Three-year outcomes of intracapsular femoral neck fractures fixed with sliding hip screws in adults aged under sixty-five years.

INTRODUCTION: Intracapsular femoral neck fractures remain associated with high rates of post-traumatic femoral head necrosis, non-union, and revision surgery. AIM: Our aim was to identify factors associated with revision surgery in intracapsular femoral neck fractures treated with sliding hip screws (SHS) in adults aged <65 years. PATIENTS AND METHODS: Consecutive admissions were identified retrospectively from the Royal Victoria Hospital, Belfast, which was the largest volume hospital on the National Hip Fracture Database. Of 2201 hip fractures between 1st August 2008 and 31st December 2010, 97 (4%) intracapsular fractures treated with SHS in adults <65 years were followed for a mean of 2.9 years (range 0-6.6). RESULTS: Twenty-one (22%) hips were revised to arthroplasty. Avascular necrosis developed in 28 (29%) femoral heads. Eight (8%) fractures proceeded to non-union. Displaced fractures (p<0.001, Fisher's exact [FE]), posterior comminution (p=0.049, FE), chronic respiratory disease (p=0.006, FE) and residual distraction (p=0.011, χ2) were associated with revision to arthroplasty. Multiple regression found displaced fractures (p=0.006) and chronic respiratory disease (p=0.017) significant; in the latter 4 of 6 were revised (67%), including all four patients with chronic obstructive pulmonary disease (COPD). Eleven (11%) individuals required walking aids before injury, which rose to 34 (35%) at one year (p<0.0001, χ2). Eighty-nine (92%) individuals could walk alone outdoors before injury, but only 76 (78%) at one year (p=0.009, χ2). CONCLUSIONS: Displaced fractures in individuals with chronic respiratory disease should be considered high risk for revision to arthroplasty. Posterior cortex deficiency should be evaluated prior to choice of operation. Fracture biology and revascularisation play a greater role than operation timing. A significant proportion of individuals do not recovery pre-morbid mobility by one year.

Traumatic central cord syndrome: neurological and functional outcome at 3 years.

STUDY DESIGN: Retrospective cohort analysis with prospective follow-up. OBJECTIVES: To evaluate neurological and functional recovery following central cord syndrome. SETTING: Northern Ireland, population 1.8 million. METHODS: Twenty-seven cords were identified in 1 year. Five managed conservatively and 22 with surgery. American Spinal Injury Association (ASIA) motor scores (AMS) were calculated to assess neurological recovery. Rotterdam scores assessed functional independence at 3 years. RESULTS: Average age was 62 years. Mechanism of injury was a fall with neck hyperextension in 81% patients. Average AMS in surgical patients improved from injury, preoperatively, postoperatively, 6 months and 3 years from 51, 81, 83, 90 to 96, respectively. Conservative patients improved from time of injury to day 10 from 57 to 86 and then fell to 84 at 6 months. By 3 years, this had recovered to 91. There was no statistical significant difference in AMS (P=0.15)/change in AMS (ΔAMS) (P=0.92) or percentage of motor deficit resolution (P=0.23) between groups at 3 years. Two patients underwent surgery within 48 h and achieved full motor recovery by 3 years, but this was not significant (P=0.2). ASIA score improvement had a positive correlation with age at injury. Patients treated with surgery had better Rotterdam scores at 3 years than those managed conservatively (P=0.05). CONCLUSIONS: This study confirms the natural history of central cord syndrome. Although it demonstrates equivocal neurological recovery for both groups, patients treated with surgery regained a greater degree of functional independence.

Extensive cervical spine and foregut anomaly in 'serpentine syndrome'.

