Biomedical subjects
Publications and source records attributed to D Summers.
The case is reported of an unusual atlas fracture with no reports of such an injury in the literature. The diagnosis of this injury emphasises the importance of simple clinical decision instruments, and systematic interpretation of investigations.
AIM: To report details concerning symptoms (especially pain) preceding the development of malignant cord compression (MCC); delays between onset/reporting of symptoms and confirmed diagnosis of MCC; accuracy of investigations carried out. METHODS: A prospective observational study examined the diagnosis, management and outcome of 319 patients diagnosed with MCC at three Scottish cancer centres between January 1998-April 1999. The process was considered from the perspectives of the patient, the GP and the hospital doctor. RESULTS: At diagnosis, most patients (82%) were either unable to walk or only able to do so with help. Pain was reported by nearly all patients interviewed (94%) and had been present for approximately 3 months (median=90 days). It was severe in 84% of cases, with the distribution and characteristics of nerve root pain in 79%. The site of pain did not correspond to the site of compression. Where reported, weakness and/or sensory problems had been noticed by the patient for some time before diagnosis (median intervals 20 and 12 days, respectively). Most patients reported early symptoms to their General Practitioner (GP) and diagnosis was established, following referral and investigation, approximately 2 months (median=66 days) later. CONCLUSION: Patients who develop spinal metastases are at risk of irreversible spinal cord damage. Weakness and sensory abnormalities are reported late and identified even later, despite patients having reported pain for a considerable time. Patients with cancer who describe severe back or spinal nerve root pain need urgent assessment on the basis of their symptoms, as signs may occur too late. Plain films and bone scans requested for patients in this audit predicted accurately the level of compression in only 21% and 19% of cases, respectively. The only accurate investigation to establish the presence and site of a compressive lesion is magnetic resonance imaging (MRI). A referral guideline based on suspicious symptoms in addition to suspicious signs is suggested.
BACKGROUND: Skin testing and RAST have verified the existence of tobacco-specific IgE. However, published studies report conflicting results concerning the clinical significance of tobacco IgE. Previous studies have not focused on the role of environmental tobacco smoke (ETS) as it relates to tobacco hypersensitivity (TH) in nonsmoking children. OBJECTIVE: We used nonsmoking pediatric patients to investigate the relationship between ETS and TH. METHODS: Children, ages 4 to 10 years, were prospectively enrolled. ETS exposure and smoke-triggered symptoms were recorded by questionnaire and physician history. Patients were given a skin test (ST) with a panel of aeroallergens plus tobacco extract. A ST reaction to at least one aeroallergen classified a patient as atopic; a ST reaction to tobacco classified a patient as TH. RESULTS: We enrolled 170 patients, mean age 7.2 years. We found 58 (34%) patients reported routine exposure to ETS and 78 (46%) patients reported ETS-induced symptoms. We found 121 (71%) atopic patients and 61 (36%) TH patients. TH was more common in atopic patients (P < .0001) and those routinely exposed to ETS (P < .05). However, TH failed to predict ETS-induced symptoms in either atopic or non-atopic patients (PPV = 0.40, NPV = 0.69). CONCLUSIONS: We evaluated the clinical significance of TH in a nonsmoking patient population related to ETS exposure. We concluded that although TH is statistically related to atopy and ETS exposure, the low predictive values of skin testing for TH limit its clinical usefulness.
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We have long known that patients with vascular disease in one system are at risk for vascular disease in other systems. Beyond this, we are recognizing the increased risk for cardiovascular patients to develop stroke not only as the result of arrhythmia, but also at the time of cardiovascular events or procedures. This presents clinical challenges to nurses with either neurological or cardiovascular expertise, requiring development of new awareness, clinical and critical thinking skills, and collaboration with their colleagues in other specialties. Three case studies illustrate patient presentations ranging from the subtle to the obvious. Pathophysiology of stroke is reviewed. Leading-edge management strategies and supporting literature highlight the benefits of prompt identification and management of the stroke patient. The Stroke Watch Action Team (SWAT) has proved to be an effective means of expediting patient identification and access to effective stroke treatment.
