Isolated toxoplasmosis of the thoracic spinal cord in a patient with acquired immunodeficiency syndrome. Case report.

Toxoplasmosis and lymphoma are the two most common causes of intraparenchymal cerebral mass lesions in patients with acquired immunodeficiency syndrome (AIDS). The clinical and radiographic features of the intracranial lesions have been well described. Because of the high frequency of toxoplasmosis in the AIDS population, common therapy for patients presenting with intracranial mass lesions consists of an empirical trial of anti-Toxoplasma chemotherapy, with biopsy reserved for cases demonstrating features considered to be more consistent with lymphoma, or for lesions that do not improve despite adequate anti-Toxoplasma treatment. A similar treatment algorithm does not exist for intramedullary lesions of the spinal cord. The authors describe a patient who presented with paraparesis resulting from an isolated thoracic intramedullary lesion. An open biopsy of the lesion revealed characteristic structures containing Toxoplasma tachyzoites. The clinical and radiographic presentation of the lesion is discussed, the available literature is reviewed, and a treatment strategy for spinal cord lesions in AIDS patients is proposed.

Antimicrobial activity and spectrum of rifaximin, a new topical rifamycin derivative.

Rifaximin, a rifamycin derivative, was evaluated in vitro to assess its spectrum and potency against a wide variety of bacteria, yeasts, viruses, and parasites. High concentrations of rifaximin were often used to reflect topically achieved levels since this compound is poorly absorbed by oral route. Like rifampin, rifaximin possessed best activity against Staphylococcus spp. (MIC50 < or = 0.015 microgram/ml), Streptococcus spp. (MIC50s, < or = 0.03-0.12 microgram/ml), Enterococcus spp. (MIC50s, 0.25-2 micrograms/ml), Bacillus cereus (MIC50, 0.06 microgram/ml), Moraxella catarrhalis (MIC50, < or = 0.03 microgram/ml), and Haemophilus influenzae (MIC50, 0.25 microgram/ml). Rifaximin demonstrated potential use as a topical agent for bacterial vaginosis by inhibiting Bacteroides bivius-disiens, Gardnerella vaginalis, Lactobacillus spp., and Mobiluncus spp. strains (all MICs < or = 1 microgram/ml). Strains of Haemophilus ducreyi and Neisseria gonorrhoeae (MIC50s, 0.25 microgram/ml) were also inhibited. However, some organisms associated with genital tract infections were rifaximin resistant, for example, Candida spp., herpes virus, mycoplasmas, Trichomonas vaginalis, and Ureaplasma urealyticum. Clinical trials appear warranted using rifaximin topical concentrations that will minimize mutations to rifamycin resistance.

Diagnosis of pulmonary arteriovenous malformation by ultrafast chest computed tomography in Rendu-Osler-Weber syndrome with cerebral ischemia--a case report.

Pulmonary arteriovenous malformations occur in 15-20% of patients with Rendu-Osler-Weber syndrome and can be the source of paradoxical emboli causing cerebral ischemia, septic emboli leading to brain abscesses, or polycythemia causing hyperviscosity and cerebral ischemia. The diagnosis of these malformations may be elusive, since classic clinical or radiologic findings may be absent in some patients. The authors report a patient with Rendu-Osler-Weber syndrome with cerebral ischemia who had normal findings from a pulmonary examination and chest roentgenogram. An ultrafast computed tomography scan of the chest demonstrated, however, a pulmonary arteriovenous malformation in the right upper lobe that was successfully resected. Ultrafast computed tomography of the chest is a relatively noninvasive method of screening for a pulmonary arteriovenous malformation in a patient with Rendu-Osler-Weber syndrome and otherwise unexplained neurologic symptoms.

Clarithromycin in vitro activity enhanced by its major metabolite, 14-hydroxyclarithromycin.

14-Hydroxyclarithromycin, an active metabolite of clarithromycin, was compared for antimicrobial activity alone and in combination with the parent compound. The 14-hydroxyclarithromycin potency was comparable to that of clarithromycin, but was more active against Haemophilus influenzae (MIC50, 1 microgram/ml). Combination MICs at pharmacokinetic ratios produced end points equal to the most active component of the combination. However, checkerboard MICs and kill-curve studies suggested enhanced interactive effects. Partial synergy and additive interactions were demonstrated in 96% of strains tested with synergy (partial) most often observed among the Enterococcus faecalis, H. influenzae, and staphylococci. To determine the best in vitro test methods for predicting the value of 14-hydroxyclarithromycin, combination disks or ratio MIC tests may not be practical. A modification of the proposed clarithromycin-susceptible breakpoint (less than or equal to 2 micrograms/ml) upward to less than or equal to 4 micrograms/ml (greater than or equal to 14 mm) was suggested to recognize the additional activity contributed by the 14-hydroxy metabolite. This modification should be applied, limited to susceptibility tests of H. influenzae and possibly the enterococci.

Biologic fate of cryopreserved human saphenous allografts: case report and hypothesis.

A femoroperoneal bypass using a cryopreserved human saphenous allograft was performed on a patient who presented with critical ischemia of the left lower extremity. The patient died of myocardial infarction 48 hours later and the graft was examined histologically. There was karryorhexis and focal neutrophilic infiltrate in the media underlying a layer of fibrin on the intimal surface. Immunoperoxidase studies showed nonspecific luminal deposition of immunoglobulins and fibrinogen. The histologic changes that occur in cryopreserved venous allografts are similar in experimental and human material and may be the result of anoxia of the vessel wall rather than immunologic mechanisms.

Achondrogenesis type II (Langer-Saldino) in association with jugular lymphatic obstruction sequence.

The prenatal diagnosis of achondrogenesis in association with cystic hygroma is described. Ultrasound findings of severe short-limbed dwarfism, decreased vertebral ossification, and normal ossification of the calvarium were all consistent with achondrogenesis type II. Although the unusual finding of associated cystic hygroma raised the suspicion of a concurrent chromosome abnormality, the karyotype of both fetal lymphocytes and fetal fibroblasts was normal. Autopsy confirmed dilated lymphatic channels in the basal endothelial layer of the skin, cystic hygroma, and coarctation of the aorta. Although previously unreported, we suggest that the features of this case of achondrogenesis indicate an association with lymphatic stasis and jugular lymphatic obstruction sequence in this syndrome.