[Comparison of the clinical efficacy of all-inside arthroscopic lateral ligament augmentation procedure and Broström procedure for the treatment of chronic lateral rotational ankle instability]

Objective: To compare the clinical efficacy of patients with chronic lateral rotational ankle instability(CLRAI) after all-inside arthroscopic lateral ligament augmentation procedure and Broström procedure. Methods: This is a retrospective cohort study. The clinical and imaging data of 106 CLRAI patients were collected at the Xuzhou Central Hospital from January 2021 to December 2022. The patients included 55 males and 51 females with an age of (32.6±8.2) years (range: 16 to 50 years). All patients were treated under all-inside arthroscopic, and were divided into Broström-Gould surgery group (n=54) and Broström surgery group (n=52) according to different ligament repair methods. At 3, 6, and 12 months after surgery, ankle inversion stress tests and anterior drawer tests were used to examine the stability of the ankle joint and observe gait. The American Orthopedic Foot and Ankle Society ankle hindfoot scale (AOFAS-AH) and Karlsson ankle function score (KAFS) were used to assess ankle function; Tegner score was used to assess the patient's level of exercise; the foot and ankle outcome score(FAOS)(including score of symptoms,pain,function, daily living,function, sports and recreational activities (sport); quality of life (QOL)) was used to assess the patient's daily activity ability. Comparisons of data were made using independent sample t test, repeated measures analysis of variance, LSD multiple comparison method, χ2 test or Mann-Whitney U test. Results: All operations were successfully accomplished. All incisions healed by first intention, without evidence of postoperative complications of implant rejection, ligation reaction, and nerve and vessel injury. All patients were followed up at 3, 6, and 12 months after surgery. Ankle varus stress test and anterior drawer test were negative. No evidence supporting lateral ankle instability was obtained. All patients eventually regained normal gait. No patients underwent revision surgery. Repeated measurement analysis of variance showed that AOFAS-AH, Tegner, KAFS and FAOS scores in the Brostrom-Gould group and the Brostrom group were significantly higher than those before surgery (P<0.01). The change trends of Tegner score and FAOS-sport score were significantly different between the two groups (F=18.839, P<0.01; F=8.169, P=0.005). Multiple comparisons revealed that at 3-, 6-and 12-month follow-up, the Tegner scores ((3 months: 3.7±0.5 vs. 3.3±0.5, t=-3.980, P<0.01; 6 months: 4.4±0.6 vs. 3.8±0.7, t=-4.792,P<0.01;12 months: 5.8±0.9 vs. 5.1±1.0, t=-3.889,P<0.01)), sport scores ((3 months: 82.5±3.7 vs. 79.3±3.8, LSD-t=-4.316, P<0.01; 6 months: 88.5±4.9 vs. 85.7±3.8, LSD-t=-3.312,P=0.001;12 months: 90.1±4.3 vs. 88.2±5.1, LSD-t=-2.112,P=0.037)) in the Broström-Gould surgery group were higher than those in the Broström surgery group, with statistical significances. Conclusions: Both Broström-Gould and Broström procedures under all-inside arthroscopic can make ankle stability and improve ankle function in the treatment of CLRAI. However, the former maybe shorten the time to return to exercise and achieve higher motor function.

[The current status and challenges of surgical treatment for chronic Achilles tendon rupture]

With the growing demand for physical activity, an increasing number of individuals with chronic Achilles tendon ruptures are opting for surgical intervention. Surgical approaches encompass end-to end anastomosis, tendon flap techniques, tendon transfer procedures, and free tendon grafting, among others. When selecting the appropriate surgical method and determining the surgical indications, it is imperative to consider factors like the length of the Achilles tendon defect, patient age, aesthetic preferences, functional requirements, and local tissue conditions. As medical devices evolve and surgical techniques advance, the criteria for surgical intervention are also evolving. Drawing from existing literature evidence, it becomes crucial to define reasonable parameters for addressing Achilles tendon defects with each surgical technique, aligning more closely with clinical needs. Additionally, auxiliary technologies such as biologic therapy and innovative biomaterials have demonstrated promising results in laboratory or animal models. The focal point of advancing these auxiliary technologies lies in facilitating the translation of pertinent clinical outcomes in the future.