There have been previously published several anecdotal cases of women in apparent or imminent ovarian failure who subsequently ovulated and became pregnant. Many of these women had been treated with estrogen. A series of cases were reported where women with hypergonadotropic hypogonadism who failed to stimulate despite gonadotropin therapy were able to ovulate when treated with pharmacologic doses of estrogen alone or in combination with human menopausal gonadotropins. Presented herein is a case of a woman with imminent ovarian failure with tubal disease who failed to stimulate with gonadotropins alone but was successful with estrogen and gonadotropins. We believe this is the first successful case of hypergonadotropic hypogonadism to conceive by in vitro fertilization.
Clinical pathways for stroke are important tools for improved case management and outcome assessment. The clinical path created at St. Luke's Hospital in Kansas City is described here. It evolved through the collaboration of a multidisciplinary team of clinical experts and is still evolving. Ideally, a clinical path should be used as a guide rather than a standard of care, which is to be individualized for each patient. This article describes the methods for writing the pathways and how they are used for documentation. It also summarizes how the pathway data support stroke outcome assessment.
Embryonic cerebellar, neocortical, and striatal tissues derived from NSE-LacZ transgenic mice were transplanted into the right cerebellar hemisphere of 8- to 10-day-old Lurcher or wild-type mice. Host mice survived for 30-90 days and the transplanted tissue was examined by light microscopy using Nissl staining, X-gal histochemistry, and immunohistochemistry for calcium binding protein and glutamic acid decarboxylase. Transplantation of cerebellar tissue, but not neocortical or striatal progenitors, resulted in robust infiltration of the lurcher mutant host cerebellar cortex by transgenic Purkinje neurons. Deep to the infiltrated molecular layer, the host granular layer was thicker and denser than the mutant granular layer, but transgenic cells did not contribute to the spared granular layer. The host inferior olivary complex consistently exhibited a noticeable bilateral asymmetry in Nissl-stained sections. A quantitative analysis of the olivary complex was performed in 10 90-day-old host mice. The results indicate that the left inferior olivary complex of 90-day-old host mice contained more neurons than the right inferior olive of the host mice and contained more neurons than was observed in 90-day-old Lurcher control mice. Analysis by olivary subdivision indicates that increased neuron numbers were present in all subdivisions of the host left inferior olive. These studies confirm the specific attractive effect of the mutant cerebellar cortex on transplanted Purkinje neuron progenitors and indicate that neural transplants may survive the neurodegenerative period to interact with developing host neural systems. The unilateral rescue of Lurcher inferior olivary neurons in cerebellar transplant hosts indicates that transplanted neurons may interact with diseased host neural circuits to reduce transneuronal degeneration in the course of a neurodegenerative disease.
Multicopy plasmids of Escherichia coli are distributed randomly at cell division and, as long as copy number remains high, plasmid-free cells arise only rarely. Copy number variation is minimized by plasmid-encoded control circuits, and the limited data available suggest that deviations are corrected efficiently under most circumstances. However, plasmid multimers confuse control circuits, leading to copy number depression. To make matters worse, multimers out-replicate monomers and accumulate clonally within the culture, creating a subpopulation of cells with a significantly increased rate of plasmid loss. Multimers of natural multicopy plasmids, such as ColE1, are resolved to monomers by a site-specific recombination system (Xer-cer) whose activity is limited to intramolecular recombination. Recombination requires the heterodimeric XerCD recombinase plus two accessory proteins (ArgR and PepA), which activate recombination and prevent intermolecular events. Evidence is accumulating that Xer-cer recombination is relatively slow, and there is a risk that cells might divide before multimer resolution is complete. The Rcd transcript encoded within cer may solve this problem by preventing the division of multimer-containing cells. Working in concert, the triumvirate of copy number control, multimer resolution and cell division control achieve an extremely high fidelity of plasmid maintenance.
Saint Luke's Hospital is a 642-bed urban, tertiary, teaching hospital in metropolitan Kansas City, Missouri. In 1992, Saint Luke's developed a "Collaborative Care" program supported by tools such as clinical paths as a means to assure quality stroke care and to continually improve outcomes. This article describes the development of a comprehensive Collaborative Care Program for stroke patients, highlights the development of a dedicated stroke unit, and stroke clinical path, and describes the clinical and fiscal outcomes from these efforts.
