The HER2 inhibitor lapatinib potentiates doxorubicin-induced cardiotoxicity through iNOS signaling

Rationale: Lapatinib (LAP) is a crucial alternative to trastuzumab upon the onset of drug resistance during treatment of metastatic human epidermal growth factor receptor 2-positive breast cancer. Like trastuzumab, LAP is commonly used alongside anthracyclines as a combination therapy, due to enhanced anti-cancer efficacy. However, this is notably associated with cardiotoxicity so it is imperative to understand the mechanisms driving this cardiotoxicity and develop cardioprotective strategies. To this end, here we utilize human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs), which exhibit several characteristics representative of in vivo cardiomyocytes that make them breakthrough models to study drug toxicity.

Methods: We investigated LAP- and doxorubicin (DOX)-induced toxicity in hPSC-CMs and evaluated the involvement of inducible nitric oxide (NO) synthase (iNOS). The significance of iNOS-mediated cardiotoxicity was furthermore evaluated in animal studies.

Results: LAP synergistically increased DOX toxicity in hPSC-CMs in a dose- and time-dependent manner. At concentrations that were otherwise non-apoptotic when administered separately, LAP significantly potentiated DOX-induced hPSC-CM apoptosis. This was accompanied by increased iNOS expression and pronounced production of NO. iNOS inhibition significantly reduced hPSC-CM sensitivity to LAP and DOX co-treatment (LAP-plus-DOX), leading to reduced apoptosis. Consistent with our observations in vitro, delivery of an iNOS inhibitor in mice treated with LAP-plus-DOX attenuated myocardial apoptosis and systolic dysfunction. Moreover, inhibition of iNOS did not compromise the anti-cancer potency of LAP-plus-DOX in a murine breast cancer xenograft model.

Conclusions: Our findings suggest that iNOS inhibition is a promising cardioprotective strategy to accompany HER2-inhibitor/anthracycline combination therapies. Furthermore, these results support the promise of hPSC-CMs as a platform for investigating cardiotoxicity and developing cardioprotectants as a whole.

Treatment efficiency and stability of skeletal Class III malocclusion with a surgery-first approach

OBJECTIVES

To compare treatment duration in skeletal Class III malocclusion patients managed with a 2-step treatment (surgery-first approach, SFA) and conventional 3-step treatment, and to compare stability of surgical outcomes between segmentation and non-segmentation in the 2-step treatment group.

SETTING AND SAMPLE POPULATION

The sample population consisted of 37 patients who completed orthognathic surgery (OGS) and orthodontic correction at the Charm Aesthetic Surgery Clinic (Taipei, Taiwan) between 2012 and 2015. Of these, 26 received 2-step treatment and 11 received 3-step treatment.

MATERIALS AND METHODS

To compare treatment efficiency and stability, three time points were analysed: T₀ , before treatment (before OGS in the 2-step group and before orthodontic treatment in the 3-step group); T₁ , after OGS but before orthodontic correction (cone beam computed tomography (CBCT) was obtained within 2 weeks of OGS); and T₂ , after orthodontic correction (CBCT was obtained on the day of bracket removal). The post-OGS (T₁ ) CBCT items were individually superimposed on the pre-treatment (T₀ ) CBCT items to determine the distance of B point migration.

RESULTS

A significant difference was found in treatment times between 2-step treatment and conventional 3-step treatment. In addition, no significant difference was found when comparing B-X (mm) and B-Y (mm) at T₂ -T₁ for the segmentation and non-segmentation groups.

CONCLUSIONS

Using SFA for skeletal Class III malocclusions saves approximately 6 months of treatment time over 3-step treatment; the stability of the segmentation group was comparable to that of the non-segmentation group, a result that is possibly associated with the fixation of 2 miniplates.

Treatment of distal clavicle fracture using Kirschner wires and tension-band wires

BACKGROUND

Nonunion frequently follows distal clavicle fracture. Traditional pinning methods using the through acromioclavicular articulation may result in osteoarthritic changes or ankylosis. This study introduces a direct pinning technique in which the acromioclavicular joint is spared.

METHODS

Twelve patients with displaced distal clavicle fractures received open reduction and fixation with Kirschner wires (K-wires) and tension-band wires, from May 1996 to March 1997. The indication for surgery was type IIa fracture or fracture with displacement. Unrestricted passive and active range of motion was performed as soon as possible after the operation. Stretching and exertional exercises were permitted after radiographs showed an osseous union and after the implants were removed.

RESULTS

Eleven patients achieved osseous union with painless full motion. Union time ranged from 3 to 6 months. One patient suffered from more comminuted fracture because of a fall 2 months after operation. This patient received a revision surgery with distal clavicle resection and coracoclavicle reconstruction. Symptomless ossification around the coracoclavicle ligament was noted on radiographs in one patient. The ossification did not progress after the 9-month follow-up.

CONCLUSION

Edwards reported a rate of 45% delayed union and 30% nonunion in type II fractures. Several techniques had been described in the relevant literature. In our practice, fixation with Kirschner wires and tension-band wires has been successful in the treatment for displaced distal clavicle fracture.

