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Biomedical subjects

W Robinson

Publications and source records attributed to W Robinson.

At least 19 recordsLinked to original sources
PubMed2002

A comparison of splinted and banded Herbst appliances: treatment changes and complications.

The aims of this study were to compare the frequency of clinical problems, such as fracture and dislodgment, and the dentofacial changes in 28 13-year-old Chinese children with Class II, division 1 nalocclusions treated with either cast-metal splinted Herbst appliances or banded Herbst appliances. ne first fourteen children were treated with a maximum anchorage type of banded Herbst appliance for six months, and the remainder were treated with cast-silver splinted Herbst appliances for seven months. The dentofacial form and the treatment changes were assessed with one aid of pre- and post-treatment lateral cephalometric radiographs. The number of visits and the number of fractured and dislodged appliances were recorded. Both appliances had similar effects on the dentofacial structures. There were no statistically significant dentofacial differences between the groups at the conclusion of treatment. During treatment relatively few banded appliances were dislodged and few splinted appliances fractured. However, a large number of banded appliances fractured, and a similar number of splinted Herbst appliances were dislodged. The latter required less clinical and laboratory time to service and/or replace. It was concluded that splinted Herbst appliances are preferable to banded Herbst appliances because of the savings in clinical and laboratory time.

Adolescent↗
PubMed2001

Osteogenesis in the glenoid fossa in response to mandibular advancement.

The purpose of this study was to identify the temporal sequence of cellular changes in the glenoid fossa and to quantify the amount of bone formation in response to mandibular advancement. One hundred 35-day-old female Sprague-Dawley rats were randomly divided into 5 experimental groups (15 rats each) and 5 control groups (5 rats each). In the experimental groups, functional appliances were used to create continuous forward mandibular advancement. The rats were killed after 3, 7, 14, 21, and 30 days. Sections were cut through the glenoid fossa in the parasagittal plane and stained with periodic acid and Schiff's reagent for evaluation of bone formation and with hematoxylin and eosin for observation of cellular response. The results showed that, in the control rats, bone formation was initially higher in the posterior and middle regions than in the anterior region then decreased over time in all regions. In the experimental group, bone formation significantly increased from day 7 to day 30 compared with control rats. Day 21 marked the highest levels of bone formation in the middle (+184%) and posterior regions (+300%). Mandibular protrusion resulted in the osteoprogenitor cells being oriented in the direction of the pull of the posterior fibers of the disc and also resulted in a considerable increase in bone formation in the glenoid fossa.

Adaptation, Physiological↗
PubMed2001

Maternal origin of monosomy 21 derived from ICSI.

With the worldwide diffusion of the intracytoplasmic sperm injection (ICSI) procedure in recent years, the issue of possible genetic risks of this new and powerful technique has attracted considerable attention. An important concern is whether ICSI facilitated the passage of genetic defects from spermatozoa to offspring. ICSI was performed with spermatozoa from a frozen-thawed sperm sample from a testicular sperm extraction (TESE) of a 38 year old man who suffered from azoospermia. His wife was 36 years old. The resulting pregnancy spontaneously aborted at 8 weeks gestation after embryo replacement. Cytogenetic investigation displayed monosomy 21. The paternal origin of the single chromosome 21 was determined by molecular analysis. The segregation error leading to loss of one chromosome 21 is likely to have occurred during oogenesis rather than as a direct consequence of ICSI. Nonetheless, monosomy 21 is extremely rare and it cannot be excluded that ICSI assisted the fertilization of an abnormal oocyte.

Abortion, Spontaneous↗
PubMed2000

FEV(1) as a guide to lung transplant referral in young patients with cystic fibrosis.

Forced expiratory volume in one second (FEV(1)) is widely used to guide referral of patients with cystic fibrosis (CF) for lung transplantation. We reasoned that the best FEV(1) in a 6-month period (bFEV(1)) would be a useful marker of the need for transplant referral. We examined both the rate of decline and different threshold values of bFEV(1) as prognostic indicators in young CF patients. In a case-control analysis, rates of decline in and threshold values of bFEV(1) of 28 patients dying between ages 7-18 years from 1980-1997 were compared to those of 28 age- and gender-matched controls. The threshold analysis of bFEV(1) values was then applied to all patients under age 19 years followed in our clinic from 1993-1997. The rate of decline in bFEV(1) differed for cases and controls over the 4-year period prior to death, but not from years 2-4 prior to death, the time at which transplant referral decisions should be made. A bFEV(1) value of 50% predicted at 2 years prior to the death of the case selected 14 of 28 cases and one control. When applied to all pediatric patients followed from 1993-1997, a bFEV1 threshold of 50% predicted selected 2 of the 3 patients who died and 3 of the 140 patients who survived. Consideration of lung transplantation referral should begin when young CF patients have a best FEV(1) <50% predicted despite aggressive conventional treatment.

