Salud mental infanto-juvenil y pandemia de Covid-19 en España: cuestiones y retos / Child mental health and covid-19 pandemic: questions and challenges

INTRODUCCIÓN: El artículo describe un modelo de intervención temprana para la prevención de patología, y promoción de la resiliencia, tras los terremotos de la isla de Puerto Rico en enero de 2020. El 7 de enero de 2020 un terremoto de magnitud 6,4 en la escala Richter, sacudió la isla de Puerto Rico. Como consecuencia, gran parte de la población sufrió desplazamientos de sus domicilios y cierres de muchas escuelas. Todo ello sobre lo ya anteriormente vivido, como el Huracán María en 2017, aumentando así su carga de estrés alostática. Tras la ayuda inicial de los cuerpos de rescate, se detecta la necesidad de apoyo psicológico a la población y a profesionales proveedores de dicho apoyo. MÉTODOS: Contando con una precaria infraestructura, se decide realizar una intervención con el objetivo de proporcionar información del impacto del estrés traumático en el organismo, así como ejercicios prácticos de mindfulness dirigidos a dichos profesionales. El programa integra lecciones de la Terapia de Claves Traumáticas y ejercicios del currículo Pure Power. RESULTADOS: Se confirma, a través de un cuestionario de satisfacción, la necesidad de este tipo de programas, y se valora extrapolar el modelo a otras poblaciones de riesgo similares, en términos de evitar las consecuencias del trauma, disminuir la carga alostática, y prevenir y promocionar la salud mental. Se sugiere realizar próximas formaciones de ampliación de este programa, para confirmar su efectividad y mantenimiento en el tiempo

INTRODUCTION: This article describes an early intervention model for the prevention of pathology, and for the promotion of resilience, after the earthquakes on the island of Puerto Rico in January 2020. On January 7, 2020, an earthquake of magnitude 6.4 on the Richter scale struck the island of Puerto Rico. As a consequence of the seismic movement, an important part of the population, suffered displacements from their homes and closing of schools. In addition to what they previously lived through, such as Hurricane Maria in 2017, increasing their burden of allostatic stress. After initial help from the rescue forces, a need to provide psychological support to the population and to the professionals involved in giving that psychological support, was detected. METHODS: Starting from a precarious infrastructure, it was decided to implement an intervention with the objective of providing information on the impact of traumatic stress on the individual, along with practical mindfulness exercises. The program integrated lessons from Cue-Centered Therapy with exercises from the Pure Power curriculum. RESULTS: Through a satisfaction questionnaire, the need of these type of programs was confirmed. The implementation of these prevention programs should be considered when planning to intervene with other similar populations at risk. Thus, avoiding the consequences of trauma, reducing the allostatic load in the individual, and preventing and promoting mental health and resilience. The discussion introduces the need to develop follow-up procedures, to confirm the effectiveness and maintenance over time

Physical fitness in preschool children: association with sex, age and weight status.

BACKGROUND: Because fitness level is a potent biomarker of health from an early age, the improvements of physical fitness performance through the promotion of physical activity could be important for the health of preschool children, particularly in obesity prevention. OBJECTIVE: The purpose of this study is to determine the physical fitness in children aged 3-6 years, discriminating performance by sex, age and body mass index (BMI). METHOD: A total of 3868 children from 3 to 6 years agreed voluntarily to participate. Demographic characteristics revealed that 1961 children were male (age: 55.71 ± 11.11 months old, BMI = 16.03 ± 1.93 kg/m2 ), and 1907 were female (age 56.16 ± 0.97 months old, BMI = 15.85 ± 1.89 kg/m2 ), and they were selected from 51 schools in southern Spain. RESULTS: Significant differences were found between sexes: boys showed a greater performance on cardio respiratory endurance, reaction time, strength and running speed. We found significant differences by sex in the different age groups (3, 4, 5 and 6 years old). CONCLUSIONS: Sex differences in physical fitness are evident at an early age; in addition, the relationship between physical fitness and BMI is inconsistent in preschool children. The improvements of physical fitness performance and its association with physical activity could be important for the health of children, particularly in obesity prevention.

Body Size, Fecundity, and Sexual Size Dimorphism in the Neotropical Cricket Macroanaxipha macilenta (Saussure) (Orthoptera: Gryllidae).

