Animal models of cartilage repair.

Cartilage repair in terms of replacement, or regeneration of damaged or diseased articular cartilage with functional tissue, is the 'holy grail' of joint surgery. A wide spectrum of strategies for cartilage repair currently exists and several of these techniques have been reported to be associated with successful clinical outcomes for appropriately selected indications. However, based on respective advantages, disadvantages, and limitations, no single strategy, or even combination of strategies, provides surgeons with viable options for attaining successful long-term outcomes in the majority of patients. As such, development of novel techniques and optimisation of current techniques need to be, and are, the focus of a great deal of research from the basic science level to clinical trials. Translational research that bridges scientific discoveries to clinical application involves the use of animal models in order to assess safety and efficacy for regulatory approval for human use. This review article provides an overview of animal models for cartilage repair. Cite this article: Bone Joint Res 2014;4:89-94.

Subchondral bone changes in three different canine models of osteoarthritis.

OBJECTIVE: To test the hypothesis that changes in subchondral bone are significantly different among three canine models of osteoarthritis (OA). DESIGN: In 21 purpose-bred mongrel dogs, OA was induced in one knee joint via either anterior cruciate ligament transection (ACLt; n = 5), medial femoral condylar groove creation (GR; n = 6), or medial meniscal release (MR; n = 5). Five dogs that had sham surgery (SH; n = 5) in one knee joint served as controls. Lameness scoring was performed every 4 weeks. Twelve weeks after surgery, the knee joints were examined by histology and histomorphometry. RESULTS: Articular cartilage pathology as determined by Mankin scores was significantly severe in all three OA models compared to SH controls in the medial tibia (P < 0.001 to P = 0.026). ACLt had significantly thinner subchondral plate thickness (Sp.Th) in both the medial and lateral tibias while MR had significantly thicker Sp.Th in the medial tibia compared to SH controls (P < 0.001 to P = 0.011). Trabecular bone volume (BV/TV) and trabecular bone thickness (Tb.Th) for ACLt were significantly less than SH controls in the tibias (P < 0.001 to P = 0.011). Tibial Sp.Th, BV/TV, and Tb.Th were all moderately to strongly correlated with lameness scores obtained throughout the study period (r = -0.436 to r = -0.738, P < 0.001 to P = 0.047) while Mankin scores showed moderate to strong correlations with Sp.Th in each OA model (r = 0.465 to r = 0.816, P < 0.001 to P = 0.033). CONCLUSIONS: Changes in Sp.Th are associated with articular cartilage damage while tibial Sp.Th and BV/TV and Tb.Th appear to be all influenced by joint loading alterations.

Polymicrogyria in standard poodles.

BACKGROUND: Polymicrogyria is a disorder of cerebrocortical migration resulting in increased numbers of small, disorganized gyri. This disorder occurs in Standard Poodles and in cattle. OBJECTIVES: To describe the clinical, electroencephalographic, imaging, and histopathologic features in poodles with polymicrogyria. ANIMALS: Five Standard Poodles with histologically confirmed polymicrogyria. METHODS: Retrospective case series. Cases were obtained by personal communication with 1 of 2 authors (TJVW, DPO). RESULTS: All dogs had cortical blindness and other neurologic abnormalities including gait and behavioral changes. Magnetic resonance imaging of 3 dogs showed multiple disorganized gyri, which were especially apparent on T2-weighted dorsal plane images. Electroencephalogram (EEG) of 1 dog revealed epileptiform discharges, including both spike and spike and wave discharges with voltage maximum potentials over the parietal/occipital region. The EEG supported that the repetitive behavior displayed by the dog was a complex partial motor seizure. One dog had concurrent hydrocephalus. All dogs had occipital lobe involvement and 2 dogs had involvement of other lobes. CLINICAL IMPORTANCE: The cases presented here demonstrate a larger age range (7 weeks to 5 years) and a decreased frequency of associated hydrocephalus when compared with the previous report.

Induction of meniscal regeneration in dogs using a novel biomaterial.