[Effect of hollow compression screw internal fixation in treating McCrory-Bladin type Ⅱ lateral process fracture of the talus: open versus arthroscopy surgery]

In order to explore the clinical efficacy of hollow compression screw internal fixation in the treatment of lateral process fracture of the talus under open surgery versus arthroscopy procedure, a retrospective cohort study was conducted to analyze the clinical data of 33 patients with lateral process fracture of the talus admitted to Xuzhou Central Hospital from January 2019 to December 2021. There were 19 males (19 feet) and 14 females (14 feet), aged 18 to 50 years, with an average age of (32.2±9.3) years. According to the modified McCrory-Bladin classification, all patients were classified as type Ⅱ. Based on the different surgical methods, the patients were divided into the arthroscopy group (21 cases, treated with double-tunnel subtalar arthroscopy combined with hollow compression screw internal fixation) and the open group (12 cases, treated with open reduction and internal fixation with hollow compression screw). The operation time was observed and the surgical effects were evaluated using the visual analogue scale (VAS) of pain, the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, the Foot Function Index (FFI), and the Foot and Ankle Ability Measure (FAAM), which includes the FAAM-ADL (activity of daily living subscale) and the FAAM-S (sport subscale). All the patients of the two groups achieved stage Ⅰ wound healing. On the first day after the operation, the mean VAS score of the arthroscopy group was 2.4±0.7, which was significantly lower than that of the open group (3.4±1.6) (P=0.020). No significant difference was observed in terms of the follow-up time, operation time and AOFAS score between the two groups (all P>0.05). The FFI score of the arthroscopy group was significantly lower than that of the open group, and the FAAM-ADL and FAAM-S scores were significantly higher than those in the open group (all P<0.05). Two cases of dorsal foot numbness occurred in the open group after the operation, and the incidence of complications was not significantly different from that of the arthroscopy group (P=0.054). For McCrory-Bladin type Ⅱ lateral process fracture of the talus, the use of compression screw internal fixation could achieve reliable results, however, compared to open surgery, arthroscopy procedure obtained mini trauma and better functions.

Evaluation of the protective efficacy of virus-like particles based on PCV 2b and 2d subtypes against mixed challenge in mice

Porcine circovirus type 2 (PCV2) is an economically important swine pathogen and, although small, it has the highest evolution rate among DNA viruses. Commercial PCV2 commercial vaccines are inactivated PCV2 isolates or a subunit vaccine based on the Cap protein of PCV2. Currently, PCV2 VLPs of individual subtype vaccines are available. Although the main prevalent genotype worldwide is PCV2b, the emerging subtype PCV2d subtype is also increasingly associated with PCV disease. The aim of the study was to evaluate the protective efficacy of VLP based on the PCV2b and 2d subtypes against the mixed challenge of two hypotype PCV2 in mice. Thirty-six female SPV Kunming mice were immunized twice with PCV2b and 2d VLPs, then challenged with PCV2b and PCV2d, to assess the immunogenicity and effectiveness of the VLPs. Vaccination of the mice with PCV2b and 2d VLPs elicited a robust antibody response specific for the PCV2. The virus load detected in the 2b and 2d spleen vaccine group was the lowest compared to other groups. Furthermore, there was no pathological damage in the HE stained sections of the 2b and 2d spleen vaccine, and no virus was detected in the immunohistochemical sections. Our data suggest that the mixed PCV2b and 2d VLP vaccine could protect mice from challenge with the mixed infection of PCV2b and PCV2d..

