Elbow Arthroscopy: Essential Principles of Positioning, Anatomy, and Portal Placement

Elbow arthroscopy is an important surgical technique for the treatment of various elbow pathologies. Range of indications for elbow arthroscopy include, but are not limited to, diagnostic evaluation, removal of loose bodies, synovectomy, contracture releases, lateral epicondylitis treatment, and adjunct use for fracture reduction. Surgeons' understanding of anatomy and portal placement is critical for successful treatment. This article reviews the relevant surgical anatomy, portal placement, patient positioning, surgical indications, and complications for this technique.

Evidence for the earliest structural use of wood at least 476,000 years ago

Wood artefacts rarely survive from the Early Stone Age since they require exceptional conditions for preservation; consequently, we have limited information about when and how hominins used this basic raw material1. We report here on the earliest evidence for structural use of wood in the archaeological record. Waterlogged deposits at the archaeological site of Kalambo Falls, Zambia, dated by luminescence to at least 476 ± 23 kyr ago (ka), preserved two interlocking logs joined transversely by an intentionally cut notch. This construction has no known parallels in the African or Eurasian Palaeolithic. The earliest known wood artefact is a fragment of polished plank from the Acheulean site of Gesher Benot Ya'aqov, Israel, more than 780 ka (refs. 2,3). Wooden tools for foraging and hunting appear 400 ka in Europe4-8, China9 and possibly Africa10. At Kalambo we also recovered four wood tools from 390 ka to 324 ka, including a wedge, digging stick, cut log and notched branch. The finds show an unexpected early diversity of forms and the capacity to shape tree trunks into large combined structures. These new data not only extend the age range of woodworking in Africa but expand our understanding of the technical cognition of early hominins11, forcing re-examination of the use of trees in the history of technology12,13.

Machine Learning Can Accurately Predict Overnight Stay, Readmission, and 30-Day Complications Following Anterior Cruciate Ligament Reconstruction

PURPOSE

This study aimed to develop machine learning (ML) models to predict hospital admission (overnight stay) as well as short-term complications and readmission rates following anterior cruciate ligament reconstruction (ACLR). Furthermore, we sought to compare the ML models with logistic regression models in predicting ACLR outcomes.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried for patients who underwent elective ACLR from 2012 to 2018. Artificial neural network ML and logistic regression models were developed to predict overnight stay, 30-day postoperative complications, and ACL-related readmission, and model performance was compared using the area under the receiver operating characteristic curve. Regression analyses were used to identify variables that were significantly associated with the predicted outcomes.

RESULTS

A total of 21,636 elective ACLR cases met inclusion criteria. Variables associated with hospital admission included White race, obesity, hypertension, and American Society of Anesthesiologists classification 3 and greater, anesthesia other than general, prolonged operative time, and inpatient setting. The incidence of hospital admission (overnight stay) was 10.2%, 30-day complications was 1.3%, and 30-day readmission for ACLR-related causes was 0.9%. Compared with logistic regression models, artificial neural network models reported superior area under the receiver operating characteristic curve values in predicting overnight stay (0.835 vs 0.589), 30-day complications (0.742 vs 0.590), reoperation (0.842 vs 0.601), ACLR-related readmission (0.872 vs 0.606), deep-vein thrombosis (0.804 vs 0.608), and surgical-site infection (0.818 vs 0.596).

CONCLUSIONS

The ML models developed in this study demonstrate an application of ML in which data from a national surgical patient registry was used to predict hospital admission and 30-day postoperative complications after elective ACLR. ML models developed performed well, outperforming regression models in predicting hospital admission and short-term complications following elective ACLR. ML models performed best when predicting ACLR-related readmissions and reoperations, followed by overnight stay.

LEVEL OF EVIDENCE

IV, retrospective comparative prognostic trial.

Respiratory Compromise After Anterior Cervical Spine Surgery: Incidence, Subsequent Complications, and Independent Predictors

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Respiratory compromise (RC) is a rare but catastrophic complication of anterior cervical spine surgery (ACSS) commonly due to compressive fluid collections or generalized soft tissue swelling in the cervical spine. Established risk factors include operative duration, size of surgical exposure, myelopathy, among others. The purpose of this current study is to identify the incidence and clinical course of patients who develop RC, and identify independent predictors of RC in patients undergoing ACSS for cervical spondylosis.

