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Biomedical subjects

J M Hammond

Publications and source records attributed to J M Hammond.

At least 19 recordsLinked to original sources
PubMed2001

Vaccination of pigs with a recombinant porcine adenovirus expressing the gD gene from pseudorabies virus.

Five week old, commercially available large white pigs were vaccinated with either a single dose or two doses of a recombinant porcine adenovirus expressing the glycoprotein D gene from pseudorabies virus (PRV). Pigs were monitored for the development of serum neutralizing antibodies to PRV and challenged 3 weeks after final vaccination. Prior to challenge, pigs given 2 doses of the vaccine demonstrated boosted levels of antibody compared with those given a single dose, and all surviving pigs had increased neutralization titres over pre-challenge levels. Following challenge, pigs were monitored for clinical signs of disease, with blood and nasal swabs collected for virus isolation. All control animals became sick with elevated temperatures for 6 days post challenge, whereas; vaccinated animals displayed an increase in body temperature for only 2-3 days. Control pigs and those given a single dose all lost condition, but the group given 2 doses remained healthy. At postmortem, gross lesions of pneumonia only occurred in control animals and those given a single dose of vaccine. Histology carried out on the brains of all animals demonstrated a difference in severity of infection and frequency of immunohistochemical antigen detection between test animals, with control and single dose groups being most severely affected and pigs given 2 doses the least. Virus isolation studies demonstrated that no viraemia could be detected, but virus was found in nasal swabs from some animals in both groups of vaccinates following challenge.

Adenoviridae↗
PubMed2001

A prime-boost vaccination strategy using naked DNA followed by recombinant porcine adenovirus protects pigs from classical swine fever.

Weaned pigs (6-week-old) and 7-day-old pre-weaned piglets were vaccinated with naked plasmid DNA expressing the gp55/E2 gene from classical swine fever virus (CSFV). Both groups of pigs were then given a booster dose of recombinant porcine adenovirus expressing the gp55 gene (rPAV-gp55). Following challenge with CSFV, 100% of weaned pigs and 75% pre-weaned piglets were protected from disease. Weaned pigs given a single dose of rPAV-gp55 were also protected, but showed a slight increase in temperature immediately post-challenge. However, weaned animals given a DNA prime before rPAV-gp55 showed no fluctuation in body temperature following challenge and no pathology in spleen or lymph nodes upon post-mortem. In addition, no CSFV could be re-isolated from the rPAV vaccinated group and from only one pig in the prime-boost group following challenge, suggesting that both vaccination regimes have the potential to reduce or prevent virus shedding following experimental challenge.

Adenoviridae↗
PubMed2001

Oral and sub-cutaneous vaccination of commercial pigs with a recombinant porcine adenovirus expressing the classical swine fever virus gp55 gene.

A recombinant porcine adenovirus expressing the classical swine fever virus (CSFV) gp55/E2 gene was administered to commercially available pigs via oral or subcutaneous routes and their susceptibility to oral and subcutaneous challenge with CSFV was determined. 100% of animals vaccinated and challenged subcutaneously were protected. In the groups of pigs vaccinated either orally or subcutaneously and then challenged orally, 60% of animals were protected. Before challenge, neutralising antibodies to CSFV were detected in 60% of pigs vaccinated subcutaneously, but in none of those given the vaccine orally. CSFV antigen was found in the spleens of surviving pigs that had been vaccinated orally. In contrast, subcutaneous vaccination was shown to preclude the presence of CSFV in the spleen of animals that survived challenge.

Adenoviruses, Porcine↗
PubMed2001

Trousseau's syndrome treated with long-term subcutaneous lepirudin (case report and review of the literature).

We report here a case of recurrent venous and arterial thromboembolism, Trousseau's syndrome, in a cancer patient who developed heparin-induced thrombocytopenia. She was treated with lepirudin and after establishing the patient-specific half-life for subcutaneous lepirudin, she was successfully maintained on this therapy for more than eight months. To our knowledge this case represents the longest reported use of subcutaneous lepirudin.

Anticoagulants↗
PubMed2001

Surveillance strategies and impact of vancomycin-resistant enterococcal colonization and infection in critically ill patients.

