Current concepts on management of cuff tear.

Among pathologies of the shoulder, rotator cuff tear is the most common. Diagnosis of cuff tear around mid twenties is unusual, but the prevalence increases significantly after the age of forty. The prevalence after the age of 60 is around 20-30%. A well recognised feature of cuff tear is being asymptomatic but, tear progression in asymptomatic is a known consequence. The spectrum of cuff tear ranges from partial, full thickness cuff tear with or without retraction. The mainstay of treatment for partial thickness cuff tear is systematic rehabilitation and for the full thickness cuff tear an initial rehabilitation is an accepted management. Failed rehabilitation for 3 months, acute traumatic tear, younger age, intractable pain, good quality muscle would be the indications for repair of a full thickness cuff tear. Though there are defined indications for surgical intervention in the full thickness rotator cuff tear, differentiating an asymptomatic tear that would not progress or identifying a tear that would become better with rehabilitation is an undeniable challenge for even the most experienced surgeon. Rehabilitation in cuff tear consists of strengthening the core stabilizers along with rotator cuff and deltoid muscles. In a symptomatic cuff tear that merits surgical intervention the objective is to do an anatomical foot print repair. In scenarios where the cuff is retracted, one has to settle for a medialised repair. As, a repair done in tension is more likely to fail than a tensionless medialised repair. The success rate of all these non anatomical procedures varies from series to series but it approximates around 60-80%. Augmenting cuff repair to enhance biological healing is a recent advance in rotator cuff repair surgery. The augmentation factors can be growth factors like PRP, scaffolds both auto and allografts. The outcome of these procedures from literature has been variable. As there are no major harmful effects, it can be viewed as another future step in bringing better outcomes to patients having rotator cuff tear surgery. Despite being the commonest shoulder pathology, the rotator cuff tear still remains as a condition with varied presenting features and a wide variety of management options. The goal of the treatment is to achieve pain free shoulders with good function. Correcting altered scapular kinematics by systematic rehabilitation of the shoulder would be the first choice in all partial thickness cuff tear and also as an initial management of full thickness cuff tears. Failure of rehabilitation would be the step forward for a surgical intervention. While embarking on a surgical procedure, correct patient selection, sound surgical technique, appropriate counselling about expected outcome are the most essential in patient satisfaction.

The management of clenched fist 'fight bite' injuries of the hand.

We present a prospective study outlining the management of clenched fist 'fight bite' injuries. Over a 4-year period all patients with such injuries had surgical exploration with further débridements as necessary. For metacarpophalangeal joint injuries, a midline tendon-splitting approach was used. For proximal interphalangeal joint injuries, an approach was made between the lateral band and central slip of the extensor mechanism. A total of 147 patients with 159 joint injuries were treated, with 130 metacarpophalangeal joint and 29 proximal interphalangeal joint injuries. The joint was penetrated in 96% of joints overall. The number of débridements ranged from two to eight. Twenty patients defaulted within 1 week of surgery and were not included in the analysis of the results. All patients with metacarpophalangeal joint injury had satisfactory or good outcomes. A total of 42% of patients with proximal interphalangeal joint injuries had poor results, four requiring amputation and one a fusion. The tendon-splitting approach to the metacarpophalangeal joint allows excellent access and avoids damage to the sagittal bands and consequent instability of the extensor mechanism.

Malignant necrotising streptococcal myositis: a rare and fatal condition.

We present a case of fatal 'malignant' necrotising streptococcal myositis in a previously healthy 39-year-old man. The infection was caused by Lancefield group-A haemolytic streptococcus highlights the clinical features and the necessity of prompt aggressive treatment.

A comparison of neonatal mortality risk prediction models in very low birth weight infants.