OBJECTIVE: To compare the survival rate and pregnancy rate (PR) of embryos from intracytoplasmic sperm injection (ICSI) or conventional IVF, which were cryopreserved at the pronuclear stage in cycles where fresh transfer was deferred. DESIGN: Comparative observational study. SETTING: University-associated IVF center. PATIENT(S): Ninety-nine patients who deferred ET and had all their embryos cryopreserved at the pronuclear stage after 153 oocyte retrievals. Thirty-nine patients had their oocytes inseminated by ICSI and 60 patients had conventional IVF insemination. INTERVENTION(S): All embryos were frozen-thawed at the two pronuclear stage and allowed to cleave for 2 days before transfer. MAIN OUTCOME MEASURE(S): Survival rate (morphologically intact after thaw), cleavage rate (cleaved by time of transfer), and the clinical PR after frozen ET. RESULT(S): In the ICSI group, 205 embryos were thawed for use in 57 frozen ETs; in the IVF group, there were 527 embryos thawed for use in 149 frozen ETs. There was no significant difference in any of the outcome measures by insemination method: survival rates (ICSI, 93.2%; IVF, 94.8%); cleavage rates (ICSI, 95.2%; IVF, 94.7%), and clinical PR (ICSI, 14.0%; IVF, 17.4%). CONCLUSION(S): Pronuclear embryos resulting from ICSI can be cryopreserved successfully, thawed, and the survival rate and PR are comparable to conventional IVF.
11 beta-Hydroxysteroid dehydrogenase (HSD) activity was measured in freshly frozen granulosa cells isolated from follicles of twenty-one infertility patients undergoing in vitro fertilization-embryo transfer (IVF-ET). A total of 213 follicles were analyzed for 11 beta-HSD activity. Both nicotinamide-adenine dinucleotide (NAD) and nicotinamide-adenine dinucleotide phosphate (NADP) dependent 11 beta-dehydrogenase activities were measured in granulosa cells. The activity in reductive direction (11-oxoreductase activity) was not measurable either with NADH or NADPH as cofactors. NAD- and NADP-dependent dehydrogenase activities are in comparable levels at 100 nmol/l and 1 mumol/l corticosteroid concentrations. For comparing enzyme activities of individual follicles, significant enzyme activity was considered to be a level of > 2 nmol/l/min/mg. 41.3% of the follicles demonstrated enzyme activity, 58.7% did not. The mean 11 beta-dehydrogenase (11 beta-DH) activity was calculated for each patient. Those patients with levels > 2 nmol/l/min/mg were considered enzyme positive; those with mean levels < 2 nmol/l/min/mg were considered negative. No significant association was noted between follicle size, oocyte maturity or fertilization rates and 11 beta-DH activity. This study noted the presence of 11 beta-DH activity in granulosa cells, however, no association with oocyte maturity and fertilization was found.
OBJECTIVE: To compare clinical pregnancy and implantation rates after transfer of frozen-thawed embryos prepared according to an assisted hatching protocol or a nonassisted hatching protocol. DESIGN: A historical cohort study in which a cohort of patients who underwent an assisted hatching protocol was matched for clinical parameters to an external historical cohort treated before assisted hatching was available. SETTING: In vitro fertilization-ET facility of a university-based practice. PATIENTS: Seventy-nine matched pairs. INTERVENTIONS: Nonassisted hatching patients: embryos were thawed, cultured in human tubal fluid + 0.5% bovine serum albumin until 48 hours and transferred. Assisted hatching patients: embryos thawed, cultured in human tubal fluid + 10% synthetic serum substitute until 72 hours, had assisted hatching and transferred. MAIN OUTCOME MEASURES: Clinical pregnancy (gestational sac) and implantation rates. RESULTS: Twelve (15.2%) clinical pregnancies per transfer in nonhatched group versus 24 (30.4%) in hatched group. Nonhatched group: 284 embryos transferred; 15 (5.3%) implanted. Three pregnancies (25.0%) had two sacs. Hatched embryos: 269 were transferred; 37 (13.7%) implanted. Eleven pregnancies (45.8%) were multiple gestations (9 twins, 2 triplets). CONCLUSION: Clinical pregnancy and implantation rates were higher for group having assisted hatching protocol. It is not clear whether the improvement is due to the overall methodology change or to assisted hatching. Assisted hatching using the zona-drilling technique is not detrimental to frozen-thawed human embryos and may be beneficial.
