Infection of normal individuals with human parvovirus (B19) results in a mild disease (erythema infectiosum) but gives rise to aplastic crises in patients with chronic hemolytic anemias. The effects of this disease on hemopoiesis were investigated following intranasal inoculation of the virus into three volunteers. A typical disease ensued with a viremia peaking at 9 d. Marrow morphology 6 d after inoculation appeared normal but at 10 d there was a severe loss of erythroid precursors followed by a 1-2-g drop in hemoglobin, and an increase in serum immunoreactive erythropoietin. Erythroid burst-forming units (BFU-E) from the peripheral blood were considerably reduced, starting at the time of viremia and persisting for 4-8 d depending on the individual. Granulocyte-macrophage colony-forming units (CFU-GM) were also affected but the loss started 2 d later. Both CFU-GM and BFU-E showed a sharp overshoot at recovery. In the marrow, BFU-E and CFU-E were reduced at 6 and 10 d in the individual having the longest period of peripheral progenitor loss. In contrast, there was an increase in BFU-E and CFU-E in the subject with least change in peripheral progenitors. In the third subject, with an intermediate picture, there was a loss at 6 d but an increase at 10 d of erythroid progenitors. It is suggested that the architecture of the marrow might partially isolate progenitors from high titers of virus in the serum and individual variation in this respect might give the results observed.
Whole-body exposure to large radiation doses can cause severe loss of hematopoietic tissue cells and threaten life if the lost cells are not replaced in a timely manner through natural repopulation (a homeostatic mechanism). Repopulation to the baseline level N0 is called reconstitution and a reconstitution deficit (repopulation shortfall) can occur in a dose-related and organ-specific manner. Scott et al. (2013) previously introduced a deterministic version of a threshold exponential (TE) model of tissue-reconstitution deficit at a given follow-up time that was applied to bone marrow and spleen cellularity (number of constituent cells) data obtained 6 weeks after whole-body gamma-ray exposure of female C.B-17 mice. In this paper a more realistic, stochastic version of the TE model is provided that allows radiation response to vary between different individuals. The Stochastic TE model is applied to post gamma-ray-exposure cellularity data previously reported and also to more limited X-ray cellularity data for whole-body irradiated female C.B-17 mice. Results indicate that the population average threshold for a tissue reconstitution deficit appears to be similar for bone marrow and spleen and for 320-kV-spectrum X-rays and Cs-137 gamma rays. This means that 320-kV spectrum X-rays could successfully be used in conducting such studies.
X rays; gamma rays; bone marrow; spleen; reconstitution
Bacteriophage HK97 maturation involves discrete intermediate particle forms, comparable to transitional states in protein folding, before reaching its mature form. The process starts by formation of a metastable prohead, poised for exothermic expansion triggered by DNA packaging. During maturation, the capsid subunit transitions from a strained to a canonical tertiary conformation and this has been postulated to be the driving mechanism for initiating expansion via switching hexameric capsomer architecture from skewed to 6-fold symmetric. We report the subnanometer electron-cryomicroscopy reconstruction of the HK97 first expansion intermediate prior to any crosslink formation. This form displays 6-fold symmetric hexamers, but, unexpectedly, capsid subunit tertiary structures exhibit distortions comparable to the prohead forms. We propose that release of this coat subunit strain acts in synergy with the first crosslinks to drive forward maturation. Finally, we speculate that the energetic features of this transition may result from increased stability of intermediates during maturation via enhanced inter-subunit interactions.
We report on a genomic and functional analysis of a novel marine siphovirus, the Vibrio phage SIO-2. This phage is lytic for related Vibrio species of great ecological interest including the broadly antagonistic bacterium Vibrio sp. SWAT3 as well as notable members of the Harveyi clade (V. harveyi ATTC BAA-1116 and V. campbellii ATCC 25920). Vibrio phage SIO-2 has a circularly permuted genome of 80,598 bp, which displays unusual features. This genome is larger than that of most known siphoviruses and only 38 of the 116 predicted proteins had homologues in databases. Another divergence is manifest by the origin of core genes, most of which share robust similarities with unrelated viruses and bacteria spanning a wide range of phyla. These core genes are arranged in the same order as in most bacteriophages but they are unusually interspaced at two places with insertions of DNA comprising a high density of uncharacterized genes. The acquisition of these DNA inserts is associated with morphological variation of SIO-2 capsid, which assembles as a large (80 nm) shell with a novel T=12 symmetry. These atypical structural features confer on SIO-2 a remarkable stability to a variety of physical, chemical and environmental factors. Given this high level of functional and genomic novelty, SIO-2 emerges as a model of considerable interest in ecological and evolutionary studies.