BACKGROUND: Risk-adjusted severity of illness is frequently used in clinical research and quality assessments. Although there are multiple methods designed for neonates, they have been infrequently compared and some have not been assessed in large samples of very low birth weight (VLBW; <1500 g) infants. OBJECTIVES: To test and compare published neonatal mortality prediction models, including Clinical Risk Index for Babies (CRIB), Score for Neonatal Acute Physiology (SNAP), SNAP-Perinatal Extension (SNAP-PE), Neonatal Therapeutic Interventions Scoring System, the National Institute of Child Health and Human Development (NICHD) network model, and other individual admission factors such as birth weight, low Apgar score (<7 at 5 minutes), and small for gestational age status in a cohort of VLBW infants from the Washington, DC area. METHODS: Data were collected on 476 VLBW infants admitted to 8 neonatal intensive care units between October 1994 and February 1997. The calibration (closeness of total observed deaths to the predicted total) of models with published coefficients (SNAP-PE, CRIB, and NICHD) was assessed using the standardized mortality ratio. Discrimination was quantified as the area under the curve (AUC) for the receiver operating characteristic curves. Calibrated models were derived for the current database using logistic regression techniques. Goodness-of-fit of predicted to observed probabilities of death was assessed with the Hosmer-Lemeshow goodness-of-fit test. RESULTS: The calibration of published algorithms applied to our data was poor. The standardized mortality ratios for the NICHD, CRIB, and SNAP-PE models were.65,.56, and.82, respectively. Discrimination of all the models was excellent (range:.863-.930). Surprisingly, birth weight performed much better than in previous analyses, with an AUC of.869. The best models using both 12- and 24-hour postadmission data, significantly outperformed the best model based on birth data only but were not significantly different from each other. The variables in the best model were birth weight, birth weight squared, low 5-minute Apgar score, and SNAP (AUC =.930). CONCLUSION: Published models for severity of illness overpredicted hospital mortality in this set of VLBW infants, indicating a need for frequent recalibration. Discrimination for these severity of illness scores remains excellent. Birth variables should be reevaluated as a method to control for severity of illness in predicting mortality.

Kinetics of zinc metabolism: variation with diet, genetics and disease.

Kinetic studies are used to investigate metabolic processes. By adding an isotope to a system and measuring its movement in the system over time, pool sizes and transport rates can be determined by mathematically modeling the data. This approach enables rate differences to be determined in conditions that have been modified by diet, environment, genetics or disease. Kinetic studies in humans have shown that there are multiple pools of zinc that turnover from minutes to years and that processes, including zinc absorption and excretion, are regulated to maintain tissue levels when zinc intake varies. Animal studies allow for greater understanding of kinetics because more tissues can be sampled and environmental and genetic factors can be controlled. Kinetic studies in animals will provide information on the overexpression or the deletion of genes coding for specific proteins involved in zinc transport and metabolism. The advances that have been made in our understanding of the role of zinc in metabolism have been aided by the development of techniques for measuring isotopes in biological materials. In the future, the kinetics of zinc bound to different compounds will be measured. Modeling will enable this information, at the molecular level, to be integrated with knowledge of zinc metabolism at the cellular, organ and whole body level. To understand more fully the role of zinc in human health, kinetic studies are needed in healthy and disease states to identify differences in metabolic processes. This knowledge can be used as a basis for dietary and therapeutic recommendations.

Tumor suppressor protein WT1 inhibits autonomous DNA replication directly, as well as indirectly by causing loss of replicated DNA as a consequence of cell death induced by the protein.

The effects of the Wilms' tumor suppressor protein WT1 on autonomous DNA replication under stable transfection conditions were investigated. COS ts2 monkey kidney cells, which express the simian virus 40 (SV40) replication initiator protein large tumor antigen (TAg) as a temperature-sensitive protein, were stably transfected with SV40 origin-containing plasmids expressing WT1 from the Zn2+ and Cd2+-inducible metallothionein promoter. Stable transformant clones of cells containing the integrated plasmids were isolated at the non-permissive temperature, expanded, and shifted to the permissive temperature to allow autonomous replication of the plasmid and overexpression of WT1. Expression of WT1 triggered apoptosis of the cells. Analysis of the kinetics of occurrence of cell death and accumulation of the replicated plasmid indicated that WT1 inhibited replication directly, and also indirectly by causing loss of replicated plasmid as a consequence of WT1-induced cell death.

Developing a shared language: interdisciplinary communication among diverse health care professionals.

Multidisciplinary teams of nurses, physicians, and other professionals may have difficulty communicating because of inconsistent theoretical underpinnings. A theoretical base that spans both clinical outcomes and professional boundaries is needed. The web of causation is a theoretical framework that provides a platform of communication connecting issues related to infant mortality among various health-related professions. It includes professional, community, and institutional issues relevant to pregnant women and new mothers as infant caregivers. The article discusses how the web was used for interdisciplinary health care professional interaction and how it was used to develop a series of research protocols that will affect the care of mothers and infants in the District of Columbia.

