Earlier dental maturation: fact or fiction?

The objective of this investigation was to determine if there is a difference in dental age of maturation between adolescents treated in the 1970s and those treated in the 1990s. Records of 150 Caucasian patients, 8.5 to 14.5 years old and treated in a private orthodontic office between 1972 and 1974, were randomly selected; records of another 150 patients of the same race and age range but treated between 1992 and 1994 were also collected. The percentage of calcification of the mandibular canines was rated according to methods used by Demirjian, who divided tooth development into eight segments, A to H. Using stage G to compare the 1970 and 1990 patient samples, we demonstrated dental age reductions of 1.21 years for males and 1.52 years for females, and a combined reduction of 1.40 years.     

Glucocorticoid-induced formation of tight junctions in mouse mammary epithelial cells in vitro

Phenotypically stable cultures of untransformed mouse mammary epithelial cells (denoted 31EG4) were established and utilized to investigate the lactogenic hormone (glucocorticoids, insulin, and prolactin) regulation of tight junction formation. When 31EG4 cells were grown on permeable supports for 4 days in medium containing the synthetic glucocorticoid dexamethasone and insulin, confluent cell monolayers obtained a transepithelial electrical resistance (TER) of 1000-3000 omega.cm2. In contrast, over the same time period, confluent monolayers treated with insulin or insulin and prolactin maintained a low TER (35-150 omega.cm2). Consistent with the formation of tight junctions, apical to basolateral paracellular permeability was decreased from 12% to 1% for [14C]mannitol and 3.3% to 0.3% for [3H]inulin when cells were cultured in dexamethasone. This effect of dexamethasone on TER required extracellular calcium, de novo protein synthesis, dose-dependently correlated with glucocorticoid receptor occupancy, and was not due to an increase in cell density. As shown by direct and indirect immunofluorescence microscopy, dexamethasone treatment did not modulate the production or location of filamentous actin, the tight junction protein ZO-1, or the cell adhesion protein E-cadherin. Our results suggest that glucocorticoids play a fundamental role in the function and maintenance of cell-cell contact in the mammary epithelia by inducing the formation of tight junctions.     

A conditional bootstrap procedure for reconstruction of the incubation period of AIDS

Data on the incubation period of AIDS patients are often fragmented and censored. parametric models have been proposed in the literature to impute the missing segment of the incubation period. The numerical results vary widely with the parametric models used. We propose a nonparametric conditional bootstrap (CB) procedure for imputation. The quality of the CB data is studied by checking the asymptotic accuracy of the CB estimators. We establish the asymptotic accuracy of the CB procedure for two basic nonparametric estimators: the empirical distribution function and a kernel-type conditional empirical distribution function. The rates of convergence of the CB approximation are obtained. The results for the kernel-type estimators hold also for the nearest-neighbor-type estimators.     

Biologic and clinical effects of continuous infusion interleukin-2 in patients with non-small cell lung cancer

BACKGROUND: Interleukin-2 (IL-2) has shown antitumor activity in some neoplasms, such as melanoma and renal carcinoma, but toxicity derived from bolus administration is significant, particularly at the cardiorespiratory level. METHODS: To test feasibility, antitumor activity, pulmonary and systemic immunologic effects, and pulmonary function changes of continuous-infusion recombinant IL-2 given to patients with non-small cell lung cancer, eleven subjects with Stage III-IV disease were treated in a standard pulmonary medicine unit with a dose of 18 million IU/m2/day from day 1 to day 13 with 1-day rest on day 7. A second induction course was given after a 3-week rest. In patients with nonprogressive disease, four maintenance courses of 6 days' duration at the same dose were planned. Immunologic tests, including lymphocyte phenotype analysis and assays for the detection of tumor necrosis factor (TNF) and of anti-IL-2 antibodies, were performed before and after treatment in serum and bronchoalveolar lavage fluid (BAL). Cardiopulmonary function tests, including spirometry, arterial blood gas analysis, diffusion capacity, and echocardiography, were obtained before, during, and after treatment. RESULTS: Twenty-one cycles (15 induction courses plus 6 maintenance courses) were administered. No patient was able to complete the six planned courses, and only 3 patients entered the maintenance phase. Reasons for discontinuation included progressive disease in five cases, toxicity in three cases, and patient request in three cases. The most common side effects were fever, hypotension, oliguria, and elevated serum creatinine and liver enzyme levels. No patient required intubation or intensive care. No objective response was seen, and the median survival time was 10 months. Lymphocytosis and eosinophilia were observed in all patients. Surface marker analysis revealed a statistically significant increase in the percentage of CD3+, CD4+, CD25+ and DR+ cells in peripheral blood. Lymphoid cells derived from BAL disclosed an increased natural killer activity after IL-2 treatment, and TNF was increased in BAL fluid. Pulmonary function tests evidenced an increased alveolar-arterial difference for oxygen allied with a decrease of forced expiratory volume in 1 second, forced vital capacity, and carbon monoxide transfer coefficient consistent with a significant, albeit not clinically relevant, interstitial lung defect. CONCLUSION: Continuous-infusion IL-2 is feasible in patients with advanced lung cancer even outside an intensive care unit, but overall compliance is poor. Although clinical pulmonary toxicity is negligible, small but statistically significant alterations of the pulmonary function are evident. In addition, this regimen produces a significant activation of the immune system at the pulmonary level.     

Dark adaptation in vertebrate photoreceptors

Exposure of the eye to bright light bleaches a significant fraction of the photopigment in rods and cones and produces a prolonged decrease in the sensitivity of vision, which recovers slowly as the photopigment is regenerated. This sensitivity decrease is larger than would be expected merely from the decrease in the concentration of the pigment. Recent experiments have shown that the decrease in sensitivity is produced largely by an excitation of the phototransduction cascade by bleached pigment; even in darkness, it produces an equivalent background similar to that produced by real steady background illumination. Thus, excitation produced by a form of rhodopsin thought previously to be inactive has a profound effect on the physiology of the photoreceptor. This raises the possibility that forms of other G protein-coupled receptors thought to be inactive might also play an important role in signal transduction and disease.     

The principles of administering drug and non-drug treatment methods in peptic ulcer

As the result of the study optimal schemes of the ulcer disease treatment were elaborated. They include microwave resonance therapy, immunomodulatory and antibacterial drugs with regard to localisation, depth and size of the ulcerous lesion, exacerbation rate, degree of secondary immune disorders and seeding of gastric mucosa with Helicobacter pylori. The treatment suggested allows to shorten the terms of ulcer cicatrization, reduces exacerbation rate and ensures clinico-endoscopic remission in most patients with ulcer disease.