Biomedical subjects

J F Smith

Publications and source records attributed to J F Smith.

At least 37 records · Page 2Linked to original sources

PubMed1999

Expression, processing, and immunogenicity of the structural proteins of Venezuelan equine encephalitis virus from recombinant baculovirus vectors.

Recombinant baculoviruses expressing the structural proteins of Venezuelan equine encephalitis virus (VEE) have been constructed and the intracellular processing, antigenicity, and immunogenicity of the expression products have been assessed. Baculoviruses expressing the entire structural protein region (C-E3-E2-6K-E1), or the complete glycoprotein region (E3-E2-6K-E1), generated products in Sf9 cells that were accurately and completely processed, and resulted in mature proteins that were antigenically and electrophoretically indistinguishable from authentic viral proteins. These products were highly immunogenic in BALB/c mice, induced efficient VEE neutralizing responses, and protected these animals against challenge with virulent VEE. Expression of individual glycoprotein regions (E3-E2 and 6K-E1) generated products that were accurately but incompletely processed, and induced non-neutralizing antibodies that reacted more efficiently with denatured than native VEE proteins. Nonetheless, immunization with the 6K-E1 expression product provided complete protection against VEE challenge.

Animals↗

PubMed1999

Umbilical artery regression: a rare complication of intravascular fetal transfusion.

BACKGROUND: Intravascular fetal transfusion is an important therapeutic advance but is associated with several complications. Regression of an umbilical artery associated with transfusion is rare. CASE: A case of red blood cell alloimmunization managed by serial transfusions was complicated by functional loss of an umbilical artery during pregnancy. Refractory fetal bradycardia occurred during the last transfusion procedure, requiring emergency preterm cesarean delivery. Coagulative necrosis, thrombosis, and focal calcification of one umbilical artery was confirmed after delivery. CONCLUSION: Umbilical artery regression associated with transfusion therapy is rare and may complicate subsequent fetal transfusions.

Adult↗

PubMed1999

The relationship between maternal work and other socioeconomic factors and child health in Bangladesh.

The relationship between maternal work status, other socio-economic factors, and incidence of diarrhoea among children was studied using the Bangladesh Demographic and Health Survey (DHS) 1994 data. This study showed that 12.4% of children had suffered from diarrhoea in the two weeks preceding the survey. Of the women in the sample, 12% were working. Logistic regression analysis revealed that children of working mothers were 65% more likely to have had diarrhoea than children of non-working mothers. We also found that children of women who work seasonally were 8% less likely to have had diarrhoea than children of women who work all year. Women's higher education was found to be one of the important determinants related to childhood diarrhoea. Religion and ownership of land also appeared to be important factors affecting the incidence of diarrhoea in early childhood.

Bangladesh↗

PubMed1999

Effects of bovine oviductal proteins on bull spermatozoal function.

The effects of bovine oviductal proteins on bull sperm viability, acrosome reaction and motility were studied. Motile frozen/thawed spermatozoa from Percoll gradients were incubated with 1.0 mg/mL oviductal proteins (>8 kDa) extracted by ammonium sulphate precipitation from oviductal extract (OE) or serum-free oviductal epithelial cell-conditioned media (CM), treated in the presence (CM+) or absence (CM-) of 1 microg/mL 17beta-estradiol. Inclusion of oviductal proteins had a significant beneficial effect on sperm viability (76.3 to 80.6%+/-5.3) compared with the control (without oviductal proteins; 57.8%+/-5.3) immediately after the commencement of incubation. After 5 h, viability was significantly higher for CM- and OE treatments than for the control, although no differences were observed at 24 h. Acrosomal status only differed among treatments after 24 h, when higher percentages of acrosome- reacted spermatozoa were found in the control (46.0%+/-2.5) than in the oviductal protein treatments (33.1 to 38.2%+/-2.5). No differences in percentages of motile spermatozoa occurred within the first hour of incubation, although inclusion of CM proteins decreased sperm velocities, beat cross frequency, linearity, and straightness but increased values for mean angular displacement. These findings suggest that proteins secreted by oviductal epithelium promote viability, delay the acrosome reaction and suppress the motion of spermatozoa.