Body size is directly or indirectly correlated with fitness. Body size, which conveys maximal fitness, often differs between sexes. Sexual size dimorphism (SSD) evolves because body size tends to be related to reproductive success through different pathways in males and females. In general, female insects are larger than males, suggesting that natural selection for high female fecundity could be stronger than sexual selection in males. I assessed the role of body size and fecundity in SSD in the Neotropical cricket Macroanaxipha macilenta (Saussure). This species shows a SSD bias toward males. Females did not present a correlation between number of eggs and body size. Nonetheless, there were fluctuations in the number of eggs carried by females during the sampling period, and the size of females that were collected carrying eggs was larger than that of females collected with no eggs. Since mating induces vitellogenesis in some cricket species, differences in female body size might suggest male mate choice. Sexual selection in the body size of males of M. macilenta may possibly be stronger than the selection of female fecundity. Even so, no mating behavior was observed during the field observations, including audible male calling or courtship songs, yet males may produce ultrasonic calls due to their size. If female body size in M. macilenta is not directly related to fecundity, the lack of a correlated response to selection on female body size could represent an alternate evolutionary pathway in the evolution of body size and SSD in insects.

Impact of limited hamstring flexibility on vertical jump, kicking speed, sprint, and agility in young football players.

This study aims to analyse the impact of limited hamstring flexibility (HF) on specific football skills, such as sprinting and jumping ability, agility, and kicking speed in young football players. Forty-three male football players (aged 14-18) from a semi-professional football academy participated voluntarily in this study. Data about anthropometric measurements, HF (unilateral passive straight-leg raise test: PSLR), vertical jumping ability (countermovement jump: CMJ), sprinting ability (5, 10, 20 m: S5 m, S10 m, S20 m), agility (Balsom agility test: BAT), and kicking speed in terms of ball speed (dominant and non-dominant leg: KSdom and KSnon-dom) were collected. Cluster analysis grouped according to HF, dividing participants into a flexible group (FG, n = 24) and a non-flexible group (NFG, n = 19) in relation to performances on the PSLR test. Despite finding no significant differences between groups in body composition and age, the FG performed better in terms of sprint scores (S5 m: 6.12%, S10 m: 4.09%, S20 m: 3.29%), BAT score (4.11%), CMJ score (10.49%), and scores for KSdom (6.86%) and KSnon-dom (8%) than the NFG. The results suggest that HF is a key factor for performing football-specific skills, such as sprinting, jumping, agility, and kicking in young football players. These results support the rationale that muscle flexibility must be specifically trained in football players beginning at early ages.

Evaluation of the contribution of the dynamic phase of lymphoscintigraphy to the detection of sentinel lymph node in breast cancer.

AIM: The aim of this study was to evaluate the contribution of an early dynamic phase (DP) of the lymphoscintigraphy (LS) to the detection of the sentinel lymph node (SLN) in breast cancer. METHODS: This prospective study included 164 breast lesions in 161 consecutive patients (160 women, mean age 57.5 years). Patients with tumor >5 cm, multicentric, palpable nodes, axillary involvement, previous surgery, lymphadenectomy, radio or chemotherapy were not included. All patients underwent preoperative LS before surgery. DP immediately after injection of [99mTc]Nanocolloid followed by early and delayed planar images (EPI and DPI) were acquired. RESULTS: SLN was detected in 162/164 lesions (98.8%). In 115 (71%) DP showed no lymph node uptake and the SLN was identified only by EPI and DPI. A focal uptake by at least one lymph node was observed in DP in the remaining 47 lesions (29%). Although in 30/74 lesions DP did not provide additional information to EPI and DPI, nevertheless in 17 cases (10.5%) DP was essential to identify correctly the SLN. CONCLUSION: We concluded that DP, by allowing a better interpretation of the lymphatic drainage pattern, provides unique information to distinguish the correct SLN from other lymph nodes and is recommended as the first part of LS.

Evaluation of the contribution of the dynamic phase of lymphoscintigraphy to the detection of sentinel lymph node in breast cancer.

