This Mother's Day holds no maternal joy for 60-year-old Maria Quinteros. It marks just one more day - the 1,050th to be exact - in the officially unadmitted imprisonment of her only daughter, Elena, by Uruguayan authorities.

The repressive military government of Uruguay continues to deny any knowledge of Elena Quinteros' whereabouts. But Uruguayan dissidents lucky enough to have been released from the dictatorship's prisons have confirmed that she is still alive. It is her mother's only solace at this point.

More than balancing out that one crumb of good news is the apparent cooling of interest in Elena's fate on the part of other governments, which were initially outraged by her case. Even the Carter administration, which has vociferously attacked human rights violations all over the world, seems to have adopted a hands-off policy, deeming the case of Elena Quinteros no business of the United States.

As head of the national teachers' union, Quinteros was an ex-efficio subversive in the eyes of the Uruguayan military, which extinguished any semblance of political freedom when it seized power in 1973. And it wasn't long before personal freedom made the junta's bit list.

On June 24, 1976, military police dragged her from her home in the capital city of Montevideo, on charges of trying to undermine the government. She had been arrested twice before as an activist in student and worker resistance movements. But this time she was subjected to torture for four days, as the government's goons tried to extact the names of other "subversives" in the union.

On June 28, Elena devised a scheme she hoped would win her asylum in the Venezuelan embassy. She told her inquisitors she would lead them to fellow union and political dissidents, at a house next to the Venezuelan embassy.

She prevailed on the two secret policemen who accompanied her to remain in the car while she entered the house to set up the "clanderstine meeting" they would then raid. Once inside the house, Elena ran to a second story window and leaped into the supposedly safe refuge of the embassy next door.

Screaming "Asilo! Asilo!" ("Asylum! Asylum!"), Elena claimed the right of refuge that is traditional in the political turmoil of Latin America.

But in this case, tradition failed. The two plainclothesmen rushed into the embassy grounds to recapture Elena. Two Venezuelan officials who tried to stop them were knocked down and beaten by the police officers, who then proceeded to beat Elena and drag her out of the embassy grounds by her hair.

The secret police threw her into their unmarked Volkswagon and drove off. The Venezuelan charge daffaires, Francisco Bocerra, flung himself on the moving vehicle in a desperate attempt to save Elena. But he was thrown off the speeding car and was left with only one of Elena's shoes - kicked off in the struggle with her captors - as evidence of the illegal kidnapping.

As a result of the incident, Venezuela broke off diplomatic relations with Uruguay. It also reported the case to the Organization of American States as a violation of international law - invading the embassing's extraterritorial sanotuary.

The Uruguayan government responded by accusing Venezuelan Ambassador Julio Ramos of fabricating the whole episode. The official Uruguayan position, unchanged to this day, was that Elena Quinteros had left the country five months earlier.

Since then, Elena's mother has traveled from one capital to another seeking support for her daughter. She has used her Uruguayan widow's pension - a strange oversight on the part of the dictatorship - to finance her one-woman shuttle diplomacy. From Lation American to Sweden, Maria Quinteros has pleaded her daughte's cause, as well as that of move than 100 other Uruguayans who have disappeared without acknowledgement by the junta.

In Washington recently, she told her story to our reporter Dave Carpenter as a meeting arranged by the Washington office on Latin America, a civic-religions group that deals with human rights violations.

Last March, at a meeting of the United Nation Human Rights Commission in Geneva, a representative of the Uruguayan government told her and American officials in private, separate conversations that her daughter was still in custody. The official said her daughter could be released or deported, and promised action within a month. But she has heard nothing since.

As for the United States, a State Department spokesman, Tim Brown, insisted that the Carter administration was conducting a "very frank, continuous" discussion with the Uruguayana on human rights. But asked whether the United States would urge the Venezuelans to hold off resumption of relations with Uruguay until Elena is released, Brown said: "Certainly not. We wouldn't want them sticking their noses in our affairs, and we're not sticking our noses in theirs."

On the Mother's Day, Maria Quinteros is determined that her daughter's plight will not be ignored and that the conscience of Jimmy Carter and other world leaders will be given no rest until Elena Quinteros is free at last.