Zinc absorption, distribution, excretion, and retention by healthy preterm infants.

Zinc (Zn) is an essential nutrient for growth, but little is known about Zn absorption, distribution, excretion, and retention in preterm infants. Nine infants with gestational age 32+/-1 wk (mean+/-SE), birth weight 1.44+/-0.08 kg, postnatal age 14+/-3 d, on Zn intake of 23+/-3 micromol/kg per d via enteral feeding of preterm formula were studied. A stable Zn isotope (70Zn) was administered orally or i.v., and plasma, red blood cells, urine, and feces were sampled for up to 30 d. Samples were analyzed for Zn by inductively coupled plasma atomic emission spectrometry and for isotope enrichment by inductively coupled plasma mass spectrometry. Data were analyzed by compartmental analysis using the Simulation Analysis and Modeling program, and absorption, distribution, excretion, and retention were calculated. Absorption was 36+/-5% or 7+/-1 micromol/kg per d; distribution in plasma was 15+/-1 micromol Zn/L and in RBC was 41+/-4 micromol Zn/L; excretion in urine was 0.55+/-0.03 micromol Zn/kg per d and in feces was 17+/-3 micromol Zn/kg per d and retention was 5+/-1 microl/kg per d. Results show that healthy preterm infants with Zn intake of 23 micromol/kg per d and expected growth rates (> 15 g/kg per d) absorb and retain Zn at rates comparable to in utero accretion. The values for absorption, distribution, and excretion by this population of healthy preterm infants provide a normal range for future studies, although further studies are required to determine endogenous excretion rates in healthy preterm infants. We speculate that these values can be used to determine whether Zn kinetics are abnormal in sick infants or in infants with slow growth.

The replication inhibition activity of the WT1 tumor suppressor protein resides in its N-terminal 298 amino acid region, and does not require specific binding of the protein to the replication origin sequence.

Using the simian virus 40 replication origin as the model, it was reported previously that the Wilms' tumor suppressor protein WT1 can inhibit DNA replication. In the present study, we found that a hybrid protein (termed GAL4-WT1AE Z) consisting of the DNA-binding domain of the yeast transcription factor GAL4 fused in-frame with the N-terminal 298 amino acid (aa) transcriptional regulatory region of WT1 retained the ability to inhibit replication. The hybrid protein and the full-length WT1 inhibited replication without regard to the presence or absence of their binding sites in the replication origin region, indicating that inhibition of replication by the proteins does not require their specific binding to the origin region. The inhibition efficiency of the hybrid protein was the same as that of WT1, indicating that the replication inhibition activity resides in the N-terminal 298 aa region, and that the C-terminal zinc finger-containing DNA-binding domain of WT1 is functionally dispensable for this effect.

Safety, tolerance and pharmacokinetics of a humanized monoclonal antibody to respiratory syncytial virus in premature infants and infants with bronchopulmonary dysplasia. MEDI-493 Study Group.

BACKGROUND: Respiratory syncytial virus (RSV) is the most common cause of lower respiratory tract infection in infants. MEDI-493 (palivizumab) is a humanized monoclonal antibody to the fusion protein of RSV and is active in animal models for prevention of pulmonary RSV replication. OBJECTIVE: To describe the safety, tolerance, immunogenicity and pharmacokinetics of repeat intravenous doses of MEDI-493 in premature infants or infants with bronchopulmonary dysplasia. DESIGN: Phase I/II multicenter, randomized, double blind, placebo-controlled, dose escalation trial. PATIENT POPULATION: Infants born prematurely (< or = 35 weeks of gestation) who were < or = 6 months of age and infants with bronchopulmonary dysplasia who were < or = 24 months of age were eligible for study participation. STUDY AGENTS: Participants received 3, 10 or 15 mg/kg MEDI-493 or 0.9% saline intravenously every 30 days for up to five doses. RESULTS: MEDI-493 was safe and well-tolerated and did not induce a specific anti-MEDI-493 response. The mean half-life of 20 days was comparable with that of other immunoglobulin G preparations. Mean trough serum concentrations 30 days after Infusion 1 were 6.8, 36.1 and 60.6 microg/ml for the 3-, 10- and 15-mg/kg dose groups, respectively. After Infusion 2 the trough concentrations were 11.9, 45.2 and 70.7 microg/ml. After subsequent doses the mean trough values ranged from 14 to 18 microg/ml in those given 3 mg/kg and were > 40 microg/ml for patients who received 10 or 15 mg/kg MEDI-493 (46 to 72 microg/ml and 88 to 96 microg/ml, respectively). CONCLUSIONS: MEDI-493 was safe and well-tolerated in this high risk pediatric population. Mean serum concentrations of MEDI-493 that have been shown to produce a 2-log reduction in pulmonary RSV titer in cotton rats were maintained when 10 or 15 mg/kg MEDI-493 was given every 30 days to pediatric patients at high risk for serious RSV disease. Monthly doses of 15 mg/kg maintained concentrations of > 40 microg/ml for the majority of patients.