Research reported here relates to comparing the relative effectiveness of 320-kV X rays compared to Cs-137 gamma rays for two in vivo endpoints in C.B-17 mice after whole-body exposure: (1) cytotoxicity to bone marrow cells and splenocytes evaluated at 24-hours post exposure and (2) bone marrow and spleen reconstitution deficits (repopulation shortfalls) evaluated at 6 weeks post exposure. We show that cytotoxicity dose-response relationships for bone marrow cells and splenocytes are complex, involving negative curvature (decreasing slope as dose increases), presumably implicating a mixed cell population comprised of large numbers of hypersensitive, modestly radiosensitive, and resistant cells. The radiosensitive cells appear to respond with 50% being killed by a dose < 0.5 Gy. The X-ray relative biological effectiveness (RBE), relative to gamma rays, for destroying bone marrow cells in vivo is > 1, while for destroying splenocytes it is < 1. In contrast, dose-response relationships for reconstitution deficits in the bone marrow and spleen of C.B-17 mice at 6 weeks after radiation exposure were of the threshold type with gamma rays being more effective in causing reconstitution deficit.
X rays; gamma rays; RBE; cytotoxicity; bone marrow; splenocytes
Cryo-transmission electron microscopy (cryoTEM), with its unique capability for providing exact visual information of a sample in its natural hydrated state, is a powerful new tool in the armamentarium of characterization techniques applied to complex biological therapeutics. The ability of this technique to yield useful information on size, shape, morphology, aggregation state, and structural information is demonstrated through application to a variety of biologics.
Samples were preserved in vitrified ice supported by holey carbon films on 400-mesh copper grids. Electron microscopy was performed using an FEI Tecnai T12 electron microscope, operating at 120keV equipped with an FEI Eagle 4k x 4k CCD camera. Vitreous ice grids were transferred into the electron microscope using a cryostage that maintains the grids at a temperature below −170 °C. Images of each grid were acquired using automated image collection software package LEGINON at multiple scales to assess the overall distribution of the specimen. After identifying potentially suitable target areas for imaging at lower magnifications, pairs of high magnification images were acquired at nominal magnifications of 52,000x (0.21 nm/pixel) and 21,000x (0.50 nm/pixel). Quantitative analysis and 3D structure determination was enabled by the automated software package APPION.
CryoTEM can be used to visualize the integrity, morphology, size, and shape of a variety of biologics in their native state. Automated data collection and processing allowed quantitative analysis of shape, size, aggregation state, and concentration. Advanced methods can be used to determine the 3D structures of biologics, thereby allowing assessment of encapsulation efficiency, lamellarity, and the location of antigen binding sites.
CryoTEM provides a useful orthogonal characterization tool for understanding complex biologics.
The genetic aetiology of osteoarthritis has not yet been elucidated. To enable a well-powered genome-wide association study (GWAS) for osteoarthritis, the authors have formed the arcOGEN Consortium, a UK-wide collaborative effort aiming to scan genome-wide over 7500 osteoarthritis cases in a two-stage genome-wide association scan. Here the authors report the findings of the stage 1 interim analysis.
The authors have performed a genome-wide association scan for knee and hip osteoarthritis in 3177 cases and 4894 population-based controls from the UK. Replication of promising signals was carried out in silico in five further scans (44 449 individuals), and de novo in 14 534 independent samples, all of European descent.
None of the association signals the authors identified reach genome-wide levels of statistical significance, therefore stressing the need for corroboration in sample sets of a larger size. Application of analytical approaches to examine the allelic architecture of disease to the stage 1 genome-wide association scan data suggests that osteoarthritis is a highly polygenic disease with multiple risk variants conferring small effects.
Identifying loci conferring susceptibility to osteoarthritis will require large-scale sample sizes and well-defined phenotypes to minimise heterogeneity.
All AKR/J mice have a subtle defect that involves malformation of the central portion of hair fibres that is best visualized under white and polarized light microscopy.
This study sought to characterize the clinical and ultrastructural features of the hair interior defect (HID) phenotype and to determine the chromosomal localization of the hid mutant gene locus.
White and polarized light microscopy combined with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the HID phenotype. Complementation testing and gene-linkage studies were performed to map the locus.