METHODS

A large, prospectively-collected registry was used to identify patients undergoing ACSS for spondylosis. Patients with posterior cervical procedures were excluded. Baseline patient characteristics were compared using bivariate analysis, and multivariate analysis was employed to compare postoperative complications and identify independent predictors of RC.

RESULTS

298 of 52,270 patients developed RC (incidence 0.57%). Patients who developed RC had high rates of 30-day mortality (11.7%) and morbidity (75.8%), with unplanned reoperation and pneumonia the most common. The most common reason for reoperations were hematoma evacuation and tracheostomy. Independent patient-specific factors predictive of RC included increasing patient age, male gender, comorbidities such as chronic cardiac and respiratory disease, preoperative myelopathy, prolonged operative duration, and 2-level ACCFs.

CONCLUSION

This is among the largest cohorts of patients to develop RC after ACSS identified to-date and validates a range of independent predictors, many previously only described in case reports. These results are useful for taking preventive measures, identifying high risk patients for preoperative risk stratification, and for surgical co-management discussions with the anesthesiology team.

Characterization of ASES score pain and functional improvement after anatomic total shoulder arthroplasty: a patient-centered perspective

BACKGROUND

Interpretation of anchor-based clinical differences in the context of pain and functional change remains undefined. The purpose of this study was to characterize American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) scores for patients after anatomic total shoulder arthroplasty with minimum 1 year of follow-up in terms of pain and change in each functional element on the ASES.

METHODS

We performed a retrospective study of a prospective institutional patient database of primary anatomic total shoulder arthroplasties from 2017-2020 with baseline and 1-year postoperative ASES scores. Three clinical outcome groups were established using an anchor-based global rating of change assessment: minimal clinically important difference (MCID), moderate clinical benefit (MCB), and substantial clinical benefit (SCB). Pain and functional outcomes in each group where then characterized and compared.

RESULTS

A total of 67 patients were analyzed in terms of demographics and clinical outcomes. Two-thirds (65%) of patients achieved the SCB, 24% achieved the MCB, and 10% achieved the MCID. Washing, reaching for a shelf, and throwing were the most common functional deficits experienced preoperatively and accounted for the largest improvement in function postoperatively. Patients in the MCID group had higher preoperative visual analog scale (VAS) pain scores (7.1 ± 3.0) than the MCB (5.8 ± 2.5) or SCB (5.8 ± 2.2) groups (P = .0612). The MCID group had the least amount of preoperative functional deficits when compared to the MCB and SCB groups (P = .041). Postoperative VAS pain scores improved by 5.1 in the SCB, 3.6 in the MCB, and 3.7 in the MCID groups. Functional change in each element of the ASES improved by 1.4/4 in the SCB, followed by 0.9/4 in the MCB group and 0.05/4 in the MCID group (P < .001).

CONCLUSION

The MCID group had higher preoperative pain scores and the least amount of preoperative functional deficits when compared to the MCB and SCB groups. The MCID was realized through pain improvement only, whereas the MCB and SCB consisted of meaningful improvements in pain and function.

Incidental Pulmonary Nodules Found on Shoulder Arthroplasty Preoperative CT Scans

With current emphasis on preoperative templating of anatomical and reverse shoulder arthroplasty (aTSA and rTSA, respectively), patients often receive thin slice (<1.0 mm) computerized tomography (CT) scans of the operative shoulder, which includes about two-thirds of the ipsilateral lung. The purpose of this study is to evaluate the prevalence and management of incidentally detected pulmonary nodules on preoperative CT scans for shoulder arthroplasty. In this single-center retrospective study, we queried records of aTSA and rTSA patients from 2015 to 2020 who received preoperative CT imaging of the shoulder. Compared to patients with negative CT findings, there were significantly more females (63.8% vs. 46.4%; P = .011), COPD (13.0% vs. 4.7%; P = .015), and asthma (18.8% vs. 6.9%; P = .003) among the patients with incidental nodules on CT. Binary logistic regression confirmed that female sex (odds ratio = 2.00; 95% CI = 1.04 to 3.88; P = .037), COPD history (OR = 3.02; 95% CI = 1.05 to 8.65; P = .040), and asthma history (OR = 3.17; 95% CI = 1.30 to 7.77; P = .011) were significantly associated with an incidental nodule finding. Incidental pulmonary nodules found on shoulder arthroplasty preoperative CT scans are often low risk in size with low risk of malignancy, and do not require further workup. This study may provide guidance to orthopedic surgeons on how to manage patients with incidental pulmonary nodules to increase chances of early cancer detection, avoid unnecessary referrals, reduce potentially harmful radiation exposure of serial CT scans, and improve cost efficiency.