A unique biomaterial, porcine small intestinal submucosa, was used to construct grafts for implantation into surgically created medial meniscal defects in dogs. Five dogs received grafts and two were left untreated as controls. All dogs were evaluated at 4, 8, and 12 weeks by means of lameness scoring, force plate analysis, and ultrasonography. Twelve weeks after implantation the dogs were sacrificed and the replacement tissue was evaluated for gross and histologic appearance, amount, glycosaminoglycan content, and type II collagen immunoreactivity. Four weeks after instrumentation, both groups had lameness scores that were significantly higher than preoperative scores, but at the 8- and 12-week evaluations, scores for the grafted dogs were not different from preoperative values. The ultrasonographic appearance of replacement tissue in grafted defects resembled normal meniscus. In the untreated defects, only unorganized tissue was present. In control dogs, replacement tissue resembled fibrous tissue and cartilage erosions were visible on the medial femoral condyles. In four of the five grafted dogs, replacement tissue was grossly indistinguishable from normal meniscus. The amount of tissue in the defect was significantly greater for the grafted dogs. Histologically, replacement tissue in control dogs was composed of vascularized connective tissue with no evidence of chondroid differentiation. Replacement tissue in grafted dogs closely resembled normal meniscal tissue with respect to chondroid differentiation, collagen content, and zonal architecture. Porcine small intestinal submucosa appeared to have beneficial effects on meniscal regeneration.

Interaction between the negative regulator of splicing element and a 3' splice site: requirement for U1 small nuclear ribonucleoprotein and the 3' splice site branch point/pyrimidine tract.

The negative regulator of splicing (NRS) from Rous sarcoma virus suppresses viral RNA splicing and is one of several cis elements that account for the accumulation of large amounts of unspliced RNA for use as gag-pol mRNA and progeny virion genomic RNA. The NRS can also inhibit splicing of heterologous introns in vivo and in vitro. Previous data showed that the splicing factors SF2/ASF and U1, U2, and U11 small nuclear ribonucleoproteins (snRNPs) bind the NRS, and a correlation was established between SF2/ASF and U11 binding and activity, suggesting that these factors are important for function. These observations, and the finding that a large spliceosome-like complex (NRS-C) assembles on NRS RNA in nuclear extract, led to the proposal that the NRS is recognized as a minor-class 5' splice site. One model to explain NRS splicing inhibition holds that the NRS interacts nonproductively with and sequesters U2-dependent 3' splice sites. In this study, we provide evidence that the NRS interacts with an adenovirus 3' splice site. The interaction was dependent on the integrity of the branch point and pyrimidine tract of the 3' splice site, and it was sensitive to a mutation that was previously shown to abolish U11 snRNP binding and NRS function. However, further mutational analyses of NRS sequences have identified a U1 binding site that overlaps the U11 site, and the interaction with the 3' splice site correlated with U1, not U11, binding. These results show that the NRS can interact with a 3' splice site and suggest that U1 is of primary importance for NRS splicing inhibition.

Chorioamnionitis: is continuation of antibiotic therapy necessary after cesarean section?

OBJECTIVE: Our purpose was to determine whether the continuation of antibiotics postoperatively after cesarean section in patients whose labors were complicated by chorioamnionitis would reduce the incidence of endometritis. STUDY DESIGN: Patients with a clinical diagnosis of chorioamnionitis treated with ampicillin during labor and who required cesarean delivery for obstetric indications received preoperative intravenous clindamycin and gentamicin and were randomized into 2 groups. Group 1 received no scheduled postoperative antibiotics and group 2 continued to receive clindamycin 900 mg every 8 hours and gentamicin 1.5 mg/kg every 8 hours until afebrile for a minimum of 24 hours (temperature

Partial-birth abortion: the final frontier of abortion jurisprudence.

Partial-birth abortion bans patterned after the federal bill passed by both houses of Congress are constitutional. The clear legislative definition can be easily distinguished from other abortion procedures. Abortion precedents do not apply to such bans because the abortion right pertains to unborn human beings, not to those partially delivered. Such bans are also rationally-related to legitimate state interests. Even if abortion jurisprudence is deemed to apply in the partial-birth abortion context, a ban is still constitutional under Casey because a ban on partial-birth abortions does not impose an undue burden on the abortion right.

PIP: This article addresses the vague and overly broad issues concerning partial-birth abortion bans and sets forth the arguments for the constitutionality of a ban patterned after the federal model, using the Michigan case as the example. It also addresses the constitutional issues not covered by the Michigan court in order to show that the federal model passes constitutional muster. The clear legislative definition can be easily distinguished from other abortion procedures. Abortion precedents do not apply to such bans because abortion rights pertain to unborn human beings rather than to those that are partially delivered. Furthermore, such bans are rationally related to the legitimate state interest in protecting life during parturition. Even if abortion jurisprudence is deemed to apply in the partial-birth context, a federal style ban is still constitutional under Casey because a ban on partial-birth abortions does not impose an undue burden on abortion rights. Thus, the partial-birth abortion debate is the defining moment in the abortion debate, and the resulting litigation is the final frontier of abortion jurisprudence.

SR protein and snRNP requirements for assembly of the Rous sarcoma virus negative regulator of splicing complex in vitro.