Using SEM, the hair-fibre structure on the surface was found to be similar to hairs obtained from normal BALB/cByJ+/+and C57BL/6 J+/+mice. There were also no differences in sulphur content. TEM revealed degenerative changes in the medulla similar to that seen by light microscopy. This autosomal recessive mutation is called HID (locus symbol: hid). We mapped the hid locus to the distal end of mouse chromosome 1. No genes reported to cause skin or hair abnormalities are known to be within this interval except for the lamin B receptor (Lbr), which had been excluded previously as the cause of the hid phenotype in AKR/J mice.
A potentially novel gene or known gene with a novel phenotype resides within this interval, which may shed light on human diseases with defects in the inner structure of the hair fibre.
Solving the structure of macromolecular complexes using transmission electron microscopy can be an arduous task. Many of the steps in this process rely strongly on the aid of pre-existing structural knowledge, and are greatly complicated when this information is unavailable. Here we present two software tools meant to facilitate particle picking, an early stage in the single-particle processing of unknown macromolecules. The first tool, DoG Picker, is an efficient and reasonably general, particle picker based on the Difference of Gaussians (DoG) image transform. It can function alone, as a reference-free particle picker with the unique ability to sort particles based on size, or it can also be used as a way to bootstrap the creation of templates or training datasets for other particle pickers. The second tool is TiltPicker, an interactive graphical interface application designed to streamline the selection of particle pairs from tilted-pair datasets. In many respects, TiltPicker is a re-implementation of the SPIDER WEB tilted-particle picker, but built on modern computer frameworks making it easier to deploy and maintain. The TiltPicker program also includes several useful new features beyond those of its predecessor.
TEM; cryo-electron microscopy; particle picking; random conical tilt; orthogonal tilt reconstruction
To determine whether rheumatoid factor (RF), anti-cyclic citrullinated peptide (CCP) antibodies, or carriage of shared epitope (SE) and PTPN22 genetic susceptibility variants predict response to therapy in patients with rheumatoid arthritis (RA) treated with anti-tumour necrosis factor (TNF) agents.
UK-wide multicentre collaborations were established to recruit a large cohort of patients treated with anti-TNF drugs for RA. Serum RF, anti-CCP antibody and SE status were determined using commercially available kits. PTPN22 R620W genotyping was performed by Sequenom MassArray. Linear regression analyses were performed to investigate the role of these four factors in predicting response to treatment by 6 months, defined as the absolute change in 28-joint Disease Activity Score (DAS28).
Of the 642 patients analysed, 46% received infliximab, 43% etanercept and 11% adalimumab. In all, 89% and 82% of patients were RF and anti-CCP positive, respectively. Patients that were RF negative had a 0.48 (95% CI 0.08 to 0.87) greater mean improvement in DAS28 compared to patients that were RF positive. A better response was also seen among patients that were anti-CCP negative. No association was demonstrated between drug response and SE or PTPN22 620W carriage.
The presence of RF or anti-CCP antibodies was associated with a reduced response to anti-TNF drugs. However, these antibodies only account for a small proportion of the variance in treatment response. It is likely that genetic factors will contribute to treatment response, but these do not include the well established RA susceptibility loci, SE and PTPN22.
carbonic anhydrase; microenvironment; pH; hypoxia-inducible factor
BACKGROUND—Increased nitric oxide (NO) synthase activity and enhanced apoptosis are features of gastric mucosa infected with Helicobacter pylori and a causative relation has been suggested. However, although NO can promote apoptosis, its actions vary with cell type.
AIMS—To determine whether exogenous NO, derived from an NO donor, might promote or counteract apoptosis in gastric mucous epithelial cells.
METHODS—Primary cultures of guinea pig gastric mucosal cells were exposed to the NO donor S-nitroso-N-acetyl-penicillamine (SNAP) for 24 hours. Apoptosis was detected from nuclear staining with Hoechst 33258, in situ nick end labelling of DNA, and the presence of DNA "ladders" in cell extracts. Cyclic GMP content and caspase activity were determined by immunoassay and fluorimetric assay respectively.
RESULTS—SNAP 1 mM did not alter the small proportion of cells on the culture plate (3-6%) which exhibited features of apoptosis. However, SNAP produced an inhibition of apoptosis, and of caspase 3 like activity, when enhanced by 25 µM N-hexanoyl-D-sphingosine (C6-ceramide), or by detachment of cells from the culture plate. The guanylate cyclase inhibitor, 1H-1, 2, 4-oxadiazole-4, 3-a-quinoxaline-1-one (ODQ), prevented the stimulation of cyclic GMP by SNAP, but not the anti- apoptotic effects of the NO donor. The cyclic GMP analogues 8-bromo-cyclic GMP and 8-(4-chlorophenylthio) guanosine-3',5'- cyclic monophosphate did not significantly inhibit apoptosis in the mucosal cells.