Comparison of Glenoid Bone Grafting versus Augmented Glenoid Baseplates in Reverse Shoulder Arthroplasty: A Systematic Review

BACKGROUND

Management of bone loss and glenoid deformity can present a significant challenge to surgeons. The purpose of this review was to compare outcomes of reverse shoulder arthroplasty (RSA) using either bone graft or augmented baseplates for the management of glenoid bone loss and deformity.

METHODS

A comprehensive search of MEDLINE, Embase, Cochrane indices was performed for studies reporting clinical outcomes following primary RSA with bone grafting or use of augmented baseplates. Pooled and frequency-weighted means were calculated where applicable. Between-group comparison was also performed.

RESULTS

Overall, 19 studies and 652 patients were included in the study. There were no significant differences in age or gender between the bone grafting (70.3 years; 47.8% female) and augmented baseplate (72.9 years; 59.0% female) groups (p=0.166; p=0.659). Overall complication and revision rates were similar for reverse shoulder arthroplasty (RSA) using either bone graft (11.7% complication rate; 4.5% revision rate) or augmented baseplates (11.8% complication rate; 3.7% revision rate) for the management of glenoid bone loss and deformity (p=0.968; p=0.562). Furthermore, range of motion as well as patient-reported and functional outcome scores were similar between both techniques. However, infections (0.7% augmented baseplate; 1.9% bone grafting) and notching (4.7% augmented baseplate; 24.6% bone grafting) were found to be more common in the bone grafting group (p=0.012; p=0.018).

CONCLUSIONS

Glenoid bone grafting and augmented baseplates have similar overall clinical outcomes, complication rates, and revision rates. However, there were some significant differences between groups with respect to notching and infections which deserve consideration and further exploration.

Magnetic Field Amplification by a Nonlinear Electron Streaming Instability

Magnetic field amplification by relativistic streaming plasma instabilities is central to a wide variety of high-energy astrophysical environments as well as to laboratory scenarios associated with intense lasers and electron beams. We report on a new secondary nonlinear instability that arises for relativistic dilute electron beams after the saturation of the linear Weibel instability. This instability grows due to the transverse magnetic pressure associated with the beam current filaments, which cannot be quickly neutralized due to the inertia of background ions. We show that it can amplify the magnetic field strength and spatial scale by orders of magnitude, leading to large-scale plasma cavities with strong magnetic field and to very efficient conversion of the beam kinetic energy into magnetic energy. The instability growth rate, saturation level, and scale length are derived analytically and shown to be in good agreement with fully kinetic simulations.

Giant periosteal aggressive epithelioid osteoblastoma: 21-year-old male presents case in the midshaft of his femur

We report a rare case of giant periosteal osteoblastoma in the femur of a 21-year-old male. The patient presented with a painful, firm, non-tender mass in his left thigh. The pain was worse at night and was temporarily relieved with NSAIDS. He had no fevers, night sweats, or weight loss. The patient underwent preoperative radiological studies including plain radiographs, MRI, bone scan, and CT scan. An open biopsy was subsequently performed that was consistent with an aggressive, epithelioid osteoblastoma. Pathology demonstrated a neoplasm characterized by cohesive sheets of epithelioid osteoblasts, mixed with areas of conventional osteoblastoma displaying prominent osteoblastic rimming of woven bone trabeculae in a fibrovascular stroma. The patient subsequently underwent resection, cryosurgery, fixation, and bone grafting with cortical strut allografts. At final follow-up, 32 months postoperatively, there was no evidence of local recurrence. The patient had resumed all his normal activities. He could run without pain and had no restrictions with activities. The goal of this case report is to aid professionals in the diagnosis and treatment of highly uncommon aggressive osteoblastomas.

What Are the Functional Results and Complications With Long Stem Hemiarthroplasty in Patients With Metastases to the Proximal Femur?