INTRODUCTION: We report an extremely rare and challenging combination of congenital anomalies. Only five similar cases have been described in the English language medical literature to date. PRESENTATION OF CASE: A male infant was born at 30(+5) weeks gestation by emergency caesarian section. Cervical spine rachischisis, shortened oesophagus, intrathoracic stomach, atretic duodenum and absent spleen were noted, in addition to respiratory insufficiency. Gastrointestinal re-anastomosis, particularly oesophageal lengthening, was not feasible at the initial thoracotomy. Surgical stabilization of the cervical spine was unlikely to be successful until two years of age. Asplenia predisposed the infant to sepsis from encapsulated organisms, and recurrent respiratory infections occurred. DISCUSSION: A close relationship exists between the upper gastrointestinal tract and cervical spine during embryonic development. An embryonic aberration at this level could account for all the deformities present in this infant. Tethering of the embryonic cervical oesophagus to the somites in the first trimester, preventing foregut elongation, and producing ischaemia at the coeliac axis, is suggested as the aetiology. CONCLUSION: This case presented a challenge to the multi-disciplinary team involved in his management and prompted extensive consultation with international experts. After considerable counseling of the parents, care was directed towards palliation.

Pseudarthrosis of femoral neck stress fracture treated with open reduction, sliding hip screw and bone morphogenic protein.

INTRODUCTION: Pseudarthrosis of femoral neck stress fractures in young adults are associated with a high incidence of complications and revision surgery. The majority are treated urgently with closed reduction and internal fixation. PRESENTATION OF CASE: We describe a displaced tension-type femoral neck fatigue fracture presenting late. Pseudarthrosis formation prior to surgery resulted in resorption and shortening of the femoral neck. Open reduction and internal fixation was performed, with adjuvant recombinant human bone morphogenic protein-7 therapy. Radiological union was achieved by twelve weeks and by one year the patient was asymptomatic. DISCUSSION: Reports of successful management of femoral neck fatigue fracture non-unions are rare. Meyer's muscle pedicle graft, valgus subtrochanteric osteotomy, and cannulated screw fixation with autologous iliac crest bone graftare alternative procedures. CONCLUSION: This extremely rare fracture type merits open reduction to enable accurate fracture reduction. Supplementing sliding hip screw fixation with an orthobiological agent was successful in this challenging situation.

Type IV hypersensitivity to a textured silicone breast implant.

We present a case of hypersensitivity to a breast implant in a 57-year old female with breast cancer and hypersensitivity to adhesive dressings. A mastectomy, axillary node clearance, latissimus dorsi flap and silicone implant-based reconstruction were performed. The mammary wound dehisced within three weeks and the implant required removal. No pus was present, and cultures were negative. Three years later, a further silicone implant was inserted. Within three weeks from insertion, the patient required readmission with serous discharge from the wound, flu-like symptoms, low-grade pyrexia and painful swelling at the operative site. The implant was removed. Capsule biopsies demonstrated a large lymphoid cell reaction, in keeping with a delayed hypersensitivity reaction. Patch testing to samples of the implant was positive.

Cryomicroscopy of human cytomegalovirus virions reveals more densely packed genomic DNA than in herpes simplex virus type 1.

All members of the herpesvirus family have a characteristic virion structure, comprising a DNA containing, icosahedral capsid, embedded in a proteinaceous layer (tegument) and surrounded by a lipid envelope. Human cytomegalovirus (HCMV, the prototypic beta-herpesvirus) has a genome that is significantly larger (>50 %) than that of the alpha-herpesvirus HSV-1. Although the internal volume of the HCMV capsid is approximately 17 % larger than that of HSV-1, this slight increase in volume does not provide adequate space to encapsidate the full length HCMV genome at the same packing density as HSV-1. We have investigated the nature of DNA packing in HCMV and HSV-1 virions by electron-cryomicroscopy and image processing. Radial density profiles calculated from projection images of HCMV and HSV-1 capsids suggest that there is no increase in the volume of the HCMV capsid upon DNA packaging. Packing density of the viral DNA was assessed for both HCMV and HSV-1 by image analysis of both full and empty particles. Our results for packing density in HSV-1 are in good agreement with previously published measurements, showing an average inter-layer spacing of approximately 26 A. Measurements taken from our HCMV images, however, suggest that the viral genomic DNA is more densely packed, with an average inter-layer spacing of approximately 23 A. We propose therefore, that the combination of greater volume in HCMV capsids and increased packing density of viral DNA accounts for its ability to encapsidate a large genome.

