[Human chromosome banding with raw extract of fruits or leaves of papaya]. / Bandeo de cromosomas humanos con extracto crudo de frutas u hojas de papaya.

One week old human chromosome preparations were treated with filtrate from one liquefied leaf (53 g) of papaya (Carica papaya) in 100 ml of distilled water, and stained with 1.5% Giemsa (pH 6.8). Good chromosome banding was obtained after 2 min of treatment. Solutions that have been frozen even for years are effective and the method is cheaper and easier than others.

[Lafora disease and founder effect in a small neotropical locality]. / Enfermedad de Lafora y efecto fundador en una pequena localidad neotropical.

The Lafora disease is an uncommon genetic condition. Four cases (two families) were detected in Zarcero, a small town in Costa Rica (population under 2000). They belonged to two separate consanguineous marriages but both families had common ancestors. The diagnosis of Lafora disease was confirmed by liver biopsy in one of the patients. The ages of onset were 13, 14, 16 and 17 years. Patients died after four, nine, six and five years of severe progressive physical and mental deterioration, respectively. The gene for Lafora disease arrive to Zarcero from one of its founders. There are no other cases reported from Costa Rica: this is an example of genetic drift, or more specifically, founder effect.

[Cytogenetics and cytochemistry of leukemia patients in 2 neotropical hospitals]. / Citogenética y citoquímica de pacientes con leucemia en dos hospitales neotropicales.

A cytogenetic and/or cytochemical study was performed in 166 individuals with leukemia or related disorders, in two major Costa Rican hospitals. In those patients treated at an adult's hospital (14 years old and over), acute leukemias represented 66% of all cases. In that hospital the most frequent types of disorders were, in decreasing order: ANLL (> M1), ALL, CML (all of them showed the Ph chromosome) and MDS. In the cases from a childrens' hospital (< 14 years old) acute leukemias were 98%. Among them the order of frequency was: ALL (70%): ALL-1 (84%), ALL-2 (16%) and ANLL (27%): M5a > M3 > M4 > M5b. In ALL 85% were type B and occurred mostly in women while 15% of them were type T and more frequent in males. There was 5.6% infant leukemia, which presented a similar number of acute lymphoids and myeloids. The cytogenetic pattern was similar among Costa Rica and other tropical and temperate countries.