Reconstruction of posttraumatic long bone defect with free vascularized bone graft: good outcome in 48 patients with 6 years' follow-up

We analyzed our clinical results in 48 patients (40 men) treated during 1990-1993 with free vascularized bone-graft reconstruction for bone defects, the follow-up being an average 6 (5-8) years. The bone defects were located in the femur (10), tibia (32), humerus (2), and forearm (4). We performed 41 fibula transfers, 4 iliac transfers, and 3 rib transfers in these patients. 3 patients required early revision surgery due to venous thrombosis. The average time needed for radiographic bone union was 4.2 months. Bone transfers to the lower extremity showed significantly more hypertrophy than those in the upper extremity. The functional outcome was good in 43 patients.

Signal transduction pathways and apoptosis in bacteria infected chondrocytes

The mechanism underlying chronic destructive arthropathy after pyogenic arthritis is not clear. This study evaluated the role of apoptosis in Staphylococcus aureus infected human articular chondrocytes and investigated the signal transduction pathways activated by bacterial infection. Chondrocytes cultured in monolayer were challenged with bacteria for 6 h and were analyzed after incubation for 2, 18, and 24 h. Chondrocytes showed morphologic and biochemical evidences of apoptosis after infection and the following incubation period. Although treatment with extensive washing and vancomycin could ameliorate the amount of apoptosis from 31% to 15% at 2 h, from 48% to 23% at 18 h, and from 58% to 33% at 24 h, the infected samples with treatment still had higher amount of apoptosis than the un-infected controls (ANOVA P < 0.001). Accompanying with the increasing amount of apoptosis, the caspase activity was upregulated in bacteria infected samples and remained high in samples with treatment (ANOVA P < 0.05). Signal transduction pathways activated by bacterial infection were assessed by co-transfection technique. After infection, the c-Jun N-terminal kinase, extracellular signal-regulated kinase, and cyclic AMP-dependent protein kinase activities were elevated by 7.6-, 7.3-, and 3.2-fold, respectively, compared to the uninfected controls. The data support the hypothesis that human chondrocytes will undergo apoptosis after infection by a single organism. Apoptosis and activated intracellular kinase activities may be related to the pathogenesis of post-infectious destructive arthropathy.

Vascularized island pedicle iliac bone grafting for avascular necrosis of the femoral head

BACKGROUND

Nontraumatic avascular necrosis of the femoral head is a common disorder causing disability of the hip joint. The methods for optimally treating this disease in active young patients are still controversial. In this study we investigated the surgical outcome of vascularized pedicle iliac bone grafting for treating nontraumatic avascular necrosis of the femoral head.

METHODS

Between 1994 and 1999, we treated 100 cases of avascular necrosis of the femoral head with vascularized pedicle iliac bone grafting. Thirty-nine hips in 33 patients were followed-up longer than 24 months. These patients included 30 men and 3 women, with an average age of 40 years. Steinberg's classification and Ohzono's types were used to categorize the diseased hips. The clinical results were evaluated using Charnley's modification of Merle d'Aubigne and Postel's numeric classification.

RESULTS

Of the 33 patients, 82% were satisfied with their decision to have vascularized pedicle iliac bone grafting for avascular necrosis of the femoral head. No serious complications arose during this study. The average operation time for vascularized pedicle iliac bone grafting was 3.5 hours for one team. The rate of conversion to replacement arthroplasty was 10.3% (4 of 39 patients).

CONCLUSION

Vascularized pedicle iliac bone grafting is a useful alternative treatment option for patients with avascular necrosis of the femoral head.

Inferior dislocation of the glenohumeral joint combined with the compartment syndrome of the upper arm: case report

Compartment syndromes occurring in the forearm and leg are not infrequent. However, reports of compartment syndrome of the upper arm are conspicuously rare. Inferior dislocation of the shoulder combined with compartment syndrome has rarely been reported in the literature. We report our experience with a patient with inferior dislocation of the glenohumeral joint combined with compartment syndrome of the upper arm. A 29-year-old man had traumatic inferior dislocation of the glenohumeral joint combined with severe swelling of the shoulder and upper arm. After close reduction, the shoulder and upper arm were still tensely swollen. Compartment pressure of the upper arm was measured using a digital manometer (Quick Pressure Monitor 295-1, Stryker) and remained very high, thus, fasciotomy was performed. After debridement and skin graft, the arm healed without sequelae. When a patient has a fracture dislocation of the shoulder joint associated with a swollen arm, compartment syndrome of the upper arm should be included as a differential diagnosis. Detecting the compartment pressure can confirm the diagnosis of compartment syndrome objectively.

Chronic refractory tibia osteomyelitis treated with adjuvent hyperbaric oxygen: a preliminary report

BACKGROUND

Refractory osteomyelitis is a serious disease that fails to respond to aggressive medical and surgical treatment. A plethora of alternative therapies have evolved. Hyperbaric oxygen has been proven to enhance bone and soft tissue healing in many in vitro and in vivo studies. This article presents the preliminary results of adjunctive hyperbaric oxygen therapy in patients with refractory osteomyelitis.

