Problems in identifying "bursts" of periodontal attachment loss

A theory of periodontal attachment loss which postulates discrete bursts of activity has recently been proposed. This paper identifies several problems in the interpretation of the experimental data that have been used to support the burst model. Major obstacles to valid inferences are associated with the following: substantial measurement error, insufficient evidence supporting a dichotomy of disease state and the use of diagnostic decision criteria with undesirable properties. The nature of these problems is discussed from the framework of receiver operating characteristic (ROC) analysis. "Bursts" of attachment loss can be explained, in whole or in part, by these factors in the absence of real change. Types of research evidence that would offer more compelling support for the burst model are identified. The questionable validity of evidence supporting the burst model may impact on both the direction of future research efforts and clinical applications.

Suggestion of a role for calmodulin and phosphorylation in regulation of rabbit ileal electrolyte transport: effects of promethazine

Suggestion of a role for protein phosphorylation in the regulation of intestinal active NaCl transport was found by studying the effects of low concentrations of promethazine on Ca2+-calmodulin (CaM)-dependent protein phosphorylation of ileal microvillus membranes and on active ileal electrolyte transport. Ca2+-CaM increased the phosphorylation of six microvillus peptides (Mr 137,000, 116,000, 77,000, 58,000, 53,000, and 50,000) in a concentration-dependent manner. Promethazine inhibited the Ca2+-CaM-induced increases in each of these phosphorylations. The effect of promethazine was concentration dependent, with concentrations of 5-12 microM (mean 8 microM) causing 50% inhibition. Promethazine also caused a concentration-dependent increase in net Cl absorption and decrease in the ileal short-circuit current, with 9 microM promethazine causing a change in short-circuit current 50% of maximum. The promethazine effect on microvillus membrane phosphorylation was specific, since neither cAMP- and cGMP-induced phosphorylation in the microvillus membrane nor the stimulation by Ca2+-CaM of myosin light chain kinase phosphorylation of myosin light chain were affected by promethazine. The similar, and unusual sensitivity to low concentrations of promethazine on ileal microvillus membrane phosphorylation increased by Ca2+-CaM and on ileal electrolyte transport is consistent with Ca2+-CaM-dependent microvillus membrane phosphorylation being involved in the regulation of active electrolyte transport in ileal absorptive cells.

Computer-assisted dental diagnosis

Computer-assisted dental diagnosis has been discussed from the perspective of applications, decision-making processes, and a specific example of a diagnostic system. Rapid technologic advancement and anticipated developments in the field of artificial intelligence will undoubtedly change both our expectations of future evolutions and our capacity to transform these expectations into reality. The ability of computers to enhance the diagnostic capabilities of practitioners will make automation integral to future dental practice.

Correlation of acute pericoronitis and the position of the mandibular third molar

Acute pericoronitis is a painful, debilitating infection that is most commonly found among young adults with erupting mandibular third molars. Prophylactic removal of third molars to prevent this disease has been advocated, but this procedure requires an accurate description of the third molar at highest risk for this infection. Clinical and radiographic measurements were compared in 25 diseased subjects and 109 normal subjects. Of 10 variables significantly related to the presence of acute pericoronitis, stepwise discriminant analysis selected 4 variables that produced a canonical correlation coefficient of 0.71. In clinical terms, these variables described the tooth at highest risk for acute pericoronitis as a fully erupted, vertical mandibular third molar that is in contact with the adjacent second molar, at or above the occlusal plane, and partially encapsulated by soft or hard tissues. Prophylactic treatment of these third molars is highly recommended.

Evaluation using sequential trials methods

Dental school faculty members, as well as many practitioners, are interested in evaluating products and procedures used in clinical practice. Research design and statistical analysis, however, can pose problems to some, while others would like to avoid detailed consideration of protocol until after a preliminary investigation. Sequential trials methods provide an analytical structure that is both easy to use and statistically valid.