HSV molecular biology: general aspects of herpes simplex virus molecular biology.

Comparison of the herpes simplex virus type 1 (HSV-1) DNA sequence with that of other alpha, beta and gamma-herpesviruses, allied with molecular genetic studies have greatly increased understanding of the HSV genome and the functions encoded by individual virus genes and has facilitated the development of rational antiviral strategies. Here we review the coding content of the HSV-1 genome and identify: genes encoding structural components of the capsid, tegument or envelope; genes whose products are essential for growth in tissue culture; and genes that are conserved between members of the alpha, beta and gamma-herpesvirinae. The HSV lifecycle and the main regulation cascade is discussed and genes that present targets for antiviral intervention identified. The protein content of the infectious virion particle is reviewed and compared with that of two additional non-infectious HSV-related particles species (L-particles and pre-DNA replication particles (PREPs)). The potential of HSV-1 L particles and PREP particles as DNA-free HSV-1 vaccine candidates and the desirability of deleting specific gene products from live HSV vaccines is discussed.

Structure of the human cytomegalovirus B capsid by electron cryomicroscopy and image reconstruction.

The three-dimensional structure of B capsids of the beta-herpesvirus human cytomegalovirus (HCMV) was investigated at a resolution of 3.5 nm from electron cryomicrographs by image processing and compared with the structure obtained for the alpha-herpesvirus herpes simplex virus type 1 (HSV-1). The main architectural features of the HSV-1 and HCMV capsids are similar: the T = 16 icosahedral lattice consists of 162 capsomers, composed of two distinct morphological units, 12 pentamers and 150 hexamers, with triplex structures linking adjacent capsomers at positions of local threefold symmetry. The main differences in the HSV-1 and HCMV capsids are found in the diameter of the capsids (125 and 130 nm, respectively); the hexamer spacing and relative tilt (center-to-center hexon spacing at outer, edge, 17.9 and 15.8 nm, respectively); the morphology of the tips of the hexons (similar in length but 33% thinner in HCMV); and the average diameter of the scaffold (44 and 76 nm, respectively). By analogy with HSV-1, the mass on the HCMV hexon tip is attributed to the smallest capsid protein (HCMV gene UL48/49). The differences in capsid structure are discussed in relation to the ability of the HCMV structure to package a genome some 60% larger than that of HSV-1.

Investigation of the Anti-HSV Activity of Candidate Antiviral Agents.

Herpes simplex virus (HSV) is a human pathogen that causes diseases ranging in medical importance from herpes labialis, through genital herpes and herpes keratitis, to herpes encephalitis-a life-threatening disease. HSV types 1 and 2 have the ability to enter a latent phase during in vivo infection, during which time the virus is able to evade immune surveillance, and from which state it is able to escape from time to time to cause disease, especially in immunocompromised individuals. This characteristic makes antiviral chemotherapy an indispensable weapon in the management of recurrent herpesvirus infection.

The published DNA sequence of human cytomegalovirus strain AD169 lacks 929 base pairs affecting genes UL42 and UL43.

Compared with the published DNA sequence (M. S. Chee, et al. Curr. Top. Microbiol. Immunol. 154:125-170, 1990), most isolates of human cytomegalovirus strain AD169 contain an additional 929 bp after nucleotide 54612. This results in a changed reading frame for the 5'-terminal 50 codons of gene UL42 and expansion of gene UL43 (a US22 family member) from 187 (3'-truncated) to 423 (full-length) codons. The UL42 and UL43 gene products are nonessential for growth in culture.

The effect of herpes simplex virus type 1 L-particles on virus entry, replication, and the infectivity of naked herpesvirus DNA.