BACKGROUND

Traditional treatments for pathological fractures of the proximal femur resulting from metastatic bone disease include fixation with intramedullary nailing supplemented with polymethylmethacrylate, osteosynthesis with a plate-screw construct and polymethylmethacrylate, or endoprosthetic reconstruction. Despite the frequent practice of these treatments, treatment outcomes have not been rigorously compared. In addition, very few studies examine specific approaches to endoprosthetic reconstruction such as long stem hemiarthroplasty.

QUESTIONS/PURPOSES

This study examines survival, functional outcomes, and complications associated with long stem hemiarthroplasty in a small group of patients treated for impending and actual pathologic fractures of the proximal femur resulting from metastatic bone disease.

METHODS

Between 2012 and 2015, 21 patients were treated with long stem cemented hemiarthroplasty in 22 limbs. During that time, indications for this approach included lesions from metastases, myeloma, or lymphoma involving the proximal femur that resulted in an impending or actual pathological fracture. An impending fracture was classified as a painful lesion with at least 50% cortical erosion. During the study period, six patients with proximal femoral metastases not deemed to meet these indications were treated with other surgical approaches such as intramedullary nailing supplemented with polymethylmethacrylate and osteosynthesis with a plate-screw construct and polymethylmethacrylate. Mortality was tracked through medical records and phone calls to the patients and their families. Followup for the entire group of patients (n = 22) ranged from 1 to 27 months with a mean duration of 11 months. For patients with at least 1 year of followup (n = 11), the mean duration was 18 months (range, 12-27 months) and for patients with less than 1 year of followup (n = 11), the mean duration was 3 months (range, 1-11 months). Functional outcomes were evaluated according to the Musculoskeletal Tumor Society (MSTS) scoring system for lower extremities, the Eastern Cooperative Oncology Group (ECOG) Scale of Performance Status, and the Karnofsky Performance Scale (KPS) Index. Scores and complications were determined by direct patient examination, retrospective chart review, review of a longitudinally maintained institutional database, and followup phone calls.

RESULTS

Ten patients died of disease within the followup period. Before surgery, the median total MSTS score for the entire group of patients (n = 22) was 4.5 (range, 0-23), the median ECOG score was 3.5 (range, 1-4), and the median KPS score was 40 (range, 30-70). Postoperatively, the median total MSTS score (measured at most recent followup) for the entire group of patients was 21 (range, 5-30), the median ECOG score was 2 (range, 0-3, 68% ≤ 2), and the median KPS score was 60 (range, 40-100). For the 11 patients with at least 1 year of followup, the median total MSTS score (measured at most recent followup) was 27 (range, 21-30), the median ECOG score was 1 (range, 0-2, 100% ≤ 2), and the median KPS score was 80 (range, 60-100). For the remaining 11 patients with less than 1 year of followup, the median total MSTS score (measured at most recent followup) was 11 (range, 5-25), the median ECOG score was 3 (range, 1-3, 36% ≤ 2), and the median KPS score was 40 (range, 40-80). Complications included one periprosthetic fracture resulting from a fall, three cases of radiation-induced edema, and two cases of sciatica that developed unrelated to the procedure.

CONCLUSIONS

Long stem cemented hemiarthroplasty results in fair levels of function in a complex population of patients whose prognosis is sometimes measured only in months and who otherwise might be disabled by their metastatic lesions. Comparative trials applying consistent indications and inclusion criteria should be performed between this approach and fixation with intramedullary nailing supplemented with polymethylmethacrylate as well as osteosynthesis with a plate-screw construct and polymethylmethacrylate.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Limb Sparing Resection for Tumors Involving the Distal Humerus and Reconstruction with a Modular Endoprosthesis

Tumors involving the distal humerus are extremely rare. Those tumors can be safely resected and then the extremity reconstructed. In this article, we present a series of patients treated with hinged semiconstrained modular distal humeral replacement for reconstruction following wide resection of tumors of the distal humerus. We retrospectively reviewed the charts of nine patients treated for tumors of the distal humerus between 2002 and 2013. The diagnoses consisted of three primaries, five metastatic, and one benign aggressive tumor. There were four male and five female patients ranging in age from 36 to 78 years old. Patients were followed for an average of 34 months (3 to 75 months). The functional status was rated using the Musculoskeletal Tumor Score System (MSTS). Five of the nine cases presented as a pathologic fracture. Six of the nine patients died of their diseases at a mean of 17 months after main surgery. Three patients were alive and disease-free at a mean follow-up of 69 months (63 to 75 months). Seven patients demonstrated significant improvement in their elbow pain after the endoprosthetic surgery. The MSTS score for the nine cases was 81% (63% to 97%). Tumors of the distal humerus can be safely resected through an anterior approach. Once the tumor is resected, the resultant defect is reconstructed with a modular semiconstrained prosthesis. This technique allows safe tumor resection with a low complication rate and good functional results.