[All-inside subtalar arthroscopy through three portals combined with rafting screws technique for the treatment of the calcaneal fractures of Sanders Ⅱ and Ⅲ]

Objective: To investigate the surgical technology and clinical efficacy of using the all-inside subtalar arthroscopy through three portals combined with rafting screws technique for the treatment of the calcaneal fractures of Sanders Ⅱ and Ⅲ. Methods: The clinical data of 33 patients (33 feet) with intra-articular displaced calcaneal fractures treated by modified all-inside arthroscopic from March 2017 to March 2019 at Department of Orthopedics,Xuzhou Central Hospital were retrospectively analyzed.There were 19 male patients,and 14 female patients,aged (32.6±11.3) years(range:20 to 55 years). According to the Sanders classification,there were 12 cases of type Ⅱ and 21 cases of type Ⅲ. The duration from injury to surgery was (101.2±32.1) hours(range:6 to 140 hours).The preoperative visual analogue scale (VAS) was 6.4±2.9 (range: 4 to 8); The preoperative American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot scale and the SF-36 score was 63.3±11.8 (range:50 to 75) and 94.8±9.1 (range:70 to 105) respectively.All the patients were managed with the all-side subtalar arthroscopy through three portals combined with rafting screws technique.The incision healing,reduction of fracture,and fracture healing were recorded.The VAS,AOFAS ankle-hindfoot scale,and SF-36 score were used to assess the pain and functional outcomes.Repeated-measurement was used to compare the scores before and after surgery. Results: The time of operation was (69.7±10.4) minutes (range:40 to 110 minutes). All patients did not undergo bone grafting.The incision healed in one stage without complications of skin sensory and peroneal tendon injury.All patients were followed up for 24 months.At the last follow-up,all the patients were satisfied with the hindfoot alignment,function,and hindfoot appearance.Postoperative calcaneal imaging indicators (calcaneal length,calcaneal width,calcaneal height,Bohler angle and Gissane angle) were significantly improved compared with those before surgery (P<0.01).There was no statistically significant difference in the imaging indexes of calcaneus at 1 day,1 year and 2 years after surgery,indicating no loss of fracture reduction (all P>0.05).The VAS,AOFAS ankle-hindfoot scale,and SF-36 score were 1.5±0.4 (range: 0 to 2),94.0±6.5 (range:90 to 100),and 119.1±7.2 (range:105 to 130),respectively,which were better than those before surgery (all P>0.05).According to the AOFAS scoring system,27 cases were excellent,4 cases were good, 2 cases were fair,and the excellent and good rate was 94.0%. Conclusion: All-inside subtalar arthroscopy through three portals combined with rafting screws technique for the treatment of the calcaneal fractures of Sanders Ⅱ and Ⅲ provides precise reduction,reliable fixation,satisfactory function and limited complications,which is an alternative method.

[Arthroscopy-assisted percutaneous reduction and screw fixation for displaced intra-articular calcaneal fractures]

Objective: To investigate the surgical technology and clinical efficacy of using the all-inside arthroscopic treatment of intra-articular displaced calcaneal fracture. Methods: A retrospective analysis was made of 46 patients (46 feet) with intra-articular displaced calcaneal fractures treated by modified all-inside arthroscopic from December 2015 to December 2017 in Xuzhou Central Hospital. Twenty-eight cases (28 feet) were male and 18 cases (18 feet) were female, aged from 19 to 60 years (mean (39±13) years). The time from injury to operation was 1 to 10 days (mean (4.5±2.2) days). The pre-operative visual analogue scale (VAS) of pain ranged from 4 to 8 points, mean (6.3±1.8) points. No other combined injuries were found in the affected feet in all patients. All patients were treated with anterolateral, lateral and posterolateral approaches of arthroscopically assisted reduction for calcaneal fractures, and fixed with hollow screw. Main outcome measures included the pain, foot appearance, and the scores of the American Orthopedic Foot & Ankle Society (AOFAS) Scale and the Maryland Scale. Paired t test was used when the data before and after the operation were compared. Results: All incisions healed in one stage without postoperative complications such as nerve, vessel and tendon injury. The mean follow-up period ranged from 12 to 36 months, mean (21±9) months. Postoperatively X-ray showed complete fracture healing time was 8 to 12 weeks, mean (10.4±2.3) weeks. At the last follow-up, the ankle and talocalcaneal joints movement and appearance were ideal, and no traumatic arthritis was found. The VAS score of talocalcaneal joint was 0. AOFAS score increased from 58±13 to 96±9 and Maryland score increased from 72±11 to 98±8 after the operation, the differences were all significant (t=15.958, 12.496, both P<0.05). Conclusion: The all-inside arthroscopic treatment of the intra-articular displaced calcaneal fracture is an effective and precise method, with accurately outcomes, precise reduction and minimally postoperative complications.