OBJECTIVE: To determine the optimal site and frequency for vancomycin-resistant enterococci (VRE) surveillance to minimize the number of days of VRE colonization before identification and subsequent isolation. SUMMARY BACKGROUND DATA: The increasing prevalence of VRE and the limited therapeutic options for its treatment demand early identification of colonization to prevent transmission. METHODS: The authors conducted a 3-month prospective observational study in medical and surgical intensive care unit (ICU) patients with a stay of 3 days or more. Oropharyngeal and rectal swabs, tracheal and gastric aspirates, and urine specimens were cultured for VRE on admission to the ICU and twice weekly until discharge. RESULTS: Of 117 evaluable patients, 23 (20%) were colonized by VRE. Twelve patients (10%) had VRE infection. Of nine patients who developed infections after ICU admission, eight were colonized before infection. The rectum was the first site of colonization in 92% of patients, and positive rectal cultures preceded 89% of infections acquired in the ICU. This was supported by strain delineations using pulsed-field gel electrophoresis. Twice-weekly rectal surveillance alone identified 93% of the maximal estimated VRE-related patient-days; weekly or admission-only surveillance was less effective. As a test for future VRE infection, rectal surveillance culture twice weekly had a negative predictive value of 99%, a positive predictive value of 44%, and a relative risk for infection of 34. CONCLUSIONS: Twice-weekly rectal VRE surveillance of critically ill patients is an effective strategy for early identification of colonized patients at increased risk for VRE transmission, infection, and death.

Critical Illness↗
PubMed2001

Optimized suspension culture: the rotating-wall vessel.

Suspension culture remains a popular modality, which manipulates mechanical culture conditions to maintain the specialized features of cultured cells. The rotating-wall vessel is a suspension culture vessel optimized to produce laminar flow and minimize the mechanical stresses on cell aggregates in culture. This review summarizes the engineering principles, which allow optimal suspension culture conditions to be established, and the boundary conditions, which limit this process. We suggest that to minimize mechanical damage and optimize differentiation of cultured cells, suspension culture should be performed in a solid-body rotation Couette-flow, zero-headspace culture vessel such as the rotating-wall vessel. This provides fluid dynamic operating principles characterized by 1) solid body rotation about a horizontal axis, characterized by colocalization of cells and aggregates of different sedimentation rates, optimally reduced fluid shear and turbulence, and three-dimensional spatial freedom; and 2) oxygenation by diffusion. Optimization of suspension culture is achieved by applying three tradeoffs. First, terminal velocity should be minimized by choosing microcarrier beads and culture media as close in density as possible. Next, rotation in the rotating-wall vessel induces both Coriolis and centrifugal forces, directly dependent on terminal velocity and minimized as terminal velocity is minimized. Last, mass transport of nutrients to a cell in suspension culture depends on both terminal velocity and diffusion of nutrients. In the transduction of mechanical culture conditions into cellular effects, several lines of evidence support a role for multiple molecular mechanisms. These include effects of shear stress, changes in cell cycle and cell death pathways, and upstream regulation of secondary messengers such as protein kinase C. The discipline of suspension culture needs a systematic analysis of the relationship between mechanical culture conditions and biological effects, emphasizing cellular processes important for the industrial production of biological pharmaceuticals and devices.

Animals↗
PubMed2000

Impact of zanamivir on antibiotic use for respiratory events following acute influenza in adolescents and adults.

