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Biomedical subjects

M H Wilson

Publications and source records attributed to M H Wilson.

At least 19 recordsLinked to original sources

Evaluation of a live attenuated, cold-adapted parainfluenza virus type 3 vaccine in children.

Cold passage 18 (CP18) parainfluenza virus type 3 (PIV-3) vaccine was evaluated in a double-blind, randomized, placebo-controlled study of 95 infants and young children. None of 19 seropositive older children 41 to 124 months old became infected when 10(6) 50% tissue culture infective doses (TCID50) of vaccine virus was administered intranasally. Two of nine and seven of twenty-four young seropositive children given 10(5) or 10(6) TCID50 of CP18 PIV-3, respectively, became infected. Each of four seronegative young children became infected, as indicated by virus shedding and antibody response, when given 10(6) TCID50 of CP18 PIV-3 intranasally. Illness was not observed in seropositive children. Two of the four seronegative children developed a mild illness characterized by rhinorrhea and wheezing on auscultation; none had fever. In one case, vaccine virus spread from a vaccine to a sibling control but did not cause illness. The vaccine is attenuated relative to wild-type PIV-3, but additional attenuation will be required to achieve a satisfactory PIV-3 vaccine.

Adaptation, Physiological

Bicycle helmet law for children: a case study of activism in injury control.

In 1990, the first regulation requiring the use of helmets for bicyclists younger than 16 years of age was passed in Howard County, Maryland. This unexpected injury control measure resulted from the convergence of multiple factors and efforts: the bicycle-related deaths of two children from the same middle school, creative students and teachers motivated by these deaths, a responsive legislator to introduce the legislation, available surveillance and research statistics supporting the need and efficacy for helmet use, increased national awareness of the importance of helmet use to prevent bicycle-related head injuries, and organized national and local public health groups to support the legislation. This case study of activism in injury control illustrates the importance of supporting research, of well-organized public health coalitions and groups, and of creative community activists motivated by local circumstances.

Adolescent

Effectiveness of an antihistamine-decongestant combination for young children with the common cold: a randomized, controlled clinical trial.

We tested the hypothesis that antihistamine-decongestant combinations cause no clinically significant relief of the symptoms of upper respiratory tract infections in young children by randomly assigning 96 children to one of three treatment groups: antihistamine-decongestant, placebo, and no treatment. There were no differences among the three study groups in the proportion of children considered "better" overall by the parent 48 hours after the initial assessment (drug, 67%; placebo, 71%; no treatment, 57%; p = 0.53). There were no differences among groups in individual or composite symptom score changes. Two thirds of parents whose children were eligible for the drug trial believed that their child needed medicine for cold symptoms. In the proportion of parents believing that their child needed medicine, there was no difference between those who consented to participate and those who refused. Parents who wanted medicine at the initial visit reported more improvement at follow-up, regardless of whether the child received drug, placebo, or no treatment. We conclude that there is no clinically significant improvement in symptoms of upper respiratory tract infection, including no significant placebo effect, in young children for whom an antihistamine-decongestant is prescribed.

Brompheniramine

The A/Mallard/6750/78 avian-human, but not the A/Ann Arbor/6/60 cold-adapted, influenza A/Kawasaki/86 (H1N1) reassortant virus vaccine retains partial virulence for infants and children.

Characteristics of avian-human (ah) and cold-adapted (ca) influenza A/Kawasaki/9/86 (H1N1) reassortant vaccine viruses were compared in 37 seronegative adults and 122 seronegative infants and children. The 50% human infectious dose (HID50) in infants and children was 10(2.9) and 10(2.6) TCID50 for the ah and ca vaccine, respectively. The ah influenza A/Kawasaki/9/86 reassortant was reactogenic: 24% of infants and children infected with greater than or equal to 100 HID50 had fever greater than or equal to 39.4 degrees C. Since H3N2 ah vaccines were previously shown to be adequately attenuated, it is reasonable to suggest that the genes that code for hemagglutinin and neuraminidase of the H1N1 virus apparently influence the reactogenicity of reassortant viruses derived from the avian influenza A/Mallard/New York/6750/78 donor virus. Because this avian virus does not reproducibly confer a satisfactory level of attenuation to each subtype of influenza A virus, it is not a suitable donor virus for attenuation of wild-type influenza viruses. In contrast, the ca A/Ann Arbor/6/60 donor virus reliably confers attenuation characteristics to a variety of H1N1 and H3N2 influenza A viruses.

