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Biomedical subjects

L R Campbell

Publications and source records attributed to L R Campbell.

At least 19 recordsLinked to original sources
PubMed2005

Widened clinical spectrum of the Q128P MECP2 mutation in Rett syndrome.

CASE REPORT: We describe a female patient with Arnold Chiari type I malformation, atypical Rett syndrome characterized by postnatal onset microcephaly, stereotypic hand movements, ataxia, severe developmental delay, intractable tonic-clonic seizures, and a MECP2 mutation with a unique set of clinical findings. Implementation of a ketogenic diet resulted in decreased seizure activity and an improvement in the patient's degree of social relatedness with her family members. DISCUSSION: An early diagnosis of Rett syndrome allows families to maximize utilization of existing treatment modalities and seek appropriate genetic counseling and prenatal diagnoses. This case also provides further evidence for the treatment benefit of ketogenic diets for seizures in patients with Rett syndrome.

Arnold-Chiari Malformation↗
PubMed2001

Digestive, salivary, and reproductive organs of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) B type.

A microscopic analysis of the morphology and ultrastructure of the digestive, salivary, and reproductive systems of adult Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) B type was conducted using light, scanning, and transmission electron microscopy. The internal anatomy of B. tabaci was found to be similar to that reported for Trialeurodes vaporariorum. In a microscopic analysis of the salivary glands, we have shown that each primary salivary gland is composed of at least 13 cells varying in morphology and staining differentially, while the accessory salivary glands are composed of four morphologically similar cells. We analyzed the course of the alimentary canal in B. tabaci, demonstrated the internal morphology of the organs, and clarified the location of the filter chamber relative to other organs in the whitefly. Our observations confirm that the pair of structures extending from the connecting chamber are caeca that may aid in fluid movement through the midgut and are not Malpighian tubules, as previously suggested. We confirm an earlier finding that the whitefly lacks Malpighian tubules, having instead specialized Malpighian-like cells within the filter chamber at the juncture with the internal ileum. Finally, we provide the first scanning electron microscopic analysis showing the reproductive organs of B. tabaci. Our investigation provides clarified terminology for several components of the digestive and excretory system. We also provide drawings and micrographs that will aid future researchers in localizing the internal organs of B. tabaci. We expect our analysis to provide a valuable tool for studying B. tabaci / plant virus interactions and physiological and biological aspects of this insect.

Animals↗
PubMed2001

Placebo-controlled evaluation of amphetamine mixture-dextroamphetamine salts and amphetamine salts (Adderall): efficacy rate and side effects.

OBJECTIVE: The primary objective of this study was to determine the efficacy rate of Adderall in children newly diagnosed with attention-deficit/hyperactivity disorder (ADHD). A secondary objective was to address the severity of side effects associated with Adderall treatment in children with ADHD using the Barkley Side Effects Questionnaire (BSEQ). DESIGN: Randomized, double-blind, placebo-controlled crossover trial. SETTING: A large rural tertiary care clinic. PATIENTS: Participants were prospectively recruited from children 5 to 18 years of age referred for academic and/or attention problems; 154 children who met the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for ADHD were enrolled. Interventions. Two doses of Adderall (0.15 mg/kg/dose and 0.3 mg/kg/dose) were compared with placebo in separate 2-week trials. Participants received each dosage regimen twice daily for 7 consecutive days. MEASUREMENTS AND MAIN RESULTS: Efficacy rates were determined by comparing Adderall with placebo during the low-dose crossover sequence and also during the high-dose crossover sequence. The criteria that defined a positive response to Adderall relative to placebo (with each patient serving as their own control) included an indication of response by at least 1 of 2 parent measures of children's behavior or at least 2 of 5 teacher measures of children's behavior. The Adderall efficacy rate was determined based on parent criteria alone, teacher criteria alone, and by a more stringent definition of response that required concurrence between parent and teacher criteria. The Adderall response rate in this study ranged from 59% when requiring concurrence between parent and teacher observers, to 82% when based on parent criteria alone. Overall, 137 of 154 participants (89%) showed a positive response by either the parent or teacher response criteria. Parents completed a modified version of the BSEQ during each week of the trial. Appetite, stomachaches, and insomnia were rated as worse by parents while children were receiving either dose of Adderall; headaches were rated as worse when children were receiving the higher dose of Adderall. Parents rated certain side effects, including staring/daydreaming, sadness, euphoria, and anxious/irritable, as worse during placebo regimens. CONCLUSIONS: We found that Adderall is highly efficacious in our population of youth diagnosed with ADHD. In addition, Adderall is well-tolerated with a side effect profile similar to that reported for other psychostimulants.