Acrosome Reaction↗

PubMed1999

The development and impact of a chronic pain support group: a qualitative and quantitative study.

To study the process of establishment, and evaluate the outcome of participation, in a self-help support group for people with chronic nonmalignant pain, members of a newly-established, consumer-led group participated in two interviews 5 months apart and a researcher observed group meetings. Participants reported significant benefits from participating in the group. They had a significant increase in functional ability and activity, and reported decreased recourse to health professionals, particularly family physicians. This study indicates that pain support groups can play a valuable role for people in pain, assisting with support and rehabilitation, and meeting needs that health professionals are often not appropriate or able to provide.

Adult↗

PubMed1999

Nurses' knowledge of pain assessment, pharmacologic and nonpharmacologic interventions.

This study compared differences in knowledge of pain assessment and pharmacologic and nonpharmacologic pain management strategies among 232 L.P.N.s and R.N.s from three hospitals. Twenty-three adult medical, surgical, and special care units were represented. The "Knowledge of Pain Management" tool measured knowledge of pain assessment, drug and nondrug strategies, and was based on AHCPR guidelines. Scores ranged from 24% to 92%. There were significant differences in scores across hospitals and between R.N.s and L.P.N.s. The mean score was 72% for L.P.N.s and 75% for R.N.s. There was a significant difference in pharmacologic scores between L.P.N.s versus A.D./A.A.-R.N.s, B.S.N-R.N.s, and M.S.N.-M.S.-R.N.s but not between L.P.N.s and diploma-R.N.s. There were significant differences in overall knowledge scores between L.P.N.s versus B.S.N.-R.N.s but not A.D./A.A.-R.N.s, diploma-R.N.s, and M.S.N./M.S-R.N.s. Finding suggest the need for aggressive nursing education programs offered in academic and clinical settings to assist nurses in effectively managing the universal phenomenon of pain.

Acute Disease↗

PubMed1999

Limited potential for mosquito transmission of genetically engineered, live-attenuated Venezuelan equine encephalitis virus vaccine candidates.

In an attempt to improve the current live-attenuated vaccine (TC-83) for Venezuelan equine encephalitis (VEE), specific mutations associated with attenuation of VEE virus in rodent models were identified. These mutations were inserted into full-length cDNA clones of the Trinidad donkey strain of VEE virus by site-directed mutagenesis, and isogenic virus strains with these mutations were recovered after transfection of baby hamster kidney cells with infectious RNA. We evaluated 10 of these strains for their ability to replicate in and be transmitted by Aedes taeniorhynchus, a natural vector of epizootic VEE virus. Two vaccine candidates, one containing a deletion of the PE2 furin cleavage site, the other a combination of three separate point mutations in the E2 glycoprotein, replicated in mosquitoes and were transmitted to hamsters significantly less efficiently than was either parental (wild type) VEE virus or TC-83 virus. Although the attenuated strains were transmitted to hamsters by mosquitoes, after intrathoracic inoculation, there was no evidence of reversion to a virulent phenotype. The mutations that resulted in less efficient replication in, or transmission by, mosquitoes should enhance vaccine safety and reduce the possibility of environmental spread to unintentional hosts.

Aedes↗

PubMed1999

Geographic distribution of Venezuelan equine encephalitis virus subtype IE genotypes in Central America and Mexico.

