BACKGROUND Synovial chondromatosis is a disease originating from the synovium and characterized by the presence of metaplastic cartilaginous nodules in synovial cavities.The exact prevalence of synovial chondromatosis...BACKGROUND Synovial chondromatosis is a disease originating from the synovium and characterized by the presence of metaplastic cartilaginous nodules in synovial cavities.The exact prevalence of synovial chondromatosis remains unknown,and the involvement of the shoulder joint is very rare.Synovial chondromatosis accompanied by subluxation of the humeral head without a history of trauma is rarely encountered,and to our knowledge,no published reports describe this condition.CASE SUMMARY We present two cases of synovial chondromatosis in the shoulder joint,accompanied by subluxation of the humeral head,in two arthroscopically managed adult patients.We performed arthroscopic labrum fixation and removal of the loose body from the shoulder joint.To identify primary and secondary categories,pathological analysis was arranged.Clinical and radiographic evaluations at the 1-mo follow-up were satisfactory.CONCLUSION The biomechanical function of the shoulder joint requires attention,especially following the detection of loose bodies,as observed with synovial chondroma occurring in rare sites.Arthroscopic management is successful in patients with synovial chondromatosis combined with shoulder subluxation.展开更多
Introduction: Acute large bursae (ALB) are a frequent reason for emergency consultations. The aim of this study was to investigate the prevalence, clinical course, treatment and evolution of ALB at Abeche University H...Introduction: Acute large bursae (ALB) are a frequent reason for emergency consultations. The aim of this study was to investigate the prevalence, clinical course, treatment and evolution of ALB at Abeche University Hospital. Patients and Method: This was a 45-month cross-sectional study from January 2020 to September 2023. Male patients of any age who had been admitted to and treated for acute large bursae at the Abeche University Hospital were included. Sociodemographic, clinical and therapeutic variables were studied. Results: Acute large bursae accounted for 7.92% of emergency admissions. The average age was 39.40 years. 60.27% of patients came from rural areas. The average consultation time was 4 days, ranging from a few hours to 18 days. The main reason for consultation was pain. Strangulated inguino-scrotal hernia was the most common, followed by acute orchi-epididymitis, accounting for 41.8% and 26% of cases respectively. Traditional treatment prior to consultation was attempted in 13.7% of cases. All patients were treated as emergencies, 41 of whom had received medical treatment. Of the patients treated surgically, orchidopexy was performed in all. Parietal suppuration and anaemia occurred in 6.2% and 4.8% of cases respectively. Conclusion: A accounts for a significant proportion of our emergency care activity. However, patients are seen with a delay, which jeopardises the functional prognosis of the testicle and intestine.展开更多
Introduction: Synovial cyst of the tibial tunnel in connection with anterior cruciate ligament (ACL) reconstruction is a rare but particularly troublesome complication. Medical treatment is often doomed to failure, an...Introduction: Synovial cyst of the tibial tunnel in connection with anterior cruciate ligament (ACL) reconstruction is a rare but particularly troublesome complication. Medical treatment is often doomed to failure, and surgical treatment usually consists of excising the cyst and filling the tunnel with bone. The aim of this study was to evaluate the results of filling the tunnel with acrylic cement. Hypothesis: Filling the tibial bone tunnel with acrylic cement should eliminate communication between the joint cavity and the pre-tibial surface and prevent cyst recurrence. Patients and Methods: This retrospective series is composed of 13 patients, 9 men and 4 women, mean age 48.5 years (31 to 64) operated on between 2011 and 2019 for an intra- and extraosseous synovial cyst consecutive to the tibial tunnel of an ACL graft. Between 1983 and 2016, 12 of the patients had had a bone graft without bone block fixation (DI-DT or Mac Intosh) and one patient, a bone-bone transplant (KJ). The cyst was of variable size, located on the anteromedial aspect of the proximal end of the tibia, and often painful, warranting consultation. At the time of the initial operation, 9 patients had undergone meniscectomies (6 medial, 2 lateral, 1 double). In 7 knees, there were 7 cartilage lesions in the femorotibial and/or patellofemoral compartments (one stage 1 lesion, 2 stage 2 lesions, 4 stage 3 lesions, and no stage 4 lesions). Only 2 knees had neither cartilage nor meniscus lesions. After curettage of the bone tunnel /− removal of the non-resorbed or PEEK interference screw, the tunnel was filled with acrylic cement /− reinforced with a ligament staple to prevent expulsion. All patients underwent regular follow-up consultations until recovery. Results: At a maximum follow-up of 8 years, only 1 cyst recurred, representing a 7.69% failure rate. It was reoperated with another technique, which involved filling the tibial bone tunnel with bone graft taken from a half-bank head. After recovery, the cyst healed definitively. All patients were able to return to their previous activity within 15 days of surgery. Conclusion: Filling the tibial tunnel with acrylic cement reinforced /− with a ligament staple is a reliable and rapid solution for the treatment of intra- and extra-articular synovial cysts in relation to the tibial tunnel of ACL grafts.展开更多