Adolescent↗
PubMed2000

Characterization of cucurbita maxima phloem serpin-1 (CmPS-1). A developmentally regulated elastase inhibitor.

We report on the molecular, biochemical, and functional characterization of Cucurbita maxima phloem serpin-1 (CmPS-1), a novel 42-kDa serine proteinase inhibitor that is developmentally regulated and has anti-elastase properties. CmPS-1 was purified to near homogeneity from C. maxima (pumpkin) phloem exudate and, based on microsequence analysis, the cDNA encoding CmPS-1 was cloned. The association rate constant (k(a)) of phloem-purified and recombinant His(6)-tagged CmPS-1 for elastase was 3.5 +/- 1.6 x 10(5) and 2.7 +/- 0.4 x 10(5) m(-)(1) s(-)(1), respectively. The fraction of complex-forming CmPS-1, X(inh), was estimated at 79%. CmPS-1 displayed no detectable inhibitory properties against chymotrypsin, trypsin, or thrombin. The elastase cleavage sites within the reactive center loop of CmPS-1 were determined to be Val(347)-Gly(348) and Val(350)-Ser(351) with a 3:2 molar ratio. In vivo feeding assays conducted with the piercing-sucking aphid, Myzus persicae, established a close correlation between the developmentally regulated increase in CmPS-1 within the phloem sap and the reduced ability of these insects to survive and reproduce on C. maxima. However, in vitro feeding experiments, using purified phloem CmPS-1, failed to demonstrate a direct effect on aphid survival. Likely roles of this novel phloem serpin in defense against insects/pathogens are discussed.

Amino Acid Sequence↗
PubMed1992

Preservice training to meet the needs of people from diverse cultural backgrounds.

The provision of speech-language pathology and audiology services to persons from culturally and linguistically diverse populations is changing. Researchers have indicated that many current ASHA certified speech-language pathologists and audiologists do not perceive themselves as competent to provide services to individuals from culturally and linguistically diverse backgrounds due to the paucity of this information during their professional education (Campbell, 1986; Shewan & Malm, 1989; Snope, 1982). ASHA has attempted to meet the needs of individuals from culturally and linguistically diverse backgrounds who are communicatively impaired and students and practitioners through the latest revisions of the requirements for the Certificates of clinical Competence and through ESB accreditation requirements for university training programs. This article discussed several important needs associated with university training programs for speech-language pathologists and audiologists that must be considered as the professions respond to the needs of specific service populations.

Adult↗
PubMed1991

Influence of grafting a smaller target muscle on the magnitude of naturally occurring trochlear motor neuron death during development.

About half of the motor neurons produced by some neural centers die during the course of normal development. It is thought that the size of the target muscle determines the number of surviving motor neurons. Previously, we tested the role of target size in limiting the number of survivors by forcing neurons to innervate a larger target (Sohal et al., '86). Results did not support the size-matching hypothesis because quail trochlear motor neurons innervating duck superior oblique muscle were not rescued. We have now performed the opposite experiment, i.e., forcing neurons to innervate a smaller target. By substituting the embryonic forebrain region of the duck with the same region of the quail before cell death begins, chimera embryos were produced that had a smaller quail superior oblique muscle successfully innervated by the trochlear motor neurons of the duck. The number of surviving trochlear motor neurons in chimeras was significantly higher than in the normal quail but less than in the normal duck. The smaller target resulted in some additional loss of neurons, suggesting that the target size may regulate neuron survival to a limited extent. Failure to achieve neuron loss corresponding to the reduction in target size suggests that there must be other factors that regulate neuron numbers during development.