The cer-Xer dimer resolution system of plasmid ColE1 is highly selective, acting only at sites on the same molecule and in direct repeat. Recombination requires the XerCD recombinase and accessory proteins ArgR and PepA. The Escherichia coli chromosome dimer resolution site dif and the type II hybrid site use the same recombinase but are independent of ArgR and PepA and show no site selectivity. This has led to the proposal that ArgR and PepA are responsible for the imposition of constraint. We describe here the characterization of a novel class of "conditionally constrained' multimer resolution sites whose properties support this hypothesis. In the presence of ArgR and PepA, plasmids containing conditionally constrained sites are monomeric, but in their absence, extensive multimerisation is seen. A mutant ArgR derivative (ArgR110), which is defective in cer-mediated dimer resolution, remains able to prevent plasmid multimerisation by a conditionally constrained site. This implies that the accessory factors block recombination in trans rather than ensuring rapid multimer resolution. When the distance between the ArgR and XerCD binding sites in a conditionally constrained site was altered by a non-integral number of helical turns, the site became unconstrained. Constraint was restored by the insertion of a full helical turn.
OBJECTIVE: To confirm successful implantation of IVF, cryopreserved human embryos after assisted hatching with acidic Tyrode's solution. DESIGN: Case report. SETTING: In vitro fertilization-ET facility of a university-based practice. PATIENT: A 28-year-old female with nonoperable bilateral tubal occlusion and > 1 1/2 years of primary infertility. INTERVENTIONS: The patient was stimulated for egg retrieval after an hMG-controlled ovarian hyperstimulation regime. Luteal phase leuprolide acetate (1 mg) was administered SC for 10 days. The dose was then reduced to 0.5 mg, and she was given hMG and FSH IM twice daily until two lead follicles reached 20 mm average diameter. The patient was administered 10,000 IU hCG 36 hours before retrieval. MAIN OUTCOME MEASURES: Viable pregnancy documented by ultrasound (US). RESULTS: After the transfer of five cryopreserved-thawed human embryos that were subjected to assisted hatching using acidic Tyrode's solution, the patient established a triplet gestation as documented by US. CONCLUSION: This case report demonstrates that zona drilling can be successfully applied to frozen-thawed pronuclear stage embryos that were cultured to 72 hours without damaging them, as evidenced by continued cleavage and resulting implantation.
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We describe three families segregating different reciprocal chromosome translocations, t(7;18)(p21.2;q23), t(2;7)(q21.1;p21.2), and t(5;7)(p15.3;p21.2). A total of seven apparently balanced carriers have been identified and all manifest features of the Saethre-Chotzen syndrome, although only two have overt craniosynostosis. In one family the carriers are immediately recognisable by their unusual ears, and clefts of the hard or soft palate are present in all three families. These observations extend previous linkage and cytogenetic evidence that a locus for Saethre-Chotzen syndrome resides in band 7p21.2.
Twenty preterm infants (25-36 weeks' gestation) were studied during intermittent mandatory ventilation (IMV) at rates of 10-34 inflations/min. Airway pressure and abdominal capsule signals were recorded at varying postnatal ages. Spontaneous interbreath interval (IBI), inspiratory (Ti) and expiratory (Te) duration were measured over 100-1000 ventilator cycles. Baseline Te was 0.48 s (+/- 0.129) and increased to 0.65 s (+/- 0.182) when associated with a mechanical inflation. Baseline Ti was 0.34 s (+/- 0.062) and increased to 0.38 s (+/- 0.081) with inflation. IBI increased from 0.82 s (+/- 0.161) to 1.03 s (+/- 0.201) with inflation. 1:1 entrainment (phase-locking) was observed at rates of ventilation below the spontaneous respiratory rate but spontaneous inspiration and mechanical inflation were always out of phase. A linear relationship was noted between the prolongation of IBI and the timing of inflation within the spontaneous respiratory cycle during IMV. This relationship could be used to estimate the range of rates of mechanical inflation capable of inducing 1:1 entrainment.