BACKGROUND: Influenza infections commonly lead to respiratory tract complications that result in antibiotic treatment. OBJECTIVES: To determine frequency of respiratory events leading to antibiotic use following influenza illness in adolescents and adults, and to assess whether treatment with topical zanamivir prevents these complications. METHODS: Meta-analysis of 7 randomized, double-blind, placebo-controlled trials; 3815 mainly healthy adolescents and adults (mean age, 34 years) with an influenzalike illness of less than 2 days' duration were randomly assigned to receive combined inhaled and intranasal zanamivir, inhaled zanamivir, or corresponding placebos. Twelve percent of enrolled subjects were high-risk patients. The main outcome was the incidence of respiratory events leading to antibiotic prescriptions in patients with proven influenza. RESULTS: Influenza infections were laboratory confirmed in 2499 (66%) of 3815 patients (influenza A in 88% and B in 12%). Placebo recipients developed a respiratory event leading to antibiotic use in 17% of cases, mainly for acute bronchitis or acute sinusitis. Among zanamivir-treated patients (n = 1494) the incidence of respiratory events leading to the use of antimicrobials was 11% (relative risk [RR] compared with placebo, 0.69; 95% confidence interval [CI], 0.57-0.84). Intranasal and inhaled zanamivir seemed to reduce the number of upper (RR, 0.59; 95% CI, 0.36-0.97) and lower respiratory tract events (RR, 0.64; 95% CI, 0.38-1.08). Inhaled zanamivir reduced the number of lower respiratory tract events (RR, 0.60; 95% CI, 0.42-0.85), but the reduction in the number of upper respiratory tract events was not statistically significant (RR, 0.90; 95% CI, 0.63-1.27). CONCLUSIONS: Respiratory complications or worsening of symptoms leading to antibiotic use occurred in about 17% of adolescents or adults with influenza infection. Early treatment of influenza illness with zanamivir reduced the number of these antibiotic prescriptions. Arch Intern Med. 2000;160:3234-3240.

Acute Disease↗
PubMed2000

Inhaled zanamivir for the prevention of influenza in families. Zanamivir Family Study Group.

BACKGROUND: As prophylaxis against influenza in families, amantadine and rimantadine have had inconsistent effectiveness, partly because of the transmission of drug-resistant variants from treated index patients. We performed a double-blind, placebo-controlled study of inhaled zanamivir for the treatment and prevention of influenza in families. METHODS: We enrolled families (with two to five members and at least one child who was five years of age or older) before the 1998-1999 influenza season. If an influenza-like illness developed in one member, the family was randomly assigned to receive either inhaled zanamivir or placebo. The family member with the index illness was treated with either 10 mg of inhaled zanamivir (163 subjects) or placebo (158) twice a day for 5 days, and the other family members received either 10 mg of zanamivir (414 subjects) or placebo (423) once a day as prophylaxis for 10 days. The primary end point was the proportion of families in which at least one household contact had symptomatic, laboratory-confirmed influenza. RESULTS: The proportion of families with at least one initially healthy household contact in whom influenza developed was smaller in the zanamivir group than in the placebo group (4 percent vs. 19 percent, P<0.001); the difference represented a 79 percent reduction in the proportion of families with at least one affected contact. Zanamivir provided protection against both influenza A and influenza B. A neuraminidase-inhibition assay and sequencing of the neuraminidase and hemagglutinin genes revealed no zanamivir-resistant variants. Among the subjects with index cases of laboratory-confirmed influenza, the median duration of symptoms was 2.5 days shorter in the zanamivir group than in the placebo group (5.0 vs. 7.5 days, P=0.01). Zanamivir was well tolerated. CONCLUSIONS: When combined with the treatment of index cases, prophylactic treatment of family members with once-daily inhaled zanamivir is well tolerated and prevents the development of influenza. In this study there was no evidence of the emergence of resistant influenza variants.

Administration, Inhalation↗
PubMed2000

Vaccination with a single dose of a recombinant porcine adenovirus expressing the classical swine fever virus gp55 (E2) gene protects pigs against classical swine fever.

A recombinant porcine adenovirus (rPAV) with the gp55 (E2) gene from the classical swine fever virus (CSFV) 'Weybridge' strain inserted into the right hand end of the PAV serotype 3 (PAV3) genome was constructed. Expression of gp55 was directed by the major late promoter and tri-partite leader sequences located and cloned from PAV3. No compensatory deletions of PAV DNA sequences were made. Vaccination of outbred pigs with a single dose of the recombinant virus (rPAV-gp55) resulted in complete protection from lethal challenge with CSFV. No adverse clinical signs were observed in vaccinated animals following administration of rPAV-gp55 and following challenge, no clinical signs of CSF were observed prior to, or at, post mortem. The insert made into the rPAV increased the genome length to 106.8% of wild type and therefore exceeded the expected maximum insert size for a stable recombinant by almost 2%. Thus rPAV-gp55 contains the largest stable insertion made into a non-deleted Mastadeno virus recombinant so far reported.