Aim: The aim of this study was to evaluate the contribution of an early dynamic phase (DP) of the lymphoscintigraphy (LS) to the detection of the sentinel lymph node (SLN) in breast cancer. Methods: This prospective study included 164 breast lesions in 161 consecutive patients (160 women, mean age 57.5 years). Patients with tumor >5 cm, multicentric, palpable nodes, axillary involvement, previous surgery, lymphadenectomy, radio or chemotherapy were not included. All patients underwent preoperative LS before surgery. DP immediately after injection of [99mTc]Nanocolloid followed by early and delayed planar images (EPI and DPI) were acquired. Results: SLN was detected in 162/164 lesions (98.8%). In 115 (71%) DP showed no lymph node uptake and the SLN was identified only by EPI and DPI. A focal uptake by at least one lymph node was observed in DP in the remaining 47 lesions (29%). Although in 30/74 lesions DP did not provide additional information to EPI and DPI, nevertheless in 17 cases (10.5%) DP was essential to identify correctly the SLN. Conclusion: We concluded that DP, by allowing a better interpretation of the lymphatic drainage pattern, provides unique information to distinguish the correct SLN from other lymph nodes and is recommended as the first part of LS.

[Evaluation of bone scintigraphy and (18)F-FDG PET/CT in bone metastases of lung cancer patients]. / Evaluación de la gammagrafía ósea y la (18)F-FDG PET/TAC en las metástasis óseas del cáncer de pulmón.

OBJECTIVE: To compare the bone scintigraphy (BS) findings and PET/CT scintigraphy with FDG (FDG PET/CT) in the detection of bone metastases in lung cancer. MATERIAL AND METHODS: We studied 32 patients with lung cancer who underwent FDG PET/CT and BS in a period of 15.9±18.6 days. The results of both techniques were compared with the histology, where available, radiological structural techniques and the clinical follow-up. In 30 patients, a definitive diagnosis was reached with the scintigraphic findings. No final diagnosis was obtained in 2 patients. RESULTS: BS was positive in 25/30 patients (83.3%) and negative in 5 patients. FDG PET/CT was positive in 21/30 patients (70%) and negative in 9. The BS and the FDG PET/CT were positive in 19/30 patients (63.3%) for the detection of bone metastases. In 6/19, both techniques showed the same number of bone lesions. In 10/19, FDG PET/CT showed a greater number of bone metastases than BS. In 3/19 patients, BS showed more lesions than FDG PET/CT and in 2/30 patients (6.6%), the BS was normal and the FDG PET/CT showed bone lesions which were confirmed as metastasis. In 6/30 patients (20%), the FDG PET/CT was negative and the BS was positive. BS and FDG PET/CT scan were normal in 3/30 patients (10%). CONCLUSIONS: In patients with lung cancer, FDG PET/CT scan detected more metastatic bone lesions than BS. It also identified bone metastasis in negative BS. In our experience, when the BS was positive and the FDG PET/CT scan was negative, the lesions observed were mostly related with degenerative bone conditions and bone fractures. In the clinical practice, the FDG PET/CT and BS have a complementary role for the assessment of bone status in lung cancer patients.

Evidence of restoration cost in the annual gynodioecious Phacelia dubia.

A negative pleiotropic effect on fitness of nuclear sex-determining genes (cost of restoration) could explain nuclear-cytoplasmic gynodioecy but rarely has been demonstrated empirically. In a gynodioecious Phacelia dubia population, maternal lineages produce only hermaphroditic progenies irrespective of the pollen parent (N) or can segregate females (S). Natural progenies of N maternal plants had lower seed viability than that of S. Full-sib progenies of unrelated hermaphrodites from all possible matings between N and S lineages had similar pollen filling but differed in sporophyte performance, mainly at seed germination stage. A discrete multivariate analysis reveals that the performance of N(female symbol) x S(male symbol) progeny at early stages of development was significantly lower than that of the other three types of mating in agreement with the silent-cost-of-restoration hypothesis, affecting the sporophyte. The restoration cost and male sterility appear to be dominant and consequence of nuclear-cytoplasmic incompatibilities that may maintain nuclear-cytoplasmic polymorphism by frequency-dependent selection.

Effect of inbreeding depression on outcrossing rates among populations of a tropical pine.