[Analysis of the effect of two medial portals for the all-inside endoscopic treatment of recalcitrant plantar fasciitis]

Objective: To examine the clinical effect of all-inside endoscopic treatment of recalcitrant plantar fasciitis through two medial portals. Methods: The recalcitrant plantar fasciitis data of 67 cases (79 feet) that underwent two medial portals all-inside endoscopic treatment at Department of Hand and Foot Microsurgery, Xuzhou Central Hospital from October 2016 to June 2018 were retrospectively analyzed.There were 24 males (30 feet) and 43 females (49 feet) aged 44.3 years old(range:24-76 years).The mean disease duration from the specialist doctor intervention to operation was (23.7±11.0) months (range: 12-60 months). All the patients were treated with the two medial portals all-inside endoscopic procedure when the 6 months conservative treatment had failed.The endoscopic procedure including debridement and partial plantar fasciotomy.The clinical results,including pain,activity,gait and foot health quality,were scored using visual analogue pain scale (VAS),American Orthopaedic Foot & Ankle Society Ankle Hindfoot Scale (AOFAS) and SF-36. Results: All the patients were followed up for (15.2±6.7) months (range: 12-24 months). All cases achieved primarily healing of the wound without postoperative complications of nerve,vessel and tendon.At the last follow-up,the VAS decreased from (5.3±2.0) preoperative to 0 prooperative (t=21.60, P=0.000), AOFAS increased from (72.6±9.4) to (97.3±4.6)(t=19.43,P=0.000),SF-36 increased from (93.6±8.4) to (119.1±7.3) (t=18.78, P=0.000), non-recurrent calcaneal spur, normal foot and ankle activity was recorded. Conclusion: The two medial portals all-inside endoscopic procedure is effective for the treatment of recalcitrant plantar fasciitis.

[Clinical analysis of ankle arthroscopy technique for treatment of tarsal tunnel syndrome]

Objective: To explore the effects of ankle arthroscopy technique in treating the tarsal tunnel syndrome. Methods: From May 2014 to May 2016, the ankle arthroscopy technique was used for surgical treatment of tarsal tunnel syndrome in the Department of Hand and Foot Microsurgery in Xuzhou Central Hospital. Twenty-two patients with 24 feet with tarsal tunnel syndrome were hospitalized for treatment, with 10 left feet and 14 right feet, aged 26-57 years. The disease duration ranged from 4 to 15 months (mean 8.3 months). The dual-portals ankle arthroscopic neurolysis and fiber membrane resection were performed. The Pfeiffer scoring system was used to evaluate the post-operative outcomes. Results: Primarily healing of the wound was achieved in all the patients. No postoperative infection was found during the follow-up. The postoperative hospitalization time was 2 to 5 days (mean 3.7 days). All patients were followed up for 12 to 24 months. At the final follow-up, all the patients had significant improvement in numbness and pain. According to the Pfeiffer scoring system, the results were excellent in 16 feet, good in 8 feet, with an excellent and good rate of 100%. Conclusion: The ankle arthroscopic neurolysis is a safe and easy treatment option for the tarsal tunnel syndrome and provides satisfactory results.