Adenoviridae↗
PubMed2000

The diagnostic value of fungal surveillance cultures in critically ill patients.

BACKGROUND: Heavy fungal colonization is a known risk factor for fungal infection, yet the value of fungal surveillance cultures is uncertain. METHODS: To evaluate the utility of fungal surveillance cultures in predicting fungal infections, we evaluated surveillance fungal cultures over a three month period in a prospective, cohort study conducted at a university medical center with a large tertiary referral population. We enrolled 172 patients in the Oncology Center and the medical and surgical intensive care units at Johns Hopkins Hospital. RESULTS: Surveillance cultures from five sites were obtained twice weekly and evaluated for prediction of subsequent fungal infection. Infections were prospectively defined and evaluated by a panel of clinicians. Test characteristics were assessed. Of 159 eligible patients, 14 (9%) developed invasive fungal infections. Having two or more surveillance sites positive in a single day had an odds ratio of 8.2 (1.1-358.0) (p = 0.03), a negative predictive value of 0.98, sensitivity of 0.92, and a likelihood ratio of 1.6 for a fungal infection. In a multiple logistic regression model and Kaplan-Meier analysis, fungal burden was strongly and independently associated with infection (p < 0.05). CONCLUSIONS: Surveillance cultures are helpful in determining fungal colonization but do not have a high positive predictive value for fungal infection in a broad population of intensive care unit patients. However, fungal infection is more likely in heavily colonized patients, and surveillance cultures show that fungal infection is extremely unlikely in patients without fungal colonization.

Adolescent↗
PubMed2000

Porcine ovarian cells express messenger ribonucleic acids for the acid-labile subunit and insulin-like growth factor binding protein-3 during follicular and luteal phases of the estrous cycle.

It has recently been shown that, in follicular fluid, as in the circulation, insulin-like growth factors (IGFs)-I and -II exist in a ternary complex with IGF binding protein-3 (IGFBP-3) and the acid-labile subunit (ALS). The current study was designed to determine whether ovarian follicular and luteal cells could synthesize IGFBP-3 and ALS. Ovaries were collected, during the follicular and early luteal phases, from mature pigs whose cycles were synchronized with PGF2alpha. We studied IGFBP-3 and ALS messenger RNA (mRNA) by in situ hybridization. These transcripts were colocalized with aromatase mRNA, a marker of healthy granulosa cells. IGFBP-3 mRNA was equally expressed in granulosa cells of all growing follicles. In contrast, granulosa cell ALS mRNA levels were higher (P < 0.05) in preantral and small antral follicles than in large antral follicles. In thecal cells, expression of mRNA for IGFBP-3, ALS and cyclin D1 (a marker of cell proliferation) was restricted to healthy (aromatase-expressing) follicles. In those follicles, thecal expression of IGFBP-3 mRNA was low or absent in preantral follicles but increased (P < 0.05) in antral follicles. Thecal cell ALS transcripts peaked in small antral follicles (P < 0.05) and then declined. In granulosa cells of atretic follicles, transcripts for aromatase were greatly reduced, whereas IGFBP-3 mRNA levels remained high. In contrast, ALS transcript levels were greatly reduced in both granulosa (P < 0.05) and thecal cells (P < 0.001) of atretic follicles. After ovulation, IGFBP-3 mRNA was moderately expressed in granulosa luteins but strongly detected in a few theca-derived cells and in vascular endothelial cells. This study demonstrates that follicular fluid IGFBP-3 and ALS, like the IGFs, originate (at least in part) from the ovary. The ability of follicular cells to synthesize, assemble, and store all components of the ternary complex may be critical in determining the bioavailability of follicular IGF-I and -II.

Animals↗
PubMed2000

Messenger ribonucleic acids for MAC25 and connective tissue growth factor (CTGF) are inversely regulated during folliculogenesis and early luteogenesis.

