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Biomedical subjects

C H Ramirez-Ronda

Publications and source records attributed to C H Ramirez-Ronda.

At least 19 recordsLinked to original sources
PubMed2000

Comparative studies of two-times-daily versus three-times-daily indinavir in combination with zidovudine and lamivudine.

OBJECTIVES: To compare the efficacy and safety of two-times-daily versus three-times-daily indinavir in combination with zidovudine and lamivudine. DESIGN: Two multicenter, open-label, randomized 24-week studies. METHODS: Adults HIV-1 infection, HIV-1 RNA greater than 10000 copies/ml, and no prior lamivudine or protease inhibitor therapy were eligible. In a pilot study (Study A), patients received indinavir at 800 mg every 8 h, 1000 mg every 12 h, or 1200 mg every 12 h. In a subsequent study (Study B), patients received indinavir at 800 mg every 8 h or 1200 mg every 12 h. All subjects received zidovudine (300 mg) and lamivudine (150 mg) every 12 h. An intent-to-treat analysis was used. RESULTS: In Study A, which enrolled 88 patients, neither HIV-1 RNA nor CD4 cell responses differed significantly between treatment groups at 24 weeks when corrected for multiple comparisons. Study B enrolled 433 patients, but was prematurely discontinued when interim analysis suggested greater efficacy of three-times-daily indinavir. Of the first 87 patients reaching week 24, HIV-1 RNA was less than 400 copies/ml in 91% receiving three-times-daily versus 64% receiving two-times-daily indinavir (P < 0.01). CONCLUSION: Three-times-daily indinavir appears more efficacious than two-times-daily dosing when administered with zidovudine and lamivudine. Two-times-daily indinavir dosing should only be considered in situations characterized by favorable pharmacokinetic drug-drug interactions.

Adult↗
PubMed1994

Didanosine compared with continuation of zidovudine in HIV-infected patients with signs of clinical deterioration while receiving zidovudine. A randomized, double-blind clinical trial. The Bristol-Myers Squibb AI454-010 Study Group.

OBJECTIVE: To determine the benefits of switching to didanosine compared with continuing zidovudine among patients infected with human immunodeficiency virus (HIV) who have previously used zidovudine and have signs of clinical deterioration. DESIGN: Randomized, double-blind, two-armed, parallel, comparative clinical trial with a blinded, compassionate crossover provision at 12 weeks. SETTING: Outpatient clinics at 19 tertiary care medical centers. PATIENTS: 312 patients infected with HIV who had received zidovudine for 6 months or more, had CD4 cell counts of 300/mm3 or less, and had signs of clinical deterioration within 12 weeks before study entry. INTERVENTION: Peroral didanosine tablets (600 mg/d adjusted for weight, "high dose") or zidovudine capsules (600 mg/d). MEASUREMENTS: Primary study end points were death, a new acquired immunodeficiency syndrome (AIDS)--defining event, or the combination of two new or recurrent HIV-related diagnoses with a 50% decrease in CD4 cells. RESULTS: Switching to didanosine was associated with fewer end points than continuing zidovudine (relative risk [RR] for zidovudine:didanosine = 1.5; 95% Cl, 1.1 to 2.0). This benefit was consistent across subgroups of patients with either AIDS-related complex or AIDS and was most apparent among those with a CD4 count at entry of 100/mm3 or more (RR = 2.2; Cl, 1.1 to 4.4). CONCLUSIONS: This study shows a positive treatment effect for switching from zidovudine to didanosine among patients with either AIDS-related complex or AIDS and validates the common practice of using clinical signs or a decrease in the CD4 count as an indication for changing therapy.

AIDS-Related Complex↗
PubMed1994

Dengue in the Western Hemisphere.