CONCLUSIONS—Exogenous NO inhibited apoptosis in guinea pig gastric mucous cells by a mechanism which did not involve elevation of cyclic GMP. NO, if produced from NO synthase during infection with H pylori, may therefore counter the proapoptotic effects of this pathogen.
Keywords: nitric oxide; gastric mucosa; stomach; apoptosis
The existence of nearshore and offshore populations of the bottlenose dolphin has been documented throughout its range. In several cases the two regional forms have been shown to be morphologically distinct, although there is considerable overlap for most characters. The populations off the eastern coast of North America have been the subject of a long-term programme of research on their distribution and movements. In this study, we compare mitochondrial and nuclear genetic markers between dolphins classified as either nearshore or offshore type. These putative populations were found to be distinct at both nuclear and mitochondrial genetic markers. Further, the level of variation among the nearshore dolphins was reduced compared with the offshore population. A broader geographical comparison suggests a shared lineage between offshore dolphins from the western North Atlantic and both offshore and nearshore dolphins from the eastern Atlantic. These results are consistent with local differentiation based on habitat or resource specialization in the western North Atlantic, and suggest differences in the character of the nearshore/offshore distinction in different parts of the world.
Neither the maternal inheritance pattern nor the early onset of congenital myotonic dystrophy are fully explained. One possible mechanism is that mitochondrial DNA (mtDNA) mutations might interact with the DM gene product, producing an earlier onset than would otherwise occur. We have used Southern hybridisation to show that high levels of major rearrangements of mtDNA are not present in muscle of five and in blood of 35 patients with congenital myotonic dystrophy. We used sequence analysis to show that no one particular mtDNA morph appears to cosegregate with congenital onset. A minor degree of depletion of mtDNA compared with nuclear DNA was present in the muscle of five patients with congenital DM, but we propose that this is not the primary cause of the muscle pathology but secondary to it. We have not found evidence that mtDNA is involved in congenital myotonic dystrophy.
Thallium-201 stress scintigraphy (TSS) and echocardiography were performed on 60 consecutive black male hypertensives and compared to 60 sex-, race-, and age-matched controls. We found a higher prevalence of left ventricular hypertrophy with repolarization abnormality in the hypertensive group; 32 of 60 (53%), compared to 10 of 60 (17%) of the controls, P < .05. Echocardiographically determined left ventricular mass index revealed a significantly higher mean value in the hypertensive group of 147 +/- 57 compared to 124 +/- 34 in the control group, P < .001. Thirty-one of 60 (52%) of the hypertensive group had a normal TSS compared to 22 of 60 (37%) of the controls. A total of 68 (38 fixed and 30 reversible) perfusion defects were noted in the hypertensive group compared to 74 (55 fixed and 19 reversible) in the controls. The severity of clinical syndromes associated with myocardial ischemia were noted in increased incidence in the presence of left ventricular hypertrophy and left ventricular mass index was noted to be predictive of severity of coronary disease independent of the standard risk factors.
A thrombin receptor (TR) demonstrating a unique activation mechanism has recently been isolated from a megakaryocytic (Dami) cell line. To further study determinants of peptide ligand-mediated activation phenomenon, we have isolated, cloned, and stably expressed the identical receptor from a human umbilical vein endothelial cell (HUVEC) library. Chinese hamster ovary (CHO) cells expressing a functional TR (CHO-TR), platelets, and HUVECs were then used to specifically characterize alpha-thrombin- and peptide ligand-induced activation responses using two different antibodies: anti-TR34-52 directed against a 20-amino acid peptide spanning the thrombin cleavage site, and anti-TR1-160 generated against the NH2-terminal 160 amino acids of the TR expressed as a chimeric protein in Escherichia coli. Activation-dependent responses to both alpha-thrombin (10 nM) and peptide ligand (20 microM) were studied using fura 2-loaded cells and microspectrofluorimetry. Whereas preincubation of CHO-TR with anti-TR34-52 abolished only alpha-thrombin-induced [Ca2+]i transients, preincubation with anti-TR1-160 abrogated both alpha-thrombin- and peptide ligand-induced responses. This latter inhibitory effect was dose dependent and similar for both agonists, with an EC50 of approximately 90 micrograms/ml. Anti-TR1-160 similarly abolished peptide ligand-induced [Ca2+]i transients in platelets and HUVECs, whereas qualitatively different responses characterized by delayed but sustained elevations in [Ca2+]i transients were evident using alpha-thrombin. Platelet aggregation to low concentrations of both ligands was nearly abolished by anti-TR1-160, although some shape change remained; anti-TR34-52 only inhibited alpha-thrombin-induced aggregation. These data establish that a critical recognition sequence for peptide ligand-mediated receptor activation is contained on the NH2-terminal portion of the receptor, upstream from the first transmembrane domain. Furthermore, alpha-thrombin-induced activation of HUVECs and platelets may be partially mediated by an alternative mechanism(s) or receptor(s).