[Arthroscopic treatment of avulsion fracture of tibial origin with Ⅰ degree supination and external rotation injury]

Objective: To analyze the clinical effects of all-inside arthroscopic treatment for the patients of avulsion fracture of tibial origin withⅠdegree supination and external rotation injury according to the Lauge-Hansen classification. Methods: A retrospective analysis of 34 patients (34 feet) who had underwent all-inside arthroscopic for avulsion fracture of tibial origin with Ⅰ degree supination and external rotation injury from September 2015 to September 2017 in Department of Hand and Foot Microsurgery, Xuzhou Central Hospital. There were 20 males and 14 females, aged (24.7±11.3)years (range:14-43 years). The duration from injury to operation was (4.3±2.5) d (range: 6 h-7 d). The pro-operation visual analogue scale(VAS) of pain was 6.8±1.4(range: 4-8). All the patients were treated with the all-inside arthroscopic procedure by using the anterolateral and near-anterolateral portals and the fractures were fixed with cannulated screws. Main outcome measures included the pain, foot appearance, and patients were scored using the American Orthopaedic Foot & Ankle Society Lesser Toe Metatarsophalangeal-Interphalangeal Scale(AOFAS). Results: Primarily healing of the wound was achieved in all cases without postoperative complications of nerve, vessel and tendon injury. The follow-up period was (16.9±6.6)months(range: 8-24 months). Postoperatively X-ray films showed complete fracture healing at (11.2±2.1)weeks after surgery.At the last follow-up, the ankle movement and appearance were good, and no ankle joint traumatic arthritis were found. The VAS and AOFAS was 0 and 95.7±9.4 respectively. Conclusion: The all-inside arthroscopic treatment of Lauge-Hansen type avulsion fracture of tibial origin with Ⅰ degree supination and external rotation injury is an effective and precise method, with accurately outcomes, precise reduction and minimally postoperative complications.

[Modified Chevron osteotomy combined distal soft tissue reconstruction to treat high-grade bunionette deformity]

OBJECTIVE

To explore the surgical method of using the modified chevron osteotomy combined distal soft tissue reconstruction to treat high-grade bunionette deformity.

METHODS

From June 2013 to June 2015, the modified chevron osteotomy combined distal soft tissue reconstruction was used for surgical treatment of high-grade bunionette deformity in the Department of Hand and Foot Microsurgery in Xuzhou Central Hospital.Twenty-six patients with 28 feet high-grade bunionette deformity were hospitalized for treatment, with 3 male (3 feet) and 23 female (25 feet) cases, aged 22-73 (mean 47.1) years old.The average fourth-fifth intermetatarsal angle, lateral deviation of the fifth metatarsal angle and metatarsophalangeal-fifth angle were measured on the pre-and post- operative anterior to posterior weight-beating X rays of treated feet.The American Orthopaedic Foot and Ankle Society (AOFAS) Lesser Toe Metatarsophalangeal-Interphalangeal Scale was used to evaluate the post-operative outcomes.

RESULTS

All of 26 patients were followed, with a mean 15.7 months (range 8-25 months). Primarily healing of the wound was achieved in all cases.No postoperative infection and nonunion on the osteotomy site was found during the follow-up time.The fracture healing time was 6-15 (mean 12.2) weeks.All the patients had satisfactory appearance and sensory function without callosum and metastatic metatarsalgia at the final follow-up.The post-operative fourth-fifth intermetatarsal angle, lateral deviation of the fifth metatarsal angle and metatarsophalangeal-fifth angle were significantly lesser than the pre-operative at the 6th week after operation, respectively [(5.5±1.7)°, (2.1±0.8)°, (5.7±2.6)°vs (16.4±4.2)°, (6.0±2.2)°, (10.5±7.4)°; all P<0.01]. The post-operative AOFAS score was significantly greater than the pre-operative [(87.1±6.7) vs (62.3±9.8) points, P<0.001].

CONCLUSION

The modified chevron osteotomy combined distal soft tissue reconstruction is a safe and easy treatment option for the high-grade bunionette deformity and provides patient satisfaction results.