Inbreeding depression is common among plants and may distort mating system estimates. Mating system studies traditionally ignore this effect, nonetheless an assessment of inbreeding depression that may have occurred before progeny evaluation could be necessary. In the neotropical Pinus chiapensis inbreeding depression was evaluated using regression analysis relating progeny F-values with seed germinability, the mating system was analysed in three populations with contrasting size, using isozymes, obtained a corrected outcrossing rate. Selfing decreased seed viability by 19%, relative to an outcrossed plant. Multilocus outcrossing rates, t(m), varied widely among populations. In the two smallest populations t(m) congruent with 1. Therefore, inbreeding depression did not affect the estimates, but overestimated t(m) by 10% in the third population, which has a true mixed mating system (selfing was the major source of inbreeding), and an unusually low t(m) for pines (t(m) = 0.54, uncorrected, t(m) = 0.49, corrected). Inbreeding depression may be an uneven source of bias for outcrossing estimates even at the infraspecific level. Accuracy [corrected] but not precision [corrected] may be gained by including inbreeding depression in outcrossing estimates. Therefore, caution should be taken when comparing t(m) among species or even populations within the same species.

Increase in song frequency decreases spermatophore size: correlative evidence of a macroevolutionary trade-off in katydids (Orthoptera: Tettigoniidae).

In many katydids, the male feeds his mate with a large gelatinous spermatophore. Males of most species also produce elaborate calling songs. We predicted a negative relationship between spermatophore size and call frequency because of trade-offs between these two costly traits. Our comparative analysis controlling phylogeny and body size supported this prediction. Although call frequency is expected to decrease with increasing body size, after controlling for phylogeny, both variables were not related. Finally, given that song frequency and spermatophore size are likely targets of sexual selection, we examined the relationship between these variables and sexual size dimorphism (SSD) which can be influenced by sexual selection on body size. We found that only female body size was positively related to SSD, suggesting that natural and/or sexual selection on female body size may be stronger than sexual selection on male and spermatophore size.

Pelvic exenteration for recurrent or persistent cervical cancer: experience of five years at the National Cancer Institute in Mexico.

Cervical cancer constitutes a major health problem in Mexico and other developing countries. The purpose of our study was to assess the experience of a comprehensive national oncological reference center on pelvic exenteration for post-radiotherapy recurrent or persistent cervical cancer, describing the prognostic value of time to recurrence, procedure complications, and survival. Medical records from 42 patients with post-radiotherapy recurrent or persistent cervical cancer who underwent a pelvic exenteration with curative purposes from 1984 to 1989 were retrospectively reviewed. Histological diagnoses were squamous cell carcinoma (32 patients), adenosquamous carcinoma (9 patients), and adenocarcinoma (1 patient). Average follow up was of 56.3 mo after the procedure and global survival at 5 yr was 65.8%. Survival for patients with early recurrence was 56.9% vs 78% for patients with late recurrence (p = 0.05). Complications were observed in 65.3% of the cases with a surgical mortality of 4.8%. Pelvic exenteration is a surgical procedure with high morbidity in spite of the recent medical advances. Pelvic exenteration should not be indicated with palliative purposes owing to the high rate of complications. Patients with tumor persistence or early recurrence have a worse prognosis. In well-selected cases, exenteration may provide a survival benefit.

[Study of the biopsied nephrotic syndrome for 20 years in the Cadiz Bay Area: histological correspondence, renal prognosis and clinical prognostic factors]. / Estudio del síndrome nefrótico biopsiado durante 20 años en la bahía de Cádiz: correspondencia histológica, pronóstico renal y factores clínicos que influyen en el mismo.

