Venous stent patency is independent of total stented length in nonthrombotic iliac vein and post-thrombotic venous stenoses.

OBJECTIVE: Venous stenting has become the preferred treatment of symptomatic outflow obstruction due to nonthrombotic iliac vein lesions (NIVLs) and post-thrombotic venous stenoses (PTs). A paucity of data exists regarding the effect of stent length on patency rates after intervention. We evaluated the association between stent length and patency in patients treated for iliofemoral venous outflow obstruction. METHODS: The institutional review board approved the present study. A total of 161 patients had undergone venous stenting for NIVLs and thrombotic disease from January 2016 to April 2021. For thrombotic disease, patients with PTs and those with acute deep vein thrombosis (DVT) with underlying outflow obstruction were included. The patient characteristics evaluated included gender, age, body mass index, diagnosed thrombophilia, a history of venous thromboembolism, and CEAP (clinical, etiologic, anatomic, pathophysiologic) score. All the patients had undergone multiplanar venography and intravascular ultrasound during the index procedure. The intravascular ultrasound findings were used to determine the diameter and length of the implanted stents. The patients were placed into two groups, those with stented lengths ≤100 mm and those with stented lengths >100 mm. The primary end point was stent patency between the two groups using duplex ultrasound at 6 months. RESULTS: A total of 108 patients (58.3% female) had had 6-month duplex ultrasound scans available for review. Their mean age was 55.6 ± 17.2 years. The mean body mass index was 31.7 ± 6.9 kg/m2. Overall, the 6-month patency was 89.9%. Of the 108 patients, 56 (51.9%) had had a total stented length of ≤100 mm with a 6-month patency of 92.9%. The remaining 52 patients (48.1%) had had a total stented length >100 mm with a 6-month patency of 86.5%. The rate of patency did not differ significantly between the two groups (P = .222). Stent patency at 6 months for patients with NIVLs was 98% (40 of 41). Stent patency for patients with PTs was 84% (32 of 38). Patency for patients with acute DVT who had undergone stenting after thrombectomy was 86% (25 of 29). Overall, 10 patients with thrombotic disease, including PT and acute DVT, had developed stent thrombosis. The total stented length was not predictive of the loss of patency. CONCLUSIONS: These findings suggest that the length of stent coverage does not confer an increased likelihood of stent thrombosis for patients with iliofemoral venous obstruction. Interventionalists should treat the affected venous segments identified on intravascular ultrasound and effectively stent from normal to normal venous areas, regardless of the stent length required. These results suggest that the total stented length is not a risk factor for stent thrombosis for both NIVL and thrombotic iliofemoral venous lesions.

Novel therapy for recanalization of chronic iliocaval venous occlusion using radiofrequency.

OBJECTIVE: Chronic venous disease of the lower extremities is one of the most common diseases in the United States. The sequelae of this disease process are the source of a significant amount of morbidity, and its prevalence is expected to increase in the coming decades. Interventional therapy is warranted for relief of patients with CEAP C3-C6 disease. With advances in endovascular therapy, chronic iliocaval venous occlusion (CICVO) pathology can be corrected through minimally invasive approaches with limited morbidity and mortality. However, failure to recanalize the venous system leads to high failure rates. The purpose of this study was to assess the procedural success for recanalization of CICVO in the community setting using the novel technique of the Baylis radiofrequency (RF) wire in patients who had failed previous endovascular intervention. METHODS: A retrospective review of patients who underwent RF recanalization for CICVO at our institution from 2019 to 2020 was conducted. All patients had failed previous endovascular attempts at recanalization. The primary outcome was recanalization (defined as restoration of >70% of luminal patency as determined on multiplanar venography [MPV] and intravascular ultrasound [IVUS]) confirmed on both IVUS and MPV. Secondary outcomes included adjunctive interventions and complications (hematoma, pulmonary embolism, new onset renal insufficiency). RESULTS: A total of 10 patients, 50% male with a mean (standard deviation) age of 58.4 (10.4), were evaluated in the study. Successful recanalization was achieved in 60% of cases, with a resolution of >70% of luminal obstruction observed using MPV and IVUS. Adjunctive interventions were performed in 70% of cases. There were no clinically significant complications or blood transfusion requirements. CONCLUSIONS: New techniques and technologies continue to be developed for advanced endovascular management of CICVO, especially with the expanding market for Food and Drug Administration approved venous stents. The Baylis RF wire can assist in recanalization and treatment of patients who had failed previous endovascular therapy.