Cell proliferation, terminal differentiation, and angiogenesis occur during cycles of follicular and luteal development. In other paradigms, mac25, a potent tumor inhibitor is strongly induced in senescent epithelial cells, whereas CTGF stimulates angiogenesis and wound healing. Using in situ hybridization and immunohistochemistry, we have examined the possibilities that mac25 is inhibited, whereas CTGF is induced during active periods of follicular development and luteogenesis. Ovaries were collected during the follicular and early luteal phases from prostaglandin F2alpha-treated mature pigs and from slaughterhouse sows. CTGF transcripts were induced during the late preantral stage in granulosa and theca cells concomitantly with the appearance of endothelial cells in the theca. CTGF mRNA expression increased in granulosa cells to a maximum (P < 0.01) in mid-antral follicles but was down regulated (P < 0.01) in preovulatory follicles. In contrast, granulosa cell mac25 mRNA expression was undetectable between the preantral and mid-antral stage but was strongly induced in terminally differentiated granulosa cells of preovulatory follicles. CTGF mRNA and peptide were also detected in the theca externa/interstitium and in vascular endothelial cells of ovarian blood vessels, whereas mac25 transcripts, which were also abundant in ovarian blood vessels increased in the theca interna with follicular development. Transcripts of cyclin D 1, a marker of cell proliferation, appeared during the early antral stage and were moderate in granulosa cells but abundant in capillary endothelial cells in the theca interna, underneath the basement membrane. Following ovulation, CTGF and cyclin D1 mRNAs were associated with the migration of endothelial cells into the CL. Subsequently, there was a marked up-regulation of CTGF mRNA expression in granulosa luteins concomitantly with an increase in endothelial cell proliferation within the CL. We hypothesize that CTGF may promote ovarian cell growth and blood vessel formation during follicular and luteal development whereas mac25, a tumor inhibitor, may promote terminal differentiation of granulosa cells in preovulatory follicles.

Animals↗
PubMed1999

Nuclear and nucleolar localization of an African swine fever virus protein, I14L, that is similar to the herpes simplex virus-encoded virulence factor ICP34.5.

PCR analysis of the genomes of 18 different African swine fever virus (ASFV) isolates showed that the I14L open reading frame (ORF) was present as either a long form or short form in all of the isolates. Sequencing of the ORF from eight isolates confirmed that both forms of the ORF were well conserved. Antisera raised against the I14L protein identified the long form of the protein as a 21 kDa protein expressed late during ASFV infection. Immunofluorescent analysis of transiently expressed haemagglutinin-tagged forms of the I14L protein showed that the long form of the protein localized predominantly to the nucleus and within the nucleoli. In contrast, although the short form of the protein was also present predominantly in the nucleus, it did not localize to the nucleoli. Deletion of the N-terminal 14 amino acids from the long form of the I14L protein, which includes a high proportion of basic Arg/Lys residues, abolished the specific nucleolar localization of the protein, although the protein was still present in the nucleus. Addition of this 14 amino acid sequence to beta-galactosidase or replacement of the N-terminal 14 amino acids of the I14L short form with those from the long form directed both of these modified proteins to the nucleolus. This indicates that this 14 amino acid sequence contains all the signals required for nucleolar localization.

African Swine Fever Virus↗
PubMed1999

The combination paclitaxel, carboplatin and megestrol acetate is effective in women with recurrent uterine papillary serous adenocarcinoma.

Uterine papillary serous adenocarcinoma is an uncommon and very aggressive type of endometrial cancer. A 76-year-old patient diagnosed with recurrent uterine papillary serous adenocarcinoma was prescribed megesterol acetate (160 mg daily), paclitaxel (135 mg/m2) and carboplatin (area under the concentration-time curve of 5) every 4 weeks for 4 courses. She demonstrated complete clinical response that was maintained for longer than 6 months with minimal toxicity. The combination megesterol acetate, paclitaxel and carboplatin may be effective in women with recurrent uterine papillary serous adenocarcinoma.

Aged↗
PubMed1998

Expression of the potyvirus coat protein mediated by recombinant vaccinia virus and assembly of potyvirus-like particles in mammalian cells.