In a retrospective study the expression of the c-erbB-2 oncogene was determined immunohistochemically in 276 breast cancer samples from 253 patients with the antibody 21N. The follow-up period was between 7 and 12 years. This study showed a trend for an inverse relationship between c-erbB-2 positive tumours and estrogen receptors (ER). A correlation was assessed between c-erbB-2 positive tumours and histological grade, liver metastases as first site of metastases, disease free survival time (DFS) in the second and third year after diagnosis and overall survival time (OST) in the third and fourth year after diagnosis. A trend was seen between c-erbB-2 positive tumours and tumour size. No correlation was found between c-erbB-2 positive tumours and age at diagnosis. The method of operation and lymph node involvement. From this study we conclude that there is a significant difference in prognosis the first years after diagnosis, but this difference seems to vanish in a longer follow-up period of 12 years. This provides us with an explanation for the discrepancies in literature concerning c-erbB-2 expression and prognosis in breast cancer. Some investigators did not show differences in prognosis between positive and negative cases after a long follow-up period whereas investigations with a short term follow-up period up to 2-3 years have indeed established a more aggressive behaviour of c-erbB-2 overexpressionary tumours.
Herpes simplex virus (HSV) types 1 and 2, typed by an enzyme linked immunosorbent assay (ELISA), were isolated at different clinical episodes from five people with genital herpes. This finding has important implications for assessing resistance to antiviral drugs in therapeutic studies.
Previous studies of boys at Christ's Hospital school have indicated that annual immunization with influenza virus vaccines did not significantly reduce the total incidence of influenza infection compared to unimmunized subjects. In view of the implications of this result, a similar study was conducted in ferrets to clarify these findings. Groups of ferrets were immunized or infected with a series of influenza A (H3N2) viruses over an 18-month period, and the immunity to subsequent live virus challenge was measured after each virus or vaccine exposure. The results indicated that live virus infection gave a more solid immunity than immunization with inactivated vaccine; and the serum haemagglutination-inhibiting antibody response was greater following immunization than following infection. In addition, differences in immunity could not be explained by measurements of cross-reacting and specific antibody, since the incidence of these antibodies was similar in both infected and immunized animals. The results do not suggest an explanation for the different levels of immunity induced following infection or immunization or the results obtained from the Christ's Hospital study. However, the relative contribution of various immune responses to virus or virus antigen is discussed, and it is suggested that the difference in immunity may lie in the ability of live virus infection to stimulate local antibody.
The effect of basement membrane components (laminin, fibronectin and type IV collagen) and lung fibroblasts on type IV collagenase and plasminogen activator activity was investigated in a primary HSV-2-induced hamster fibrosarcoma, and its in vivo derived sublines and in vitro derived clones of varying metastatic potential. Fibronectin and type IV collagen were ineffective at influencing the expression of either type IV collagenase or plasminogen activator activity. Laminin, however, at concentrations of 1-10 micrograms ml-1 added to the serum-free culture supernatants, increased the release of type IV collagenase by up to 100% for the parental cell line. Three highly metastatic sublines (two from in vivo origin and one from in vitro cloning) showed increases of up to 300%. Non-metastatic sublines (two from in vivo origin and one from in vitro cloning), however, showed no increase in type IV collagenase activity. Plasminogen activator release from either the parental line cell or its metastatic sublines and clones, was unaffected by the addition of laminin. Addition of tumour cells to lung fibroblast monolayers resulted in an increased expression of PA activity in the supernatant, whilst type IV collagenase activity was reduced.
