Genetic diversity of protease and reverse transcriptase sequences in non-subtype-B human immunodeficiency virus type 1 strains: evidence of many minor drug resistance mutations in treatment-naive patients

Most human immunodeficiency virus (HIV) drug susceptibility studies have involved subtype B strains. Little information on the impact of viral diversity on natural susceptibility to antiretroviral drugs has been reported. However, the prevalence of non-subtype-B (non-B) HIV type 1 (HIV-1) strains continues to increase in industrialized countries, and antiretroviral treatments have recently become available in certain developing countries where non-B subtypes predominate. We sequenced the protease and reverse transcriptase (RT) genes of 142 HIV-1 isolates from antiretroviral-naive patients: 4 belonged to group O and 138 belonged to group M (9 subtype A, 13 subtype B, 2 subtype C, 5 subtype D, 2 subtype F1, 9 subtype F2, 4 subtype G, 5 subtype J, 2 subtype K, 3 subtype CRF01-AE, 67 subtype CRF02-AG, and 17 unclassified isolates). No major mutations associated with resistance to nucleoside reverse transcriptase inhibitors (NRTIs) or protease inhibitors were detected. Major mutations linked to resistance to non-NRTI agents were detected in all group O isolates (A98G and Y181C) and in one subtype J virus (V108I). In contrast, many accessory mutations were found, especially in the protease gene. Only 5.6% of the 142 strains, all belonging to subtype B or D, had no mutations in the protease gene. Sixty percent had one mutation, 22.5% had two mutations, 9.8% had three mutations, and 2.1% (all group O strains) had four mutations. In order of decreasing frequency, the following mutations were identified in the protease gene: M36I (86.6%), L10I/V (26%), L63P (12.6%), K20M/R (11.2%), V77I (5.6%), A71V (2.8%), L33F (0.7%), and M46I (0.7%). R211K, an accessory mutation associated with NRTI resistance, was also observed in 43.6% of the samples. Phenotypic and clinical studies are now required to determine whether multidrug-resistant viruses emerge more rapidly during antiretroviral therapy when minor resistance-conferring mutations are present before treatment initiation.

Pseudofracture of an ICD lead

A proximal pseudofracture of a Medtronic 6936 defibrillating lead adjacent to the ICD pulse generator was found on X ray. At this site, the multifilar metallic connector joins the stimulating lead before coiling around it. Conventional X ray of the abdomen does not visualize this connection. During ICD replacement, lead impedance should be routinely measured.

Posttransplantation cytotoxic immunoglobulin G is associated with a high rate of acute allograft dysfunctions in heart transplant recipients

BACKGROUND

The significance of anti-human leukocyte antigen immunoglobin G (IgG) detected in the posttransplantation course of heart graft recipients remains unclear.

METHOD

Sera from 121 cardiac allograft recipients transplanted between January 1992 and December 1994 were screened for the presence of lymphocytotoxic antibodies in the first year after transplantation. Dithiothreitol was used to differentiate IgG from immunoglobulin M.

RESULTS

Nineteen patients (15%) had cytotoxic IgG develop, mainly during the first month after transplantation. The percentage of women was higher in this group (42% vs 15.7%; P <.05). Donor to recipient mismatches for sex, blood typing, cytomegalovirus serology, and human leukocyte antigen typing were comparable between IgG producers and nonproducers. The frequency of acute allograft dysfunction during the first year after transplantation was significantly higher among patients producing IgG (42% vs 5.9; P <.001). Most of these acute allograft dysfunctions were independent of cellular rejection lesions but were associated with a thickening of the posterior wall and the interventricular septum during the acute episode. Finally, all the patients but one recovered. Recurrences were not uncommon and, at 1 year after transplantation, the dose of cyclosporine used in patients producing IgG was significantly greater, as was the left ventricular thickness.

CONCLUSION

Posttransplantation cytotoxic IgG is not uncommon and appears to be associated with a high rate of acute allograft dysfunction. Development of these antibodies can be caused by a previous undetected immunization, as suggested by the higher percentage of women in the producer group. Correlation with histologic lesions of humoral rejection are discussed.