AIMS: To analyse the histological correspondence, the renal survival and the clinical prognostic factors in the nephrotic syndrome for more than 20 years in our environment as well as the influence of the nephrotic proteinuria in the renal survival in the different histological particular types of glomerulonephritis. PATIENTS AND METHODS: Among the 542 primary and secondary glomerulonephritis diagnosed by kidney biopsy for two decades in the Cadiz Bay Area, we selected 242 patients whose clinical presentation and the biopsy indication was the nephrotic syndrome. Statistics methods: means +/- typical deviation, percentiles, percentages, Kaplan-Meier curves, long-rank test, student's t-test, chi-square analysis and Cox proportional hazards model test. RESULTS: 242 patients with nephrotic syndrome (44.66% out of the total of glomerulonephritis), average age of 39.15 +/- 18 years old. Average proteinuria 6.75 +/- 4.53 g/day. ETIOLOGY: membranous nephropathy (33.85%), lupus nephritis (14.46%), minimal change disease (11.57%), focal segmental glomerulosclerosis (10.33%), renal amyloidosis (9.95%). 33%, 45%, 63% and 72% of the patients with nephrotic syndrome developed to the End-stage Renal Disease and starting point of dialysis in 5, 10, 15 and 20 years respectively. After the multivariate model, the age older than 60 years old, the high levels of proteinuria and the coexistence with hypertension or renal failure, in the moment of diagnosis, showed to be independents clinical prognostic factors. The nephrotic proteinuria had a negative influence in the prognosis in the different histological types, especially in the IgA nephropathy and the lupus nephritis. CONCLUSIONS: The nephrotic syndrome is the main indication of the renal biopsy in our environment. In general, as an independent group, its development is slowly progressive to the End-stage Renal Disease, having the possibility of being also conditioned by certain clinical factors present in the moment of the biopsy. The presence of nephrotic proteinuria is also a negative factor in the progression in many of the glomerulonephritis.

[Darbepoetin in the treatment of the renal anaemia in the patient undergoing peritoneal dialysis previously treated with epoetin alfa]. / Darbepoetina alfa en el tratamiento de la anemia del paciente en diálisis peritoneal previamente tratado con epoetina alfa.

INTRODUCTION: In 2002, it was contraindicated the use of epoetin alfa by a subcutaneous way to avoid the risk of the pure red cell aplasia in chronic renal failure patients. This forced to change the prescription in the way it was supplied, which was especially problematic in predialysis and peritoneal dialysis, as treating out-patients, that is why it was necessary to change to epoetina beta o darbepoetin, where this contraindication was not established, in order to continue using this way. The darbepoetin has an average lifetime longer than the epoetin. Its efficacy and security have been well studied, especially in pre-dialysis and haemodialysis, but little less in peritoneal dialysis. AIMS: To evaluate our experience about the efficacy and security of darbepoetin alfa, by a subcutaneous way, in our programme of peritoneal dialysis, after the conversion of the patients previously treated with epoetin alfa. PATIENTS AND METHODS: 35 patients. 7 analytical and clinical controls are evaluated, 2 before and 5 after the conversion, with an interval of 6 weeks. Statistics methods: means +/- typical deviation, medians, distribution of frequencies, Wilcoxon test and Friedman test. RESULTS: The change into darbepoetin alfa has been successful in maintaining stable haemoglobin levels in patients in peritoneal dialysis, without meaningful changes in the mean levels of haemoglobin before and after the conversion. The percentage of patients with haemoglobin in the rank 11-13 g/dl (85%) has been higher with the darbepoetin, probably due to the dose increment in the patients with previous levels of haemoglobin less than 11 g/dl. The dosages might have been widely separated (7.5 +/- 3 vs 9.2 +/- 3.2 days). The darbepoetin has been well tolerated, without any important adverse effects. CONCLUSIONS: The conversion of epoetin alfa into darbepoetin alfa in peritoneal dialysis was simple, effective, secure and well tolerated.

Nuclear androdioecy and gynodioecy.

We formulate two single-locus Mendelian models, one for androdioecy and the other one for gynodioecy, each with 3 parameters: t the male (female) fertility rate of males (females) to hermaphrodites, s the fraction of the progeny derived from selfing; and g the fitness of inbreeders. Each model is expressed as a transformation of a 3 dimensional zygotic algebra, which we interpret as a rational map of the projective plane. We then study the dynamics for the evolution of each reproductive system; and compare our results with similar published models. In this process, we introduce a general concept of fitness and list some of its properties, obtaining a relative measure of population growth, computable as an eigenvalue of a mixed mating transformation for a population in equilibrium. Our results concur with previous models of the evolution of androdioecy and gynodioecy regarding the threshold values above which the sexual polymophism is stable, although the previous models assume constant the fraction of ovules from hermaphrodites that are self pollinated, while we assume constant the fraction of the progeny derived from selfing. A stable androdioecy requires more stringent conditions than a stable gynodioecy if the amount of pollen used for selfing is negligible in comparison with the total amount of pollen produced by hermaphrodites. Otherwise, both models are identical. We show explicitly that the genotype fitnesses depend linearly on their frequencies. Simulations show that any population not at equilibrium always converges to the equilibrium point of higher fitness. However, at intermediate steps, the fitness function occasionally decreases.