Antibody response to Raboral VR-G® oral rabies vaccine in captive and free-ranging black-backed jackals (Canis mesomelas).

Rabies is a zoonotic disease that remains endemic in large parts of southern Africa because of its persistence in wildlife and domestic dog vectors. The black-backed jackals (Canis mesomelas) is primarily the wildlife vector responsible for rabies outbreaks in northern parts of South Africa. Two trials were carried out to investigate antibody responses to the oral rabies vaccine Raboral V-RG® in black-backed jackals under captive and free-ranging conditions. In captive jackals 10/12 (83%; 95% confidence interval [CI]: 52% - 98%), seroconverted after single oral vaccination. Nine captive jackals had protective antibody titres ( 0.5 IU/mL) at 4 weeks (median: 2.1 IU/mL; inter quartile range [IQR]: 0.6-5.7) and 10 jackals had at 12 weeks (median: 3.5 IU/mL; IQR: 1.5-8.3) and three maintained antibody titres for up to 48 weeks (median: 3.4 IU/mL; IQR: 2.0-6.3). Four sites were baited with Raboral V-RG® vaccine for wild jackals, using fishmeal polymer and chicken heads. Baits were distributed by hand or from vehicle at three sites in north-eastern South Africa, with an average baiting density of 4.4 baits/km2 and at one site in central South Africa, at 0.12 baits/km2. This resulted in protective antibody titres in 3/11 jackals (27%; 95% Cl: 6-61) trapped between 3 and 12 months after baiting in north-eastern South Africa, compared with 4/7 jackals (57%; 95% Cl: 18-90) trapped after 3-18 months in central South Africa. This study shows the potential utility of oral rabies vaccination for the control of wildlife-associated rabies in north-eastern and central South Africa, but extensive studies with wider distribution of bait are needed to assess its potential impact on rabies control in wild jackals.

Comparison of aspiration thrombectomy to other endovascular therapies for proximal upper extremity deep venous thrombosis.

OBJECTIVE: Catheter-directed thrombolysis (CDT) provides an effective method for clearing deep venous thrombosis (DVT). Unfortunately, CDT is associated with hemorrhagic complications. This study evaluated the technical success of the various endovascular therapies including a new mechanical aspiration thrombectomy (AT) device for the treatment of acute upper extremity DVT (UEDVT). METHODS: This single-center retrospective review included patients with acute symptomatic proximal UEDVT secondary to venous thoracic outlet syndrome. Undergoing endovascular therapy from December 2013 to June 2019. Patients were treated with a variety of methods including CDT, ultrasound-assisted thrombolysis (USAT), rheolytic thrombectomy, and AT. We evaluated outcomes for patients undergoing AT compared with nonaspiration thrombectomy (NAT) techniques. The primary outcome was technical success, defined as resolution of more than 70% of the thrombus. The secondary end point was the ability to complete the therapy in a single session. RESULTS: There were 22 patients who had endovascular management of their symptomatic proximal UEDVT. All 22 patients (100%) were successfully treated with more than a 70% thrombus resolution. Ten patients underwent AT, of which 50% (5/10) had single session therapies. Twelve patients underwent NAT (three had CDT or USAT alone; three had USAT with rheolytic thrombectomy; and six had CDT followed by rheolytic thrombectomy), with single session therapy occurring in only 8.3% of the NAT group (1/12). The average total dose of thrombolytics was 12.6 ± 9.65 mg in the AT group compared with 19.0 ± 5.78 mg in the NAT group (mean difference, -6.4; 95% confidence interval, -1.1 to 13.9). All but one of the patients in the AT group went on to have successful first rib resections. All NAT patients had successful first rib resections. A venogram was not performed at the time of decompression. All patients except one underwent resection via the infraclavicular approach, with rib removal posterior to the brachial plexus, a median of 8.0 (interquartile range, 6.0-12.0) days after DVT therapy. CONCLUSIONS: In this study, a technical success rate of 100% was achieved for acute symptomatic proximal UEDVT therapies. AT technology allows for higher rates of treatment in a single session, thereby minimizing a patient's risks of bleeding complications. More research is needed to further define the role of this new technology in the treatment paradigm of UEDVT management.