Adult

Do postpartum nursery visits by the primary care provider make a difference?

A prospective, randomized, clinical trial was conducted to investigate whether a postpartum visit between a mother and her neonate's future primary care provider combined with telephone access would improve health care utilization, enhance identification of the provider as a source of advice, increase maternal knowledge of infant care, and decrease maternal anxiety and depression. Of 251 mother-neonate pairs, 122 were randomized to the control group and 129 to the intervention group. Outcome variables included health care utilization and results of maternal interviews. More mothers in the intervention group made a scheduled clinic visit in the first 30 days (P = .003), were more likely to seek some form of care at the clinic (P = .006), and tried to reach their physician by phone more often than the control group (P less than .001). There were no differences between the groups' emergency room utilization, the percent who received immunizations by 90 days of age, maternal knowledge of infant care, maternal anxiety, or postpartum depression. The intervention succeeded in improving some measures of health care utilization and results suggest that the relationship between the mother and clinician was strengthened.

Adult

Comparison of live attenuated cold-adapted and avian-human influenza A/Bethesda/85 (H3N2) reassortant virus vaccines in infants and children.

Randomized, placebo-controlled studies with 10(3)-10(7) 50% tissue-culture infectious dose (TCID50) of avian-human (ah) and cold-adapted (ca) influenza A/Bethesda/85 (H3N2) reassortant viruses were completed in 106 seronegative young children 6-48 months of age. Although the reassortants differed in six of eight RNA segments, they exhibited similar properties in level of attenuation, infectivity, immunogenicity, and efficacy. The 50% human infectious dose was 10(4.6) TCID50 for ah and 10(4.4) for ca vaccines. Both reassortants were satisfactorily attenuated with restricted replication and were no more reactogenic than placebo. The mean peak titer of virus shed was 10(1.5) (ah) to 10(2.0) (ca) TCID50/ml, and each of 37 isolates tested retained their characteristic vaccine phenotypes. Infection with ah or ca virus conferred immunity to experimental challenge with homologous virus. These findings indicate that both ah and ca influenza A/Bethesda/85 (H3N2) reassortants should be suitable vaccine candidates for use in healthy infants and young children.

Antibodies, Viral

The use of consumer injury registry data to evaluate physical abuse.

Health care workers called upon to evaluate trauma in children must frequently decide if a given injury may have been intentionally inflicted. Some injuries are considered to be virtually diagnostic of abuse, but most are not at present readily associated with a particular type of intentional or nonintentional trauma. This study presents an example of how epidemiologically derived injury pattern data might be used by health care workers to better detect cases where intentional injury may have occurred. Injury pattern data were obtained for one type of trauma, falls from children's highchairs, from the U.S. Consumer Product Safety Commission (CPSC). Medical personnel at four training levels were randomized to receive a case description, which included an account of a fall from a highchair as the explanation of an injury, with or without the CPSC data. The injury described in the case was not one found in the CPSC pattern data. They were subsequently asked about their confidence in the explanation given and their desire to make a report of suspected abuse. Respondents given the CPSC data appropriately had less confidence in the explanation (p less than .001), although both groups felt strongly that a report should be made. Decreased confidence was demonstrated at all training levels. We concluded that clinicians could make use of injury pattern data in their examination of trauma cases, although such data cannot substitute for a thorough medical and social evaluation.

Accidental Falls

Poxvirus in scaled quail and prevalences of poxvirus-like lesions in northern bobwhites and scaled quail from Texas.

Prevalences of poxvirus-like lesions were determined for 177 northern bobwhites (Colinus virginianus) and 24 scaled quail (Callipepla squamata) trapped in southern Texas from 1976 to 1979 and for 190 northern bobwhites and 105 scaled quail shot at five locations in southern Texas from 1980 to 1981. None of the northern bobwhites trapped in 1976-1977 was infected, but 54% of the trapped scaled quail were infected; 17% of the northern bobwhites and 34% of the scaled quail shot in 1980-1981 had pox lesions, primarily on the wings. Prevalence was unrelated to sex or age of birds. For both species, prevalence was greatest during late spring and early summer. Histologic and electron microscopic examination confirmed poxvirus in two scaled quail, which constituted the first report of poxvirus in this species.