Circulacion extracorporea y corazon latiendo: una tecnica quirurgica prometedora para la cirugia valvular y el cierre de defectos septales / Extracorporeal circulation and beating heart

En el mundo occidental, el uso de la circulación extracorpórea continúa siendo el medio más seguro y eficaz para realizar la cirugía de las válvulas cardíacas y el cierre de los defectos septales. De igual forma, se ha estimado que el arresto cardíaco con soluciones cardiopléjicas, es el mejor método para realizar esta clase de cirugías. Sin embargo, pese a las facilidades quirúrgicas que ofrece el período de isquemia con cardioplejía, el daño que éste y la reperfusión añaden a un corazón ya de por si insuficiente, continúa siendo un problema sin resolver. Es probable que poco se pueda hacer para evitar el uso de la circulación extracorpórea en estos casos, pero sí se pueden evitar la isquemia miocárdica y el arresto cardíaco. Tomando como base los reportes anteriores y los avances en la circulación extracorpórea y en la fisiología cardíaca y coronaria, se ha desarrollado en la clínica Nuestra Señora de los Remedios de la ciudad de Cali, una técnica quirúrgica para cirugía valvular y cierre de los defectos septales, con el corazón latiendo en circulación extracorpórea, con clampeo aórtico y perfusión sanguínea continua en forma anterógrada por la raíz de la aorta o retrógrada a través del seno coronario. En este artículo se describen los procedimientos y se presentan los resultados obtenidos en los doce pacientes iniciales. Igualmente, se discuten sus ventajas e inconvenientes y se hacen conclusiones con expectativas futuras.

Patterns of genetic variation in Pinus chiapensis, a threatened Mexican pine, detected by RAPD and mitochondrial DNA RFLP markers.

Pinus chiapensis (Pinaceae) is a large conifer, endemic to central and southern Mexico and north-western Guatemala. In order to assess the extent of genetic variation within and between populations of this species, samples were obtained from throughout the natural range and analysed using random amplified polymorphic DNA (RAPD) and mtDNA RFLPs markers. Probes for the CoxI mitochondrial gene enabled two mitotypes to be observed. Populations from the eastern and western limit of the range of the species were fixed for one mitotype ('A'), whereas two populations distributed near the centre of the range were fixed for another ('B'). When the samples were screened with eight 10-mer RAPD primers, a total of 12 polymorphic bands were detected. The proportion of polymorphic bands was unusually low (24.5%) compared with other tree species. AMOVA analysis indicated that a significant proportion of the variation (P < 0.002) was distributed between populations; the extent of population differentiation detected (Phi(st) = 0.226; G(ST ) = 0.194) was exceptionally high for a pine species. Pair-wise comparison of Phi(st) values derived from AMOVA indicated that populations were significantly (P < 0.05) different from each other in virtually every case. These results are interpreted in the context of the evolutionary history of the species, and the implications for its in- and ex situ conservation are discussed.

Genetic associations under mixed mating systems: the Bennett-Binet effect.

Using elementary algebraic geometry and computational commutative algebra, supported by the program Macaulay2, we studied and developed operators that define the zygotic and gametic evolution under a mixed-mating system with parameters s selfing rate, r recombination rate, and g relative fitness of inbreeders, for any possible combination of initial zygotic or gametic frequencies with two alleles at each of two loci. We found that (i) the allelic frequencies are preserved in every generation; (ii) the gametic frequencies converge to values that depend exclusively on the allelic frequencies; (iii) every zygotic population converges to a population in equilibrium with double heterozygotes equally frequent; (iv) the rate of convergence decreases to arbitrary small values with sufficiently small values of r or with sufficiently large values of s and (v) as g decreases, the maximal 'association between the two loci' occurs with higher values of selfing. We also found generalizations for the case of several alleles at each locus.

Effect of ring liner and casting ring temperature on the dimension of cast posts.