The management of symptomatic lumbar synovial cysts is still a challenge and a matter of debate with no existing strong consensus. There are different treatment techniques and strategies, the most debated matter is to...The management of symptomatic lumbar synovial cysts is still a challenge and a matter of debate with no existing strong consensus. There are different treatment techniques and strategies, the most debated matter is to fuse or not to fuse, efficiency of less invasive techniques. One of our purposes was to provide an updated review of a literature about treatment of juxta facet synovial cysts and as standard surgical strategies are inconsistent, we present a small series of patients treated using different approaches, most of them were treated with MISS techniques, endoscopy, providing good results.展开更多
Primary gastric synovial sarcoma is rare and challenging to diagnose. We present a case of a gastric ulcer that was diagnosed as primary gastric synovial sarcoma only after surveillance endoscopy with repeat biopsies....Primary gastric synovial sarcoma is rare and challenging to diagnose. We present a case of a gastric ulcer that was diagnosed as primary gastric synovial sarcoma only after surveillance endoscopy with repeat biopsies. The diagnosis was established with the identification of the pathognomonic chromosomal translocation t(X;18)(p11;q11). The patient was treated with wedge resection and has remained disease-free on surveillance imaging and endoscopy. This case demonstrates the difficulty in diagnosing primary gastric synovial sarcoma and the benefits of early disease detection.展开更多
To determine passive haemagglutination (PHA) antibody titer that would protect chicks against Nigerian isolates of the Infectious Bursa Disease Virus (IBDV), five groups of chicks aged 30 days which had different anti...To determine passive haemagglutination (PHA) antibody titer that would protect chicks against Nigerian isolates of the Infectious Bursa Disease Virus (IBDV), five groups of chicks aged 30 days which had different antibody titers were challenged with a Nigerian isolate of virulent IBDV. Mortality rates of the different groups were plotted against their respective mean PHA antibody titers. A group with zero antibody titer had a mortality rate of 75% while those with PHA antibody titers of 185.6, 243.2, 256 and 307.2 had mortality rates of 40%, zero, zero and zero respectively. Linear equation generated for a line of best fit of the graph of mortality rates of the chicks on their IBD antibody titers gave antibody titer (X) at which mortality (Y) would be zero as 300. A mortality of 75% and the high antibody level needed to protect chicks suggest that the isolate may be a hypervirulent strain.展开更多
Objective: To investigate the feasibility and significance of detecting SYT-SSX fusion gene in paraffin-embedded tissues of synovial sarcoma (SS) by reverse-transcriptase polymerase chain reaction(RT-PCR) methods. Met...Objective: To investigate the feasibility and significance of detecting SYT-SSX fusion gene in paraffin-embedded tissues of synovial sarcoma (SS) by reverse-transcriptase polymerase chain reaction(RT-PCR) methods. Methods: Twenty cases of SS tumors from archival materials were collected and all samples were formalin-fixed and paraffin-embedded (FFPE). SYT-SSX fusion transcript was detected by RT-PCR. Home-keeping gene Porphobilinogen Deaminase (PBGD) was regarded as internal control.Results: PBGD mRNA was detected in all 20 tumor cases (100%). SYT-SSX fusion transcript was detected in 18 tumor cases (90%). In 18 SYT-SSX positive SS cases, there are 12 present SYT-SSX1 fusion transcript and 6 present SYT-SSX2 fusion transcript. SYT-SSX1 fusion transcript can be seen in 9 monophasic SS and 3 biphasic SS. In 6 SYT-SSX2 positive SS cases, 4 were monophasic SS and 2 were biphasic. Conclusion: Detection of SYT-SSX fusion transcripts in FFPE tissues for diagnosis of SS is feasible and sensitive. Subtypes of SYT-SSX fusion gene may provide prognosis information.展开更多