Regulation of tamoxifen sensitivity by a PAK1-EBP1 signalling pathway in breast cancer

Background:

EBP1, an ErbB3-binding protein, sensitises breast cancer cells to tamoxifen in part by decreasing ErbB2 protein levels. The p21-regulated serine/threonine kinase PAK1, implicated in tamoxifen resistance, phosphorylates EBP1 in vitro and in vivo at T261. Phosphorylation of EBP1 at this site induces tamoxifen resistance. We thus postulated that inhibition of PAK1 activity, by restoring EBP1 function, could ameliorate the hormone refractory phenotype of ErbB2-overexpressing breast cancer cells.

Methods:

Effects of EBP1 on ErbB2 levels were measured by western blotting. Effects of EBP1 and IPA-3 on tamoxifen sensitivity were measured using a tetrazolium based cell viability assay.

Results:

Transient transfection studies indicated that an EBP1 T261E mutant, which mimics EPB1 phosphorylated by PAK1, increased ErbB2 protein levels. An EBP1 T261A mutant, unable to be phosphorylated by PAK1, ameliorated PAK1-induced tamoxifen resistance, suggesting that phosphorylation of EBP1 by PAK1 contributes to tamoxifen resistance. We then tested if pharmacological inhibition of PAK1 activity might render hormone resistant cells, which endogenously overexpress PAK1, tamoxifen sensitive. IPA-3, a specific small MW PAK1 inhibitor, sensitised cells to tamoxifen only when EBP1 was ectopically expressed. IPA had no effect on tamoxifen resistance in T47D cells in which EBP1 protein had been ablated by shRNA. The IPA-induced increase in tamoxifen sensitivity was accompanied by a decrease in ErbB2 levels only in EBP1-overexpressing cells.

Conclusion:

These studies suggest that phosphorylation of EBP1 may be one mechanism of PAK1-induced hormone resistance and that PAK1 inhibitors may be useful in cells in which EBP1 is overexpressed.

Chemical inhibition through conformational stabilization of Rho GTPase effectors

The Rho family of small GTP-binding proteins can activate a large number of downstream effectors and participate in a wide variety of biological processes, including cell motility, membrane trafficking, cell polarity, gene transcription, and mitosis. Specific small-molecule inhibitors of individual effector proteins downstream of Rho GTPases would be powerful tools to elucidate the contributions of particular effectors to these processes. In this chapter we describe the identification of a chemical inhibitor of a Rho effector and scaffolding protein neural-Wiskott-Aldrich syndrome protein (N-WASP), and the discovery of its novel mechanism of action, stabilization of N-WASP's native autoinhibited conformation. Inasmuch as several other Rho GTPase effectors are regulated by autoinhibition, we discuss how this regulatory mechanism could be exploited by small molecules to develop highly specific inhibitors of other Rho GTPase effectors. We illustrate this concept with the Rac/Cdc42 effector p21-activated kinase (Pak1) and the Rho effector mammalian diaphanous-related formin (mDia1).

Effect of tumour necrosis factor alpha antagonists on serum transaminases and viraemia in patients with rheumatoid arthritis and chronic hepatitis C infection

BACKGROUND

Tumour necrosis factor alpha (TNF alpha) antagonists are effective for the treatment of rheumatoid arthritis (RA), but concerns remain about the safety of these agents in the presence of chronic infections, including hepatitis C virus (HCV) infection.

OBJECTIVE

To examine the influence of treatment with TNF alpha antagonists on levels of HCV viraemia and serum transaminases in patients with RA and HCV.

METHODS

In a retrospective survey the course of 16 HCV infected patients with RA who had received the TNF alpha antagonists etanercept or infliximab was analysed. Eight additional patients with RA and HCV were also enrolled into a three month prospective trial of etanercept. Serum concentrations of albumin, alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, and HCV were followed.