STATEMENT OF PROBLEM: If a post does not fit passively, binding with the radicular tooth structure occurs, possibly increasing the risk for root fracture. Therefore, it is necessary to fabricate slightly undersized cast posts to allow for passive fit and cement placement. Shrinkage of the mold cavity may be a desired effect during the casting of posts. PURPOSE: This study evaluated the influence of: (1) a cellulose ring liner, and (2) a lower casting temperature of the metal ring, on the dimensions of a cast post. MATERIAL AND METHODS: Eighty plastic posts were divided in 4 equal groups (group 1, 815 degrees C, liner; group 2, 815 degrees C, no liner; group 3, 600 degrees C, liner; and group 4, 600 degrees C, no liner), invested in phosphate-bonded investment and cast with a noble alloy. Posts were measured at 2 locations, the tip and base, before and after casting. RESULTS: Investing in a lined metal ring and using a casting ring temperature of 815 degrees C (group 1) resulted in markedly oversized posts (tip: +25.8 microm; base: +20.3 microm). The absence of the cellulose liner in the casting ring (group 2) decreased the expansion of the investment producing slightly oversized castings (tip: +9.75 microm; base: +4.52 microm). Lined rings that were heated to a final temperature of 600 degrees C (group 3) produced posts that were oversized (tip: +16.65 microm; base: +11.05 microm). Final casting ring temperature of 600 degrees C and the absence of a cellulose liner (group 4) resulted in posts slightly undersized (tip: -4.1 microm; base: -2.2 microm). CONCLUSION: The use of 2 casting ring temperatures (815 degrees C or 600 degrees C) and the influence of a ring liner were investigated. Decreasing the casting ring temperature from 815 degrees C to 600 degrees C and the absence of a ring liner significantly decreased the dimensions of a cast post.

Defect morphology: effects on regenerative predictability and membrane selection.

In clinical experience, guided tissue regeneration has been associated with complications, which include membrane exposure. The maintenance of a stable blood clot under the membrane is key to a successful regenerative outcome. This requires adequate membrane stabilization, tension-free suturing, and maintenance of a good vascular supply to the defect. Careful selection of defects after a thorough periodontal evaluation and modification of surgical techniques from those used for conventional resective procedures can lead to predictable outcomes for guided tissue regeneration.

Efficacy of control measures in preventing nosocomial transmission of multidrug-resistant tuberculosis to patients and health care workers.

OBJECTIVE: To assess the efficacy of control measures in decreasing nosocomial transmission of multidrug-resistant tuberculosis. DESIGN: Retrospective cohort study. SETTING: A teaching hospital in New York City. POPULATION: 40 patients hospitalized with multidrug-resistant tuberculosis (case-patients) and health care workers receiving tuberculin skin testing. INTERVENTIONS: Centers for Disease Control and Prevention (CDC) 1990 guidelines for preventing transmission of tuberculosis, including 1) prompt isolation and treatment of patients with tuberculosis; 2) rapid diagnostic techniques for processing Mycobacterium tuberculosis specimens; 3) negative-pressure isolation rooms; and 4) molded surgical masks for health care workers. MEASUREMENTS: Proportion of case-patients with nosocomially acquired tuberculosis and rate of tuberculin skin test conversion among health care workers before and after implementation of control measures. RESULTS: The proportion of patients with multidrug-resistant strains of M. tuberculosis decreased after the interventions (10 of 70 [14%] compared with 30 of 95 [32%] patients before the intervention; relative risk [RR], 0.5; 95% CI, 0.2 to 0.9). Before onset of multidrug-resistant tuberculosis, case-patients in the intervention period were as likely to be hospitalized on high-risk wards containing patients with tuberculosis (4 of 10 compared with 17 of 30 patients; RR, 0.7; P = 0.5) but were less likely to be exposed to another case-patient with tuberculosis (1 of 10 compared with 20 of 30 patients; RR, 0.2; P = 0.003). Tuberculin skin test conversion rates for health care workers assigned to wards housing patients with tuberculosis were lower in the intervention period than in the preintervention period (4 of 78 [5%] compared with 15 of 90 [17%] conversions; P = 0.02), decreasing to levels observed for workers assigned to other wards (4 of 78 [5%] compared with 9 of 228 [4%] conversions; P = 0.7). CONCLUSIONS: Implementing control measures reduced nosocomial transmission of multidrug-resistant strains to patients and health care workers.