Adolescent↗
PubMed2000

Palliative care in cystic fibrosis.

Although advances in therapy for cystic fibrosis (CF) have dramatically increased the average life span of patients, the disease is still uniformly fatal. Little attention has been paid to methods of palliative care for patients with cystic fibrosis in the medical literature. The primary palliative care issue in end-stage CF is the management of dyspnea. An observational study done at Children's Hospital in Boston suggested that doses of morphine in the range of 5 mg per hour can control the end-stage dyspnea in CF of over 50% of patients; the rest required increasing doses with the highest dose required being 30 mg/hour. The use of mechanical ventilation at the end of life is increasing in CF, particularly for those patients awaiting lung transplantation, and it appears that the consensus against the use of aggressive care at the end of life in CF may be eroding. The use of various modes of assisted ventilation in end-stage CF will add new challenges to the compassionate provision of end-of-life care. In addition to these medical issues, palliative care in CF presents some unique psychosocial issues: there may be more than one family member with the disease, and there is an involved patient community also affected by end-of-life plans. A family-centered approach to end-of-life care for patients with CF is essential.

Journal Article↗
PubMed2000

Allelic loss and microsatellite alterations of chromosome 3p14.2 are more frequent in recurrent cervical dysplasias.

Epidemiological studies have documented the unpredictable clinical progression or recurrence of cervical dysplasia. Recent studies have shown several molecular changes in cervical cancers and their associated dysplasia. We conducted molecular analyses on a retrospectively ascertained cohort of recurrent and nonrecurrent cervical dysplasia cases in an attempt to define molecular biomarkers to predict progressive or recurrent disease. Cases were chosen if long-term follow-up (3-5 years after conization) and biopsy confirmation were available. Paraffin-embedded, postconization cervical tissues from 19 recurrent and 18 nonrecurrent dysplasias were analyzed. Human papillomavirus (HPV) was identified by PCR for general and type-specific (HPV-16 and HPV-18) primers. Allelotyping analysis was performed by multiplex PCR using a panel of 16 microsatellite markers targeting putative tumor suppressor gene regions on chromosomes 3p, 5p, 6p, 9p, 11q, and 17p. The overall rate of HPV infection was similar in both groups. In the allelotyping analysis, loss of heterozygosity at the fragile histidine triad region in 3p14.2 was significantly higher in the recurrent group than in the nonrecurrent group (P = 0.005). Furthermore, microsatellite alterations (MAs) were more frequent in the recurrent group (mean MA index, 0.254) as compared with the nonrecurrent group (mean MA index, 0.085; P = 0.0025). These findings suggest that HPV status alone does not predict recurrence and that loss of heterozygos. ity at the fragile histidine triad region may represent a potential biomarker in predicting recurrence. Frequent MAs in the recurrent group may represent an underlying genomic instability that creates susceptibility for allelic loss, thus increasing the risk for recurrence or progression.

Adult↗
PubMed2000

Invasive and preinvasive cervical neoplasia in human immunodeficiency virus-infected women.

An association between human immunodeficiency virus (HIV) infection and cervical neoplasia in women has recently been recognized. Cervical cancer was designated as a diagnostic criteria for acquired immunodeficiency syndrome (AIDS) in HIV-infected women in 1993. The two conditions share a number of risk factors, including a history of multiple sexual partners and disproportionate effect on younger women and ethnic minorities. HIV appears to accelerate the pathogenesis of cervical neoplasia at the molecular level, although clinical evidence of disease progression is limited. The optimal strategy for screening HIV-infected women for cervical neoplasia is unclear, but should include at least an annual Papanicolaou (Pap) smear. Preinvasive cervical neoplasia in HIV-infected women should be treated with standard excisional/ ablative therapy, followed by vaginal 5-flourouracil cream. Invasive cervical cancer should be treated with standard surgical therapy or radiotherapy. Recurrence rates are high following treatment of either invasive or preinvasive disease, but are reduced in women undergoing highly active antiretroviral therapy.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Overexpression of mutant ras in human melanoma increases invasiveness, proliferation and anchorage-independent growth in vitro and induces tumour formation and cachexia in vivo.