RESULTS

Viraemia was measured in 22 patients receiving a TNF alpha antagonist at the start of treatment and after 1-34 months (median 9 months follow up). Twenty four patients had serial tests of liver related enzymes and albumin. None of the differences between liver related tests at baseline and at follow up achieved significance (p>0.05). Similarly, the mean HCV measurement at 1-3, 4-6, 7-12, and 13-34 months did not differ significantly from baseline (p>0.05).

CONCLUSION

In this study, liver related blood tests and HCV viral load measurements did not change substantially. These findings suggest that TNF alpha antagonists merit further study for the treatment of RA in HCV infected patients. Larger and longer term studies are still needed.

A chemical inhibitor of N-WASP reveals a new mechanism for targeting protein interactions

Cell morphology and motility are governed largely by complex signaling networks that ultimately engage the actin cytoskeleton. Understanding how individual circuits contribute to the process of forming cellular structures would be aided greatly by the availability of specific chemical inhibitors. We have used a novel chemical screen in Xenopus cell-free extracts to identify compounds that inhibit signaling pathways regulating actin polymerization. Here we report the results of a high-throughput screen for compounds that inhibit phosphatidylinositol 4,5-bisphosphate (PIP(2))-induced actin assembly and the identification of the first compound, a cyclic peptide, known to block actin assembly by inhibiting an upstream signaling component. We identify the target of this compound as N-WASP, a protein that has been investigated for its role as a node interconnecting various actin signaling networks. We show that this compound prevents activation of the Arp2/3 complex by N-WASP by allosterically stabilizing the autoinhibited conformation of N-WASP.

In vitro reconstitution of calreticulin-substrate interactions

Calreticulin is a soluble, endoplasmic reticulum-resident protein and a molecular chaperone for glycoproteins. We have reconstituted the binding of recombinant calreticulin to two glycoprotein substrates, vesicular stomatitis virus G protein and influenza hemagglutinin, in vitro. The binding was found to be direct and to require monoglucosylated, asparagine-linked oligosaccharides on the substrate glycoprotein but no other cellular factors. The binding could be modulated in vitro by incubation of substrate with purified preparations of the glycan modifying enzymes glucosidase II and the UDP-glucose:glycoprotein glucosyltransferase, thus recapitulating the regulation of calreticulin-binding by glycan modification that occurs in vivo. Using the purified ER enzymes and the recombinant calreticulin, an assay was established for reconstituting a complex, multicomponent chaperone binding cycle in vitro. We demonstrated, moreover, that the acidic C-terminal 62 residues of calreticulin are dispensable for substrate binding whereas further deletions inhibit substrate binding.

Time-intensity trading in the late auditory evoked potential

The present study investigated physiological correlates of the time-intensity trading relationship in late components (N1, P2) of the auditory evoked potential. Late-potential and behavioral thresholds were estimated in five normal-hearing, young adult participants for 1000- and 4000-Hz tone bursts having durations of 8, 16, 32, 64, and 128 ms. The results showed that late-potential thresholds decreased by an average of 24 dB for 1000-Hz conditions and 18 dB for 4000-Hz conditions. Behavioral thresholds also improved by about 22 dB and 18 dB for 1000-Hz and 4000-Hz conditions, respectively. The slope of improvement for both late-potential and behavioral thresholds was on the order of -4 to -6 dB per doubling of stimulus duration, depending on stimulus frequency. Stimulus duration also influenced latency and amplitude measures of the N1 and P2 components such that response latency decreased and amplitude increased as stimulus duration increased. The present results demonstrate a time-intensity trading relationship in components of the late potentials that is consistent with previous psychophysical and physiological data.

Acupuncture in the 1990s. A review for the primary care physician

The purpose of this article is to educate primary care providers regarding the theory and basic principles of acupuncture. Various indications for acupuncture are discussed. It is hoped that this article will allow the primary care practitioner to correctly identify patients in his or her practice who might benefit from acupuncture treatment.

Intra-articular ganglion cyst arising from the anterior cruciate ligament: a case report

Intra-articular ganglion cysts have been reported in the medical literature but are extremely rare. A MEDLINE search from 1966 to July 1995 revealed no reported cases in the Physical Medicine literature. This case report details the presentation, evaluation and treatment course of a patient with knee complaints who was subsequently diagnosed to have a ganglion cyst arising from the anterior cruciate ligament. The patient was a 38-year-old woman with a 6-month history of knee swelling and pain. She had difficulty walking. Non-steroidal anti-inflammatory agents had not alleviated her symptoms significantly. Physiatric evaluation revealed a supra-patellar effusion and a mass lateral to the patellar tendon. MRI evaluation revealed an intra-articular cyst. The patient underwent surgical removal of what was subsequently determined to be an intra-articular ganglion cyst arising from the anterior cruciate ligament. The patient has had progressive resolution of her knee symptoms post-operatively. Physiatrists need to be aware of this cause of mechanical knee symptoms.

