somatic symptom benefits. Reduction in health care usage was not found, and this outcome may require the identification and treatment of patients who need additi

Emergency treatment of orodental injuries: a review

There has been an increase in the incidence of injuries to the incisor teeth in the primary and permanent dentitions over the last decade; one study reported that roughly 35% of 9-year-old children will have damaged their teeth in some way. Much has been written about dental injuries, and there may be confusion about the appropriate emergency treatment for different types. Classification and understanding of the types of injury are essential before diagnosis and treatment can be undertaken. Although dental injuries can occur singly, they more usually involve a combination of injuries to a tooth and its supporting structures. Prompt, accurate diagnosis and appropriate emergency treatment as outlined in this paper will greatly improve the prognosis for many dentoalveolar injuries. The aim must be to ensure that the third of the population of preteenage children who damage their teeth are not resigned to loss of an incisor in later life because of inaccurate diagnosis and poor treatment of the emergency condition.

Requirement of Ras-GTP-Raf complexes for activation of Raf-1 by protein kinase C

Receptor tyrosine kinase-mediated activation of the Raf-1 protein kinase is coupled to the small guanosine triphosphate (GTP)-binding protein Ras. By contrast, protein kinase C (PKC)-mediated activation of Raf-1 is thought to be Ras independent. Nevertheless, stimulation of PKC in COS cells led to activation of Ras and formation of Ras-Raf-1 complexes containing active Raf-1. Raf-1 mutations that prevent its association with Ras blocked activation of Raf-1 by PKC. However, the activation of Raf-1 by PKC was not blocked by dominant negative Ras, indicating that PKC activates Ras by a mechanism distinct from that initiated by activation of receptor tyrosine kinases.