Malignant melanoma is the deadliest form of skin cancer. Previous studies have shown that the incidence of ras mutation increases with progression of melanoma, but that such mutations may not be present in the earliest radial growth phase melanomas. Recently it has been proposed that introduction of ras mutations into cells deficient in tumour suppressor genes such as p16 (INK4a) is sufficient to induce characteristics of cellular transformation such as anchorage-independent growth and tumour formation in vivo. To test this hypothesis in human melanoma, mutant N-ras, mutant H-ras or wild-type H-ras genes were transfected by electroporation into WM35 cells, a p16-deficient human melanoma cell line of low invasive potential. Increased expression of mutant ras p21 enhanced anchorage-dependent cell growth on tissue culture plastic. In addition, overexpression of mutant N-ras and H-ras, but not of wild-type H-ras, increased the experimental invasive potential, inducing anchorage-independent growth in soft agar, increasing cell motility measured by time-lapse video microscopy, and increasing invasiveness through reconstituted basement membranes. Finally, overexpression of mutant H-ras in melanoma cells was shown to increase tumorigenicity and to induce cachexia when H-ras transfected cell lines were injected subcutaneously in severe combined immunodeficiency (SCID) mice. Thus the addition of activating ras mutations to a melanoma cell line already deficient in p16 leads to enhanced proliferation, survival and migration in vitro and to enhanced subcutaneous tumour formation in vivo. This phenotype is typical of the behaviour of vertical growth phase (VGP) melanoma, and we propose that activation of the ras signalling pathway in the presence of deletions in p16 or related tumour suppressors can induce the VGP melanoma phenotype.

Animals↗
PubMed1996

Complete paternal isodisomy for chromosome 8 unmasked by lipoprotein lipase deficiency.

Uniparental disomy (UPD)-the inheritance of two homologous chromosomes from a single parent-may be unmasked in humans by the unexpected appearance of developmental abnormalities, genetic disorders resulting from genomic imprinting, or recessive traits. Here we report a female patient with familial chylomicronemia resulting from complete lipoprotein-lipase (LPL) deficiency due to homozygosity for a frameshift mutation in exon 2 of the LPL gene. She was the normal term product of an unremarkable pregnancy and had shown normal development until her current age of 5.5 years. The father (age 33 years) and the mother (age 24 years) were unrelated and healthy, with no family history of stillbirths or malformations. The father was a heterozygous carrier of the mutation, whereas no mutation in the LPL gene was detected in the mother. Southern blotting did not reveal any LPL gene rearrangement in the proband or her parents. The proband was homozygous for 17 informative markers spanning both arms of chromosome 8 and specifically for the haplotype containing the paternally derived LPL gene. This shows that homozygosity for the defective mutation in the LPL gene resulted from a complete paternal isodisomy for chromosome 8. This is the first report of UPD for chromosome 8 unmasked by LPL deficiency and suggests that normal development can occur with two paternally derived copies of human chromosome 8.

Adult↗
PubMed1996

Chronic pain in cystic fibrosis.

OBJECTIVE: The objective of this study was to examine the incidence and therapy of chronic pain in a group of older patients with cystic fibrosis (CF). PATIENTS: We identified two groups of patients followed at the CF Center at Children's Hospital (Boston); the first group consisted of all patients above the age of 5 years who died between 1984 and 1993, and the second was a cohort of 23 additional CF patients who had been referred to the Pain Treatment Service. DESIGN: Medical charts were reviewed for the etiology and therapy of all pain episodes requiring medical intervention. RESULTS: The incidence of chronic pain in this population increased sharply in the last 6 months of life. Headaches (55% of patients) and chest pain (65%) were frequently reported, although back pain (19%), abdominal pain (19%), and limb pain (16%) were also reported. In patients with headache, the main etiologies were hypercarbia or hypoxia, migraine, and sinusitis. The majority of chest pain was musculoskeletal, with pleuritis, pneumothorax, and rib fracture also reported as the cause of chest pain. INTERVENTIONS: A variety of nonpharmacological and pharmacological therapies were reported. Forty-one patients (53%) had pain severe enough to require opioid treatment, and 10 patients (13%) received opioids for more than 3 months. In eight patients with more severe pain, regional analgesia was found to be particularly effective. CONCLUSIONS: Chronic pain is a common problem in CF, particularly as the patient population ages. When administered with caution, opioids have proven to be effective and safe in this population; regional anesthesia can be used to preserve pulmonary toilet while adequately treating severe pain.

Adolescent↗
PubMed1995

Genotype-phenotype correlation in a series of 167 deletion and non-deletion patients with Prader-Willi syndrome.

A total of 167 patients with Prader-Willi syndrome (PWS) was studied at the clinical and molecular level. Diagnosis was confirmed by the PW71 methylation test. Quantitative Southern blot hybridizations with a probe for the small nuclear ribonucleoprotein N were performed to distinguish between patients with a deletion (116 patient or 69.5%) and patients without a deletion (51 patients or 30.5%). These two types of patients differed with respect to the presence of hypopigmentation, which was more frequent in patients with a deletion (52%) than in patients without (23%), and to average birth weight of females and males, which was lower in patients with a deletion than in patients without. Newborns with PWS had a lower birth weight and length at term, but normal head circumference in comparison with a control group. This finding aids the identification of the neonatal phenotype. In addition, our data confirm an increased maternal age in the non-deletion group.

Adolescent↗