Animals↗
PubMed1991

Significance of seizures associated with extracorporeal membrane oxygenation.

We previously reported a predominance of left focal motor seizures in infants receiving extracorporeal membrane oxygenation (ECMO), raising concerns about possible ischemia resulting from the right common carotid artery ligation. We therefore evaluated the neurologic and psychologic outcome at 2 years of age of all infants with ECMO-related seizures. Although 8 of 12 infants had left focal seizures in infancy, there was no lateralization of motor findings at 2 years of age; left hemiparesis was present in three of the infants and right hemiparesis in three. The developmental quotient was normal in 6 of 12 infants, low-average in three, borderline in two, and in the mentally handicapped range in one. We conclude that any ischemia resulting from carotid ligation is not great enough to produce long-term lateralizing findings but that seizures during ECMO are a risk factor for later cerebral palsy or developmental delay.

Child Behavior↗
PubMed1991

Factors associated with delay in diagnosis of childhood amblyopia.

The prevention of permanent visual impairment from amblyopia is an important goal of pediatric vision screening. Unfortunately, many cases of amblyopia are not diagnosed until the child is too old to benefit maximally from treatment. A review of patient records from the practice of a private pediatric ophthalmologist confirmed that late detection is a frequent occurrence among children with amblyopia who have had good access to health care. A case-control study was then used to identify factors associated with delayed diagnosis, in which children with an adverse outcome (diagnosed at or after 5 years of age) were compared with those with an optimal outcome (diagnosed before 5 years of age). The chart review identified 161 children with amblyopia who participated in this study; 75 had late diagnoses (case patients) and 86 served as control patients. Children with early diagnoses more often had the following characteristics: a positive family history of strabismus, greater degrees of strabismus (when strabismus was present), higher maternal educational level, greater parental suspicion that an eye problem existed, and an increased chance that the parents requested the eye examination that led to the diagnosis. The parents of children with late diagnoses expressed less concern over the seriousness of amblyopia but were more likely to report that their children had suffered adverse consequences of amblyopia. When diagnosed early, amblyopia was more often detected by the child's primary health care provider. Physicians of the children with early diagnoses more often reported compliance with both the American Academy of Pediatrics guidelines for vision screening in infancy and referral for vision problems.(ABSTRACT TRUNCATED AT 250 WORDS)

Amblyopia↗
PubMed1990

Synapse formation on quail trochlear neurons transplanted in duck embryos before naturally occurring motor neuron death.

About half of the trochlear motor neurons in duck and quail embryos die during normal development. In a previous study the role of target muscle in controlling the number of surviving motor neurons was investigated by reducing the number of neurons innervating the muscle. This was accomplished by removing the midbrain of the duck embryo and grafting in its place the midbrain of the quail embryo before motor neuron death begins. It was observed that the number of surviving trochlear motor neurons in the quail-duck chimera embryos was not significantly different from that of the normal quail. The present investigation was undertaken to determine whether trochlear motor neurons in the chimera embryos received afferent synapses. Brains of duck, quail and chimera embryos on days 16 and 20 were processed for electron microscopical observations. Synapses formed on motor neurons of the chimera embryos. Surprisingly, synapses on motor neurons of quail differed from those of duck, both qualitatively and quantitatively. Synapses on the motor neurons of the chimera embryos developed in a fashion similar to that for the duck motor neurons. Our failure to rescue trochlear motor neurons in the chimera embryos suggests that the developing motor neurons may respond to a larger target muscle only if they received a normal complement of afferent synaptic input.

Animals↗
PubMed1990

An 8-year experience with depth electrodes in the evaluation of ablative seizure surgery candidates.