Using models to explore whole-body metabolism and accessing models through a model library.

A model is a mathematical representation of a system that can be used to explore the system in a number of ways: to determine the system's internal connections, to calculate properties of the system such as flow rates and pool sizes, and to make predictions about the system's behavior under different conditions. The use of modeling to explore whole-body metabolism is demonstrated using a compartmental model of zinc kinetics as an example. Because models are useful tools for exploring systems, a facility called a "model library" is being established on the Internet to provide access to working versions of published models.

Zinc kinetics in preterm infants: a compartmental model based on stable isotope data.

Zinc is an essential nutrient for growth; however, little is known about zinc kinetics (absorption, distribution, and excretion) in preterm infants (< 38-wk gestation). Zinc kinetics were studied in two preterm infants (gestational ages, 32 and 33 wk) following oral or intravenous administration of a stable isotope (70Zn). Plasma, red blood cells (RBC), urine, and feces were sampled for up to 30 days. Isotope enrichment was measured in tissues by inductively coupled plasma (ICP)-mass spectrometry, and zinc was determined by ICP-atomic emission spectrometry. Data were analyzed by compartmental analysis using SAAM31. Zinc intake increased during the studies, and, because body zinc was not in steady state, both tracer (70Zn) and tracee (Zn) data were fitted using analogous models. A model for adults [M. E. Wastney, R. L. Aamodt, W. F. Rumble, and R. I. Henkin. Am. J. Physiol. 251 (Regulatory Integrative Comp. Physiol. 20): R398-R408, 1986] was modified to fit data from the preterm infants. RBC data were fitted using one compartment (vs. 2 in adults), and an adult RBC subsystem was included in the model to account for zinc introduced during blood transfusions. Exchange of zinc between compartments that were not sampled was based on zinc distribution in neonates. Absorption was 42 and 34%, and endogenous fecal excretion, based on intravenous data, was 15 micrograms.kg-1.day-1. The model can be used to quantify changes in zinc kinetics of preterm infants with age, weight, and zinc intake for evaluating nutritional requirements with growth.

Care of critically ill newborns in India. Legal and ethical issues.

PIP: The nature of neonatal care in India is changing. While the quality of care will most likely improve as the economy grows, the eventual scope of change remains to be seen. Attitudinal and behavioral changes, in addition to better economic conditions, are needed to realize more appropriate interventions in neonatal care. Economic, cultural, religious, social, political, and other considerations may limit or affect neonatal care, especially for ELBW infants or infants with congenital malformations or brain injury. Various protections for critically ill newborns exist under Indian law and the Constitution of India. New laws are being enacted to enhance the level of protection conferred, including laws which ban amniocentesis for sex determination and define brain death in connection with the use of human organs for therapeutic purposes. The applicability of consumer protection laws to medical care is also being addressed. It is noted, however, that India lacks a multidisciplinary bioethics committee. An effort should be made to discuss the legal and ethical issues regarding the care of critically ill newborns, with discussions considering religious, cultural, traditional, and family values. Legal and ethical guidelines should be developed by institutions, medical councils, and society specific to newborn care, and medical, nursing, and other paramedical schools should include these issues as part of the required coursework. Physicians, nurses, philosophers, and attorneys with expertise in law and ethics should develop and teach these courses. Such measures over the long term will ensure that future health care providers are exposed to these issues, ideally with a view toward enhancing patient care.^ieng

Intravenous immune globulin prophylaxis of late-onset sepsis in premature neonates.