Pressure-induced superconductivity in topological parent compound Bi2Te3

We report a successful observation of pressure-induced superconductivity in a topological compound Bi(2)Te(3) with T(c) of ∼3 K between 3 to 6 GPa. The combined high-pressure structure investigations with synchrotron radiation indicated that the superconductivity occurred at the ambient phase without crystal structure phase transition. The Hall effects measurements indicated the hole-type carrier in the pressure-induced superconducting Bi(2)Te(3) single crystal. Consequently, the first-principles calculations based on the structural data obtained by the Rietveld refinement of X-ray diffraction patterns at high pressure showed that the electronic structure under pressure remained topologically nontrivial. The results suggested that topological superconductivity can be realized in Bi(2)Te(3) due to the proximity effect between superconducting bulk states and Dirac-type surface states. We also discuss the possibility that the bulk state could be a topological superconductor.

HCPTPA, a protein tyrosine phosphatase that regulates vascular endothelial growth factor receptor-mediated signal transduction and biological activity

Angiogenesis is a tightly controlled process in which signaling by the receptors for vascular endothelial growth factor (VEGF) plays a key role. In order to define signaling pathways downstream of VEGF receptors (VEGFR), the kinase domain of VEGFR2 (Flk-1) was used as a bait to screen a human fetal heart library in the yeast two-hybrid system. One of the signaling molecules identified in this effort was HCPTPA, a low molecular weight, cytoplasmic protein tyrosine phosphatase. Although HCPTPA possesses no identifiable phosphotyrosine binding domains (i.e. SH2 or phosphotyrosine binding domains), it bound specifically to active, autophosphorylated VEGFR2 but not to a mutated, kinase-inactive VEGFR2. Recombinant VEGFR2 and endogenous VEGFR2 were substrates for recombinant HCPTPA, and HCPTPA was co-expressed with VEGFR2 in endothelial cell lines, suggesting that HCPTPA may be a negative regulator of VEGFR2 signal transduction. To pursue this possibility, an adenovirus directing the expression of HCPTPA was constructed. When used to infect cultured endothelial cells, this adenovirus directed high level expression of HCPTPA that resulted in impairment of VEGF-mediated VEGFR2 autophosphorylation and mitogen-activated protein kinase activation. Adenovirus-mediated overexpression of HCPTPA also inhibited VEGF-induced cellular responses (endothelial cell migration and proliferation) and inhibited angiogenesis in the rat aortic ring assay. Taken together, these findings indicate that HCPTPA may be an important regulator of VEGF-mediated signaling and biological activity. Potential interactions with other signaling pathways and possible therapeutic implications are discussed.

PGE receptor characteristics on porcine luteal cells during the estrous cycle and early pregnancy

This study examined the affinities and concentrations of prostaglandin E (PGE) receptors on porcine luteal cells during the estrous cycle and early pregnancy. Corpora lutea (CL) were obtained from nonpregnant gilts at days 9 (n = 4), 12 (n = 3), and 14 (n = 6); three gilts possessed red, vascular CL and three gilts had white nonvascular CL) of the estrous cycle, and days 9 (n = 4), 12 (n = 3), 14 (n = 5), and 30 (n = 5) of pregnancy. The CL were dissociated enzymatically to disperse single cells and the red blood cells were removed by elutriation. The luteal cells were assayed for specific PGE binding by displacement analysis with use of [3H] PGE2 and varying concentrations of unlabeled PGE2. The specific binding of [3H] PGE2 to luteal cells decreased (p < 0.05) from days 9 to 14 of the estrous cycle, but only decreased (p < 0.05) from days 9 to 12 of pregnancy. Specific binding was higher (p < 0.05) on day 14 of pregnancy than the comparable stage of the estrous cycle. The affinities of PGE receptors decreased (p < 0.05) only on the luteal cells dissociated from red, vascular CL of day 14 nonpregnant gilts compared with those of other days of the estrous cycle and pregnancy. The number of PGE receptors on porcine luteal cells was similar (p > 0.05) in pregnant and nonpregnant gilts, but decreased (p < 0.05) on days 12-14 postestrus. During early pregnancy, it was evident that high affinity PGE receptors are sustained on porcine luteal cells; however, the role of the PGE receptors in maternal recognition of pregnancy remains speculative.