Effects of fixed-appliance orthodontic treatment on DMF indices

An investigation was conducted to clarify the relationship between orthodontic treatment and caries incidence. DMF indices from 308 orthodontically treated and 305 untreated naval recruits were compared. Contrary to expectations, there was no evidence that orthodontic treatment increases caries experience. Orthodontically treated subjects had significantly fewer diseased surfaces--a difference averaging one less diseased surface per patient. Treatment status did not generally affect the number of filled surfaces. Treated subjects had more missing teeth if first premolars were considered, but untreated subjects had more missing teeth if first premolars were not considered. No significant correlation was found between caries incidence and duration of orthodontic treatment. The epidemiologic basis and significance of these findings are discussed.

Recent developments in pediatric neuro-oncology

Although brain tumors represent the second most common malignancy in childhood, there are only 1200 to 1500 children diagnosed with brain tumors each year in the US. Approximately 50% of these children are treated at university or cancer treatment centers. Thus, therapeutic trials by default rather than design have been restricted to small numbers of patients. Information on histopathologic groupings, incidence of various tumor types according to age, general treatment trends and survival statistics are available from the Surveillance, Epidemiology, and End Results (SEER) registries of the National Cancer Institute. Although survivals in brain tumor cancers are worse than in other forms of childhood cancer, treatment advances in surgery, radiation and chemotherapy have significantly improved survivals in at least one brain tumor of childhood, medulloblastoma. Ironically, this treatment may have significant long-term adverse effects on intellect, endocrine function, and on the development of second malignancies. Prompt recognition of these delayed effects is of clinical importance, as some effects are amenable to treatment and others may be prevented by careful monitoring of drug and radiation administration.

Reflex augmentation of a tap-elicited eyeblink: the effects of tone frequency and tap intensity

The amplitude of the human eyeblink elicited by a mild tap between the eyebrows can be increased if a brief tone is presented simultaneously with the tap. In two experiments we examined how this reflex augmentation effect varies with changes in the frequency characteristics of the tone and with changes in the intensity of the tap. We also examined how these effects change in the course of development. For newborn infants and for adults, fixed intensity tones with frequencies of either 1, 2, or 4 kHz produced equivalent amounts of reflex augmentation. Furthermore, while blink amplitude was an increasing function of tap intensity in both populations, the amount of reflex augmentation engendered by a simultaneously presented tone was independent of the intensity of the tap.

Prognostic factors in brainstem gliomas

Although brainstem gliomas carry the worst prognosis of any brain tumor in children, with median survivals of 9 to 12 months, there may be a subgroup of long-term survivors. We have identified 12 children with brainstem gliomas, 5 of whom have survived greater than 6 years and 6 less than or equal to 12 months. Another child, alive and well 3 years following diagnosis, was considered in the long-term survivor group. Favorable prognostic factors included neurofibromatosis, symptoms greater than or equal to 12 months before diagnosis, calcification on CT, exophytic location, and pathology suggesting a low-grade tumor. Recognition that certain patients with brainstem gliomas may have prolonged survivals even in the absence of definitive treatment must be taken into consideration when new treatment regimens are being formulated.

Survival of children with brain tumors: SEER Program, 1973-1980

Eight hundred eighty-seven children with brain tumors were identified by the SEER registries (1973-1980). Twenty-five percent were low-grade supratentorial astrocytomas, medulloblastomas were 23%, cerebellar astrocytomas 12%, high-grade supratentorial astrocytomas 11%, brainstem gliomas 9%, and ependymomas 8%. The worst survivals were in children less than 2 years of age, and the best were in those aged 10 to 14 years. Five-year survivals of children with cerebellar astrocytomas were 91%, low-grade supratentorial astrocytomas 71%, high-grade supratentorial astrocytomas 35%, medulloblastomas 39%, ependymomas 28%, and brainstem gliomas 18%.

Unusual biochemical and clinical features in a girl with ornithine transcarbamylase deficiency

A girl, ultimately diagnosed as having profound ornithine transcarbamylase (OTC) deficiency, presented as a neonate with feeding intolerance, irritability, and seizures without concurrent hyperammonemia. Developing normally until ten months of age, the girl subsequently experienced two episodes of hyperammonemia, which were associated with focal seizures and residual hemiparesis. She continued to have profound neurologic impairment and seizures and died at 26 months of age, despite appropriate dietary protein restriction, sodium benzoate, and arginine supplementation. Symptomatic OTC deficiency has not been previously reported unassociated with hyperammonemia. The recurrent cerebrovascular episodes are distinctly uncommon in patients with urea cycle enzymopathies.

