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Biomedical subjects

G M Johnson

Publications and source records attributed to G M Johnson.

At least 19 recordsLinked to original sources
PubMed2000

The fine connective tissue architecture of the human ligamentum nuchae.

STUDY DESIGN: An anatomic study of the posterior midline structures of the cervical spine was performed using a new sheet-plastination (E12) technique in conjunction with gross anatomic dissection. OBJECTIVES: To clarify the structural status of the human ligamentum nuchae. SUMMARY OF BACKGROUND DATA: Little is known about the arrangement of connective tissue attachments of the neighboring neck muscles to the ligamentum nuchae. In addition, it is not clear whether the cervical supraspinous ligaments form part of the ligamentum nuchae. METHODS: This study used a combined approach of a detailed gross anatomic study on eight cadavers and a macroscopic and microscopic study of the connective tissue organization of the posterior midline structures on serial horizontal thin (2.5 mm) plastinated slices of the cervical spine (occiput-T1) from an adult female cadaver. RESULTS: The dorsal and ventral portions of the ligamentum nuchae are a single entity formed by the aponeurotic fibers of the trapezius, splenius capitis, rhomboideus minor, and serratus posterior superior muscles. CONCLUSIONS: The regional differences in the connective tissue organization of the ligamentum nuchae and its well-defined attachments to the C6 and C7 vertebrae suggest that it is designed to function in the lower cervical spine.

Aged↗
PubMed2000

Developmental antecedents of sexual coercion in juvenile sexual offenders.

Previous research has linked adult sex offending behavior to a multiplicity of variables, including juvenile delinquency and the experience of childhood abuse. The purpose of this study was to explore developmental pathways among childhood abuse, juvenile delinquency, and personality dimensions possibly conducive to adolescent sexual coercion. Using a retrospective self-report inventory, we measured the extent to which juvenile sexual offenders experienced childhood trauma, engaged in adolescent delinquency, and exhibited particular dispositions and cognitive biases. The effects of childhood and adolescent antecedents on sexual coerciveness were then analyzed through simultaneous multiple regression path analyses. Results suggest that sexual compulsivity and hypermasculinity, through misogynistic fantasy behavior, significantly discriminate verbally and physically coercive juvenile offenders from those offenders who do not report using force in their offenses. Results also suggest that alcohol abuse may play a more salient role in the expression of coercive juvenile sexual coercion than previously hypothesized.

Adolescent↗
PubMed1999

Reye's syndrome.

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Adolescent↗
PubMed1999

Gomco circumcision.

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Circumcision, Male↗
PubMed1999

Flavobacterium meningosepticum sepsis in an infant with a diarrheal prodrome.

A full term, previously normal 2 1/2-month-old black boy was transferred to our hospital from an outlying facility on hospital day 5 for failure to thrive. Three weeks before transfer, the infant was hospitalized for a diarrheal illness with fever. The baby received 3 days of ceftriaxone empirically and was discharged home after the sepsis evaluation was negative. Mild diarrhea and steady weight loss continued and the baby was readmitted. Blood culture done on admission grew Flavobacterium meningosepticum, an organism previously described as an uncommon cause of sepsis in neonates and immunocompromised individuals. As it is water-borne, it has been associated with infection via contaminated water. This organism is usually resistant to antibiotics commonly used for empiric treatment. To our knowledge, this is the first reported case of Flavobacterium bacteremia associated with a prodromal and concurrent diarrheal illness.

Bacteremia↗
PubMed1998

The correlation between surface measurement of head and neck posture and the anatomic position of the upper cervical vertebrae.

STUDY DESIGN: Repeated measurements were made of surface postural angles registering the relative positions of the head and neck in photographs and of angles of the upper cervical vertebrae recorded in lateral cephalometric radiographs in the same subjects. For all registrations, subjects assumed the natural head rest position. OBJECTIVES: To examine the correlation between external measurement of head and neck posture and the anatomic positions of the upper four cervical vertebrae. SUMMARY OF BACKGROUND DATA: Interpretation of surface cervical posture measurement is confounded by lack of knowledge about the extent of the underlying compensatory adjustments among the upper cervical vertebrae that may accompany variation in head and neck posture. The correlation between surface measurement and postural characteristics of the upper cervical spine has not been reported to date. METHODS: The association between a set of angles describing the anatomic position of the four upper cervical vertebrae on lateral cephalometric radiographs and a surface measurement of head and neck posture, the craniovertebral angle, was studied in 34 young adult women aged between 17.2 and 30.5 years, mean age, 24.5 years. Anatomic positions of the upper four cervical vertebrae were expressed by angles relative to the true vertical or horizontal. Surface angles registering head and neck position for each subject were obtained from photographs recorded on two occasions. RESULTS: No strong correlation could be established between the angles taken from the lateral cephalometric radiographs measuring the extent of upper cervical lordosis, orientation of the atlas, vertebral inclination, or odontoid process tilt and surface angles recording head and neck position. This finding was attributed principally to the much greater positional variability demonstrated within the upper cervical spine when compared with the surface measurements of head and neck position. CONCLUSION: Anatomic alignment of the upper cervical vertebrae cannot be inferred from variation in surface measurement of head and neck posture. This is the case even in those people identified with more extreme head and neck postural tendencies.