Phylogenetic analysis of 20 strains of Venezuelan equine encephalitis (VEE) virus subtype IE isolated from 1961 to 1996 in Mexico and throughout Central America showed that VEE virus subtype IE was monophyletic with respect to other VEE virus subtypes. Nonetheless, there were at least three distinct geographically separated VEE virus IE genotypes: northwestern Panama, Pacific coast (Mexico/Guatemala), and Gulf/Caribbean coast (Mexico/Belize). Strains from the Caribbean coast of Guatemala, Honduras, and Nicaragua may cluster with the Gulf/Caribbean genotype, but additional isolates from the region between Guatemala and Panama will be required to firmly establish their phylogenetic position. Viruses associated with two separate equine epizootics in Mexico in the 1990s were phylogenetically related to nonepizootic viruses from neighboring Guatemala and may represent the emergence or re-emergence of equine-virulent VEE virus subtype IE in Middle America.

Adult↗

PubMed1999

Acute effects of thirty minutes of light-intensity, intermittent exercise on patients with chronic fatigue syndrome.

BACKGROUND AND PURPOSE: Currently, there is no consensus on exercise prescription for patients with chronic fatigue syndrome (CFS). This investigation examined whether light-intensity, intermittent physical activity exacerbated symptoms in patients with CFS immediately following exercise to 7 days following exercise. Subjects. Subjects were 9 women (mean age=44.2 years, SD=8.4, range=29-56; mean weight=74.2 kg, SD=18.8, range=56.36-110.91; and mean height=1.63 m, SD=0.8, range=1.55-1.78) and 1 man (age=48 years, weight=97.1 kg, and height= 1.98 m) who met the Centels for Disease Control and Prevention's criteria fi)r (FS. METHODS: Subjects performed 10 discontinuous 3-minute exercise bouts (separated by 3 minutes of recovery) at a self-selected, comfortable walking pace on a treadmill. Oxygen consumption, minute ventilation, respiratory exchange ratio, and heart rate were measured every minute during the exercise session. To assess degree of disability, general health status, activity level, symptoms, and mood, subjects completed various questionnaires before and after exercise. RESULTS: Results indicated that degree of disability, general health status, symptoms, and mood did not change immediately and up to 7 days following exercise. CONCLUSION AND DISCUSSION: Thirty minutes of intermittent walking did not exacerbate symptoms in subjects with CFS. The physiological data did not show any abnormal response to exercise. Although this study did not determine whether 30 minutes of continuous versus intermittent exercise would exacerbate symptoms, all 10 subjects felt that they could not exercise continuously for 30 minutes without experiencing symptom exacerbation. Despite this limitation, the results indicate that some individuals with CFS may be able to use low-level, intermittent exercise without exacerbating their symptoms.

Adult↗

PubMed1998

Mutations in the Exo III motif of the herpes simplex virus DNA polymerase gene can confer altered drug sensitivities.

Two herpes simplex virus mutants containing mutated residues within the conserved Exo III motif of the polymerase gene were previously shown to be defective in 3'-5' exonuclease activity and exhibited extremely high mutation frequencies. In this study, we have shown that these mutants also exhibited higher resistance to phosphonoacetic acid and sensitivity to aphidicolin and all nucleoside analogs tested, including acyclovir and gangciclovir, compared to wild-type virus. Marker transfer experiments and sequencing analyses demonstrated that these altered phenotypes were the result of mutations within the Exo III motif. The data indicate that, aside from leading to exonuclease deficiency, mutations in the Exo III motif may also affect interaction of nucleoside triphosphates with the catalytic sites of polymerase activity.

Amino Acid Sequence↗

PubMed1998

Isolation and characterization of PDE9A, a novel human cGMP-specific phosphodiesterase.