Effects of LH, prostaglandin E2, 8-bromo-cyclic AMP and forskolin on progesterone secretion by pig luteal cells

The present study examined the effects of LH, prostaglandin E2 (PGE2), 8-bromo-cyclic AMP (cAMP) and forskolin on progesterone secretion by small and large pig luteal cells. Corpora lutea were isolated from gilts (n > or = 3 per day) on days 9, 12 and 14 of the oestrous cycle and days 9, 12, 14 and 30 of pregnancy. After enzymatic dissociation of the corpora lutea, small and large luteal cells were obtained by elutriation. Culture plates (24-well) were then seeded with 150,000 small luteal cells or 30,000 large luteal cells per well in 1 ml M199 medium in the absence or presence of LH, PGE2, LH plus PGE2, 8-bromo-cAMP or forskolin. After 12 h of incubation, culture plates were centrifuged, and the supernatant collected and frozen for subsequent assay of progesterone. Differences within day were not detected between cyclic and pregnant gilts, and thus, results were combined for days 9, 12 and 14. Basal progesterone secretion by small luteal cells was less (P < 0.05) on days 14 and 30 than days 9 and 12. Treatment with LH, PGE2, 8-bromo-cAMP or forskolin increased (P < 0.05) progesterone secretion by small luteal cells on days 9 and 12; however, treatments had no effect on days 14 and 30. Basal progesterone production by large luteal cells was less (P < 0.05) on day 30 compared with other days. PGE2 stimulated (P < 0.001) progesterone production by large luteal cells at all days. In contrast, 8-bromo-cAMP and forskolin inhibited progesterone production by large luteal cells on day 12 (P < 0.05), and day 14 (P < 0.001). These data show that pregnancy status does not alter luteal cell response to the aforementioned secretagogues. However, regulation of progesterone secretion differs between small and large luteal cells, and the age of the corpora lutea. Also, it is unlikely that the stimulatory actions of PGE2 involve increased cAMP production in pig large luteal cells.

Identification and distribution of prostaglandin E receptors on porcine luteal cells

This study examined whether pig luteal cells contain specific prostaglandin (PG) E receptors. Corpora lutea, from PG 600R -induced cycling prepubertal gilts or naturally cycling gilts, were dissociated enzymatically, and large, small, and mixed cells were obtained by elutriation. Preliminary experiments demonstrated that optimal [3H]PGE2 binding to mixed cells was obtained after incubation at 22 degrees C for 2 h in binding buffer containing 1% BSA at pH 7.38. In addition, [3H]PGE2 binding was displaced by prostaglandins in the order of PGE2 approximately or = to PGE1 > PGF2a > > PGI2. The mixed, large, and small cells were assayed for specific PGE2 binding by displacement analysis with [3H]PGE2 and varying concentrations of unlabeled PGE2. Each gilt was assigned to group A (n = 6) or group B (n = 3) on the basis of whether the serum progesterone concentrations in that pig had increased or decreased, respectively, from 2 days before ovary collection to the time of ovary collection. Luteal cells from PG 600R -induced cycling prepubertal gilts had similar (p > 0.1) affinities and numbers of PGE receptors. In group A, the mixed cells contained a PGE binding site with a Kd of 21.1 +/- 1.1 nM and a concentration of 5.0 x 10(5) sites per large cell. Affinities of PGE receptors were similar (p > 0.1) regardless of cell types and functional status. PGE receptor concentrations were higher on large cells than on small cells (p > 0.05) and in group A than in group B (p = 0.006). These data demonstrated that PGE receptors primarily exist on porcine large luteal cells and that the concentration of PGE receptors appeared to be related to corpus luteum functional status.