Background: The aim of this study was to compare the analgesic efficacy of subacromial bursae block (LA), suprascapular nerve block (SSB), and interscalene brachial plexus block (ISB) after arthroscopic shoulder surge...Background: The aim of this study was to compare the analgesic efficacy of subacromial bursae block (LA), suprascapular nerve block (SSB), and interscalene brachial plexus block (ISB) after arthroscopic shoulder surgery. Methods: 91 patients scheduled to undergo an arthroscopic shoulder acromioplasty under GA in an outpatient setting were included. The patients were prospectively randomized into 4 groups: 1) interscalene brachial plexus block, 2) suprascapular nerve block, 3) subacromial bursae block, 4) control group for comparison. Pain scores (VAS), supplemental analgesia, and side effects were recorded in the recoveryroom, 4 hours and 24 hours after surgery. Results: Group ISB had significantly lower pain scores at rest in the postanesthesia care unit than the SSB group (p = 0.037) and the control group (p = 0.0313). The same results were seen 4 hours follow-up. The LA group had significantly lower pain scores at rest in the postanesthesia care unit than the control group (p = 0.046) and after 4 hours follow-up significantly lower pain scores than both the SSB group (p = 0.021) and the control group (p = 0.037). After 24 hours, there were no differences between the two groups. Conclusion: In this prospective, randomized, blinded study we demonstrated that a single-dose interscalene brachial plexus block (ISB) and a subacromial bursae block (LA) are equal and the most efficient analgesic techniques after arthroscopic shoulder acromioplasty. LA is less expensive, faster and with fewer complications than ISB and therefore we suggest subacromial bursae block is an effective, safe and easy way of postoperative pain reduction after arthroscopic acromioplasty. Level of evidence: Level I. Treatment study.展开更多
BACKGROUND Synovial sarcoma(SS)is an uncommon and highly malignant soft tissue sarcoma in the clinic,with primary pulmonary SS(PPSS)being extremely rare.Here,we describe the clinical characteristics,diagnosis,and trea...BACKGROUND Synovial sarcoma(SS)is an uncommon and highly malignant soft tissue sarcoma in the clinic,with primary pulmonary SS(PPSS)being extremely rare.Here,we describe the clinical characteristics,diagnosis,and treatment of a solitary PPSS case confirmed via surgical resection and fluorescence in situ hybridization(FISH).CASE SUMMARY A 33-year-old man was admitted because of intermittent coughing and hemoptysis for one month,with lung shadows observed for two years.Wholebody positron emission tomography-computed tomography(PET-CT)revealed a solitary mass in the upper lobe of the right lung,with uneven radioactivity uptake and a maximum standardized uptake value of 5.6.The greyish-yellow specimen obtained following thoracoscopic resection was covered with small multinodulated structures and consisted of soft tissue.Hematoxylin and eosin staining revealed spindle-shaped malignant tumor cells.Immunohistochemistry indicated these tumor cells were CD99 and BCL-2-positive.Furthermore,the FISH test revealed synovial sarcoma translocation genetic reassortment,which confirmed the diagnosis of SS.CONCLUSION PPSS is extremely rare and tends to be misdiagnosed as many primary pulmonary diseases.PET-CT,histologic analysis,and FISH tests can be used to differentiate PPSS from other diseases.Surgical resection is regularly recommended for the treatment of solitary PPSS and is helpful for improving the prognosis.展开更多
BACKGROUND Synovial sarcoma(SS)accounting for 6%-10%of primary soft tissue malignancies mainly occurs in deep soft tissue adjacent to joints of the limbs.Primary pulmonary SS(PPSS)is rare and has a poor prognosis.Case...BACKGROUND Synovial sarcoma(SS)accounting for 6%-10%of primary soft tissue malignancies mainly occurs in deep soft tissue adjacent to joints of the limbs.Primary pulmonary SS(PPSS)is rare and has a poor prognosis.Cases of secondary distant metastases of PPSS occur rarely and there is a lack of corresponding imaging reports.We summarized the imaging findings of PPSS with multiple metastases confirmed by surgery and pathology,and shared valuable information on PPSS.CASE SUMMARY A 43-year-old female patient had a solid space occupying lesion in the right upper lobe of the lung.The results of a hemogram,erythrocyte sedimentation rate(ESR)and tumor markers were all within the normal range,tuberculin skin test(5 TU PPD)was negative(-).Chest computed tomography examination showed similar round soft tissue density in the posterior segment of the right upper lobe.Thoracoscopic-assisted wedge resection of the right upper lobe of the lung,right upper lobe resection and lymph node dissection were performed.Nine months after surgery,ultrasound examination showed multiple metastases on the chest wall and kidney.CONCLUSION PPSS is a rare malignant lung tumor with strong invasiveness,early distant metastasis and poor prognosis.There are very few imaging reports.PPSS is often manifested as irregular tumor and calcification,and the metastases have extremely low echo on ultrasonography.Contrast-enhanced ultrasound indicates that the arterial phase of tumor metastases shows rapid centripetal high enhancement,manifested as“fast forward and fast regression”.展开更多
基金Supported by the Natural Science Foundation of Jilin Province,No.20200201536JC.