We have cloned and characterized the first human isozyme in a new family of cyclic nucleotide phosphodiesterases, PDE9A. By sequence homology in the catalytic domain, PDE9A is almost equidistant from all eight known mammalian PDE families but is most similar to PDE8A (34% amino acid identity) and least like PDE5A (28% amino acid identity). We report the cloning of human cDNA encoding a full-length protein of 593 amino acids, including a 261-amino acid region located near the C terminus that is homologous to the approximately 270-amino acid catalytic domain of other PDEs. PDE9A is expressed in all eight tissues examined as a approximately 2. 0-kilobase mRNA, with highest levels in spleen, small intestine, and brain. The full-length PDE9A was expressed in baculovirus fused to an N-terminal 9-amino acid FLAG tag. Kinetic analysis of the baculovirus-expressed enzyme shows it to be a very high affinity cGMP-specific PDE with a Km of 170 nM for cGMP and 230 microM for cAMP. The Km for cGMP makes PDE9A one of the highest affinity PDEs known. The Vmax for cGMP (4.9 nmol/min/microg recombinant enzyme) is about twice as fast as that of PDE4 for cAMP. The enzyme is about twice as active in vitro in 1-10 mM Mn2+ than in the same concentration of Mg2+ or Ca2+. PDE9A is insensitive (up to 100 microM) to a variety of PDE inhibitors including rolipram, vinpocetine, SKF-94120, dipyridamole, and 3-isobutyl-1-methyl-xanthine but is inhibited (IC50 = 35 microM) by zaprinast, a PDE5 inhibitor. PDE9A lacks a region homologous to the allosteric cGMP-binding regulatory regions found in the cGMP-binding PDEs: PDE2, PDE5, and PDE6.

3',5'-Cyclic-GMP Phosphodiesterases↗

PubMed1998

Isolation and characterization of PDE8A, a novel human cAMP-specific phosphodiesterase.

As part of our efforts to understand the regulation of intracellular cAMP and to generate new targets for pharmacological intervention, we have cloned and characterized the first isozyme in a new family of cyclic nucleotide phosphodiesterases, PDE8A. PDE8A is most similar to PDE4 (38.5% amino acid identity in the catalytic domain), but is clearly not a member of any of the seven known PDE families. We report the cloning of human cDNA encoding the C-terminal 713 amino acids of the protein, including a 283 amino acid region located near the C-terminus that is homologous to the approximately 270 amino acid catalytic domain of other PDEs. In addition, we found cDNA sequences consistent with alternative 5' mRNA splicing analogous to that seen in other PDE genes. PDE8A is expressed in a wide variety of tissues as a approximately 4.5 kb mRNA, with highest levels in testis, ovary, small intestine, and colon. The C-terminal 545 amino acids of PDE8A (the region shared among all splice variants) were expressed in baculovirus. Kinetic analysis of the baculovirus expressed enzyme shows it to be a very high affinity cAMP specific PDE with a Km of 55 nM for cAMP and 124 microM for cGMP. The Vmax (150 pmol/min/microgram recombinant enzyme) is about 10 times slower than that of PDE4. The cAMP hydrolytic activity of PDE8A is not modulated by cGMP at concentrations up to 100 microM. The enzyme requires the presence of at least 1 mM Mn2+ or Mg2+ for maximal activity in vitro, while 100 mM Ca2+ restores only about 20% activity. PDE8A is insensitive (up to 100 microM) to a variety of PDE inhibitors including rolipram, zaprinast, vinpocetine, SKF-94120, and IBMX, but is inhibited (IC50 = 9 microM) by the PDE inhibitor dipyridimole. To give PDE8A a descriptive name that distinguishes it from the other two known high affinity cAMP-specific phosphodiesterases (PDE4 and PDE7), we denote PDE8A as the high affinity cAMP-specific and IBMX-insensitive PDE.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1998

Studies on aromatic amino acid oxidase activity in ram spermatozoa: role of pyruvate as an antioxidant.