The coat protein of the potyvirus, Johnsongrass mosaic virus (JGMV), was expressed using a recombinant vaccinia virus (VV) system. Ultra-thin section electron microscopy demonstrated that the coat protein assembled into potyvirus-like particles (PVLPs) in recombinant VV infected cells. Infection of cells with two additional VV recombinants expressing coat protein plus N-terminal and N- and C-terminal extensions also resulted in the formation of PVLPs. These results suggest that the ability of VV to express the potyvirus coat protein at sufficient levels to allow PVLP formation in vitro, could make VV a suitable vector for the delivery of PVLPs displaying vaccine antigens in vivo without the need for particle purification and/or inclusion of adjuvant. Use of such a vaccine strategy would also benefit from the proven advantages of poxviruses as vaccines such as stability in a freeze dried form, resistance to environmental factors and the potential for oral administration.

Animals↗
PubMed1998

Expression of mouse ovarian insulin growth factor system components during follicular development and atresia.

Insulin growth factor I (IGF-I) appears necessary for the completion of follicular development in mice. However, little is known about changes in the IGF system components during follicular development and luteinization. This study determined the relation between gene expression of specific IGF system components and follicular growth, survival, or atresia in mice. Immature mice from three different strains (129, C57, and MF1), with or without gonadotropin treatment (2.5 IU PMSG/2.5 IU human CG (hCG)], were used. The strains were similar in all parameters measured. Apoptosis, as detected by in situ labeling of nicked DNA, preceded the appearance of morphological signs of atresia. In healthy follicles, IGF-I transcripts were low during the primary follicular stage but increased to a maximum in the late preantral and early antral stages (P < 0.001) irrespective of hormone treatment. Occasionally, IGF-I transcripts were also detected in apoptotic follicles but decreased (P < 0.05) as a function of atresia as assessed by morphological criteria. IGF binding protein-4 (IGFBP-4) messenger RNA (mRNA) expression in granulosa cells was restricted to apoptotic and atretic follicles (P < 0.001). IGFBP-5 transcript levels, on the other hand, were elevated in granulosa cells of healthy primary and secondary follicles but decreased in subsequent follicular stages and in atretic follicles (P < 0.001). Conversely, IGFBP-2 mRNA was constitutively expressed in granulosa cells. PMSG/hCG treatment induced the appearance of IGFBP-2 transcripts in the ovarian interstitium. Following PMSG/hCG-induced ovulation, IGFBP-2 and -4 and IGF type-I receptor mRNAs were strongly expressed in virtually all luteal cells, whereas IGFBP-3 and -5 transcripts were selectively localized to some cell types in the corpus luteum. Conversely, IGF-I mRNA was essentially undetectable in the corpus luteum. This study represents the most comprehensive and detailed analysis of the physiology and anatomy of the mouse ovarian IGF system, and shows that 1) IGFBP-5-is linked to the survival of the slow growing and immature preantral follicles; 2) IGF-I is associated with the growth and survival of the rapidly growing large preantral and antral follicles; 3) IGFBP-4 is an atretogenic candidate for mouse ovarian follicles; 4) ovulatory doses of PMSG/hCG up-regulate IGFBP-2 mRNA expression in the ovarian interstitium; and 5) transcripts of IGF type-I receptor and IGFBP-2 through -5, but not those of IGF-I are highly expressed in the mouse corpus luteum.

Animals↗
PubMed1997

A synthetic vaccinia virus promoter with enhanced early and late activity.

A synthetic vaccinia virus promoter (Psel) was constructed based upon sequences which increase activity of the P7.5 early/late promoter. Comparison of luciferase activity in lysates from cells infected with recombinant vaccinia viruses expressing the luciferase gene either under the control of the P7.5 promoter or Psel, demonstrated significantly enhanced activity mediated by Psel at both early and late times post infection. This promoter may be of considerable benefit in the construction of recombinant poxviruses where early foreign gene expression is important for generating a protective immune response in vaccinated animals, or in reporter/target gene expression in vitro.

Genes, Reporter↗