Adolescent↗
PubMed1998

A randomized study of combined zidovudine-lamivudine versus didanosine monotherapy in children with symptomatic therapy-naive HIV-1 infection. The Pediatric AIDS Clinical Trials Group Protocol 300 Study Team.

OBJECTIVE: The Pediatric AIDS Clinical Trials Group (PACTG) Protocol 300 assessed the clinical efficacy and safety of combination zidovudine/lamivudine (ZDV/3TC) compared with either didanosine (ddI) alone or combination ZDV/ddI. STUDY DESIGN: Children with symptomatic human immunodeficiency virus (HIV) infection, 6 weeks through 15 years of age, were stratified according to age and randomly assigned to receive ddI, ZDV/3TC, or ZDV/ddI. The primary endpoint was time to first progression of HIV disease or death. Enrollment in the ZDV/ddI arm stopped after 11 months on the basis of results of PACTG Protocol 152, but blinded follow-up continued. RESULTS: For the 471 children who could be evaluated, the median age was 2.7 years, median CD4 cell count was 699 cells/mm3, and median log10 HIV RNA was 5.1/mL. Median follow-up was 9.4 months. Patients receiving ZDV/3TC had a lower risk of HIV disease progression or death than those receiving ddI alone (15 vs 38 failures, P = .0006) and a lower risk of death (3 vs 15 deaths, P = .0039). Weight and height growth rates, CD4+ cell counts, and RNA concentrations showed results favoring ZDV/3TC. For patients concurrently randomized to all 3 treatment arms, both ZDV/3TC and ZDV/ddI recipients had lower risk of HIV disease progression than those who received ddI alone (P = .0026 and P = .0045). CONCLUSIONS: Combination therapy with either ZDV/3TC or ZDV/ddI was superior, as determined by clinical and laboratory measures, to monotherapy with ddI.

Adolescent↗
PubMed1997

Immunizations.

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Diphtheria-Tetanus-Pertussis Vaccine↗
PubMed1996

Effect of nitrogen dioxide and other combustion products on asthmatic subjects in a home-like environment.

Nitrogen dioxide (NO2) is one of a number of nitrogen compounds that are by-products of combustion and occur in domestic environments following the use of gas or other fuels for heating and cooking. In this study, we examined the effect of two levels of NO2 on symptoms, lung function and airway hyperresponsiveness (AHR) in asthmatic adults and children. In addition, in the same subjects, we examined the effects of the same levels of NO2 mixed with combustion by-products from a gas space heater. The subjects were nine adults, aged 19-65 yrs, and 11 children, aged 7-15 yrs, with diagnosed asthma which was severe enough to require daily medication. All subjects had demonstrable AHR to histamine. Exposures were for 1 h on five separate occasions, 1 week apart, to: 1) ambient air, drawn from outside the building; 2) 0.3 parts per million (ppm) NO2 in ambient air; 3) 0.6 ppm NO2 in ambient air; 4) ambient air+combustion by-products+NO2 to give a total of 0.3 ppm; and 5) ambient air+combustion by-products+NO2 to give a total of 0.6 ppm. Effects were measured as changes in lung function and symptoms during and 1 h after exposure, in AHR 1 h and 1 week after exposure, and in lung function and symptoms during the week following exposure. Exposure to NO2 either in ambient air or mixed with combustion by-products from a gas heater, had no significant effect on symptoms or lung function in adults or in children. There was a small, but statistically significant, increase in AHR after exposure to 0.6 ppm NO2 in ambient air. However, there was no effect of 0.6 ppm NO2 on AHR when the combustion by-products were included in the test atmosphere nor of 0.3 ppm NO2 under either exposure condition. We conclude that a 1 h exposure to 0.3 or 0.6 ppm NO2 has no clinically important effect on the airways of asthmatic adults or children, but that 0.6 ppm may cause a slight increase in airway hyperresponsiveness.

Adolescent↗
PubMed1995

Priming of tyrosine phosphorylation in GM-CSF-stimulated adherent neutrophils.