Transient, lectin-like association of calreticulin with folding intermediates of cellular and viral glycoproteins

The soluble, calcium-binding protein calreticulin shares high sequence homology with calnexin, a transmembrane chaperone of glycoprotein folding. Our experiments demonstrated that calreticulin, like calnexin, associated transiently with numerous newly synthesized proteins in the endoplasmic reticulum. The population of proteins that bound to calreticulin was partially overlapping with those that bound to calnexin. Hemagglutinin (HA) of influenza virus was shown to associate with both calreticulin and calnexin. Using HA as a model substrate, it was found that both calreticulin- and calnexin-bound HA corresponded primarily to incompletely disulfide-bonded folding intermediates and conformationally trapped forms. Binding of all substrates was oligosaccharide-dependent and required the trimming of glucose residues from asparagine-linked core glycans by glucosidases I and II. In vitro, alpha-mannosidase digestion of calreticulin-bound HA indicated that calreticulin was specific for monoglucosylated glycans. Thus, calreticulin appeared to be a lectin with similar oligosaccharide specificity as its membrane-bound homologue, calnexin. Both are therefore likely to play an important role in glycoprotein maturation and quality control in the endoplasmic reticulum.

Antimicrobial properties of alkaloids from Xanthorhiza simplicissima

The organic extract of the whole plant Xanthorhiza simplicissima was found to exhibit good activity against the AIDS-related opportunistic pathogens Candida albicans, Cryptococcus neoformans, and Mycobacterium intracellularae. Bioassay-directed fractionation of the extract led to the isolation of the known alkaloid berberine as the major active component. A second alkaloid of the isohomoprotoberberine family, puntarenine, was isolated from this plant family for the first time. Puntarenine also showed marginal activity against the dermatophytic fungus Trichophyton mentagrophytes and the yeast Saccharomyces cerevisiae.

Isolation of a mouse cDNA encoding Rab23, a small novel GTPase expressed predominantly in the brain

The full-length cDNA encoding Rab23, a novel Ras-related small GTPase, was isolated using the sequence of a previously described [Chavrier et al., Gene 112 (1992) 261-264] short cDNA fragment and the rapid amplification of cDNA ends (RACE) PCR techniques. The deduced amino acid sequence was not very closely related to any previously described small GTPase, but was within the Rab subfamily. A Northern analysis revealed that the rab23 mRNA is predominantly expressed in the brain, which places the protein, together with Rab3a and Rab15, in the group of small GTPases characteristic of the nervous system.

Copyrine alkaloids: synthesis, spectroscopic characterization, and antimycotic/antimycobacterial activity of A- and B-ring-functionalized sampangines

Several A- and B-ring-substituted sampangines were synthesized and evaluated for antifungal and antimycobacterial activity against AIDS-related opportunistic infection pathogens. Electrophilic halogenation provided a channel for structural elaboration of the sampangine B-ring at position 4, while the synthesis of A-ring 3-substituted sampangines and benzo[4,5]sampangine (24) were achieved from the corresponding functionalized cleistopholines. Two-dimensional NMR spectroscopy was used to rigorously characterize the A- and B-ring substituent patterns. Structure-activity relationship studies revealed the activity of the sampangines was enhanced by the presence of a substituent at position 3 or by a 4,5-benzo group.

X-ray structure and crystal lattice interactions of the taxol side-chain methyl ester

A colorless, parallelepiped crystal of methyl (2R,3S)-N-benzoyl-3-phenylisoserinate belonging to the space group P2(1) with a = 5.414(4), b = 7.813(1), c = 17.802(7) A, beta = 90.87(4) degrees, Z = 2, V = 752.9 A3, Dcalc = 1.32 g cm-3, and mu calc = 1.02 cm-1 was selected and the structure solved using direct methods. Refinement led to a final R = 0.079 for 819 [Fo greater than or equal to 5 sigma (Fo)] reflections. Intermolecular hydrogen-bonding interactions are prevalent in the crystal lattice of this compound.