MATERIALS AND METHODS

Fifteen patients who were diagnosed with refractory tibia osteomyelitis were treated prospectively with adjunctive hyperbaric oxygen therapy, aggressive surgical debridement, and parenteral antibiotic treatment. The effectiveness was evaluated with an average follow-up of 17.2 months.

RESULTS

The hyperbaric oxygen therapy averaged 26 daily sessions. Successful treatment was achieved in 13 patients (86%). The mean length of treatment was 45 days. The preliminary results are comparable with other series.

CONCLUSION

Hyperbaric oxygen is effective as an adjunct to aggressive medical and surgical management in refractory osteomyelitis. A precise clinical staging system for patient selection and treatment organization is imperative to successful outcome.

Purification and partial amino acid sequence of a novel protein of the reticulocalbin family

Binding proteins in neuronal membranes for a phospholipase A2 with presynaptic neurotoxicity have been purified. Three polypeptides of 87, 65, and 50 K Da were obtained from the synaptic membrane fraction of guinea pig brain utilizing an immobilized crotoxin (a phospholipase A2) column. For large scale purification, porcine brain was used instead, and two polypeptides of 50 and 18 K Da were found. The 65 and 18 K polypeptides may represent hitherto unidentified components of the crotoxin-binding proteins. Partial N-terminal amino acid sequence and a partial sequence for an internal peptide fragment have been determined for the 50 K polypeptide. Search of protein data bank reveals that this polypeptide or protein is a novel member of the reticulocalbin family of calcium-binding proteins.

Hyperbaric oxygen in the treatment of diabetic foot infection

BACKGROUND

Although hyperbaric oxygen therapy to treat diabetic foot lesions has been approved for insurance reimbursement in Taiwan, its clinical application has not yet been well accepted. This study evaluated multiple healing predictive factors in patients with diabetic foot infections to determine the usefulness of adjunctive hyperbaric oxygen in the treatment of such patients.

METHODS

From March 1995 to May 1996, we treated 31 diabetic patients presenting with infected foot lesions with a regimen of adequate metabolic control, frequent wound debridement and hyperbaric oxygen therapy. Age, gender, leukocyte count, total lymphocyte count, hemoglobin, erythrocyte sedimentation rate (ESR), c-reactive protein (CRP), glycosylated hemoglobin Alc (HbAlc), albumin, ankle-brachial index, types of bacterial cultures and number of debridements were compared between successful and failed treatments. Independent t-test and Fisher's exact test were used to identify the prognostic factors associated with outcome of treatment.

RESULTS

The mean age of the patients was 63.0 +/- 9.7 years (range 43 to 81). The mean number of hyperbaric oxygen therapies was 35.3 +/- 21.8 treatments (range 5 to 83). Of the 31 patients, 6 received below knee amputation, and 25 had their foot preserved or achieved a lower level of amputation. Elevated leukocyte count and low ankle-brachial index were significantly related to poor outcome.

CONCLUSIONS

In the treatment of diabetic foot infection, adjunctive hyperbaric oxygen therapy seems to be a useful tool to enhance wound healing provided that there are preserved circulation and controlled infection.

In vivo immunosuppressive effect and the decreasing expression of MHC class II antigens by purine nucleoside phosphorylase inhibitor 8-amino-9-benzylguanine in recipient tissues of canine renal allograft rejection

8-Amino-9-benzylguanine (8-ABG), a potent purine nucleoside phosphorylase inhibitor, was administered to dogs for 10 days following single renal transplantation. A significant prolongation of graft survival was observed in the groups treated with 100 and 150 mg kg/day of 8-ABG per os compared with the control group that was not treated with any immunosuppressant. Expression of major histocompatibility complex (MHC) class II antigens (Ag) was investigated in the normal kidney(s) and renal allografts of mongrel dogs after single renal transplantation. The 8-ABG was administered to the normal and renal allografted dogs and no detectable MHC class II Ag in the normal kidneys was found. During acute rejection, the MHC class II Ag was expressed on the renal tubular epithelium and glomerular vascular endothelium in graft kidneys. The intensity of the MHC class II Ag expression was correlated to the severity of rejection. This abnormal expression of MHC class II Ag on allograft kidney was suppressed by 8-ABG treatment. Our results suggest that MHC class II Ag expression can be induced on the renal allografts during acute rejection. This abnormal expression of MHC class II Ag may serve as a specific index for diagnosis of kidney allograft rejection. That 8-ABG can suppress abnormal expression of MHC class Ag on allografted kidney and prolong graft survival indicates that 8-ABG may provide an alternative approach for the development of a potential new immunosuppressant.

Simultaneous renal cell carcinoma and angiomyolipoma in a kidney--a case report and literature review

Renal cell carcinoma (RCC) is the most common tumor of the kidney. Angiomyolipoma is frequently present in the patient who has the stigma of tuberous sclerosis. We reported a case of a 39-year-old female, without the stigma of tuberous sclerosis, who was admitted on account of a firm, huge, fixed and palpable mass over the left flank region for one week. After radical nephrectomy, the pathological report was renal cell carcinoma, granular cell type, associated with angiomyolipoma. The literature concerning this unusual case is reviewed.