Mesenteric ischemia after coronary artery bypass grafting: should local continuous intra-arterial perfusion with papaverine be regarded as a treatment?

Mesenteric ischemia after cardiac surgery is rare but dramatic. We present a patient who had acute mesenteric ischemia following low cardiac output after coronary artery bypass grafting. Our patient was successfully treated with continuous intra-arterial perfusion with papaverine. We think that selective angiography must be performed as early as mesenteric ischemia is suspected, to get earlier diagnosis and treatment of an ischemic patient.

[Pulmonary lymphangioleiomyomatosis. Immunohistochemical and ultrastructural study of two cases]

The authors report two cases of pulmonary lymphangioleiomyomatosis which were diagnosed by surgical biopsies. Immunohistochemical study showed positive staining of the smooth muscle cells using antibodies directed against smooth muscle actin, specific muscle actin, HMB45 and vimentin. Ultrastructural study showed some smooth muscle differentiation features, with numerous myofilaments and some dense bodies near the plasma membrane. In one case, the patient was treated by a double-lung transplantation. LAM is a non-familial disease occurring exclusively in females. The etiology is unknown. This disease can be complicated by chronic respiratory failure. Extrapulmonary sites are not rare, particularly in the uterus. Anti-estrogen treatment can slow the course of the disease. Lung transplantation is actually the only effective treatment at the present time therapy. The differential diagnosis of this disease is discussed.

[Isolated prolonged cough caused by Horton's disease]

Pulmonary involvement is very rare in giant cell arteritis. The sign that is most often encountered seems to be dry cough which can remain, for a long time, the sole manifestation of this disease. We report a case of giant cell arteritis in a 66 year old woman that expressed for only symptom a dry cough during one year. A rapid regression of clinical symptoms and radiologic signs have been observed with steroid therapy. Presence of isolated cough along with biological marks of inflammation in a elderly patient should lead to temporal biopsy when no other evidence cause has been found.

[Enzyme determination in vitro of inhibitor activity of beta-lactamase from tazobactam. Comparison with high performance liquid chromatography]

We developed an enzymatic method using nitrocefin to assay tazobactam in vitro. Tazobactam was incubated with TEM-1 beta-lactamase. Then, residual beta-lactamase activity was assayed by adding nitrocefin. This activity corresponded indirectly to the initial concentration of tazobactam. Within-assay, between-assay and accuracy coefficients of variation were below 15%. The correlation coefficients between enzymatic method and high performance liquid chromatography (the reference method)was 0.98. The enzymatic method is rapid, easy to perform and should be applied to daily clinical practice.

Unusual erythema elevatum diutinum with fibrohistiocytic proliferation

A 78-year-old woman with a history of symmetrical erythematous plaques on the arms, and a monoclonal gammopathy, developed a strange striped reticulate papular dermatosis with central atrophy. Histological examination was compatible with a very late stage of erythema elevatum diutinum (EED), showing a fibrohistiocytic proliferation with areas of granulation tissue. This fibrosis may result from the chronic dermal injury of leucocytoclastic vasculitis and is sometimes the predominant histology of EED. Investigations for underlying haematological anomalies, such as paraproteinaemia and infection with human immunodeficiency virus, must be performed. Dapsone is ineffective once the fibrous nodules have appeared.

In-vitro evaluation of beta-lactamase inhibition by latamoxef and imipenem

The in-vitro 50% inhibitory concentrations (IC50s) of latamoxef and imipenem against a set of plasmid-mediated beta-lactamases including TEM-1, TEM-3, TEM-5 and TEM-10 were determined by an enzymatic method using nitrocefin as substrate. The IC50s of both antibiotics against extended-spectrum beta-lactamases were below 0.2 mg/L. The conventional spectrum beta-lactamase TEM-1 was not inhibited by either antibiotic at the highest concentration tested. Except for TEM-10 for which the IC50s of the two antibiotics were the same, imipenem showed significantly greater activity than latamoxef against TEM-3 and TEM-5. Clavulanic acid taken as a control demonstrated greater and wider inhibitory activity, but on the other hand it has no significant antibiotic activity.