The decreased serum urea nitrogen-creatinine ratio

Sometimes, readily available laboratory data can provide valuable hidden information. Such is the case with the serum urea nitrogen-creatinine ratio. A normal ratio is 8:1 to 10:1. It is well known that an elevated ratio is seen in cases of prerenal or postrenal uremia. Less appreciated are the diagnostic possibilities suggested by a decreased serum urea nitrogen-creatinine ratio (ie, <8). Several clinical circumstances can lead to a decreased serum urea nitrogen-creatinine ratio.

Case reports: trimethoprim-sulfamethoxazole-induced meningitis in patients with HIV infection

Meningitis is a frequent complication of the human immunodeficiency infection. Possible causes include bacterial, fungal, mycobacterial, syphilitic, and vital pathogens (including the human immunodeficiency virus). Drugs must also be considered in the differential diagnosis. Two patients with probable trimethoprim-sulfamethoxazole-induced meningitis are described in the setting of human immunodeficiency virus infection.

Human herpesvirus-6 and the course of human immunodeficiency virus infection

The aim of this study is to investigate the relationship between human herpesvirus type 6 (HHV-6) and cytomegalovirus (CMV) infection and progression of AIDS disease. A group of 52 HIV-1-seropositive patients was examined for HHV-6 DNA expression in peripheral blood mononuclear cells and for CMV DNA in serum. We found that 21.1% (n = 52) and 12% (n = 25) of them tested positive for HHV-6 and CMV DNA, respectively. In contrast, only 3.3% (n = 29) and 0% (n = 29) of control healthy HIV-1-seronegative donors tested positive for HHV-6 and CMV, respectively. In light of these results, the possible role of HHV-6 as a cofactor in AIDS development has also been assessed by closely following, over 6 years, the course of an HIV-1-seropositive person who had a dramatic loss in the total number of CD4+ cells along with a spontaneous production of HIV-1 p24 antigen in vitro and who also showed progression to AIDS when coinfected with HHV-6. These observations have spurred our prospective analysis of the possible clinical significance of coinfection with HHV-6 and HIV.

[Anticardiolipin antibodies in parenteral drug addicts: relationship with HIV]

The IgG isotype of anticardiolipin antibodies (aCL) and its possible relationship with the immunodeficiency virus (HIV) were studied in 65 parenteral drug addicts (PDA). Thirty-seven patients were infected in the present study. Nineteen (51%) fulfilled diagnostic criteria of AIDS. Thirty-two of these 37 HIV-positive patients (86%) were IgG-aCL positive. Fourteen (50%) of the 28 HIV-negative patients were IgG-aCL positive. Our study reveals a lack of correlation between aCL and thrombocytopenia. None of the patients had thromboembolic complications. In AIDS patients no relationship was found between IgG-aCL levels and the presence of Pneumocystis carinii, other infections by opportunist microorganism, and clinical deterioration. Highly increased levels of IgG-aCL (> 80 GPL) were observed in three patients with AIDS and infectious endocarditis. In conclusion, given the non-specificity of aCL en PDA, it is our opinion that its measurement is of little help in daily clinical praxis.

Leishmania esophagitis in an AIDS patient: an unusual form of visceral leishmaniasis

Esophageal disease is a common cause of morbidity in patients infected by human immunodeficiency virus (HIV). Although gastrointestinal involvement of leishmaniasis has been previously reported, we believed that we describe the first case of leishmania esophagitis. Clinical data and the endoscopic and histologic hallmarks are described.

Successful treatment of antimony-resistant visceral leishmaniasis with liposomal amphotericin B in patients infected with human immunodeficiency virus

We describe two cases of visceral leishmaniasis in patients infected with human immunodeficiency virus (HIV); both cases were resistant to antimony compounds but were cured with liposomal amphotericin B, with no significant toxicity. A review of the previous reported cases of antimony-resistant visceral leishmaniasis in HIV-infected patients confirmed the effectiveness of treatment with liposomal amphotericin B, which directly targets infected macrophages and reaches high levels in plasma and tissue.