Stereotactically implanted depth electrodes are one means of localization of seizure foci. Unilateral seizure focus localization was obtained in 72.7% mesial temporal (MT) implants and 50% of focus/extramesial temporal (MT-XMT) implants. Recent increase in localization to over 80% in MT implants was possible because a larger percentage of patients had MT-XMT implants. Increased localization to 60% in MT-XMT implants was related to using more XMT electrodes per patient and to orienting electrodes to monitor larger limbic XMT and neocortical areas. Since MT foci were localized in 25% of MT-XMT cases, MT electrodes should be included with all MT-XMT implants. Depth electrography can also be used to rule out certain patients as surgical candidates. Therefore, a surgical decision can be reached in a very high percentage of patients undergoing depth implantation. Surgical results are comparable to those in our overall series.

Brain Mapping↗
PubMed1990

Management of attention deficit hyperactivity disorder (ADHD). A continuing dilemma for physicians and educators.

The American Academy of Pediatrics (AAP) has recommended that the initial treatment of attention deficit hyperactivity disorder (ADHD) should be educational and behavioral. The authors surveyed the directors of special education in the United States to determine whether these services are available to children with ADHD. They determined that the diagnosis of ADHD qualifies a child for services in only 1 out of 51 departments of special education surveyed. ADHD and classroom underachievement qualifies a child for special education services in 2 out of 51 departments. Thus, in most areas of the United States, special educational services are not available to meet the guidelines of the AAP.

Attention Deficit Disorder with Hyperactivity↗
PubMed1990

The pattern of neural tube defects created by secondary reopening of the neural tube.

The usual location of human neural tube defects at the rostral or caudal end of the primary neural tube suggests they are caused by failure of closure of the neural tube. In this study, neural tube defects were created by surgical reopening of the neural tube of 3-day-old duck embryos in one of three sites: the forebrain, cervicothoracic region, or thoracolumbar region. It was determined that of the 31 survivors with forebrain incisions, 39% had exencephaly; of the 42 survivors with thoracolumbar incisions, 31% had myeloschisis; but of the 37 with a cervicothoracic incision, only 14% had exposed spinal cord. This indicates that a rostral-caudal distribution of neural tube defects can be seen in a model created by secondary reopening of the neural tube.

Anencephaly↗
PubMed1988

Right common carotid artery ligation in extracorporeal membrane oxygenation.

The effect of right common carotid artery ligation required for arteriovenous extracorporeal membrane oxygenation (ECMO) was investigated in 35 infants. Their neonatal course was reviewed for evidence of right-sided ischemia of the brain, as suggested by the presence of focal seizures, hemiparesis, focal abnormalities on electroencephalography, or infarct or hemorrhage demonstrable on neuroimaging studies. A significant incidence of left focal seizures (9/35) versus right focal seizures (2/35) was noted, suggesting an effect of the carotid ligation on right hemisphere function. Computed tomographic scans (20/35 infants), electroencephalograms (18/35), ultrasound scans (31/35), and neurologic examinations did not reveal an increased incidence of right hemisphere abnormalities. These data suggest that systematic evaluation of the effects of right common carotid ligation should proceed as discussion continues on expanding the use of ECMO.

Brain↗
PubMed1988

Neurologic aspects of bronchopulmonary dysplasia.

Thirty seven infants were identified with bronchopulmonary dysplasia (BPD). Their hospital records were examined and survivors evaluated to determine the neurologic aspects of BPD. Five infants exhibited progressive neurologic disease; nine infants, Five infants exhibited progressive neurologic disease; nine infants, nonprogressive neurologic disease; and 19, normal neurologic outcome. In four, neurologic outcome was indeterminate because of early death. Thus, evaluation of this population of infants with BPD has established two syndromes of neurologic disease--progressive and nonprogressive. The patients with nonprogressive neurologic disease exhibited static neurologic deficits identical to those described in earlier reports of outcome in infants with BPD. The infants with apparently progressive neurologic disease had clinical courses comparable to the fatal pattern of cerebral deterioration previously described. The syndromes appear to be distinct in etiology and clinical presentation. Intraventricular hemorrhage complicated by hemorrhagic intracerebral involvement appears the factor most clearly associated with nonprogressive neurologic disease. The etiology of the striking progressive neurologic syndrome could not be so clearly established but appears to be related to the course and treatment of BPD.