Dengue is an important insect-borne viral disease, transmitted in the Western hemisphere by the A. aegypti mosquito. It is endemic in the Caribbean with sporadic outbreaks in different regions. Cases in the United States are mostly imported cases but can be seen in the Gulf states as well as the Southeast. Dengue is most frequently a self-limiting illness characterized by sudden onset of fever, chills, headache, retroocular pain, general malaise, myalgias, arthralgias, and a skin rash. In a small group of patients, the same viruses may cause dengue hemorrhagic fever and dengue shock syndrome. In the Western hemisphere, dengue with hemorrhagic manifestations and dengue with shock syndrome have been documented frequently in adults. There are four serotypes of dengue viruses and all have been documented to be present in the Western hemisphere. The clinical illness is similar for any of the four serotypes; after infection there is lifelong homotypic immunity and heterotypic immunity for several months. The diagnosis of dengue is based on clinical findings and can be confirmed by serologic tests or virus isolation. There is no specific treatment for dengue; hydration is important as well as aggressive fluid management if hypotension develops. It is important to avoid aspirin and salicylates. The best treatment is prevention through mosquito control and public education to eradicate the breeding grounds for the mosquito.

Animals↗
PubMed1989

A comparative analysis of aztreonam + clindamycin versus tobramycin + clindamycin or amikacin + mezlocillin in the treatment of gram-negative lower respiratory tract infections.

One hundred ten patients were randomized to receive one of the following antibiotic combinations: aztreonam + clindamycin, tobramycin + clindamycin, or amikacin + mezlocillin for the treatment of lower respiratory tract infections (LRTI) caused by gram-negative bacilli. Of the 68 patients who received aztreonam + clindamycin, 60 were clinically evaluable and 50 were bacteriologically evaluable. Of the 60 clinically evaluable patients, 54 were cured and 5 were treatment failures or died during the study period. Of the 50 bacteriologically evaluable patients, 46 were cured and 3 failed to respond to therapy. Of the 26 clinically evaluable patients in the tobramycin + clindamycin group, 22 were cured and 4 either failed to respond or died during the study period. Of 18 bacteriologically evaluable patients in this group, 16 were cured and 2 failed to respond. In the amikacin + mezlocillin group, 14 of the 15 clinically and bacteriologically evaluable patients were cured, and 1 failed to respond. The most commonly isolated pathogens were Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa. The very few adverse drug reactions that were seen were transient and comparable in all three groups except for renal function parameters, which deteriorated in 6-8% of patients receiving the aminoglycoside combination. All three antibiotic combinations were similar in effectiveness and safety.

Adult↗
PubMed1989

Oral ciprofloxacin vs parenteral cefotaxime in the treatment of difficult skin and skin structure infections. A multicenter trial.

A prospective, randomized, double-blind, multicenter study was conducted of hospitalized patients to compare the efficacy and safety of oral ciprofloxacin (dosage, 750 mg every 12 hours) with intravenous cefotaxime (dosage, 2.0 g every 8 hours) as monotherapy for difficult skin and skin structure infections requiring hospitalization. Five hundred seventy patients were assessed for an analysis of safety and 461 patients were assessed for an analysis of efficacy. The most common infections were infected ulcers and abscesses. At the end of therapy, there was a higher incidence of recurrent or persistent organisms in the cefotaxime group compared with ciprofloxacin. Adverse reactions related to either therapy were rare. By pathogens, there were no differences in activity, except the higher rate of recurrent or persistent Pseudomonas aeruginosa infection in the cefotaxime group. By diagnosis, the two drugs had comparable efficacy, except for the higher incidence of bacteriologic failure in patients with polymicrobial infected ulcers in the cefotaxime group. Larger studies are needed to evaluate emergence of resistance to ciprofloxacin. Oral ciprofloxacin therapy is as safe and effective as parenteral cefotaxime in the treatment of difficult infections of the skin and skin structure, and affords the prospect of early discharge from the hospital and significant cost savings.

Administration, Oral↗
PubMed1987

Comparative, double-blind study of oral ciprofloxacin and intravenous cefotaxime in skin and skin structure infections.