Age Factors

Changes in the fluoride-induced modulation of maturation stage ameloblasts of rats.

The maturation stage of enamel development is characterized by a cyclic modulation of the ameloblasts between bands of smooth-ended cells and longer bands of ruffle-ended cells. There are cyclic patterns of calcein staining of and 45Ca uptake in the enamel associated with this cellular modulation. Rats were given 0, 75, 100, or 150 ppm fluoride in their drinking water. Fluoride disrupted the cyclic patterns of the maturation stage, resulting in fewer bands of smooth-ended ameloblasts, fewer calcein-stained stripes, and fewer cycles of 45Ca uptake. When animals were given water containing 0 ppm fluoride following ingestion of water containing 100 ppm fluoride, the pattern of calcein staining returned to that of the control enamel. The disruption of the cyclic patterns in the maturation stage and the increased protein content of maturation enamel seem to be among the early events in the development of fluorosis.

Ameloblasts

Ultrastructural study of Mycoplasma pneumoniae in organ culture.

The ultrastructure of Mycoplasma pneumoniae M129 was studied by using specialized staining methods for thin-section transmission electron microscopy. Nucleic acid was shown in the cytoplasmic granules and fibrillar material in the nuclear region. The central filament of the highly structured tip contained basic protein. With one method of fixation, parallel filaments were seen in the central core. M. pneumoniae was enveloped in an extracellular mucoprotein layer that was especially concentrated around its terminal structure.

Animals

Loss of agglutinating specificity in stock cultures of Rhizobium meliloti.

Several strains of Rhizobium meliloti which have been subcultured for 23-33 years have changed from being markedly specific in their somatic agglutination reactions to become widely cross-reactive. On the other hand a fresh collection of the same species obtained from naturally nodulated, field-grown plants revealed the high degree of agglutinating specificity which had previously characterised the old cultures. Attempts to reselect a specific substrain from old cross-agglutinating cultures by six plant passages, or to detect change to cross reactivity by ten successive subcultures of recent isolates were unsuccessful. However, one strain, isolated in 1939, was recently found to contain both specific and cross-reactive substrains. Practically all the cultures, both old and recent, showed considerable mutability in colony characteristics but none of these was consistently correlated with cross agglutinability. Instability in 6.4% (w/v) NaCl was characteristic of the cross-agglutinating cultures. Cross reactivity was associated with a shared lipopolysaccharide antigen (LPS) which appeared to be obscured by an outer antigen in most strains still showing specific agglutinability. In the exceptional case of strain SU27, agglutination could be attributed to its specific LPS.

Agglutination

Lead-induced inclusion bodies: results of ethylenediaminetetraacetic acid treatment.

Earlier studies have shown that lead-induced nuclear inclusion bodies are composed of a lead-protein complex. Twenty-four hours after treatment of a lead-poisoned rat with a single dose of ethylenediaminetetraacetic acid (EDTA), urinary excretion of lead is maximally increased and the lead content of the kidneys is significantly decreased. Inclusion bodies in renal cell nuclei at this time are found in various stages of dissolution and migration out of the nucleus. The outer fibrillary margin becomes loosened, and slight disruption occurs at the periphery of the inclusion. Some inclusion bodies appear to be moving through the nuclear membrane. There is an invagination of both inner and outer nuclear membranes. Numerous cytoplasmic vacuoles occur which contain fibrillar material resembling portions of intact nuclear inclusions. Kidney nuclei of rats 24 hours after three daily injections of EDTA have no inclusion bodies. Whether the nuclear-cytoplasmic exchange occurs by dilation of a nuclear pore or by another mode of separation of nuclear membranes cannot be determined. This experiment demonstrates that nuclear inclusion bodies formed in lead poisoning are disrupted and removed from the nuclei by the administration of EDTA. This change corresponds with peak urinary excretion of lead. The sharp increase in urinary lead following EDTA therapy must reflect, at least in part, chelation and excretion of sequestered lead bound to nuclear protein.

Animals