Technical success and short-term results from mechanical thrombectomy for lower extremity iliofemoral deep vein thrombosis using a computer aided mechanical aspiration thrombectomy device.

BACKGROUND: The symptoms of deep vein thrombosis (DVT) include severe pain and swelling, and the complications can include post-thrombotic syndrome and recurrent venous thromboembolism. Aspiration thrombectomy (AT) treats arterial and venous disease by removing acute thrombus without reliance on thrombolytic agents but also has the potential to remove fresh blood. Intelligent aspiration is designed to minimize blood loss during AT by aspirating continuously in the thrombus but only intermittently when in a patent vascular segment with active flow. The Indigo System with Lightning 12 intelligent aspiration (Penumbra, Inc, Alameda, Calif) uses an automatic valve controlled by a proprietary computer algorithm to optimize thrombus removal and minimize blood loss. This computer-aided mechanical AT (CMAT) system was used for 16 consecutive patients. METHODS: The present retrospective review included 16 patients who had undergone CMAT for iliofemoral acute DVT from July 2020 to June 2021. The primary outcome was >70% thrombus removal as determined by multiplanar venography. The secondary outcomes included single-session therapy, blood loss during aspiration, the need for postprocedure blood transfusion, thrombolytic use, symptom resolution before discharge, and periprocedural complications. RESULTS: Sixteen patients (mean age, 58.6 years; range, 31-80 years; 75.0% women) had undergone CMAT with the Lightning 12 system. All the patients had presented with pain and swelling of 2 to 16 days in duration. No patient had presented with phlegmasia. Access was obtained via the popliteal (n = 11), posterior tibial (n = 3), small saphenous (n = 1), or soleal (n = 1) vein. Thrombus reduction of ≥70% was achieved for all 16 patients (100%). Single-session therapy was successful for 15 patients (93.8%). Eight patients (50%) had received stents. All patients had experienced symptom resolution before discharge. The median blood loss was 155.0 mL (interquartile range, 95.0-187.5), and no patient had required a postprocedure transfusion. One patient had undergone angioplasty after thrombectomy, and one patient (6.2%) had received adjunctive tissue plasminogen activator therapy. No patient had developed postoperative acute kidney failure. No periprocedural complications occurred. At 1 to 8 months of follow-up, 15 of the 16 patients (93.8%) had patency of the treated iliofemoral area, and 14 (87.5%) had no recurrent symptoms. CONCLUSIONS: These results suggest that CMAT using the Lightning 12 system is safe for clot removal for patients with acute iliofemoral DVT with a high rate of single-session technical success and symptom resolution. In the present case series, the Lightning 12 system was also associated with low blood loss, and no patient had required a blood transfusion.

Intravascular Lithotripsy for Treatment of Calcified Lesions During Carotid Artery Stenting.

PURPOSE: To report the use of intravascular lithotripsy (IVL) in the treatment of calcified carotid artery lesions. MATERIALS AND METHODS: The records of 21 high-surgical-risk patients (mean age 75.1±8.1 years; 17 men) who were treated at 8 centers for carotid artery stenosis ≥70% were retrospectively reviewed. Twelve patients had a history of cerebrovascular disease. All patients had heavily calcified carotid artery lesions: 19 de novo and 2 in-stent restenoses (ISR). The mean baseline stenosis was 82.3%±9.7%. IVL was utilized at the discretion of the operator, followed by balloon angioplasty. Embolic protection devices were used in all cases. RESULTS: In 19 patients, IVL was followed by stent implantation; the 2 ISR lesions were dilated only. The mean IVL balloon diameter was 4.64±1.13 mm, and the mean number of IVL pulses applied was 67.2±61.4 (range 10-180). All procedures were technically successful (<30% residual stenosis). No patients developed symptomatic bradycardia or hypotension due to IVL, and there were no adverse events associated with IVL delivery. All patients were discharged on dual antiplatelet therapy. Seventeen days after the procedure, 1 patient experienced an ischemic stroke that was deemed due to aortic arch manipulation during transfemoral access. Carotid duplex ultrasound examination identified significant restenosis (>70%) in 1 asymptomatic patient at 12 months after the index procedure. No patients required reintervention during a median follow-up of 6 months (range 1-12). CONCLUSION: This preliminary experience demonstrates that IVL can be a safe and effective approach for the management of severely calcified carotid lesions. Further research is warranted to determine the longer-term safety and efficacy of IVL for dilation of calcified carotid artery lesions as an adjunct to carotid artery stenting.