The effectiveness and safety of orally administered ciprofloxacin and intravenously administered cefotaxime were compared in a double-blind study of 60 men with infections of skin and soft tissue, including cellulitis, ulcers, abscesses, cellulitis with ulcers or abscesses, wound infections, and post-traumatic infections. Patients in the ciprofloxacin group received 750 mg orally every 12 hours for a mean duration of 9.6 days (six to 18 days), and those in the cefotaxime group received 2.0 g intravenously every eight hours for a mean duration of 9.3 days (five to 14 days). Infection was documented bacteriologically in 78 percent of the patients in the ciprofloxacin group and in 83 percent of the patients in the cefotaxime group. Pathogens included Staphylococcus aureus, enterococci, group B streptococci, Escherichia coli, Proteus mirabilis, and Klebsiella and Pseudomonas species. Half of the infections were mixed infections. Ninety percent (19 of 21) of the infections were bacteriologically eradicated with ciprofloxacin, and 82 percent (18 of 22) were eradicated with cefotaxime. Treatment was completely successful in 79 percent (22 of 28) of the patients in the ciprofloxacin group and in 68 percent (19 of 28) in the cefotaxime group (p greater than 0.1). The side effects in both treatment groups were comparable. This study demonstrates that orally administered ciprofloxacin is comparable in effectiveness and safety to cefotaxime administered intravenously in the treatment of infections of skin and soft tissue, and that it can offer an alternative in the treatment of such infections.

Administration, Oral↗
PubMed1987

Dengue in Puerto Rico: clinical manifestations and management from 1960's to 1987.

Dengue is a viral disease transmitted by the Aedes aegypti mosquito. It is endemic in Puerto Rico and the Caribbean with periodic epidemics occurring at varying intervals. There are three dengue serotypes present in Puerto Rico, at the present time. The clinical manifestations of dengue in Puerto Rico are presented from a historical perspective. Dengue in Puerto Rico has evolved from a clinically mild illness in the 1960's to a devastating disease with hemorrhagic manifestations in the 1980's and dengue shock syndrome in 1987. The approach to clinical diagnosis and management is presented with emphasis on early recognition, performance of tourniquet test, serial hematocrits and aggressive intravenous fluid replacement with crystalloids of colloids in DSS. The best way to treat dengue is eliminating the vector, therefore, prevention.

Dengue↗
PubMed1982

Activity of N-formimidoyl thienamycin and cephalosporins against isolates from nosocomially acquired bacteremia.

The in vitro activity of N-formimidoyl thienamycin was compared with that of seven beta-lactam agents against bacteremic clinical isolates, including gentamicin-resistant, gram-negative bacilli, Staphylococcus aureus, Staphylococcus epidermidis, streptococci, and enterococci. N-formimidoyl thienamycin was the most active antibiotic against all of the gram-positive cocci studied, with the exception of Staphylococcus epidermidis, and the only agent active against the enterococci. N-formimidoyl thienamycin was less active than some of the other agents against Enterobacteriaceae, except for the strains of Serratia and Citrobacter studied. For Pseudomonas aeruginosa, N-formimidoyl thienamycin was the most active agent (4 micrograms/ml was the lowest concentration that inhibited 90% of the strains tested).

Anti-Bacterial Agents↗
PubMed1981

Increased pharyngeal bacterial colonization during viral illness.

The oropharyngeal colonization by Staphylococcus aureus and Gram-negative bacilli (GNB) and its duration were studied in 89 house staff officers, with biweekly quantitative cultures for 11 months. Eighty-two episodes of upper respiratory tract infection were documented during the study period. The oropharyngeal colonization during illness-free periods ranged from 12% to 18% for GNB and from 5% to 14% for S aureus. During an episode of upper respiratory tract infection, the oropharyngeal colonization of GNB increased to 60%; S aureus colonization increased to 43%. The colonization with both GNB and S aureus was transient and lasted for approximately two weeks. The increased colonization by S aureus and GNB during a viral respiratory tract infection may be a factor contributing to the increased risk of pneumonia in patients with this condition.

Adult↗
PubMed1980

Effects of molecular weight of dextran on the adherence of Streptococcus sanguis to damaged heart valves.

