Hip pain · difficulty walking · tenderness along the anteromedial thigh and groin · Dx?

A 14-year-old Caucasian boy presented to our clinic with a complaint of left anterior hip pain. The patient had been running during a flag football match when he suddenly developed a sharp, stabbing pain in his left hip. He said he felt a "pop" in his left groin while his left foot was planted and he was cutting to the right. The patient said this was followed by worsening pain with ambulation and hip flexion. The patient had considerable difficulty walking into the exam room. On physical examination, he had significant tenderness to palpation along the anteromedial thigh and groin. The patient's strength was 1/5 with left hip flexion. There was apparent muscle firing, but no significant leg movement. He had full passive range of motion and there was no soft-tissue swelling, erythema, or other integumentary changes.

Levamisole-adulterated cocaine: a case series.

The percentage of cocaine adulterated with levamisole is steadily increasing in the United States. In susceptible persons, this combination of drugs leads to a clinical syndrome that can include leukopenia and cutaneous manifestations. Many patients also demonstrate positive autoimmune markers. Biopsies of skin lesions often reveal a thrombotic pattern, leukocytoclastic vasculitis, or both. We report 2 cases of this clinical phenomenon, one of which was severe enough to require skin grafting. It is important for clinicians be aware of this emerging public health threat.

Pyrimidine deoxynucleoside and nucleoside reverse transcriptase inhibitor metabolism in the perfused heart and isolated mitochondria.

BACKGROUND: The metabolism of pyrimidine deoxynucleosides and nucleoside reverse transcriptase inhibitors has been studied in growing cells. However, many of these drugs are associated with mitochondrial toxicities observed in non-replicating tissues, such as in the heart, where their metabolism has not been investigated. METHODS: The aims of this study were twofold. The first was to investigate the metabolism of the thymidine analogues 3'-azido-3'deoxythymidine (AZT) and 2',3'-didehydrodideoxy-thymidine (d4T), and the deoxycytidine (dCyd) analogues 2'-deoxy-3'-thiacytidine (3TC) and 2',3'-dideoxycytidine (ddC) with regard to phosphorylation and breakdown. The second was to investigate their potential effects, singly or in combination with AZT, on metabolism of the naturally occurring deoxynucleosides in the perfused rat heart and in isolated heart mitochondria. RESULTS: The analogue d4T was not metabolized in perfused heart or in isolated mitochondria, and had no effect on either thymidine or dCyd metabolism. The dCyd analogues were both phosphorylated in perfused heart to the triphosphate, but only at the limit of detection and they were not phosphorylated in isolated mitochondria. Neither ddC nor 3TC had any effect on thymidine or dCyd metabolism in either perfused heart or in isolated mitochondria. AZT has been previously shown to inhibit thymidine phosphorylation. When d4T, 3TC or ddC were given with AZT, only ddC caused a significant further decrease in thymidine phosphorylation. CONCLUSIONS: These results indicate that with the exception of the competition between AZT and thymidine, there was little competition for phosphorylation among and between these other nucleoside reverse transcriptase inhibitors and the naturally occurring deoxynucleosides in cardiac tissue and isolated heart mitochondria.

Origin of pyrimidine deoxyribonucleotide pools in perfused rat heart: implications for 3'-azido-3'-deoxythymidine-dependent cardiotoxicity.

In adult non-replicating tissues such as heart, demand for dNTPs (deoxynucleoside triphosphates) is low but essential for mitochondrial DNA replication and nuclear DNA repair. dNTPs may be synthesized from salvage of deoxyribonucleosides or by reduction of ribonucleotides. We have hypothesized that the cardiac mitochondrial toxicity of the nucleoside analogue AZT (3'-azido-3'-deoxythymidine; known as zidovudine) is caused by inhibition of thymidine kinase 2 of the salvage pathway and subsequent TTP pool depletion. The extent to which this hypothesis has merit depends on how much the heart relies on thymidine phosphorylation for maintenance of the TTP pool. In the present study, we used isotopic tracing to demonstrate that both TTP and dCTP are solely synthesized by phosphorylation of thymidine and deoxycytidine respectively, with no evidence for synthesis from other precursors. We have also shown that UTP and CTP are synthesized by phosphorylation of uridine and cytidine respectively, with no detectable role for the de novo pyrimidine synthesis pathway. Lastly, we have demonstrated that AZT decreased the TTP pool by 50% in 30 min of perfusion, while having no effect on other dNTPs. In summary, the present study demonstrated that adult rat heart has a limited mechanism for dCTP and TTP synthesis and thus these pools may be more sensitive than replicating cells to drugs such as AZT that affect the salvage pathway.