In the present study we have confirmed that approximately one third of human colorectal carcinomas fail to express the HLA - A,B,C monomorphic determinant reactive with the W6/32 MAb, and 44% express class II HLA antigens as shown by reactivity with NFK-1 MAb. Reduced staining with the W6/32 MAb was not always associated with the loss of beta 2m. In addition, the expression of HLA-A2 and Bw4 class I specific haplotypes on normal colon epithelium and tumour biopsy tissue was assessed. All normal colonic epithelia stained positively with MAb against A2 and Bw4 antigens, but a loss of these determinants was shown on tumour biopsies from patients tissue typed for the respective specificities. Loss of the A2 haplotype was shown in 4 of 15 tumour tissue samples, and loss of Bw4 specificities in 5 out of 7 tissue samples. The failure to detect specific loci determinants was not necessarily associated with loss of reactivity with W6/32 MAb.
Mechanisms for transport of bilirubin and its conjugates in hepatocytes have not been defined. We investigated the hepatic processing of bilirubin glucuronides and their precursors, and characterized the disposition of bile pigments arising from intraversus extrahepatic sources. Tracer doses of purified radiolabeled biliverdin, bilirubin, bilirubin monoglucuronide (BMG) or diglucuronide (BDG) were administered intravenously to intact normal or jaundiced homozygous Gunn rats. Rapid sequential analysis of radiolabeled BMG and BDG in bile revealed comparable excretion patterns following biliverdin and bilirubin injection, with BDG as the major pigment. Biliary excretion of radiolabeled conjugates from injected BMG was more rapid, with BMG predominating. Excretion of injected BDG in normal rats and BMG or BDG in Gunn rats was virtually identical to that of unaltered BMG in normal rats. Model independent analysis by deconvolution provided objective comparison of the disposition of radiolabeled pigments from the different sources. These findings indicate that bilirubin glucuronides formed in the liver from endogenous (hepatic) and exogenous (extrahepatic) sources of bilirubin follow a similar excretory pathway. BMG formed endogenously is converted preferentially to BDG, whereas circulating BMG is excreted predominantly unchanged. Exogenous conjugated bilirubins are excreted more rapidly than those generated intrahepatically, by a transcellular pathway that is largely independent of the conjugation system.
Fifty patients presenting with first episode genital herpes were randomly allocated to seven day treatment with either oral acyclovir plus 5% acyclovir cream or oral acyclovir plus matching placebo cream. Combined treatment with oral and topical acyclovir was associated with a shorter duration of itching in women alone (p = 0.04) but gave no clinical relief of other symptoms, the time to healing of lesions, or the subsequent recurrence rate. Concomitant topical treatment with 5% acyclovir cream confers no advantages on patients who receive oral acyclovir.
The effect of a short course of rifampin on the oral microflora was evaluated in 17 healthy volunteers. Salivary specimens were collected before and after two 600-mg doses of rifampin administered 6 h apart. Salivary bacteria were identified to species, and total quantitative colony counts were determined for each isolate. For all 17 subjects, treatment with rifampin led to a reduction in total bacterial colony counts; the mean inhibitory activity was 85.8% (range, 48.3 to 99.8%). Both aerobic and anaerobic bacteria were inhibited in every case: 45.5 to 99.8% for aerobic bacteria, mean inhibitory activity of 85.8%; 40.9 to 100% inhibition for anaerobic bacteria, mean inhibitory activity of 87.6%. However, total counts were reduced by greater than or equal to 2 logarithms in only 18% of individuals; for aerobes, in 29%; and for anaerobes, in 41%. All classes of bacteria were inhibited, with mean inhibitory activities ranging from 8.4 to 99.9%. However, only streptococci, Haemophilus spp., Bacteroides spp., and aerobic and anaerobic gram-positive nonsporeforming rods were reduced in counts close to 2 logarithms after treatment with rifampin. Clinical studies are needed to clarify the significance of these in vitro data and to delineate a possible role for rifampin in preoperative prophylaxis of patients undergoing head and neck cancer surgery.
Forty patients presenting with first episode genital herpes were randomly allocated to seven day treatment with oral acyclovir alone, placebo alone, oral acyclovir plus co-trimoxazole, or placebo plus co-trimoxazole. Patients receiving acyclovir had significantly shorter periods of viral shedding (p less than 0.001), pain (p = 0.03), and times to lesion healing (p less than 0.05). Averaged over all patients there was no evidence that co-trimoxazole affected any of the variables, though in women cotrimoxazole was associated with a shorter time to lesion healing (p less than 0.01). Furthermore, the combination treatment gave significantly shorter times to lesion healing than acyclovir alone, placebo alone, or placebo and co-trimoxazole (p = 0.01) and good trends elsewhere (external lesions and duration of pain). Neither drug was associated with any adverse events or toxicity or influenced the subsequent recurrence rate.