Fever, bacteriuria, and pyuria in spinal cord injured patients with indwelling urethral catheters

Little is known about the significance of pyuria in spinal cord injury patients with indwelling urethral catheters (IUCs). The hospital courses of 32 such patients admitted to a rehabilitation hospital from January 1986 to December 1987 were reviewed to determine the incidence of unexplained febrile episodes, ie, no obvious nonurinary source of infection. All patients had positive admission urine cultures (greater than 100,000 colony-forming units/mL). Patients were divided into two groups based on the level of pyuria in admission urinalyses. Group A (the low pyuria group) was composed of 22 patients with less than or equal to 50 white blood cells per high-power field (WBC/HPF). Group B (the high pyuria group) was composed of ten patients with less than 50 WBC/HPF. None were admitted to the rehabilitation program taking antibiotics; none were prophylactically treated for urinary tract infection. The difference in incidence of fever between febrile episodes. Group B had an incidence of 6/10 (60%) febrile episodes. The difference in incidence of fever between the groups was statistically significant (chi2 = 7.31, p less than .01). These results suggest that SCI patients with IUCs and gross pyuria may be at risk for increased morbidity secondary untreated urinary tract infection.

Platelet activating factor antagonist design. 3. X-ray crystal structure and intermolecular crystal lattice interactions of methyl trans-4-acetoxymethyl-4,5-dihydro-2,5-bis(3,4-methylenedioxyphenyl)- 3-furancarboxylate

C23H20O9, Mr = 440.41, monoclinic, P21/c, a = 11.433 (1), b = 7.808 (2), c = 23.313 (3) A, beta = 99.67 (1) degree, V = 2052 A3, Z = 4, Dx = 1.43 g cm-3, lambda(MoK alpha) = 0.71073 A, mu = 0.69 cm-1, F(000) = 920, T = 293 K, final R = 0.048 for 1645 observed [Fo greater than or equal to 5 sigma(Fo)] reflections. The observed structure reveals a trans relationship for the 4-acetoxymethyl and 5-aryl substituents. The 4,5-dihydrofuran ring system adopts an envelope conformation. There is no crystallographically imposed symmetry. Several intermolecular van der Waals interactions occur in the cell lattice of this compound.

Platelet activating factor antagonist design. 2. X-ray structure of dimethyl 2,3,4,5-tetrahydro-5 beta-(3,4-methylenedioxyphenyl)-2-oxo-3 beta-(3,4,5-trimethoxybenzoyl)-3 alpha,4 alpha-furandicarboxylate

C25H24O12, Mr = 516.46, triclinic, P-1, a = 8.780 (3), b = 11.298 (4), c = 13.271 (6) A, alpha = 71.77 (4), beta = 70.31 (3), gamma = 72.66 (3) degrees, V = 1189 A3, Z = 2, Dx = 1.44 g cm-3, lambda (Mo K alpha) = 0.71073 A, mu = 0.74 cm-1, F(000) = 540, T = 293 K, final R = 0.046 for 2495 observed [Fo greater than or equal to 5 sigma (Fo)] reflections. The observed structure reveals a trans disposition for the methoxycarbonyl and aryl substituents at positions 4 and 5 of the heterocycle and a cis-3,4-bis(methoxycarbonyl) relationship. There is no crystallographically imposed symmetry. Several intermolecular van der Waals interactions occur in the cell lattice of this compound.

Platelet activating factor antagonist design: structure of methyl trans-5-(3,4-dimethoxyphenyl)-2,3,4,5-tetrahydro-2-oxo-4- furancarboxylate

C14H16O6, Mr = 280.28, monoclinic, P2(1)/c, a = 6.070 (2), b = 9.526 (5), c = 22.418 (5) A, beta = 94.32 (2) degrees, V = 1293 A3, Z = 4, Dx = 1.44 g cm-3, lambda(Mo K alpha) = 0.71073 A, mu = 0.71 cm-1, F(000) = 592, T = 293 K, final R = 0.043 for 1400 observed [F0 greater than or equal to 5 sigma(F0)] reflections. The observed structure confirms a trans stereorelationship for the two substituents and an envelope conformation for the lactone ring. There is no crystallographically imposed symmetry. An analysis of the closest contacts in the cell lattice reveals two types of intermolecular interactions for this compound.