Computerized tomography scan findings in children with acute lymphocytic leukemia treated with three different methods of central nervous system prophylaxis

Computerized tomography (CT) scans of the head were done on 93 children with acute lymphocytic leukemia in continuous complete remission who had been randomly assigned to three different methods. of central nervous system (CNS) prophylaxis. Twenty-nine children had received six doses of intrathecal methotrexate, 30 had received six doses of intrathecal methotrexate plus 2400 rad of cranial irradiation, and 34 had received six doses of intrathecal methotrexate plus three courses of intermediate-dose intravenous methotrexate. The overall incidence of abnormal scans was 35%, of which 91% were felt to represent minimal abnormalities. CT scan abnormalities were noted in 30% of the children receiving intrathecal methotrexate only, in 40% of those receiving intrathecal methotrexate plus cranial irradiation, and in 35% of those receiving intrathecal methotrexate plus intermediate dose methotrexate. These differences were not statistically significant. None of the three methods of CNS prophylaxis resulted in significant CT scan abnormalities. However, the few moderately or markedly abnormal scans evaluated were restricted to patients who received intrathecal methotrexate plus cranial irradiation. The clinical significance of CT scan abnormalities in leukemic children receiving these treatments remains unclear.

Long-term effects of cranial irradiation on endocrine function in children with brain tumors. A prospective study

This study prospectively evaluated the endocrine function of 11 children treated with cranial irradiation (CRT) for brain tumors. All tumors were remote from the hypothalamic-pituitary axis. Children were studied before treatment and at 3, 6, and 12 months after the completion of CRT. T4, thyroid-stimulating hormone, prolactin, plasma cortisol, and urinary follicle-stimulating hormone and luteinizing hormone values were normal before and after treatment in all patients. Growth hormone (GH) deficiency was identified in 0 of 7 patients before treatment, in 2 of 7 patients 3 months post-CRT, in 9 of 11 patients 6 months post-CRT, and in 7 of 8 patients 12 months post-CRT. Growth deceleration was identified in five of seven prepubertal patients. GH deficiency is an extremely common sequelae of CRT, beginning as early as 3 months after the completion of CRT. The deficit is progressive over time.

Radiologic guidelines in assessing children with intracranial tumors

Computed tomography (CT) is currently the primary and generally the definitive imaging modality for the diagnosis, evaluation, and management of intracranial neoplasms in children. The value of CT in the postoperative period is discussed. The role of CT and myelography is stressed in the evaluation of cerebrospinal fluid seeding. CT is also important in demonstrating the iatrogenic disturbances of the central nervous system as a result of radiation and chemotherapy. The authors recommend that CT scans with and without contrast be obtained 2 weeks after surgery and before starting any form of adjuvant treatment. CT slices should be contiguous and 5-mm thick. Subsequent scans should be obtained every 3 to 4 months for the first year and every 6 months thereafter. Where necessary, CT scans after the introduction of intrathecal metrizamide may be necessary to evaluate the lower portion of the posterior fossa and brain stem.

The influence and reliability of neurologic assessment and Karnofsky performance score on prognosis

The neurologic examination is important in the early diagnosis of brain tumors in children. Only in brain stem gliomas may the neurologic examination be better than computed tomographic scans in determining the progression. However, in general, the traditional neurologic examination has little or no value for prognosis. Reversible, associated features of brain tumors such as seizures or increased intracranial pressure may alter the patient's ability to function neurologically, but may not influence the prognosis regarding the tumor status. The Karnofsky functional status, to a large extent, reflects an adult's ability to work and has prognostic value but is largely inapplicable to children. Thus, a quality-of-life scale for children is needed.

Toward the development of a play performance scale for children (PPSC)

Performance scales (i.e., Karnofsky), as they measure quality of life, have been used effectively as an integral part of repeated assessment of adult cancer patients for the last several years. An equally concise measure of performance has not been developed for children. The task of developing a scale to assess performance in infants, toddlers, school-age children, and adolescents is formidable, as the activity measured should be of equal merit at each age level. Although all childhood cancer patients could benefit from a simple-to-administer, rapid assessment, children with brain tumors have the greatest need for a repeated measure of performance. The goal, then, is to develop a simplified set of criteria that can be used for assessment of children with brain tumors during hospitalization, at the time of clinic visits, and/or at the time of diagnostic procedures when the patient is in a reasonable state of health. The assessment should be able to performed by nonprofessional persons.

