Henry M. Rosevear

Lessons Learned from a Case of Calf Compartment Syndrome After Robot-Assisted Laparoscopic Prostatectomy

Robot-assisted laparoscopic prostatectomy is rapidly gaining favor as a minimally invasive method to surgically address prostate cancer. The sophisticated equipment and unique positioning requirements of this technology require exceptional preparation and attention to detail to minimize the chance of surgical complications. We present the case of a 57-year-old man who developed left calf compartment syndrome after (robot-assisted laparoscopic prostatectomy) requiring fasciotomies. We use this example to highlight specific areas of risk unique to the da Vinci Surgical System® using intraoperative photos to show danger areas as well as review basic positioning requirements common to all prolonged pelvic surgeries performed in Trendelenburg position.

Hypoxia-inducible factor-1alpha is a critical mediator of hypoxia induced apoptosis in cardiac H9c2 and kidney epithelial HK-2 cells

BackgroundHypoxia inducible factor-1 (HIF-1) is a transcription factor that functions to maintain cellular homeostasis in response to hypoxia. There is evidence that HIF-1 can also trigger apoptosis, possibly when cellular responses are inadequate to meet energy demands under hypoxic conditions.MethodsCardiac derived H9c2 and renal tubular epithelial HK-2 cells expressing either the wild type oxygen regulated subunit of HIF-1 (pcDNA3-Hif-1α) or a dominant negative version that lacked both DNA binding and transactivation domains (pcDNA3-DN-Hif-1α), were maintained in culture and exposed to hypoxia. An RNA interference approach was also employed to selectively knockdown expression of Hif-1α. Apoptosis was analyzed in both H9c2 and HK-2 cells by Hoechst and TUNEL staining, caspase 3 activity assays and activation of pro-apoptotic Bcl2 family member Bax.ResultsOverexpression of pcDNA3-DN-Hif-1α led to a significant reduction in hypoxia -induced apoptosis (17 ± 2%, P < 0.01) in H9c2 cells compared to both control-transfected and wild type Hif-1α transfected cells. Moreover, selective ablation of HIF-1α protein expression by RNA interference in H9c2 cells led to 55% reduction of caspase 3 activity and 46% reduction in the number of apoptotic cells as determined by Hoechst 33258 staining, after hypoxia. Finally, upregulation of the pro-apoptotic protein, Bax, was found in H9c2 cells overexpressing full-length pcDNA3-HA-HIF-1α exposed to hypoxia. In HK-2 cells overexpression of wild-type Hif-1α led to a two-fold increase in Hif-1α levels during hypoxia. This resulted in a 3.4-fold increase in apoptotic cells and a concomitant increase in caspase 3 activity during hypoxia when compared to vector transfected control cells. HIF-1α also induced upregulation of Bax in HK-2 cells. In addition, introduction of dominant negative Hif-1α constructs in both H9c2 and HK-2 -cells led to decreased active Bax expression.ConclusionThese data demonstrate that HIF-1α is an important component of the apoptotic signaling machinery in the two cell types.