Chemical antioxidants and catalase have been shown to be ineffective in improving the motility of ram spermatozoa in a chemically-defined diluent (RSD-1). In an attempt to identify the biochemical basis of this observation, the activity of aromatic amino acid oxidase (AAAO), the enzyme responsible for generation of hydrogen peroxide in ram and bull spermatozoa, has been investigated. Ram spermatozoa contained higher levels of AAAO activity than bull spermatozoa, although the physico-chemical properties of the enzyme were generally similar in both species. Components of the medium had a marked effect upon AAAO activity. In the presence of glutamate and 3-(N-morpholino)propanesulfonic acid (MOPS), AAAO activity was decreased. Pyruvate appeared to increase AAAO activity. This was due to the ability of this substance to destroy hydrogen peroxide. Pyruvate in RSD-1 works as an effective antioxidant and therefore eliminates the need for other antioxidants in the semen diluent.

Amino Acid Oxidoreductases↗

PubMed1998

The use of a reverse transcription-polymerase chain reaction for the detection of viral nucleic acid in the diagnosis of Crimean-Congo haemorrhagic fever.

A reverse transcription-polymerase chain reaction (RT-PCR) was applied retrospectively to 80 stored serum samples from 45 confirmed Crimean-Congo haemorrhagic fever (CCHF) patients in southern Africa, and it was found that viral RNA could be detected in a proportion of samples up to day 16 of illness. Early in the disease there is relatively good correlation between the results obtained by RT-PCR and virus isolation, but after the first week it appears that infective virus is progressively cleared from serum while nucleic acid remains demonstrable in a proportion of patients well into convalescence. A further 47 serum samples from 38 patients with suspected viral haemorrhagic fever, 19 of whom proved to be cases of CCHF, were tested prospectively on being received at the laboratory. The combined use of RT-PCR with ethidium bromide stained gels for the detection of viral RNA, plus indirect immunofluorescence for the detection of IgG and IgM antibodies to CCHF virus, permitted a presumptive diagnosis to be reported within 8 h of receiving the first specimen from 18/19 cases of the disease studied prospectively. The nineteenth case was confirmed within 48 h when antibody response was demonstrated in a second serum sample. Viral nucleic acid was not detected in serum samples from 19 patients in whom alternative diagnoses were established.

Blotting, Southern↗

PubMed1998

Induction of protective immune responses against Venezuelan equine encephalitis (VEE) virus aerosol challenge with microencapsulated VEE virus vaccine.

Venezuelan equine encephalomyelitis (VEE) virus, a member of the family Togaviridae, genus Alphavirus, causes disease in humans and equids. The virus is normally transmitted by the bite of an infected mosquito however, it can also be highly infectious by aerosol. The purpose of the present study was to determine the effectiveness of formalin-fixed, 60Co-irradiated VEE virus microencapsulated in poly DL-lactide-co-glycolide in inducing immune responses protective against aerosol challenge with virulent VEE virus. Balb/c mice were primed by subcutaneous injection of microencapsulated VEE virus vaccine, followed 30 days later by a single immunization with the same vaccine given via the oral, intratracheal (i.t.) or subcutaneous (s.c.) route. Mice boosted by the i.t. or s.c. route had higher plasma IgG anti-VEE virus levels than orally immunized animals. The responses in the former groups were similar in magnitude to those seen in mice primed and boosted by the i.t. route. Antibody activity was detected in bronchial-alveolar and intestinal washes, fecal extracts and saliva from immunized animals. The levels of IgG and IgA antibody activity in bronchial-alveolar wash fluids from mice boosted by the i.t. route were higher than those seen in animals immunized by the oral or s.c. route with the microsphere vaccine. Mice immunized with the microencapsulated VEE virus vaccine were protected from lethal VEE virus infection following aerosol challenge at approximately three months after the initial immunization. Mucosal immunization via the i.t. route appeared to be the most effective regimen, since 100% of the mice resisted aerosol challenge.

Administration, Inhalation↗

PubMed1998

Intrapartum labetalol for the treatment of maternal and fetal thyrotoxicosis.