Dextran-producing streptococci such as Streptococcus sanguis are the organisms most frequently associated with infective endocarditis in humans. A series of experiments was designed to study how the molecular weight of dextrans affects the adherence of an endocarditis strain of S. sanguis to canine heart valves covered with platelets and fibrin. The data indicated that this adherence was dependent on dextrans of high molecular weight, such as dextran T-2000 or glucans isolated from S. sanguis or S. mutans. The adherence properties of the strain studied were not modified by prior exposure of the bacterial cells of valve leaflets to high-molecular-weight dextrans. Preexposure of bacterial cells or valve leaflets to low-molecular-weight dextrans decreased their adherence. Low-molecular-weight dextrans interfered with adherence of dextran-positive strains to damaged heart valves.

Animals↗
PubMed1979

Dengue hemorrhagic shock in the western hemisphere.

A 39-year-old man after visiting an endemic dengue area during a local outbreak developed a febrile illness complicated by skin petechiae, bleeding, shock, hemoconcentration, and death. The presumptive diagnosis of dengue was made based on hemagglutination inhibition and complement fixation titers in a single sample. The serologic evidence and ancillary laboratory findings are compatible with a secondary antibody response.

Adult↗
PubMed1978

Adherence of glucan-positive and glucan-negative streptococcal strains to normal and damaged heart valves.

The adherence of 18 strains of streptococci to sections of normal canine and human aortic, mitral, and tricuspid valves and to canine interatrial septum was compared in an in vitro system. Quantitative measurements of adherence ratios were performed by two independent methods. Adherence ratios for Streptococcus mutans, S. sanguis, S. bovis, and Group D streptococci were higher (0.0058-0.0101) than for the other streptococcal strains studied (0.0025-0.0041). With the exception of Group D streptococci, adherence ratios for each bacterial strain were similar with the aortic, mitral, and tricuspid valve sections. Adherence ratios with normal human and canine valve leaflets were similar, but adherence ratios with interatrial septum were lower than with normal valve sections. Adherence ratios for glucan-positive and glucan-negative strains of streptococci with normal and with damaged aortic valve leaflets were also compared. The adherence ratios of the glucan-positive streptococci (S. mutans, S. sanguis, and S. bovis) and one glucan-negative enterococcal strain (KG-3) were approximately five times higher with damaged aortic valves (0.039-0.051) than with normal aortic valves (0.009-0.010). For glucan-positive strains, adherence ratios with normal aortic leaflets were similar when bacteria were grown in media which contains or lacks sucrose. In striking contrast, growth of the glucan-positive strains in medium which lacks sucrose, with resultant deficiency of glucan production, decreased the adherence ratios with damaged aortic valve leaflets to those found with normal aortic leaflets. Treatment of glucan-positive strains with dextranase resulted in a decrease in their adherence ratios to levels seen with bacteria grown in medium lacking sucrose, but the higher adherence ratios could be restored in the presence of exogenous dextran.It is concluded that glucan production is one quantitatively important factor that contributes to the greater adherence of glucan-positive streptococci to damaged rather than to normal aortic heart valve leaflets. However, glucan production is not the only factor that determines preferential adherence of streptococci to damaged heart valves, because glucan-negative strains may also show some degree of increased adherence to damaged valves. Thus, bacterial glucan production is one of the factors that could contribute to the pathogenesis of bacterial endocarditis.

Animals↗
PubMed1975

Clindamycin. A Trojan horse?

Clindamycin is a widely used antibiotic with a spectrum that includes Gram-positive bacteria, with the exception of enterococci, and Gram-negative anaerobes. Toxicities include clindamycin colitis, a pseudomembranous colitis that can be fatal. The colitis usually is related to dosage and duration of therapy, but can occur after ingestion of only several capsules. Once diarrhea develops in a patient taking clindamycin, the drug should be stopped and diagnostic measures to define colitis initiated. If colitis is present, it should be managed aggressively, probably with corticosteroids and with intensive supportive measures.

Bacteria↗