Duplex Ultrasound Surveillance after Transcarotid Artery Revascularization (TCAR) in Clinical Practice.

BACKGROUND: To propose a protocol for the routine clinical use of duplex ultrasound (DUS) assessment after transcarotid artery revascularization (TCAR) procedures, with its specific point of vascular access, based on DUS data from routine clinical practice. METHODS: DUS data were retrospectively collected at 2 centers from a total of 97 patients who underwent a TCAR procedure with at least 30-day and up to 12-month follow-up. Peak systolic velocity (PSV), end diastolic velocity (EDV), and the internal carotid artery (ICA)/common carotid artery (CCA) PSV ratio were collected at baseline (≤30 days after the procedure) and compared with subsequent measurements. RESULTS: Baseline data were established within 30 days after the procedure. There were no access site stenoses, pseudoaneurysms, or dissections detected in follow-up. Average hemodynamics measurements at 12 months after the procedure (36% of patients reached this time point to date) were PSV 167 ± 153 cm/sec, EDV 51 ± 55 cm/sec, and ICA/CCA PSV 2.3 ± 1.9. Five patients (5.2%) exhibited velocities indicative of ≥80% in-stent restenosis (ISR) at 12 months after the procedure. Two patients (2.1%) underwent repeat intervention for ISR based on high velocities and before significant clinical consequence. The other 3 patients (3.1%) were asymptomatic and are being managed medically and monitored for neurological symptoms. One intraprocedural stroke (1.0% of total treated) was observed. CONCLUSIONS: This protocol not only illustrates the utility of using the CCA for the arterial access sheath for carotid stenting, but also successfully identifies patients with clinically significant restenosis >80%-99%. A surveillance regimen of baseline at ≤30 days after the procedure, followed by assessment at 6 and 12 months, and yearly thereafter appears to be a safe and effective protocol, based on the data available to date. A PSV >340 cm/sec and ICA/CCA ratio >4.15 is consistent with an 80-99% restenosis after TCAR. Although a small number, this study serves as a starting point for those who perform TCAR to specifically look at the CCA access site to rule out these potential pitfalls which did occur in the early trials.

Transcarotid repair of carotid artery pseudoaneurysm after carotid artery endarterectomy with tandem distal internal carotid artery stenosis.

Pseudoaneurysm development after carotid endarterectomy is a rare occurrence. Even rarer is pseudoaneurysm formation associated with a distal carotid artery stenosis. We report the case of stent grafting of a carotid artery pseudoaneurysm and tandem high-grade distal stenosis through a transcarotid approach with active flow reversal. No reported cases of a transcarotid artery approach to address a carotid artery aneurysm with tandem stenosis were found in the literature. We show that it may be a safe alternative to a transfemoral artery approach or open surgery.

New fossil remains of Homo naledi from the Lesedi Chamber, South Africa.

The Rising Star cave system has produced abundant fossil hominin remains within the Dinaledi Chamber, representing a minimum of 15 individuals attributed to Homo naledi. Further exploration led to the discovery of hominin material, now comprising 131 hominin specimens, within a second chamber, the Lesedi Chamber. The Lesedi Chamber is far separated from the Dinaledi Chamber within the Rising Star cave system, and represents a second depositional context for hominin remains. In each of three collection areas within the Lesedi Chamber, diagnostic skeletal material allows a clear attribution to H. naledi. Both adult and immature material is present. The hominin remains represent at least three individuals based upon duplication of elements, but more individuals are likely present based upon the spatial context. The most significant specimen is the near-complete cranium of a large individual, designated LES1, with an endocranial volume of approximately 610 ml and associated postcranial remains. The Lesedi Chamber skeletal sample extends our knowledge of the morphology and variation of H. naledi, and evidence of H. naledi from both recovery localities shows a consistent pattern of differentiation from other hominin species.