To determine whether a single dose of intravenously administered immune globulin (IVIG) decreases late-onset sepsis in premature infants, we prospectively entered 753 neonates with birth weight 500 to 2000 gm, gestation < or = 34 weeks, and age < or = 12 hours into a multicenter, double-blind, controlled trial. Infants were randomly selected to receive a single intravenous infusion, 10 ml/kg, of either IVIG (500 mg/kg) or albumin (5 mg/kg) and were observed for 8 weeks for infection. Maternal and neonatal risk factors for infection did not differ between groups. Although serum IgG values before infusion were related to gestation (R = 0.62), the change in serum IgG or half-life of IgG after IVIG infusion was not (R < or = 0.09). The serum IgG concentration was increased (p < 0.05) in IVIG-treated patients for 8 weeks. There were 88 episodes of late-onset sepsis in 79 neonates (10.5%). Causative organisms included the following: Staphylococcus epidermidis (37 episodes), Enterococcus (9), Staphylococcus aureus (7), Candida (6), Escherichia coli (6), and multiple organisms (11). Sepsis, death, and death as a result of infection were unaffected by treatment. We conclude that a single infusion of IVIG, 500 mg/kg, shortly after birth was not effective prophylaxis for late-onset infection in premature neonates. Future studies of late-onset sepsis prophylaxis should consider IVIG with known pathogen-specific antibody concentrations against organisms causing these infections, in particular S. epidermidis.

Novel replication inhibitory function of the developmental regulator/transcription repressor protein WT1 encoded by the Wilms' tumor gene.

The tumor suppressor/developmental regulator protein WT1 encoded by the Wilms' tumor gene is a zinc finger-containing transcription factor which binds to the G+C-rich motif 5'-GCGGGGGCG-3' and represses transcription. Alternatively spliced variants of WT1 (termed+KTS) having an insertion in the zinc finger region are defective for binding to and hence for repression of transcription from promoters containing this motif. Due to the known interactions of two other tumor suppressor proteins with the simian virus 40 (SV40) oncoprotein large tumor antigen (TAg) [which in one case (p53) results in inhibition of the replication initiation activity of TAg], and because of the presence of G+C-rich sequences in the SV40 origin region, we tested the effect of WT1 on TAg- and SV40 origin-dependent DNA replication. WT1 and its alternatively spliced variants were found to be potent inhibitors of replication. Inhibition of replication by WT1 required portions of the N-terminal transcription repression domain and the C-terminal DNA binding domain, while other WT1 sequences needed for transcriptional regulation were dispensable. WT1 neither inhibited the synthesis of TAg nor formed a stable complex with it. Studies of the requirement of cis-active origin sequences in vivo and protein-DNA interactions in vitro indicated that WT1 and its alternatively spliced variants might inhibit replication by their novel binding to the GC box promoter motifs of the SV40 21 bp repeat replication-auxiliary sequence.

Transcriptional activity of the homopurine-homopyrimidine repeat of the c-Ki-ras promoter is independent of its H-forming potential.

The mouse c-Ki-ras protooncogene promoter contains an unusual DNA element consisting of a 27 bp-long homopurine-homopyrimidine mirror repeat (H-motif) adjacent to a d(C-G)5 repeat. We have previously shown that in vitro these repeats may adopt H and Z conformations, respectively, causing nuclease and chemical hypersensitivity. Here we have studied the functional role of these DNA stretches using fine deletion analysis of the promoter and a transient transcription assay in vivo. We found that while the H-motif is responsible for approximately half of the promoter activity in both mouse and human cell lines, the Z-forming sequence exhibits little, if any, such activity. Mutational changes introduced within the homopurine-homopyrimidine stretch showed that its sequence integrity, rather than its H-forming potential, is responsible for its effect on transcription. Electrophoretic mobility shift assays revealed that the putative H-motif tightly binds several nuclear proteins, one of which is likely to be transcription factor Sp1, as determined by competition experiments. Southwestern hybridization studies detected two major proteins specifically binding to the H-motif: a 97 kD protein which presumably corresponds to Sp1 and another protein of 60 kD in human and 64 kD in mouse cells. We conclude that the homopurine-homopyrimidine stretch is required for full transcriptional activity of the c-Ki-ras promoter and at least two distinct factors, Sp1 and an unidentified protein, potentially contribute to the positive effect on transcription.

Intravenous immune globulin therapy for early-onset sepsis in premature neonates.