文摘BACKGROUND Synovial chondromatosis is a disease originating from the synovium and characterized by the presence of metaplastic cartilaginous nodules in synovial cavities.The exact prevalence of synovial chondromatosis remains unknown,and the involvement of the shoulder joint is very rare.Synovial chondromatosis accompanied by subluxation of the humeral head without a history of trauma is rarely encountered,and to our knowledge,no published reports describe this condition.CASE SUMMARY We present two cases of synovial chondromatosis in the shoulder joint,accompanied by subluxation of the humeral head,in two arthroscopically managed adult patients.We performed arthroscopic labrum fixation and removal of the loose body from the shoulder joint.To identify primary and secondary categories,pathological analysis was arranged.Clinical and radiographic evaluations at the 1-mo follow-up were satisfactory.CONCLUSION The biomechanical function of the shoulder joint requires attention,especially following the detection of loose bodies,as observed with synovial chondroma occurring in rare sites.Arthroscopic management is successful in patients with synovial chondromatosis combined with shoulder subluxation.
文摘Introduction: Acute large bursae (ALB) are a frequent reason for emergency consultations. The aim of this study was to investigate the prevalence, clinical course, treatment and evolution of ALB at Abeche University Hospital. Patients and Method: This was a 45-month cross-sectional study from January 2020 to September 2023. Male patients of any age who had been admitted to and treated for acute large bursae at the Abeche University Hospital were included. Sociodemographic, clinical and therapeutic variables were studied. Results: Acute large bursae accounted for 7.92% of emergency admissions. The average age was 39.40 years. 60.27% of patients came from rural areas. The average consultation time was 4 days, ranging from a few hours to 18 days. The main reason for consultation was pain. Strangulated inguino-scrotal hernia was the most common, followed by acute orchi-epididymitis, accounting for 41.8% and 26% of cases respectively. Traditional treatment prior to consultation was attempted in 13.7% of cases. All patients were treated as emergencies, 41 of whom had received medical treatment. Of the patients treated surgically, orchidopexy was performed in all. Parietal suppuration and anaemia occurred in 6.2% and 4.8% of cases respectively. Conclusion: A accounts for a significant proportion of our emergency care activity. However, patients are seen with a delay, which jeopardises the functional prognosis of the testicle and intestine.