Initial Experiences with Endovascular Management of Submassive Pulmonary Embolism: Is It Safe?

BACKGROUND: Interventional strategies for massive and submassive pulmonary embolism (smPE) have historically included either systematic intravenous thrombolytic alteplase or surgical embolectomy, both of which are associated with significant morbidity and mortality. However, with the advent of endovascular techniques, recent studies have suggested that an endovascular approach to the treatment of acute smPE may be both safe and effective with excellent outcomes. The purpose of this study was to evaluate the outcomes of patients who have undergone catheter-directed thrombolysis (CDT) for smPE at our institution in an effort to determine the safety of the procedure. METHODS: A retrospective review was conducted from December 2012 to June 2015 to identify patients whom underwent CDT in the treatment of a smPE at our institution. Primary measure was safety of the procedure. Outcome variables were classified as serious or minor adverse events. Serious events included death, stroke, myocardial infarction, and bleeding complications requiring surgical intervention or transfusion. Minor events included groin hematoma, development of arteriovenous fistula, and bleeding requiring interruption or cessation of CDT. In addition, a secondary measure included effectiveness of CDT based on preinterventional and postinterventional clinical examination and radiographic findings. RESULTS: A total of 27 patients undergoing CDT for smPE at our institution were evaluated. The standard procedure included access via bilateral femoral veins and placement of bilateral EKOS catheters for ultrasound-assisted thrombolysis (USAT), with Activase (alteplase) at 1 mg per hour in each catheter for a total of 12 hr. There were no serious adverse events and only 4 patients (14.8%) had minor events, of which only 1 patient required premature termination of therapy due to bleeding resulting in a 3.7% clinically relevant bleeding rate. In addition, a reduction in a right-to-left ventricular end-diastolic diameter ratio (RV/LV ratio) on follow-up imaging was observed in each of the 18 patients where preinterventional and postinterventional imaging was available. Likewise, via chart review, all patients reported significant cessation of shortness-of-breath and resolution of chest pain with associated decrease in supplemental oxygen requirement. CONCLUSIONS: Current evidence, the majority of which has been industry funded, suggests that CDT should be considered as the first-line therapy for smPE. Our experience, in this single-institution retrospective review, demonstrates that CDT with USAT in the treatment of smPE is safe, while providing immediate resolution of both RV strain and clinical symptoms such as shortness-of-breath and chest pain. We hope that these data will allow other institutions to consider CDT as a plausible option in the treatment of smPE.

Fossil Carder Bee's Nest from the Hominin Locality of Taung, South Africa.

The Buxton-Norlim Limeworks southwest of Taung, South Africa, is renowned for the discovery of the first Australopithecus africanus fossil, the 'Taung Child'. The hominin was recovered from a distinctive pink calcrete that contains an abundance of invertebrate ichnofauna belonging to the Coprinisphaera ichnofacies. Here we describe the first fossil bee's nest, attributed to the ichnogenus Celliforma, from the Plio-Pleistocene of Africa. Petrographic examination of a cell lining revealed the preservation of an intricate organic matrix lined with the calcitic casts of numerous plant trichomes-a nesting behaviour unique to the modern-day carder bees (Anthidiini). The presence of Celliforma considered alongside several other recorded ichnofossils can be indicative of a dry, savannah environment, in agreement with recent work on the palaeoenvironment of Plio-Pleistocene southern Africa. Moreover, the occurrence of ground-nesting bees provides further evidence that the pink calcrete deposits are of pedogenic origin, rather than speleogenic origin as has previously been assumed. This study demonstrates the potential value of insect trace fossils as palaeoenvironmental indicators.

Venous duplex and pathologic differences in thrombus characteristics between de novo deep vein thrombi and endovenous heat-induced thrombi.

