BY JACQUELINE CHARLES

  There was no bed, no blanket, no bathroom facilities. Only a cell and Eriberto Mederos, a politicized nurse working for Fidel Castro's communist regime who violently subdued prisoners with the help of two assistants before dispensing his own brand of treatment: electroshock therapy.

  This is how Nilo Jerez, a former Cuban political prisoner, described his three months at an infamous Havana psychiatric hospital. He took the stand Wednesday on behalf of the U.S. government, which is seeking to yank Mederos' U.S. citizenship.

  ACCUSED OF LYING

  The former psychiatric nurse is accused of lying on his citizenship application about his affiliation with the Communist Party and allegations that he tortured political
  prisoners at a Havana psychiatric hospital between 1968 and 1978. If convicted, Mederos, 79, could be sentenced to as much as 10 years in prison. The Immigration and Naturalization Service would then seek to deport him.

  Jerez spent four hours on the stand Wednesday, the first of several witnesses expected to testify in the federal trial before U.S. District Judge Alan Gold. He described his three-month stint at the Havana hospital known as Mazorra -- from how he got there, to the living conditions, to the frequent electroshock treatments administered by Mederos.

  ''Mr. Mederos is the person who had complete control of the unit. No one other than Mr. Mederos would come into the unit,'' Jerez recalled about his stay in the ward.

  Asked to described the conditions inside the unit, Jerez said, ''That was like Dante's Inferno. You had to urinate inside the cell. You had to defecate inside the cell.''
  Waste was eventually removed with a water hose, he said.

  As Jerez spoke, Mederos -- a frail, elderly man -- listened quietly. He has consistently declined comment since his arrest on federal charges Sept. 4, but in interviews with The Herald when the allegations surfaced in 1992, he acknowledged that he administered electroshock treatment but only when medically prescribed by doctors.

  NO DISCRETION

  ''He had no ability to make discretionary calls,'' his attorney, David Rothman, told the jury Wednesday in opening statements. ``If he gave treatment to those to whom it was prescribed, it wasn't torture. It was not given to them because of their political beliefs.''

  Assistant U.S. Attorney Frank Tamen told jurors the case against Mederos is about American citizenship -- who can and can't become a citizen. The privilege, he said, has applicable laws and standards.

  ''We simply don't allow people to lie their way into American citizenship,'' he said.

  Accusing Mederos of lying on his citizenship application about his affiliation with Cuba's Communist Party, Tamen said Mederos ``did not lawfully begin his path to
  citizenship.''

  ``He was not qualified to be admitted because of his affiliation with the Communist Party.''

  In addition to Jerez, a former political prisoner who spent 15 years in Cuba's jails, the government also called an expert on electroshock therapy, Dr. Roberto Rodriguez, a psychiatrist who has prescribed the treatment for patients.

  VIVID TESTIMONY

  But it was Jerez's testimony that provided jurors with a sense of what Jerez and other political prisoners allegedly experienced at the hands of Mederos.

  During cross-examination, Rothman attempted to discredit Jerez's testimony by pointing out discrepancies between his testimony on the stand and statements made to an INS agent a year ago.

  At times, Jerez contradicted himself over the exact dates of his arrest and imprisonment in Cuba. When asked about the contradiction by Rothman, he said, ``You are making reference to things 30 years ago. I can certainly make a mistake about the date.''

  Rothman also questioned Jerez's motives, asking him whether his testimony Wednesday had been influenced by the fact that the FBI, years ago, declined to follow up on similar allegations he made about Mederos.