文摘Introduction: Synovial cyst of the tibial tunnel in connection with anterior cruciate ligament (ACL) reconstruction is a rare but particularly troublesome complication. Medical treatment is often doomed to failure, and surgical treatment usually consists of excising the cyst and filling the tunnel with bone. The aim of this study was to evaluate the results of filling the tunnel with acrylic cement. Hypothesis: Filling the tibial bone tunnel with acrylic cement should eliminate communication between the joint cavity and the pre-tibial surface and prevent cyst recurrence. Patients and Methods: This retrospective series is composed of 13 patients, 9 men and 4 women, mean age 48.5 years (31 to 64) operated on between 2011 and 2019 for an intra- and extraosseous synovial cyst consecutive to the tibial tunnel of an ACL graft. Between 1983 and 2016, 12 of the patients had had a bone graft without bone block fixation (DI-DT or Mac Intosh) and one patient, a bone-bone transplant (KJ). The cyst was of variable size, located on the anteromedial aspect of the proximal end of the tibia, and often painful, warranting consultation. At the time of the initial operation, 9 patients had undergone meniscectomies (6 medial, 2 lateral, 1 double). In 7 knees, there were 7 cartilage lesions in the femorotibial and/or patellofemoral compartments (one stage 1 lesion, 2 stage 2 lesions, 4 stage 3 lesions, and no stage 4 lesions). Only 2 knees had neither cartilage nor meniscus lesions. After curettage of the bone tunnel /− removal of the non-resorbed or PEEK interference screw, the tunnel was filled with acrylic cement /− reinforced with a ligament staple to prevent expulsion. All patients underwent regular follow-up consultations until recovery. Results: At a maximum follow-up of 8 years, only 1 cyst recurred, representing a 7.69% failure rate. It was reoperated with another technique, which involved filling the tibial bone tunnel with bone graft taken from a half-bank head. After recovery, the cyst healed definitively. All patients were able to return to their previous activity within 15 days of surgery. Conclusion: Filling the tibial tunnel with acrylic cement reinforced /− with a ligament staple is a reliable and rapid solution for the treatment of intra- and extra-articular synovial cysts in relation to the tibial tunnel of ACL grafts.
文摘The management of symptomatic lumbar synovial cysts is still a challenge and a matter of debate with no existing strong consensus. There are different treatment techniques and strategies, the most debated matter is to fuse or not to fuse, efficiency of less invasive techniques. One of our purposes was to provide an updated review of a literature about treatment of juxta facet synovial cysts and as standard surgical strategies are inconsistent, we present a small series of patients treated using different approaches, most of them were treated with MISS techniques, endoscopy, providing good results.
文摘Primary gastric synovial sarcoma is rare and challenging to diagnose. We present a case of a gastric ulcer that was diagnosed as primary gastric synovial sarcoma only after surveillance endoscopy with repeat biopsies. The diagnosis was established with the identification of the pathognomonic chromosomal translocation t(X;18)(p11;q11). The patient was treated with wedge resection and has remained disease-free on surveillance imaging and endoscopy. This case demonstrates the difficulty in diagnosing primary gastric synovial sarcoma and the benefits of early disease detection.
文摘To determine passive haemagglutination (PHA) antibody titer that would protect chicks against Nigerian isolates of the Infectious Bursa Disease Virus (IBDV), five groups of chicks aged 30 days which had different antibody titers were challenged with a Nigerian isolate of virulent IBDV. Mortality rates of the different groups were plotted against their respective mean PHA antibody titers. A group with zero antibody titer had a mortality rate of 75% while those with PHA antibody titers of 185.6, 243.2, 256 and 307.2 had mortality rates of 40%, zero, zero and zero respectively. Linear equation generated for a line of best fit of the graph of mortality rates of the chicks on their IBD antibody titers gave antibody titer (X) at which mortality (Y) would be zero as 300. A mortality of 75% and the high antibody level needed to protect chicks suggest that the isolate may be a hypervirulent strain.
文摘Objective: To investigate the feasibility and significance of detecting SYT-SSX fusion gene in paraffin-embedded tissues of synovial sarcoma (SS) by reverse-transcriptase polymerase chain reaction(RT-PCR) methods. Methods: Twenty cases of SS tumors from archival materials were collected and all samples were formalin-fixed and paraffin-embedded (FFPE). SYT-SSX fusion transcript was detected by RT-PCR. Home-keeping gene Porphobilinogen Deaminase (PBGD) was regarded as internal control.Results: PBGD mRNA was detected in all 20 tumor cases (100%). SYT-SSX fusion transcript was detected in 18 tumor cases (90%). In 18 SYT-SSX positive SS cases, there are 12 present SYT-SSX1 fusion transcript and 6 present SYT-SSX2 fusion transcript. SYT-SSX1 fusion transcript can be seen in 9 monophasic SS and 3 biphasic SS. In 6 SYT-SSX2 positive SS cases, 4 were monophasic SS and 2 were biphasic. Conclusion: Detection of SYT-SSX fusion transcripts in FFPE tissues for diagnosis of SS is feasible and sensitive. Subtypes of SYT-SSX fusion gene may provide prognosis information.