Herpes simplex virus type 1(HSV-1) L-particles are known to be composed mainly of envelope and tegument proteins, to lack the nucleocapsid, and to be noninfectious. Thus L-particles represent interesting vaccine candidates. L-particles at > 1000/cell interfered with HSV-1 virion adsorption and penetration While L-particles did not affect HSV-1 growth kinetics in resting or nonresting BHK cultures infected with purified virions, treatment with L-particles before, or after, transfection with HSV-1 DNA resulted in a progressive increase in plaque numbers (five- to sixfold at 1000 L-particles/cell). Transfection assays using HSV-1 ts mutant DNA (ts 1201) revealed that enhancement was due to induction of otherwise nonreplicating genomes. The enhancement obtained with L-particles produced by WT HSV-1 or by mutants that are either deleted, or defective, in certain gene products was compared. Most important were the Vmw110 (ICP0) and Vmw65 (alpha-TIF) proteins, but VP11/12, VP13/14, and vhs also have a role. The L-particle-associated Vmw175 (ICP 4) protein did not appear be involved. The effect of homologous and heterologous combinations of pseudorabies virus, equineherpesvirus-1, and HSV-1 DNA's and L-particles was investigated in transfection assays. The L-particles of each virus, to varying extent, enhanced the plaquing efficiency of their own DNA but were also effective in heterologous combinations.

Suppression of amber nonsense mutations of herpes simplex virus type 1 in a tissue culture system.

We have investigated the ability of monkey kidney cell lines (SupD3 and SupD12) inducibly expressing an amber suppressor tRNA(ser) to suppress amber nonsense mutations in three genes of herpes simplex virus type 1 (HSV-1). HSV-1 mutant TK4, which contains a nonsense mutation in the non-essential viral thymidine kinase (TK) gene, synthesized a full-length TK polypeptide at about 30% of the wild-type (wt) level in induced SupD3 cells but not in the parental non-suppressor (Sup0) cells. Using complementing cells, we constructed HSV-1 mutants carrying nonsense mutations in an essential gene, UL8, encoding a protein essential for viral DNA replication (ambUL8) or in a partially dispensable gene, UL12, encoding alkaline nuclease (ambUL12). The growth of the mutants in Vero or Sup0 cells was either totally (ambUL8) or severely (ambUL12) impaired, whereas in cells expressing suppressor tRNA the mutants produced infectious virus. However, the yields were much lower than obtained with wt HSV-1. In Vero or Sup0 cells the mutants ambUL8 and ambUL12 failed to synthesize full-length UL8 and UL12 protein products, respectively. Western immunoblotting showed that the virus ambUL12 produced full-length UL12 protein in SupD12 cells which yielded a level of 25.9% of the alkaline nuclease activity of the wt HSV-1 control. Our results show that the levels of suppression of the nonsense mutations in ambUL8 and ambUL12 are insufficient to allow their continuing propagation in the available Sup+ cells. Possible reasons are discussed.

PREPs: herpes simplex virus type 1-specific particles produced by infected cells when viral DNA replication is blocked.

Herpes simplex virus (HSV)-infected cells produce not only infectious nucleocapsid-containing virions but also virion-related noninfectious light particles (L-particles) composed of the envelope and tegument components of the virus particle (J. F. Szilágyi and C. Cunningham, J. Gen. Virol. 62:661-668, 1991). We show that BHK and MeWO cells infected either with wild-type (WT) HSV type 1 (HSV-1) in the presence of viral DNA replication inhibitors (cytosine-beta-D-arabinofuranoside, phosphonoacetic acid, and acycloguanosine) or with a viral DNA replication-defective mutant of HSV-1 (ambUL8) synthesize a new type of virus-related particle that is morphologically similar to an L-particle but differs in its relative protein composition. These novel particles we term pre-viral DNA replication enveloped particles (PREPs). The numbers of PREPs released into the culture medium were of the same order as those of L-particles from control cultures. The particle/PFU ratios of different PREP stocks ranged from 6 x 10(5) to 3.8 x 10(8), compared with ratios of 3 x 10(3) to 1 x 10(4) for WT L-particle stocks. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western immunoblot analyses revealed that true late proteins, such as 273K (VP1-2), 82/81K (VP13/14), and gC (VP8), were greatly reduced or absent in PREPs and that gD (VP17) and 40K proteins were also underrepresented. In contrast, the amounts of proteins 175K (VP4; IE3), 92/91K (VP11/12), 38K (VP22), and gE (with BHK cells) were increased. The actual protein composition of PREPs showed some cell line-dependent differences, particularly in the amount of gE. PREPs were biologically competent and delivered functional Vmw65 (VP16; alpha TIF) to target cells, but the efficiency of complementation of the HSV-1 (strain 17) mutant in1814 was 10 to 30% of that of WT L-particles.