Retroviruses use unspliced RNA as mRNA for expression of virion structural proteins and as genomic RNA; the full-length RNA often constitutes the majority of the viral RNA in an infected cell. Maintenance of this large pool of unspliced RNA is crucial since even a modest increase in splicing efficiency can lead to impaired replication. In Rous sarcoma virus, the negative regulator of splicing (NRS) was identified as a cis element that negatively impacts splicing of viral RNA. Components of the splicing apparatus appear to be involved in splicing inhibition since binding of a number of splicing factors (snRNPs and SR proteins) and assembly of a large complex (NRS-C) in nuclear extracts correlate with NRS-mediated splicing inhibition. In determining the requirements for NRS complex assembly, we show that NRS-C assembly can be reconstituted by addition of total SR proteins to an S100 extract that lacks these factors. Of the purified SR proteins tested, SF2/ASF was functional in NRS-C assembly, whereas SC35 and SRp40 were not. The participation of snRNPs in NRS-C assembly was addressed by selectively depleting individual snRNPs with oligonucleotides and RNase H or by sequestering critical snRNA domains with 2'-O-methyl RNA oligonucleotides. The results indicate that in addition to U11 snRNP, U1 snRNP and SR proteins, but not U2 snRNP, are involved in NRS-C assembly.

Preterm premature rupture of membranes: aggressive tocolysis versus expectant management.

The objective of our study is to determine whether aggressive tocolysis in patients with preterm premature rupture of membranes between 24 and 34 weeks gestation improves neonatal outcome. Patients with documented preterm premature rupture of membranes between 24 and 34 weeks gestation were prospectively randomized to group I, aggressive tocolysis with intravenous magnesium sulfate, or to group II, no tocolysis. The lecithin/sphingomyelin ratio was determined upon hospital admission and every 48-96 hours until delivery. Both groups received weekly steroids and antibiotics pending culture results and were promptly delivered when chorioamnionitis, fetal stress, or an Lecithin/sphingomyelin ratio of > or = 2.0 occurred. The study group involved 145 patients. No statistically significant differences between groups I (n = 78) and II (n = 67) were observed regarding demographic characteristics, gestational age at enrollment or at delivery, latency, development of clinical chorioamnionitis, birth weight, number of days in neonatal intensive care unit, days on oxygen or ventilatory support, frequency of hyaline membrane disease, necrotizing enterocolitis, intraventricular hemorrhage, neonatal sepsis, or neonatal mortality. Our data suggest that tocolysis in patients with preterm premature rupture of membranes does not significantly improve perinatal outcome.

Scapular fractures in dogs: epidemiology, classification, and concurrent injuries in 105 cases (1988-1994).

A retrospective study of canine scapular fractures diagnosed and treated from 1988 through 1994 at four veterinary teaching hospitals was performed. Dogs (n = 105) with 109 scapular fractures were included. Most scapular fractures occurred in young (i.e., less than four years of age), male, medium- to large-breed (i.e., greater than 10 kg) dogs as the result of vehicular trauma. Concurrent injuries (primarily thoracic trauma) occurred in approximately 70% of cases. In-house follow-up evaluations were considered adequate in only 17% of the cases. A classification system that includes biomechanical principles for categorization is described to avoid discrepancies between various traditional classification systems.

Gestational herpes simplex virus hepatitis.

Hepatitis due to herpes simplex virus (HSV) is unusual in healthy individuals. To date, only 56 cases of HSV hepatitis in adult patients have been reported, including 21 pregnant patients. We describe a 25-year-old white woman in her 30th week of gestation who had progressive acute hepatitis. Histologic examination of the liver biopsy specimen showed diffuse microabscesses involving more than 50% of the hepatic parenchyma, with multiple hepatocytes containing Cowdry type A and ground-glass nuclear inclusions. The diagnosis of herpes hepatitis was confirmed by positive immunoreactivity to HSV antibodies in the tissue sections. Intravenous acyclovir therapy was immediately initiated, and the patient's condition improved dramatically. She then had a normal baby at term. Subsequently, the patient had a second pregnancy and an uncomplicated vaginal delivery without recurrence of the disease. Even though alterations of the humoral and cell-mediated immunity occur during pregnancy, herpes hepatitis is rare in pregnant women. Since the prompt administration of antiviral drugs is a lifesaving measure, we recommend including HSV hepatitis in the differential diagnosis of acute hepatitis in pregnancy.

Characterization of an RNP complex that assembles on the Rous sarcoma virus negative regulator of splicing element.