文摘Background: The aim of this study was to compare the analgesic efficacy of subacromial bursae block (LA), suprascapular nerve block (SSB), and interscalene brachial plexus block (ISB) after arthroscopic shoulder surgery. Methods: 91 patients scheduled to undergo an arthroscopic shoulder acromioplasty under GA in an outpatient setting were included. The patients were prospectively randomized into 4 groups: 1) interscalene brachial plexus block, 2) suprascapular nerve block, 3) subacromial bursae block, 4) control group for comparison. Pain scores (VAS), supplemental analgesia, and side effects were recorded in the recoveryroom, 4 hours and 24 hours after surgery. Results: Group ISB had significantly lower pain scores at rest in the postanesthesia care unit than the SSB group (p = 0.037) and the control group (p = 0.0313). The same results were seen 4 hours follow-up. The LA group had significantly lower pain scores at rest in the postanesthesia care unit than the control group (p = 0.046) and after 4 hours follow-up significantly lower pain scores than both the SSB group (p = 0.021) and the control group (p = 0.037). After 24 hours, there were no differences between the two groups. Conclusion: In this prospective, randomized, blinded study we demonstrated that a single-dose interscalene brachial plexus block (ISB) and a subacromial bursae block (LA) are equal and the most efficient analgesic techniques after arthroscopic shoulder acromioplasty. LA is less expensive, faster and with fewer complications than ISB and therefore we suggest subacromial bursae block is an effective, safe and easy way of postoperative pain reduction after arthroscopic acromioplasty. Level of evidence: Level I. Treatment study.
文摘BACKGROUND Synovial sarcoma(SS)is an uncommon and highly malignant soft tissue sarcoma in the clinic,with primary pulmonary SS(PPSS)being extremely rare.Here,we describe the clinical characteristics,diagnosis,and treatment of a solitary PPSS case confirmed via surgical resection and fluorescence in situ hybridization(FISH).CASE SUMMARY A 33-year-old man was admitted because of intermittent coughing and hemoptysis for one month,with lung shadows observed for two years.Wholebody positron emission tomography-computed tomography(PET-CT)revealed a solitary mass in the upper lobe of the right lung,with uneven radioactivity uptake and a maximum standardized uptake value of 5.6.The greyish-yellow specimen obtained following thoracoscopic resection was covered with small multinodulated structures and consisted of soft tissue.Hematoxylin and eosin staining revealed spindle-shaped malignant tumor cells.Immunohistochemistry indicated these tumor cells were CD99 and BCL-2-positive.Furthermore,the FISH test revealed synovial sarcoma translocation genetic reassortment,which confirmed the diagnosis of SS.CONCLUSION PPSS is extremely rare and tends to be misdiagnosed as many primary pulmonary diseases.PET-CT,histologic analysis,and FISH tests can be used to differentiate PPSS from other diseases.Surgical resection is regularly recommended for the treatment of solitary PPSS and is helpful for improving the prognosis.
文摘BACKGROUND Synovial sarcoma(SS)accounting for 6%-10%of primary soft tissue malignancies mainly occurs in deep soft tissue adjacent to joints of the limbs.Primary pulmonary SS(PPSS)is rare and has a poor prognosis.Cases of secondary distant metastases of PPSS occur rarely and there is a lack of corresponding imaging reports.We summarized the imaging findings of PPSS with multiple metastases confirmed by surgery and pathology,and shared valuable information on PPSS.CASE SUMMARY A 43-year-old female patient had a solid space occupying lesion in the right upper lobe of the lung.The results of a hemogram,erythrocyte sedimentation rate(ESR)and tumor markers were all within the normal range,tuberculin skin test(5 TU PPD)was negative(-).Chest computed tomography examination showed similar round soft tissue density in the posterior segment of the right upper lobe.Thoracoscopic-assisted wedge resection of the right upper lobe of the lung,right upper lobe resection and lymph node dissection were performed.Nine months after surgery,ultrasound examination showed multiple metastases on the chest wall and kidney.CONCLUSION PPSS is a rare malignant lung tumor with strong invasiveness,early distant metastasis and poor prognosis.There are very few imaging reports.PPSS is often manifested as irregular tumor and calcification,and the metastases have extremely low echo on ultrasonography.Contrast-enhanced ultrasound indicates that the arterial phase of tumor metastases shows rapid centripetal high enhancement,manifested as“fast forward and fast regression”.