Identification and characterization of the protein product of gene 71 in equine herpesvirus 1.

Equine herpesvirus 1 (EHV-1) strain Ab4 gene 71 is predicted to encode a primary product with a M(r) of 80.1K. We have previously constructed a deletion/lacZ insertion mutant, ED71, and demonstrated that gene 71 is dispensable for growth of virus in cell culture. We have now constructed a gene 71 revertant, Re71. To identify and characterize the product of gene 71, we produced a specific antiserum, anti-71, against a beta-galactosidase fusion protein containing the carboxy terminus of the gene 71 polypeptide. Using the anti-71 serum, mutant ED71 and the revertant Re71, we have demonstrated that gene 71 encodes a 192K polypeptide. Experiments with glycosylation inhibitors revealed that the protein product of gene 71 is N-glycosylated and heavily O-glycosylated. When the 192K polypeptide is synthesized in the presence of monensin, the M(r) of the polypeptide is reduced to 80K, the predicted unmodified M(r) of the gene 71 polypeptide. The gene 71 product is found in virions and L particles in a fully processed form that runs as a diffuse band in electrophoresis, with a M(r) in excess of 200K. Immunofluorescence and virion surface labelling experiments showed that the polypeptide product of gene 71 is located on cellular membranes and the virion envelope. A time course of infection confirmed that gene 71 is regulated as a leaky late gene in infected cells. Finally, using wild-type EHV-1 Ab4, mutant ED71, revertant Re71 and two antibodies (P19 against EHV-1 glycoprotein gp300, and anti-71) we conclusively demonstrated that gene 71 encodes gp300. This contradicts published results with P19 alone, which indicated gp300 was the product of EHV-1 gene 28.

The effect of cicloxolone sodium on the replication of vesicular stomatitis virus in BSC-1 cells.

The effect of cicloxolone sodium (CCX) on the replication of vesicular stomatitis virus (VSV) was investigated. The drug was active during all stages of the virus replication cycle, indicating that it does not operate by the specific inhibition of any single essential virus gene product. The drug reduced the number of VSV particles assembled and released by 100- to 1000-fold. Infectious virus yield was reduced 1000- to 10000-fold, giving a 10-fold or greater increase in the particle/p.f.u. ratio. The reduced number of virus particles produced in the presence of CCX results from two superimposed effects: suppression of VSV secondary transcription and viral protein synthesis, and perturbation of virion assembly. The inhibition of VSV assembly is due to impairment of a Golgi apparatus function related to transport of VSV glycoprotein G to the cell surface, and is characterized by accumulation of viral G and M proteins within the cell. Incubation of VSV-infected cells in the presence of two glycosylation inhibitors, tunicamycin and monensin, similarly leads to intracellular accumulation of G and M proteins, suggesting a common mechanism of action affecting VSV virion assembly. The differential effect of CCX concentration on intracellular levels of the L, N and NS proteins was analysed. CCX also possesses a virucidal effect on mature infectious VSV particles in suspension, 300 microM reducing the VSV titre about 10-fold in 24 h at 4 degrees C or 37 degrees C. The mode of antiviral activity against VSV is compared with that against herpes simplex virus.

The effect of cicloxolone sodium on the replication in cultured cells of adenovirus type 5, reovirus type 3, poliovirus type 1, two bunyaviruses and Semliki Forest virus.