Computed tomography in the diagnosis of intracranial neoplasms in children

The authors discuss their original observations using computed tomography (CT) in the diagnosis of posterior fossa neoplasms in children. The subject of CT diagnosis of childhood supratentorial tumors is also reviewed. However, despite the documented value of CT, the authors believe that magnetic resonance imaging (MRI) will eventually offer certain advantages that will make MRI the primary imaging modality for intracranial neoplasms in children.

A classification system for primitive neuroectodermal tumors (medulloblastoma) of the posterior fossa

Tumors of the posterior fossa are described. Although the preoperative staging system of Chang and associates has proven prognostic relevance, a proposed new system may have even greater impact on prognosis because it considers the tumor burden postoperatively. This system (MAPS: metastasis, age, pathology, and surgery) incorporates age and pathologic characteristics into the staging system. The value of this proposed staging system, in particular, the impact of pathology, must be assessed in controlled trials.

The long-term effects of cranial irradiation on the central nervous system

Cranial irradiation and chemotherapy may have significant long-term deleterious effects on children with brain tumors. Intellectual deterioration, endocrinopathies, leukoencephalopathy, extraneural metastases, and oncogenesis may all complicate the treatment of central nervous system neoplasia. These long-term effects of therapy have important implications, as some are amenable to treatment and others may be prevented by the careful monitoring of drug and radiation administration. Until recently, the survivals of children with brain tumors were limited, so that concerns over long-term effects of therapy were unnecessary. As children with certain types of brain tumors now have a better prognosis, these long-term and possibly remediable effects have important implications. This article emphasizes radiation effects on intellect, endocrine function, and oncogenesis. Recommendations for baseline and longitudinal evaluations of children with brain tumors are suggested.

Myelography for staging medulloblastoma

Thirty-eight patients with newly diagnosed medulloblastoma were studied with myelography and cerebrospinal fluid (CSF) cytology studies before radiotherapy. Seventeen (45%) patients had evidence of dissemination beyond the posterior fossa. Spinal cord lesions were demonstrated in ten patients (26%). Negative results of CSF cytology studies did not preclude demonstration of cord involvement. Children younger than 5 years were more likely than older patients to have spinal cord involvement at diagnosis. Patients who were truly M-0 did better in terms of absolute survival but not relapse-free survival when compared with patients with dissemination. Myelography and cytology studies are necessary in the evaluation of all newly diagnosed patients with medulloblastoma and may also be indicated for patients with other brain tumors with a known propensity for dissemination.

Magnetic resonance imaging in the evaluation of intracranial tumors of childhood

Magnetic resonance imaging (MRI) is a noninvasive imaging technique that demonstrates intracranial anatomy without the use of ionizing irradiation and intravenous contrast agents. Image quality is dependent on various factors, including field strength, scanning sequence, and imaging time. Although there is currently no concensus as to how to visualize intracranial lesions optimally, MRI has already been shown to be sensitive in the detection of brain tumors. It can detect many different types of tumors; however, its specificity is unclear. Intracranial tumor extent is extremely well-demonstrated by MRI. The advantages and disadvantages of MRI compared with computerized tomography are reviewed.

The argument for a combined cancer consortium research data base

Epidemiologic data that were obtained through the SEER registry (Surveillance Epidemiology End Results Program) are presented. Survival statistics for five major brain tumor types in childhood are presented for the years 1968 through 1979. Further survival statistics are compared in patients treated in community hospitals versus university hospitals. The lack of uniform reporting, absence of pathologic conformation, and limited number of patients seen throughout the country are emphasized. There is a need for the establishment of a data base composed of the member institutions of the childhood cancer consortiums. This data base would address questions of patterns of failure, benefits of surgical and clinical staging, and the value of a new putative pathologic grading system. Additionally, the opportunity to collect these patients should permit identification of long-term treatment effects. Identification of early morbidity may lead to modification of treatment programs. A data base containing treatment and diagnostic parameters would allow significant cross-correlations and would lead to the design of future studies that are based upon accurate data.