We have characterized an RNP complex that assembles in nuclear extracts on the negative regulator of splicing (NRS) element from Rous sarcoma virus. While no complex was detected by native gel electrophoresis under conditions that supported spliceosome assembly, gel filtration revealed a specific ATP-independent complex that rapidly assembled on NRS RNA. No complexes were formed on non-specific RNA. Unlike the non-specific H complex, factors required for NRS complex assembly are limiting in nuclear extract. The NRS complex was not detected in reactions containing ATP and pre-formed complexes were dissociated in the presence of ATP. In addition, the assembly process was sensitive to high salt but NRS complexes were salt stable once formed. Assembly of the NRS complex appears functionally significant since mutated NRS RNAs that fail to inhibit splicing in vivo are defective for NRS complex assembly in nuclear extract. The probable relationship of the NRS complex to spliceosomal complexes is discussed.

Aggressive intrapartum management of lethal fetal anomalies: beyond fetal beneficence.

OBJECTIVE: To evaluate management recommendations from the current literature for patients whose fetuses are certain to have lethal anomalies or absent (or virtually absent) cognitive function. These recommendations include termination of pregnancy or, for cases in the third trimester, nonaggressive intrapartum management, avoiding cesarean delivery for fetal indications. METHODS: We report our experience with several patients who voiced opposition to nonaggressive intrapartum care and present a rationale for selectively aggressive, intrapartum management for some of these cases. RESULTS: Four women whose fetuses had lethal anomalies requested aggressive intrapartum management. For three of the four, standard aggressive management of labor resulted in vaginal delivery of live-born infants who died shortly thereafter. The patients found comfort in the live births. The fourth patient accepted a recommendation to avoid fetal monitoring during labor, and the fetus was stillborn. This patient found the intrapartum experience to be very stressful. CONCLUSION: When a patient's desire to avoid an intrapartum stillbirth is strong enough that substantial psychological harm might result from one, the physician's beneficence-based obligation to her and respect for maternal autonomy justify selectively aggressive intrapartum therapy, even if no beneficence-based obligation to the fetus exists.

Herpes in pregnancy.

The management of genital herpesvirus infections in pregnancy has seen many changes over the past decade as we have continued to learn more about the epidemiology of the disease. This article reviews these changes and highlights ongoing controversies. Clinical management schemes are proposed based upon this most recent information.

Cost-saving impact of pharmacist-calculated i.v. aminophylline dosing schedules.

To determine pharmacy impact on hospital costs, a retrospective chart review of IV aminophylline dosing requirements for 43 patients was undertaken. Aminophylline dosing requirements (loading and maintenance doses, dosage adjustments, serum level monitoring) were made solely by physicians for 22 patients and solely by pharmacists for 21 patients for two selected DRGs (96 and 97). Average length of stay was studied for both groups. The length of stay was decreased by a mean of 1.96 days when aminophylline was dosed by pharmacists (p less than 0.05). This corresponded to a savings of $490 per patient for room and board charges alone. Age and the severity of disease appeared to have no affect on outcome. The results of this study support the use of clinical pharmacy services. These services are potentially cost saving, improve patient care (by providing patients with state-of-the-art dosing techniques), and allow physicians to concentrate more of their efforts on patients' medical care rather than on time-consuming dosage calculations.

Studies of marked and persistent sodium retention in previously fasted and sodium-deprived obese subjects.

To further delineate the effects of fasting and sodium deprivation on the handling of sodium when sodium intake is resumed, balance studies were performed on seven obese female subjects. All subjects underwent a period of total fasting, which continued for 27 to 29 days prior to resumption of sodium intake. Natriuresis in the first week of fasting and continued sodium chloride deprivation resulted in cumulative deficits of 383 +/- 47 mEq (SEM) and 371 +/- 41 mEq of sodium and chloride, respectively. Chloride space decreased from 21.2 +/- 2.7 L to 18.7 +/- 2.5 L, and aldosterone secretory rates (ASR) increased from 43 +/- 13 micrograms/24 h to 597 +/- 138 micrograms/24 h. Following resumption of sodium intake and simultaneous refeeding on low calorie diets in studies on four subjects (group I), cumulative sodium balances during the first seven days ranged from +586 mEq to +1,109 mEq; sodium retained/previously existing sodium deficit = 2.4, 3.2, 2.0, and 1.6 in the four subjects, respectively. Continued sodium retention resulted in cumulative sodium balances ranging from +670 mEq to +1,249 mEq at the end of 19 to 22 days in studies on three subjects whose cumulative sodium balance was +1,249 mEq, sodium retained/sodium deficit = 3.6. During the first five days of sodium intake and refeeding ASR decreased to 74 +/- 26 micrograms/24 h. Sodium chloride administration without refeeding in studies on three subjects (group II) also resulted in retention of more than enough sodium to replenish previously existing sodium deficits.(ABSTRACT TRUNCATED AT 250 WORDS)