The effect of cicloxolone sodium (CCX) on the replication of typical representatives of different virus families [adenovirus type 5 (Ad-5), reovirus type 3 (Reo-3), Bunyamwera and Germiston viruses, poliovirus type 1 (Polio-1) and Semliki Forest virus (SFV)] in tissue culture was investigated. The Golgi apparatus inhibitor monensin (Mon) and CCX were shown to have analogous effects on some aspects of virus replication. Although the Mon-like effect of CCX played no role in the antiviral activity against Ad-5, Reo-3 or Polio-1, it could entirely account for the antiviral activity against the Bunyamwera and Germiston viruses, for which inhibition of glycoprotein processing was responsible for the antiviral activity. In the case of SFV, the Mon-like activity of CCX caused cytoplasmic assembly of fully infectious SFV within vacuoles and thus impaired virus release without altering total infectious virus yield. Fewer Ad-5 and Reo-3 progeny were produced in the presence of the drug. CCX had a dose-dependent biphasic effect on the particle:p.f.u. ratio of the Reo-3 yield. At low CCX concentration (less than 50 microM) the virus yield contained poor quality, non-infectious virus, but at higher CCX concentration (greater than or equal to 100 microM) low quality virus could no longer be successfully assembled. We conclude that the antiviral effect can be manifested in three ways: (i) by a reduction in the virus particle yield produced; (ii) by a loss of quality (relative infectivity); (iii) by a virucidal effect of the drug. We have previously defined three CCX sensitivity classes. Mechanisms (i), (ii) and (iii) operate against viruses belonging to class CCXs-1 [herpes simplex virus (HSV) type 1, HSV-2 and vesicular stomatitis virus], but essentially only (i) and (ii) affect Reo-3 (CCXs-2), whereas (i) and possibly (iii) affect Ad-5 (CCXs-2). In the case of SFV (CCXs-3) none of these mechanisms operate, but relocation of assembled virus is found.

The difference in sensitivity to cicloxolone sodium between herpes simplex virus types 1 and 2 maps to the locations of genes UL22 (gH) and UL44 (gC).

Cicloxolone sodium (CCX) is a broad spectrum antiviral agent which has a largely non-specific and complex mode of antiviral action. However, the experimental finding that herpes simplex virus type 2 (HSV-2) (strain HG52) is consistently more sensitive to inhibition by CCX than HSV-1 (117 syn+) additionally implies the specific involvement of HSV genes. HSV-1/HSV-2 intertypic recombinants have been utilized to investigate this genetic difference by comparing their CCX ED50 concentrations. No short stretch of HSV-2 DNA was associated with its greater sensitivity to CCX, implying that two or more non-contiguously located HSV genes are involved. Correlating CCX sensitivity with recombinant virus genome structures allowed separate evaluation of the gene regions encoding glycoproteins gB, gC, gD, gE, gG, gH and gI and this suggests that the gene locations encoding gH and gC determine the CCX sensitivity difference. The selective inhibitor of Golgi apparatus glycosylation, monensin, gave results analogous to those obtained with CCX.

The effect of triterpenoid compounds on uninfected and herpes simplex virus-infected cells in culture. III. Ultrastructural study of virion maturation.

Electron microscope studies been made of mock-infected or herpes simplex virus (HSV) type 1 (strain 17)- or HSV-2(strain HG52)-infected Flow 2002 cells grown in the absence or presence of various concentrations of cicloxolone sodium (CCX). Fifty non-serial, thin sections of mock-infected or HSV-infected cells, which contained a portion of the nucleus, were examined by transmission electron microscopy. With increasing drug concentration, counts of capsid structures both in the nucleus and cytoplasm showed a decrease in the number of virions per cell section, an increase in the ratio of nuclear to cytoplasmic virus, a relative reduction in the percentage of cytoplasmic enveloped virus particles, but no effect on the ratio of empty to core-containing capsid structures. The high particle to p.f.u. ratio induced by CCX treatment is thus not explained through failure to assemble morphologically mature core-containing capsids. In part it can be explained by non-envelopment, but in addition, specific effects on other virion proteins (tegument and envelope) must be involved. The extracellular virus particle yield was unaffected, indicating that CCX treatment enhances the egress of HSV. In the presence of CCX the encapsidation of HSV DNA into DNase-resistant structures was unaffected.

The antiviral activity against herpes simplex virus of the triterpenoid compounds carbenoxolone sodium and cicloxolone sodium.