Reflex modification by acoustic signals in newborn infants and in adults

This research asked whether the reflexive eyeblink elicited by a tap to the glabella (the flat region of skin between the eyebrows) is modified by acoustic signals which either precede or accompany the tap. Five experiments employing identical reflex modification procedures on neonates and adults suggest developmental differences in processing auditory stimuli. Neonates failed to exhibit reflex inhibition by either prior acoustic or tactile stimuli. Adults exhibited robust reflex inhibition to these same stimuli. Neonates, however, exhibited reliable reflex augmentation when mild (70 dB re: 0.0002 dyne/cm2) tones were presented simultaneously with the tap. For adults, tone intensities of at least 90 dB were necessary to obtain reliable reflex augmentation. The developmental processes implied by these findings are discussed.

Dental anxiety and DMFS status: association within a US naval population versus differences between groups

Measurement of dental treatment anxiety and oral health, in a sample of naval recruits, confirmed the generally held expectation that a high anxiety group would have significantly greater numbers of diseased surfaces (DS) than a low anxiety group. However, it was also shown that dental anxiety was not a predictor of DS within the ungrouped sample. In evaluating the public health impact of dental treatment anxiety on oral health, attention must be paid to the context of data collection and analysis. Evidence bearing on group differences does not necessarily describe the situation within a population.

The role of neurologists in pediatric neuro-oncology

Because of advances in the diagnosis and management of brain tumors, the opportunity for neurologists to participate in the care of children with central nervous system neoplasms has greatly increased. Data developed by various study groups has allowed a more systematic approach to childhood brain tumors. Much more information will become available. New data must be reviewed and recommendations for therapy made by individuals with clinical neuroscience experience and training. The training needs of such individuals must be met in neurology training programs.

Current therapy in childhood brain tumors

This article reviews the current approach to the treatment of childhood brain tumors. Common childhood brain tumors are profiled in separate sections, and the conclusion includes a discussion of the long-term clinical effects of radiation and chemotherapy.

Role of the inferior colliculus in the inhibition of acoustic startle in the rat

Fifteen rats were tested for amplitude reduction of the acoustic startle response using auditory and visual prestimuli. Eight subjects then received large lesions of the inferior colliculus, and the remaining subjects served as normal controls. All animals were reassessed on a post-test identical to the pre-test. In addition, all subjects were tested for latency reduction of startle using auditory prestimuli. There were no significant differences between groups on the pre-test for startle amplitude, visual amplitude reduction, or auditory amplitude reduction, nor did the control group differ significantly on these measures from pre-test to post-test. After surgery, the lesion group displayed a large, significant increase in startle amplitude. Auditory prestimuli were no longer effective in reducing startle amplitude in this group, but visual prestimuli still produced reliable amplitude reduction. Both groups displayed reliable latency reduction to auditory prestimuli; the groups were not significantly different from each other on this measure. These data support the proposition that the inferior colliculus is part of a neural circuit for startle amplitude reduction by auditory prestimuli.

Treatment of brain tumors in babies and very young children

Approximately 13% of brain tumors in childhood occur in children less than 2 years of age. Although the survivals of older children with certain forms of brain tumors have increased over the past 20 years, this treatment has been least effective in very young children with brain tumors. These poor survival rates may be due in part to the highly malignant nature of the neoplasms; the delay in diagnosis because of low index of suspicion; the large bulk of tumor found at presentation, and the reduction in radiation dosage to the central nervous system. Since standard treatment has produced both poor results and severe neurotoxicity, new approaches have been sought. A conservative approach is recommended in some children with optic gliomas and low-grade supratentorial astrocytomas. Radiation is deferred until the child reaches 3-4 years of age when he can better tolerate its effects on the CNS. Current therapy of malignant brain tumors of infancy is not only toxic, but inadequate. There are several centers which currently use postoperative chemotherapy and delayed radiation. Early results have been encouraging and neurotoxicity has been low.

