Statistical considerations in the methodology of quantifying immunocompetent cells in tumors.

OBJECTIVE: To quantify immunocompetent cell (IC) density for different testicular tumors and antibodies and to verify if the results of the comparisons depend on the antibody used. STUDY DESIGN: T-lymphocytes were studied with CD3 and UCHL1 antibodies and macrophages with MAC387 and CD68 in 43 patients with seminomas, mature teratomas, immature teratomas and embryonal carcinomas of the testis. Counts were expressed as number of IC per square millimeter. RESULTS: Use of different antibodies produced significant differences in the IC cell number; moreover, in the case of macrophages, the tumor type sequence by increasing cell number was different according to the antibody used. CONCLUSION: These results suggest the existence of a statistical interaction between the type of tumor and antibody.

[Primary septicemias in pediatric patients. Hospital Infantil de la Paz (1990-1993)]. / Septicemias primarias en enfermos pediátricos. Hospital Infantil de la Paz (1990-1993).

BACKGROUND: Septicemias comprise more than one third of nosocomial infections in children. Their risk factors are related with the exposition time, therefore they are evaluated in relationship to it. PATIENTS AND METHODS: Prospective observational study along 4 years in surgical children and in those entered in the Internal Medicine Unit patients of a children Hospital, with stays higher than two days. Data were collected from admission to discharge. Bivariant analysis of stay time until infection with Wilcoxon-Gehan test, followed by Cox regression with time interaction terms for the risk factors that did not fulfill the requisite of proportional risks. RESULTS: 4,098 children were studied. 3.8% suffered primary septicemia and more than one half had coagulase-negative staphylococci. Cox regression showed the following risk factors: type of surgery, peripheral and central venous catheter, urinary catheterization, stay previous to surgery and duration of intervention. The protection factors were more than 3 days of antibiotherapy, age higher than 1 year and male sex. The factors with interaction with time were: stay previous to surgery, sex and duration of intervention. CONCLUSIONS: The stay previous to surgery, antibiotherapy reduction and duration of instrumentations are risk factors susceptible to be modified in order to reduce the incidence of infection in children. Protection by means of antibiotics requires to be evaluated through an ad hoc designed study.

Quantification of immunocompetent cells in testicular germ cell tumours.

The immunocompetent cells present in the different histological patterns of 43 testicular germ cell tumours were evaluated. CD3 + and CD45RO + (UCHL1 +) T lymphocytes, CD68 + and MAC 387 + macrophages, CD20 + (L26 +) B lymphocytes, and kappa and lambda + plasma cells were counted. The number of immunocompetent cells per mm2 of tumour tissue, excluding the necrotic areas, was evaluated. Microscopic fields were randomly selected by two observers. In order to guarantee randomization each surface was divided into parts, numbered through a lattice, and some fields were chosen via a random numbers table. This procedure yielded significantly different counts from those obtained on subjective selection. The number of T-lymphocytes and macrophages was higher in seminomas than in the non-seminomatous testicular germ cell tumours (P < 0.05) Embryonal carcinomas had more T-lymphocytes than immature teratomas. No significant differences were found among testicular germ cell tumours with regards to the B-lymphocytes, with the exception of the high number of B-lymphocytes in mature teratomas. Kappa + and lambda + plasma cells were few in the testicular germ cell tumours. Randomization in the quantification of immunocompetent cells in testicular germ cell tumours is a good means for evaluation of immune response in all the tumour mass, not only in the areas with the most intense inflammatory cell infiltrate, and permits comparison of testicular germ cell tumours with other malignant tumours. Study of immunocompetent cells in every histological type of testicular germ cell tumour is useful in comparing them with other extra-testicular germ cell tumours.