OBJECTIVE: Superficial venous reflux disease has been treated with endovenous ablation techniques for more than 15 years. Thrombi discovered in the postoperative period are referred to as endovenous heat-induced thrombi (EHIT). In spite of the few studies of the ultrasound differentiation between EHIT and deep vein thrombi (DVT), there remains a paucity of literature regarding the evaluation of ultrasound examination and pathologic differentiation. METHODS: Six Yorkshire cross swine underwent femoral vein thrombosis by suture ligation or endovenous radiofrequency ablation. At 1 week after the procedure, each femoral vein was imaged by color Duplex ultrasound and sent for histologic interpretation for differentiation between EHIT and DVT. Five blinded vascular surgery faculty, two vascular surgery fellows, and three vascular surgery residents reviewed the ultrasound images. RESULTS: Thrombi associated with radiofrequency ablation demonstrated a greater degree of hypercellular response, fibroblastic reaction, and edema (3.42 vs 2.92; 3.75 vs 2.42; 2.83 vs 1.33). Specimens harvested from the iatrogenic-induced DVT swine demonstrated a more prolific response to trichrome staining (3.42 vs 2.67). Evidence of revascularization was found in all of the EHIT specimens but in 33% of DVT specimens. On the basis of histologic findings, the pathologist predicted correct modality 92% of the time. Subgroup analysis comparing paired specimens from each swine failed to demonstrate any marked pathologic differences. Recorded ultrasound images from EHIT and DVT samples were reviewed by fellows, residents, and vascular surgery staff to determine whether clot was stationary or free-floating (n = 111; 93%), evidence of retracted or adherent vein (n = 105; 88%), and absence of color flow (n = 102; 85%). The degree of occlusion (partial vs total) and degree of distention of a visualized vein were least likely to be agreed on by reviewers (n = 95; 79% each, respectively). In subgroup (DVT vs EHIT) analyses, the percentage agreement was greatest among vascular surgery fellows (89% and 92%) compared with residents (82% and 79%) and faculty (78% and 77%). CONCLUSIONS: It is possible to differentiate the thrombus origin on pathologic examination but not clinically on ultrasound. Wide variability exists for ultrasound diagnosis of EHIT and de novo DVT. Care must be taken in evaluating post-treatment duplex scans to not assign diagnosis of EHIT when DVT may well be present and extending into the deep venous system. The modulation of collagen production in the treatment of DVT may be helpful in preventing vascular dysfunction and reducing the post-thrombotic changes. Further studies on injury after radiofrequency ablation and laser ablation are needed.

Initial experience with HARMONIC FOCUS® inguinal exposure in endovascular aortic aneurysm repair.

BACKGROUND: An inguinal exposure provides adequate access to the femoral vessels, but with it comes risk of wound complications. Ultrasonic shears and blades have been shown to decrease complications in other anatomic dissections. There remains a paucity of literature on the usage of ultrasonic harmonic dissection techniques in the vascular surgery realm. This study depicts the initial experience using HARMONIC FOCUS(®) (HF) for inguinal exposure in both endovascular abdominal aortic aneurysm repair (EVAR) and thoracic endovascular abdominal aortic aneurysm repair (TEVAR) operations. METHODS: Patients who underwent an EVAR or a TEVAR operation with an open inguinal exposure during an 11-month period were included. RESULTS: Over the study period, 30 patients underwent an endovascular aortic aneurysm repair with open inguinal exposure; 25 patients had an EVAR and 5 patients underwent a TEVAR. Conventional electrocautery was used in 32 inguinal exposures and HF was used in 28. Six inguinal wounds developed postoperative complications in the study (10%). These occurred in 5 patients over a 4-month follow-up period. Conventional electrocautery dissection was used in 5 of the wounds (15.6%) and ultrasonic harmonic scalpel was used in 1 (3.6%). The complications consisted of 3 lymphocutaneous fistulas, 1 wound infection and 2 lymphoceles without fistula formation. CONCLUSIONS: We present the initial experience of HF dissection in inguinal exposure in a small population of patients who underwent EVAR and TEVAR. In this study, we demonstrate this technique may be associated with a lower incidence of postoperative wound complications when compared with conventional electrocautery inguinal exposure.

Brief communication: beyond the South African cave paradigm--Australopithecus africanus from Plio-Pleistocene paleosol deposits at Taung.