Adherence of human neutrophils to plastic, fibronectin, or collagen-coated surfaces modifies their response to several agonists including granulocyte-macrophage colony-stimulating factor (GM-CSF), tumor necrosis factor alpha (TNF-alpha), and fMet-Leu-Phe, permitting them to trigger superoxide anion (O2-) release, which they are unable to do as cells in suspension. Adherence of neutrophils causes a slight decrease in the basal level of tyrosine phosphorylation compared with that of suspended cells. The addition of GM-CSF, however, brings all proteins to a level of phosphorylation at least equal to that seen in suspended cells. In the case of a 130-kDa (p130) and a 42-kDa (p42) protein, the increase in tyrosyl phosphorylation in response to GM-CSF challenge is clearly larger in adherent than in suspended cells (6- and 4-fold increases for p130 and p42, respectively, in adherent cells vs. 1.7- and 2.1-fold in suspended cells). This is even more patient in the case of collagen-coated plates (9.4-fold increase for p42). Therefore, once neutrophils attach to surfaces, they become primed and respond to GM-CSF with greater potency than when they are in suspension. By Western blot analysis with anti-MAP kinase antibodies, we demonstrate that p42 is one member of the mitogen-activating protein kinase, namely the p42MAPK. The tyrosyl phosphorylation of p42MAPK is elevated in GM-CSF-treated adherent neutrophils in a time-dependent fashion as measured by the formation of a doublet composed of the phospho (or activated) form and the dephospho (or inactive) form of MAP kinase. MAP kinase activation and tyrosine phosphorylation are inhibited by tyrosine kinase inhibitors genistein and tyrphostin-23. Our results indicate that adherence acts to prime neutrophils for enhanced functionality and that tyrosine phosphorylation is involved in this process.

Amino Acid Sequence↗
PubMed1995

Long-term follow-up of blood donors with indeterminate human immunodeficiency virus type 1 results on Western blot.

BACKGROUND: At present, tens of thousands of United States blood donors who are at low risk for human immunodeficiency virus type 1 (HIV-1) infection are indefinitely deferred. These persons are repeatably reactive for HIV-1 antibody in enzyme immunoassay (EIA) and are indeterminate in Western blot. STUDY DESIGN AND METHODS: To determine the significance and persistence of anti-HIV-1 reactivity in plasma from volunteer blood donors with HIV-1-indeterminate Western blots, 66 donors were retested for HIV-1 antibody by the same manufacturers' EIA and Western blot 5 to 7 years after the initial Western blot. In addition, donors' peripheral blood mononuclear cells were tested by polymerase chain reaction (PCR) for HIV-1 DNA gag sequences. RESULTS: Thirty-five (53%) of 66 donors were still repeatedly reactive for HIV-1 on EIA and indeterminate on Western blot, 23 (35%) were negative on EIA and indeterminate on Western blot, 7 (11%) were negative in EIA and Western blot, and 1 (2%) was repeatedly reactive on EIA and negative on Western blot. Donors with persistently indeterminate Western blots had a band pattern nearly identical to that on the original Western blot. No donor was positive in Western blot, p24 antigen, or PCR testing. No donor had signs or symptoms of HIV-1 infection. CONCLUSION: Long-term follow-up of Western blot-indeterminate blood donors does not reveal evidence of HIV-infection. A mechanism to return these donors to the donor pool should be considered.

Base Sequence↗
PubMed1995

Vaccination update. Hib, hepatitis, polio, varicella, influenza, pneumococcal and meningococcal disease.

Immunization of infants and children is the most effective strategy for decreasing the incidence of some infectious diseases. Most invasive disease due to Haemophilus influenzae type b occurs before age 5 years, and routine vaccination of infants for hepatitis B is currently recommended because selective immunization of high-risk persons has not been feasible. Decades of use of poliovirus vaccine has effectively eliminated cases of wild-virus infection, although some vaccine-related cases still occur. The newly approved varicella vaccine appears to be a cost-effective way to decrease infection rates in children. Improved immunization rates for influenza and pneumococcal and meningococcal diseases could help decrease excess mortality in elderly persons and those with chronic illness.

Bacterial Vaccines↗
PubMed1995

Vaccination update. Diphtheria, tetanus, pertussis, mumps, rubella, measles.

Despite the availability of many effective vaccines, some vaccine-preventable diseases still cause significant morbidity and mortality. Increased prevention should be attainable through proper education about the efficacy and safety of vaccines, improved immunization rates, and adherence to recommended vaccination guidelines from the Advisory Committee on Immunization Practices. Childhood immunization should include a complete diphtheria, tetanus, and pertussis series and a measles, mumps, and rubella series. Booster doses for tetanus should be given every 10 years throughout life.