Selective decrease of CD26 expression in T cells from HIV-1-infected individuals

The decrease of CD4+ cells in AIDS patients is widely documented, although the selective loss within different subsets of CD4+ cells and the mechanisms involved in this phenomenon are controversial. In the present report we have analyzed the proliferative response to Ag and mitogen of peripheral blood T lymphocytes from HIV-infected individuals, the phenotype profile of CD26+ and CD26- subset of cells and their infectivity by the HIV. The expression of CD26 Ag, either in CD4+ or CD8+ cells, was clearly diminished in all the patients tested. On the other hand, the expression of CD29 seems not to be affected, nevertheless T cells from these patients were unable to generate a proliferative response against soluble Ag. In 11 out of 13 patients, polymerase chain reaction studies demonstrated that the CD26- subset of CD4+ cells was the main reservoir for HIV-1 in infected individuals and HIV-1 virus preferentially infected in vitro CD4+/CD26- subpopulation. This capacity for preferential infectivity, together with the selective loss of cells expressing CD26 Ag, helps to explain the progressive impairment in the immune system of these patients and sheds new light on our understanding of the AIDS pathophysiology.

Selective decrease of CD26 expression in T cells from HIV-1-infected individuals

The decrease of CD4+ cells in AIDS patients is widely documented, although the selective loss within different subsets of CD4+ cells and the mechanisms involved in this phenomenon are controversial. In the present report we have analyzed the proliferative response to Ag and mitogen of peripheral blood T lymphocytes from HIV-infected individuals, the phenotype profile of CD26+ and CD26- subset of cells and their infectivity by the HIV. The expression of CD26 Ag, either in CD4+ or CD8+ cells, was clearly diminished in all the patients tested. On the other hand, the expression of CD29 seems not to be affected, nevertheless T cells from these patients were unable to generate a proliferative response against soluble Ag. In 11 out of 13 patients, polymerase chain reaction studies demonstrated that the CD26- subset of CD4+ cells was the main reservoir for HIV-1 in infected individuals and HIV-1 virus preferentially infected in vitro CD4+/CD26- subpopulation. This capacity for preferential infectivity, together with the selective loss of cells expressing CD26 Ag, helps to explain the progressive impairment in the immune system of these patients and sheds new light on our understanding of the AIDS pathophysiology.

Cardiovascular effects of a nifedipine infusion during fentanyl-nitrous oxide anesthesia in dogs

The hemodynamic effects of a nifedipine infusion were investigated in eight dogs given fentanyl/pancuronium/nitrous oxide/oxygen anesthesia. Nifedipine (20 micrograms/kg) was given intravenously over two minutes immediately prior to each 30-minute infusion at 2 micrograms/kg/min, 4 micrograms/kg/min, and 6 micrograms/kg/min. The range of plasma nifedipine levels obtained was 52.1 to 113.7 ng/mL. The predominant hemodynamic effects were significant reductions in systemic vascular resistance (SVR) and mean aortic pressure (MAP), accompanied by a rise in cardiac index and heart rate (HR). Administration of calcium chloride (20 mg/kg) after the nifedipine infusion had no effect on SVR or MAP, but HR was significantly reduced. Serum epinephrine and norepinephrine levels increased after the infusion of nifedipine and suggested that fentanyl did not completely overcome the sympathetic response to the profound vasodilatation. The resulting tachycardia in combination with diastolic hypotension from nifedipine could have a detrimental effect on the myocardial oxygen balance.

Reversal of the adverse cardiovascular effects of intravenous diltiazem in anesthetized dogs

Intravenous diltiazem can be used to treat myocardial ischemia, hypertension, and supraventricular dysrhythmias, but significant adverse effects including atrioventricular block and hypotension have been reported. At the present time, there is controversy as to which drug is most effective in reversing these sequelae. This study was designed to assess the effectiveness of calcium chloride v epinephrine in reversing these side effects. The hemodynamic and electrophysiologic effects of diltiazem infusion were investigated in eight dogs anesthetized with fentanyl and nitrous oxide/oxygen. This study confirmed that diltiazem infusions in high concentrations produced predominantly atrioventricular conduction depression followed by profound hypotension. Epinephrine infusion proved to be most effective in attenuating and eliminating each of these deleterious side effects. In contrast, calcium chloride did not significantly increase heart rate or blood pressure or reverse atrioventricular block. In two instances calcium chloride produced further depression of atrioventricular conduction, leading to severe bradycardia and sinus arrest. Although calcium chloride increased left ventricular contractile force (LV dP/ dt) and cardiac index (CI), mean arterial pressure was not affected and SVR was further decreased. This study indicates that calcium chloride should not be given to reverse the side effects of diltiazem in the presence of atrioventricular conduction block or profound hypotension. Calcium chloride is indicated only when isolated myocardial depression is present and after the calcium channels have been reopened by epinephrine.