Reflex modification in the rat: the inhibitory effects of intensity and frequency changes in steady tones

In laboratory rats (as in humans) a low-intensity tone that precedes a high-intensity burst of noise by approximately 100 ms can reduce the amplitude of the startle reaction elicited by the burst of noise. A series of four experiments with rats investigated the relation between the inhibitory effects of tonal frequency change and the length of the silent period (gap) preceding it. The major findings were the following: (a) A gap in an otherwise continuous pure tone inhibited startle when the gap occurred approximately 100 ms prior to the noise burst. (b) Although an increase in gap duration increased the inhibition afforded by the gap, the maximum inhibition was yielded by gaps of 100 ms and greater; this maximum was equivalent to the inhibition yielded by the presentation of a postgap tone alone. (c) A shift in tonal frequency across a 10-ms gap yielded more inhibition than did the same gap with no frequency shift; again the shift yielded equivalent inhibition to the presentation of the postgap tone alone. (d) An increase in the frequency shift increased inhibition when the shift occurred across a 10-ms gap, but not when the shift occurred across a 100-ms gap.

Age-specific angulation of unerupted human third molar teeth in a cross-sectional sample

For males aged 18 to 21, the angulation of unerupted third molars was unrelated to age. A counterbalancing loss of data resulting from tooth eruption and extraction accounted for this null finding. The value of age-specific angulation in determining whether a tooth will eventually erupt may be limited.

Development of decision making rules for transportable, microcomputer-based expert systems in medicine

Computerized decision making aids have been developed for use in certain medical specialties over the last decade. These programs are designed to give expert-level advice within their limited domains. Two major components are required in the design of these systems: development of software and development of a knowledge base to handle the specific medical application. The advantage of the knowledge-based approach is that the application can be changed by replacement of the knowledge base, without requiring changes to the software. In this paper, EMERGE, a medical decision making system, originally developed for analysis of chest pain in the emergency room environment, is described. EMERGE uses production rules for representation of its knowledge base. The method by which this system can accommodate new rule bases for other applications is emphasized, as well as the transportability of the system.

Alpha level distortions with repeated testing of follow-up dental data

The statistical consequences of repeated significance testing of follow-up dental data were evaluated by computerized Monte Carlo simulation. Substantial distortions in nominal alpha level were noted, particularly when the scores for individual subjects were not highly correlated between statistical observations. Suggested methods of controlling this distortion include the pre-specification of a terminal statistical analysis that would be given best evidence status and the partitioning of alpha error among all analyses by Bonferroni's inequality.

The predictive value of endodontic diagnostic tests

The diagnostic usefulness of common endodontic tests was evaluated through the retrospective analysis of studies in which histologic examinations were performed. In general, tests were able to adequately identify persons who were likely to be free of disease but were substantially less effective in identifying disease-positive persons. Thus, persons who are test-positive for irreversible pulpal disease are frequently disease-negative on the basis of histologic examination. These findings suggest that practitioners continue to use all available evidence in making a diagnosis of irreversible pulpal disease.

Ca2+-calmodulin-, cyclic AMP- and cyclic GMP-induced phosphorylation of proteins in purified microvillus membranes of rabbit ileum

Evidence is available to suggest that Ca2+-calmodulin and cyclic nucleotides are involved in the regulation of ion transport in rabbit ileum. Since both Ca2+-calmodulin and cyclic nucleotides exert many of their effects by phosphorylation, the effects of Ca2+-calmodulin and cyclic nucleotides on phosphorylation of purified microvillus membrane from rabbit ileal mucosa were evaluated. Ca2+-calmodulin increased phosphorylation of five microvillus-membrane peptides, with Mr values of 137000, 77000, 58000, 53000 and 50000. The increases in phosphorylation caused by Ca2+-calmodulin were: Mr-137000 peptide, 111 +/- 26%; Mr-77000 peptide, 71 +/- 17%; Mr-58000 peptide, 51 +/- 8%; Mr-53000 peptide, 113 +/- 20%. These increases were maximal at 1 microM-calmodulin and 0.3-0.9 microM free Ca2+; concentrations of Ca2+ causing half-maximal effects on phosphorylation for the different peptides were 0.06-0.12 microM. Cyclic AMP and cyclic GMP increased phosphorylation of two peptides, of Mr 137000 and 85000. The concentrations of cyclic nucleotides giving half-maximal phosphorylation of the Mr-137000 peptide were 0.3 microM-cyclic AMP and 4.6 microM-cyclic GMP, and for the Mr-85000 peptide, 3.9 microM-cyclic AMP and 0.05 microM-cyclic GMP. The maximal increase in phosphorylation of the Mr-137000 peptide was 200% for cyclic AMP and 95% for cyclic GMP, and that of the Mr-85000 peptide was 220% for cyclic AMP and 120% for cyclic GMP. These studies demonstrate the existence of Ca2+-calmodulin-, cyclic AMP- and cyclic GMP-dependent protein kinases and substrate proteins in purified rabbit ileal microvillus membranes and that Ca2+ can regulate phosphorylation of these proteins over the presumed physiological concentration range of cytosol free Ca2+.