Newborn infants may have IgG deficiencies that increase their susceptibility to bacterial infection. To determine whether intravenous immune globulin (IVIG) therapy improves survival rates in early-onset sepsis, we prospectively entered 753 neonates (birth weight 500 to 2000 gm, gestation less than or equal to 34 weeks, age less than or equal to 12 hours) into a multicenter, double-blind, controlled trial. Blood culture specimens were obtained and infants randomly assigned to receive 10 ml (per kilogram) intravenously of a selected IVIG (500 mg/kg) or albumin (5 mg/kg) preparation. Maternal and neonatal risk factors were not different between groups. Thirty-one babies (4.2%) had early-onset sepsis; the causative organisms were group B streptococcus (12 babies), Escherichia coli (6), and others (13). Of these 31 neonates, 7 (23%) died. Total serum IgG was higher for 7 days after IVIG therapy than after albumin treatment (p less than 0.05). During these 7 days, 5 (30%) of 17 albumin-treated and none of 14 IVIG-treated patients died (p less than 0.05). The survival rate at 56 days of age, however, was not significantly improved. Group B streptococcus type-specific IgG antibody was significantly increased after IVIG treatment and appeared to be related to the amount of IVIG specific antibody. Infusion-related adverse reactions were less frequent in patients receiving IVIG therapy (0.5%) than in those receiving albumin. The IVIG therapy in neonates with early-onset sepsis, while reducing the early mortality rate, did not significantly affect the overall survival rate. Further studies are necessary to confirm these findings and to determine more effective therapeutic regimens.

Efficient replication of plasmids containing the SV40 origin in N-myc overexpressing human neuroblastoma cells.

Using test plasmids containing the SV40 origin, we found a wide spectrum of permissiveness to their replication in different human cell lines. N-myc overexpressing neuroblastoma cells were highly permissive. LA-N-1 neuroblastoma cells were the most permissive of all the cell lines that we tested including the homologous CV-1 or COS-1 monkey kidney cells. Other human cell lines expressing various amounts of c-myc, and the 293 cell line expressing adenovirus E1A and E1B exhibited intermediate levels of permissiveness. T24 and EJ bladder carcinoma cells, which do not express the myc genes, were nonpermissive. Transient expression of c-myc or N-myc from plasmid vectors resulted in a modest stimulation of replication. Replication of test plasmids containing different configurations of the SV40 origin region was activated by the myc proteins. The high efficiency of replication in LA-N-1 cells is due to a combination of reasons including the overproduction of N-myc, high efficiency of expression of the SV40 replication initiator protein large T antigen from a cotransfected expression plasmid (containing the T antigen gene under the RSV LTR control), and other unknown host cell replication stimulatory factors. Replication of test plasmids was not detected in N-myc or c-myc overexpressing cells when the T antigen expression plasmid was not provided, showing that the myc proteins cannot substitute for T antigen in SV40 DNA replication.

Sequence requirements for activation of replication by the SV40 transcriptional promoter or enhancer elements.

Previous studies have demonstrated that the 21- or the 72-bp repeat transcriptional control elements enhance the efficiency of SV40 DNA replication in vivo, provided either of these repeats is located near the end of the core replication origin containing the 17-bp A + T-containing sequence. Using two sets of point mutants we have investigated the contributions of the various sequence motifs present in the 21- or the 72-bp repeats toward activation of replication. Regarding the contribution of the six GC motif components of the 21-bp repeats, we find that GC motif I, located closest to the core origin, is dispensable for activation of replication. A mutation in GC-I in fact causes an increase in replication efficiency. We also find that GC motifs I and II present in the nontandem copy of the 21-bp repeats are not sufficient to activate replication. Our present study indicates that a combination of three GC motifs such as II, III, and IV (including one of the two perfect, tandem copies of the 21-bp repeats) is important for activation of replication. Regarding the 72-bp repeat transcriptional enhancer region, we find mutations in a number of its individual motifs to have a negative consequence on replication, with mutations in the GT-I*/TC-II and Sph-II/octamer motifs exhibiting the most negative effects. Overall, we find that the replication activation effects of the 21- and the 72-bp repeats require the participation of multiple motifs present in them. Cellular factors binding to these motifs are expected to mediate their replication activation effects. For the most part, the motifs required for activation of replication are the same as those reported in earlier studies to be important for efficient early and late viral mRNA transcription.