Analysis of Variance↗
PubMed1987

Relationship of early neural tube appearance to myeloschisis in a chick embryo model.

Myeloschisis, a form of neural tube defect involving the spinal cord, was induced in chicks by creating a window in the eggshell of the fertilized egg at 26 h after placement in an incubator. The embryos were stained and photographed through the window at 48 to 60 h after commencement of incubation and the neural tube was determined to be normal, delayed, irregular, or abnormally open for the developmental stage of the embryo. The eggs were then reincubated until 14 days of age. At that time the chicks were determined to have normal spinal cords or myeloschisis by gross examination, dissection, and histology. The appearance of the neural tube at 48 to 60 h was then correlated with the appearance of the spinal cord at 14 days of age. It was determined that in the chick embryo model of myeloschisis induced by windowing, a normal neural tube at the time of neural tube closure results in a 2.3% incidence of myeloschisis, a widely open neural tube a 47% incidence of myeloschisis, an irregular neural tube a 37% incidence of myeloschisis, and delayed closure of the neural tube a 14% incidence of myeloschisis. Thus, no appearance of an early neural tube can be said to always correlate with myeloschisis or a normal outcome. Additionally, it appears that within a single model there may be multiple mechanisms of production of myeloschisis.

Animals↗
PubMed1986

Neural tube defects: a review of human and animal studies on the etiology of neural tube defects.

Although neural tube defects are a common congenital anomaly, their etiology is not known. Human studies have emphasized the pathology and epidemiology of the defects and suggest that in the majority of cases the etiology is multifactorial. Factors which appear possibly to be important are genetic predisposition, maternal illness, and fetal drug exposure. Animal studies have utilized naturally occurring neural tube defects and teratologically induced lesions. No animal model has been convincingly established as the equivalent of human neural tube defects. However, animal models have allowed investigation of the mechanisms of suggested human teratogens and determination of the pathogenesis of naturally occurring animal defects. Their most important contribution has been in furthering the understanding of the normal mechanisms of neural tube closure. It may be through this understanding that the etiology of human neural tube defects will be determined.

Animals↗
PubMed1985

Development of the trochlear nucleus in quail and comparative study of the trochlear nucleus, nerve, and innervation of the superior oblique muscle in quail, chick, and duck.

The present study was undertaken to examine the development of the trochlear nucleus in quail and to compare the mature trochlear nucleus, nerve, and their sole target of innervation, the superior oblique muscle, in quail, chick, and duck. Study of the trochlear nucleus in quail from embryonic day 5 through hatching shows a maximum of 1,248 neurons on embryonic day 10 followed by spontaneous degeneration of 40% of the neurons between days 10 and 16. Previous studies have shown that although the initial and final number of neurons is different in chick and duck, the magnitude of trochlear cell loss in both species is about 40%. This study shows the average number of neurons in the nucleus of quail, chick, and duck, 2 weeks post-hatching, to be 658, 743 and 1,459, respectively. Fiber counts in the trochlear nerve from electron micrograph montages at the same period indicated a ratio of about 1:1 between neurons and axons. While a majority of the fibers in these nerves are myelinated, an average of 3-6% of the fibers are unmyelinated. The nucleus in the quail not only contains the smallest number of neurons but it also innervates the smallest muscle in terms of total number of muscle cells and endplates. However, the opposite relationship does not hold true. The nucleus in duck contains the largest number of neurons, yet the largest number of muscle cells and endplates were found in the chick. The ratios between the neurons and muscle cells as well as between neurons and endplates are about the same in quail and duck. These ratios are much higher in the chick, reflecting the relatively small neuron pool destined for a relatively large target. In spite of variations in the number of neurons, muscle fibers, and endplates the average number of endplates per muscle fiber is relatively constant among the three species.

Animals↗