Following the discovery of the "Taung Child" (Australopithecus africanus) in 1924 in the Buxton-Norlim Limeworks near Taung, the fossil-bearing deposits associated with the Dart and Hrdlicka pinnacles have been interpreted as the mined remnants of cave sediments that formed within the Plio-Pleistocene Thabaseek Tufa: either as a younger cave-fill or as contemporaneous carapace caves. When combined with the Plio-Pleistocene dolomitic cave deposits from the "Cradle of Humankind," a rather restricted view emerges that South African early hominins derived from cave deposits, whereas those of east and central Africa are derived from fluvio-lacustrine and paleosol deposits. We undertook a sedimentological and paleomagnetic analysis of the pink-colored deposit (PCS) from which the "Taung Child" is purported to have derived and demonstrate that it is a calcrete, a carbonate-rich pedogenic sediment, which formed on the paleo-land surface. The deposit extends 100 s of meters laterally beyond the Dart and Hrdlicka Pinnacles where it is interbedded with the Thabaseek Tufa, indicating multiple episodes of calcrete development and tufa growth. The presence of in situ rhizoconcretions and insect trace fossils (Celliforma sp. and Coprinisphaera sp.) and the distinctive carbonate microfabric confirm that the pink deposit is a pedogenic calcrete, not a calcified cave sediment. Paleomagnetic and stratigraphic evidence indicates that a second, reversed polarity, fossil-bearing deposit (YRSS) is a younger fissure-fill formed within a solutional cavity of the normal polarity tufa and pink calcrete (PCS). These observations have implications for the dating, environment, and taphonomy of the site, and increase the likelihood of future fossil discoveries within the Buxton-Norlim Limeworks.

Carnivoran remains from the Malapa hominin site, South Africa.

Recent discoveries at the new hominin-bearing deposits of Malapa, South Africa, have yielded a rich faunal assemblage associated with the newly described hominin taxon Australopithecus sediba. Dating of this deposit using U-Pb and palaeomagnetic methods has provided an age of 1.977 Ma, being one of the most accurately dated, time constrained deposits in the Plio-Pleistocene of southern Africa. To date, 81 carnivoran specimens have been identified at this site including members of the families Canidae, Viverridae, Herpestidae, Hyaenidae and Felidae. Of note is the presence of the extinct taxon Dinofelis cf. D. barlowi that may represent the last appearance date for this species. Extant large carnivores are represented by specimens of leopard (Panthera pardus) and brown hyaena (Parahyaena brunnea). Smaller carnivores are also represented, and include the genera Atilax and Genetta, as well as Vulpes cf. V. chama. Malapa may also represent the first appearance date for Felis nigripes (Black-footed cat). The geochronological age of Malapa and the associated hominin taxa and carnivoran remains provide a window of research into mammalian evolution during a relatively unknown period in South Africa and elsewhere. In particular, the fauna represented at Malapa has the potential to elucidate aspects of the evolution of Dinofelis and may help resolve competing hypotheses about faunal exchange between East and Southern Africa during the late Pliocene or early Pleistocene.

Geological setting and age of Australopithecus sediba from southern Africa.

We describe the geological, geochronological, geomorphological, and faunal context of the Malapa site and the fossils of Australopithecus sediba. The hominins occur with a macrofauna assemblage that existed in Africa between 2.36 and 1.50 million years ago (Ma). The fossils are encased in water-laid, clastic sediments that were deposited along the lower parts of what is now a deeply eroded cave system, immediately above a flowstone layer with a U-Pb date of 2.026 +/- 0.021 Ma. The flowstone has a reversed paleomagnetic signature and the overlying hominin-bearing sediments are of normal polarity, indicating deposition during the 1.95- to 1.78-Ma Olduvai Subchron. The two hominin specimens were buried together in a single debris flow that lithified soon after deposition in a phreatic environment inaccessible to scavengers.

Deep Snow Immersion Deaths.

In brief Three snowboarders died in separate but nearly identical accidents after becoming buried head down in deep snow. After extricating each patient, the ski patrol immediately began cardiopulmonary resuscitation. On arrival at the emergency department, each patient was asystolic, apneic, cold, and stiff. Vigorous resuscitation and active rewarming were not successful in reviving the patients. These deaths indicate a need for education about the hazards of deep powder, tree wells, and snowboarding outside groomed areas. Equipment changes might also contribute to the sport's safety.