Injectable debris associated with dental anesthetic delivery

Injectable foreign matter may originate in part from: anesthetic cartridge diaphragm surfaces, diaphragm polymer materials, and debris in the lumen of sterile, manufacturer-sealed needles. Particles ranging from 30 to 305 microns were collected from four brands of dental anesthetic cartridges (320 cartridges/brand). Results of this study suggest that rubber and aluminum debris may commonly be injected with anesthetic solutions. Debris on the outer surface of the needle may also be drawn into injection sites. Possible health implications of injectable matter are discussed and remain conjectural.

Computerized method for the graphic representation of multivariate periodontal data

Appreciation of the multivariate features of data from periodontal research studies is sometimes difficult. This appears to be due to the form of tables and graphs in which information is made available in published studies. A computerized graphical technique, which appears well suited to the multivariable situation, is described. It uses structural analogy between the measurement scales and the variables measured and provides what can be a compelling iconic description of multifaceted data.

CT abnormalities and altered methotrexate clearance in children with CNS leukemia

Seventeen children with CNS leukemia treated with chemotherapy and 5 children treated with both cranial radiation (CRT) and chemotherapy were evaluated. Eighty-eight percent of patients treated with chemotherapy alone had CT abnormalities, and all treated with CRT and chemotherapy had abnormal CT. The severity of CT abnormality paralleled intraventricular methotrexate levels and clinical signs of leukoencephalopathy. Children who receive chemotherapy for CNS leukemia, even without cranial irradiation, are more likely to have leukoencephalopathy than children without CNS leukemia. Moreover, patients with CNS leukemia may have abnormalities of CSF clearance of intraventricularly administered drugs.

Myelopathy with severe structural derangement associated with combined modality therapy

Myelopathy is a known complication of radiation therapy, but its association with chemotherapy has been less well documented. The authors report the case of a 12-year-old boy with medulloblastoma who had been followed for an 8 1/2-year period. In the context of accepted doses of intrathecal methotrexate and spinal irradiation, he developed an extensive myelopathy. At postmortem he was found to have profound fibrosis of the leptomeninges and necrosis with structural derangement of the spinal cord. It is speculated that these findings are secondary to a combination of radiation acting in synergism with methotrexate. The pertinent literature relating to myelopathy associated with radiation and chemotherapy is reviewed.

Long-term effects of treatment on endocrine function in children with brain tumors

Fourteen children with brain tumors received endocrine evaluations at least one year following completion of cranial irradiation. Treatment consisted of operation (13 patients), craniospinal irradiation (6), whole brain irradiation (5), posterior fossa irradiation (3), and chemotherapy (10). Endocrine evaluation included bone age roentgenography and measurement of growth hormone (using sequential arginine and insulin stimulation), thyroxine, thyroid-stimulating hormone, plasma cortisol, testosterone, prolactin, and urinary follicle-stimulating hormone and luteinizing hormone. Ten of 12 children (83%) had abnormal responses to both tests of growth hormone stimulation. All growth hormone-deficient patients treated prior to puberty and tested at least 2 years following completion of cranial irradiation had decelerated linear growth. Results of thyroid function tests were abnormal in 4 patients: 2 patients had evidence of primary hypothyroidism, and 2 showed secondary or tertiary hypothyroidism. Two patients had inadequate cortisol responses to insulin hypoglycemia. Urinary follicle-stimulating hormone and luteinizing hormone, serum prolactin, and serum testosterone levels were appropriate for age in all patients.