Diphtheria↗
PubMed1994

Effects of subanesthetic concentrations of isoflurane and their interactions with epinephrine on acquisition and retention of the rabbit nictitating membrane response.

BACKGROUND: Evidence concerning the concentrations of volatile anesthetics that prevent learning and recall is limited. Epinephrine is believed to enable learning during anesthesia. We investigated the effects of isoflurane and its interaction with epinephrine on learning and subsequent retention of the rabbit's classically conditioned nictitating membrane response. METHODS: In experiment 1, a tone (conditioned stimulus, CS) preceded paraorbital shock (unconditioned stimulus, US) during 60-min daily sessions of 60 presentations of these paired stimuli for 6 days of acquisition training under 0, 0.4%, or 0.8% isoflurane (n = 8, 13, and 9, respectively). Responses were recorded as conditioned responses (CRs) if they occurred during the CS and before the onset of the US. After 1 day of rest, the animals were given 3 days of extinction consisting of 60 presentations of CS-alone and without isoflurane to assess the retention of CRs from acquisition training. In experiment 2, epinephrine in a dose of 0, 0.01, or 0.1 mg/kg was injected subcutaneously in rabbits receiving 0.4% isoflurane. Two types of epinephrine were used, a sustained release form and epinephrine hydrochloride. Acquisition and retention were tested in the same way as in experiment 1. No isoflurane or epinephrine was used during retention testing. RESULTS: Learning was significantly suppressed during 0.4% isoflurane (approximately equal to 0.2 MAC) treatment and eliminated during 0.8% (approximately equal to 0.4 MAC). Information learned during administration of 0.4% isoflurane was not retained (P < 0.05). Although the low doses of epinephrine improved learning during the last day of the acquisition phase (P < 0.05), there were no differences between the treatment groups on any of the remaining acquisition or extinction days. CONCLUSIONS: There was no learning during treatment with 0.8% concentration. Even a 0.4% concentration, which allowed some learning, abolished CRs in extinction, perhaps because of state-dependent retrieval. Epinephrine did not alter substantially the rates of CR acquisition or resistance to extinction.

Animals↗
PubMed1992

Superoxide anion production by rat neutrophils at various stages of bleomycin-induced lung injury.

This study investigated the level of activation of neutrophils isolated from rats at various stages of bleomycin-induced lung injury. Neutrophils were collected from blood and bronchoalveolar lavage (BAL) fluid and their superoxide anion (O2-)-generating capacity measured in response to phorbol myristate acetate (PMA) and opsonized zymosan (OZ) stimulation. When stimulated with PMA, BAL neutrophils isolated from animals 3 days after bleomycin treatment had a significantly greater capacity to produce O2- than BAL neutrophils from animals 7 days after bleomycin treatment. The O2- levels of 7 day BAL neutrophils more closely resembled the resting levels obtained with circulating neutrophils from both control and bleomycin-treated animals. There were no differences observed in any of the neutrophils when stimulated with OZ. Myeloperoxidase levels were measured in plasma and BAL and found to be elevated only in plasma at 7 days after bleomycin. These data demonstrate that neutrophil activation does occur in this model and that the activation appears to be transient, in response to specific stimuli and compartmentalized between the lung and blood.

Animals↗
PubMed1992

Autologous blood transfusion. Current trends, nursing implications.

Developing a quality perioperative autologous blood recovery program is a team effort. Members of transfusion committees, hospital blood bank personnel, OR staff members, and the members of the surgery committee are all possible sources of information. Your local blood center also may have literature or services that could be of assistance. Knowledge of current autologous transfusion alternatives will help nurses communicate with patients regarding transfusion therapy and will make nurses more valuable participants in the crucial decisions necessary to deliver optimal patient care in the perioperative period.

Blood Transfusion, Autologous↗
PubMed1992

Suspect value of non-CSF viral cultures in the diagnosis of enteroviral CNS infection in young infants.

Laboratory criteria used for presumptive diagnosis of enteroviral meningitis were evaluated as predictors of cerebrospinal fluid (CSF) infection. Records were retrospectively analysed of infants under four months of age admitted to hospital between 1977 and 1987 with viral CSF cultures: those with enteroviruses isolated from CSF (group 1) were compared with those with enteroviruses isolated only from non-CSF sites (group 2). Predictive value computations demonstrated that no single or combined non-CSF culture accurately predicted isolation of enteroviruses from the CSF. These results suggest that CSF viral culture is imperative in establishing the diagnosis of enteroviral meningitis in young infants.

Cerebrospinal Fluid↗