Dose-response experiments show that the presence of 300 microM cicloxolone sodium (CCX) or 500 microM carbenoxolone sodium (CBX) during the HSV replication cycle reduced the infectious virus yield by 10,000- to 100,000-fold: CCX is the more potent anti-herpes agent. HSV-2 replication was consistently more severely restricted by either drug than was that of HSV-1. The ED50 values obtained for either drug against HSV-1 or HSV-2 correlate well with data from dose-response curves. CCX, and to a lesser extent CBX, can be cytotoxic but the degree of cytotoxicity varies between cell lines and is also affected by the physiological state of the cells. Triterpenoid drugs exhibit some activity against virus particles in suspension but the effect is small and contributes little to the overall antiviral effect. The drugs appear to be active throughout the replication cycle. In contrast to all other anti-herpesvirus agents in clinical use the triterpenoid compounds do not appear to act directly to block virus DNA synthesis. HSV mutants resistant to ACG and PAA, or lacking a thymidine kinase gene, appear as sensitive as wild-type virus to CCX inhibition. HSV growth in the presence of the drugs resulted in a lower number of assembled virus particles but reduced to a much greater extent the infectious virus yield: thus the progeny virus quality is greatly diminished. Thermolability of progeny virus correlated well with this diminution of quality in increasing CCX concentration. SDS PAGE analysis of the structural proteins of virus particles made in cells treated with 300 microM CCX revealed numerous differences in the relative intensities of protein bands, which is in keeping with the changed quality of the drug-produced virus. SDS PAGE analysis of the polypeptides induced in drug treated infected cells revealed two effects; some polypeptides were synthesised in reduced amounts and the nuclear/cytoplasmic distribution of certain proteins was affected. Post-translational processing by glycosylation and sulphation of both cellular and HSV induced proteins was strongly inhibited by the triterpenoid drugs, while phosphorylation of only a few polypeptides appeared to be affected.

The effect of triterpenoid compounds on uninfected and herpes simplex virus-infected cells in culture. II. DNA and protein synthesis, polypeptide processing and transport.

The effect of the triterpenoid drugs carbenoxolone sodium (CBX) and cicloxolone sodium (CCX) on DNA and protein synthesis in uninfected and herpes simplex virus (HSV)-infected BHK-21 or Flow 2002 cells has been studied. No consistent effect of 500 microM-CBX or 300 microM-CCX on HSV DNA synthesis was identified. With 300 microM-CCX, some inhibition of cellular DNA synthesis was observed, but this was relatively slight. The restriction enzyme digest profiles of HSV DNA from drug-treated cells appeared normal. The synthesis of several HSV-specified polypeptides was much reduced by treatment with CBX or CCX and the transport of certain proteins between the nuclear and cytoplasmic compartments of infected cells was also affected. CBX or CCX treatment strongly inhibited post-translational glycosylation and sulphation of both host- and HSV-specified proteins, but the phosphorylation of only a few proteins appeared affected. The drugs induced quantitative changes in the synthesis of some BHK cell polypeptides, but these were not considered important. CCX treatment of Flow 2002 cells, however, induced the synthesis of several new polypeptides, some of which had the same apparent molecular weights as identified Flow 2002 cell stress proteins. When treated with concentrations greater than 50 microM-CCX, the plasma membranes of both uninfected and HSV-infected cells became increasingly leaky. The SDS-PAGE polypeptide profile of purified virus particles made in BHK cells treated with 300 microM-CCX differed markedly from that synthesized under drug-free conditions. The greatly reduced amount of infectious virus made in cells treated with 300 microM-CCX was more thermolabile at 42 degrees C than virus produced in the absence of the drug. Our results indicate that the antiviral activity of the triterpenoid drugs is non-specific and operates by interfering with or changing the normal function of cell membranes so that cells, although retaining their viability, can no longer assemble the virus components efficiently into infectious particles. As a consequence, the population of virus particles made is of inferior quality. While we have no evidence that there is also a specific anti-HSV effect, this possibility cannot yet be ruled out.