Maternal thyrotoxicosis complicates approximately 0.2% of pregnancies. Simultaneous occurrence of maternal and fetal thyrotoxicosis during labor is rare, and control of maternal tachycardia and hypertension, as well as fetal manifestations of thyrotoxicosis, are cornerstones of management. An 18-year-old nulliparous female at 33 weeks gestational age presented in labor with thyrotoxicosis. Fetal tachycardia was present as well. Labetalol therapy resulted in a decrease in maternal pulse and blood pressure, and resolution of fetal tachycardia. Vaginal delivery occurred. Subsequent evaluation demonstrated neonatal thyrotoxicosis and high maternal titers of thyroid-stimulating immunoglobulin. In conclusion, labetalol was beneficial in the treatment of maternal and fetal thyrotoxicosis during labor.

Adolescent↗

PubMed1998

Venezuelan equine encephalitis febrile cases among humans in the Peruvian Amazon River region.

A survey was conducted from October 1, 1993 to June 30, 1995 to determine the arboviral etiologies of febrile illnesses in the city of Iquitos in the Amazon River Basin of Peru. The study subjects were patients who were enrolled at medical care clinics or in their homes by Peruvian Ministry of Health (MOH) workers as part of the passive and active disease surveillance program of the MOH. The clinical criterion for enrollment was the diagnosis of a suspected viral-associated, acute, undifferentiated febrile illness of < or = 5 days duration. A total of 598 patients were enrolled in the study. Demographic information, medical history, clinical data, and blood samples were obtained from each patient. The more common clinical features were fever, headache, myalgia, arthralgia, retro-ocular pain, and chills. Sera were tested for virus by the newborn mouse and cell culture assays. Viral isolates were identified initially by immunofluorescence using polyclonal antibody. An ELISA using viral-specific monoclonal antibodies and nucleotide sequence analysis were used to determine the specific variety of the viruses. In addition, thin and thick blood smears were observed for malaria parasites. Venezuelan equine encephalitis (VEE) virus subtype I, variety ID virus was isolated from 10 cases, including three cases in October, November, and December 1993, five cases in January and February 1994, and two cases in June 1995. The ELISA for IgM and IgG antibody indicated that VEE virus was the cause of an additional four confirmed and four presumptive cases, including five from January through March 1994 and three in August 1994. Sixteen cases were positive for malaria. The 18 cases of VEE occurred among military recruits (n = 7), agriculture workers (n = 3), students (n = 3), and general laborers (n = 5). These data indicated that an enzootic strain of VEE virus was the cause of at least 3% (18 of 598) of the cases of febrile illnesses studied in the city of Iquitos in the Amazon Basin region of Peru.

Adolescent↗

PubMed1998

Identification and genetic analysis of Panama-genotype Venezuelan equine encephalitis virus subtype ID in Peru.

Venezuelan equine encephalitis (VEE) virus was isolated in 1993, 1994, and 1995 from human cases of acute, undifferentiated, febrile illness in the Peruvian Amazon Basin. Two virus isolates were recovered in 1994 from Peruvian soldiers at a jungle outpost near Pantoja in northern Peru, and 10 isolates were obtained from military personnel and civilians in 1993-1995 in Iquitos, an urban center in northeastern Peru. The genetic relationship of these isolates to other VEE virus strains was determined by sequencing 856-867 nucleotide reverse transcription-polymerase chain reaction fragments derived from the PE2 glycoprotein gene. The sequences were compared with those of other VEE virus strains, including representatives of the IAB, IC, ID, IE, II, and IIIC subtypes. The two Pantoja isolates were most closely related to subtype IC and ID viruses previously isolated in Colombia and Venezuela, and to the ID viruses isolated during the 1970s in Iquitos. All of the recent Iquitos isolates were similar to one another, but they were more closely related to Panamanian ID strains than to isolates previously obtained in Iquitos, Peru, or in Colombia and Venezuela. The recent Iquitos VEE viral isolates were the first Panama-genotype VEE ID virus strains identified outside of the Republic of Panama.

Animals↗