Rehabilitation of the trans-femoral amputee with an osseointegrated prosthesis: the United Kingdom experience

Osseointegration for the trans-femoral amputee has been used in the United Kingdom since 1997. To date, 11 candidates have undergone the procedure. The rehabilitation programme for the osseointegration candidate is a long and intensive programme following two surgical operations. This paper outlines the importance of a pre-osseointegration assessment to explore candidates' suitability and expectations for the procedure. The physical and prosthetic advantages of direct skeletal attachment have led to improvements in candidates' comfort, function and quality of life. However, some aspects of this promising developmental procedure for the management of the trans-femoral amputee need to be critically evaluated before it becomes a routine clinical procedure in the United Kingdom.

Exposure to ambient fine particulate matter and primary cardiac arrest among persons with and without clinically recognized heart disease

The authors studied the association between incidence of primary cardiac arrest and daily measures of fine particulate matter (</=2.5 micro m) using a case-crossover study of 1,206 Washington State out-of-hospital cardiac arrests (1985-1994) among persons with (n = 774) and without (n = 432) clinically recognized heart disease. The authors compared particulate matter levels on the day of the cardiac event and the 2 days preceding the event with levels from matched reference days. The estimated relative risk for a 13.8- micro g/m(3) increase in fine particulate matter (nephelometry: 0.54 x 10(-1) km(-1 )bsp) on the day prior to cardiac arrest was 0.94 (95% confidence interval: 0.88, 1.02). Pollutant levels measured on the same day as the event and on the 2 days preceding the event demonstrated similar results. No increased risk was found among all cases with preexisting cardiac disease (odds ratio = 0.97, 95% confidence interval: 0.89, 1.07); however, an unexpected association appeared between current smokers with preexisting heart disease and increased particulate matter levels 2 days prior to the event (odds ratio = 1.29, 95% confidence interval: 1.06, 1.55). This association was not present in the 0- or 1-day lag analyses or in persons with other diseases. There was no consistent association between increased levels of fine particulate matter and risk of primary cardiac arrest.

Quality control in urodynamics: a review of urodynamic traces from one centre

OBJECTIVE

To investigate quality control in our unit and to enable other units to compare their results, as experience from central reviews of urodynamic traces for multicentre trials has suggested that poor quality control is common.

PATIENTS AND METHODS

All consecutive male urodynamic tests conducted over 1 year were reviewed. A list of criteria to assess the quality of the records was devised, based upon International Continence Society guidelines on "good urodynamic practice", and on other sources. Eligible traces were analysed for aspects of quality control, e.g. baseline pressures and coughs to test pressure transmission. The data were analysed to establish how often quality criteria were met, and identify areas for improvement.

RESULTS

In 100 eligible traces, the baseline detrusor pressure was 0-10 cmH2O in 86, and - 5 to +10 cmH2O in 94%. Baseline intravesical and abdominal pressure were 30-50 cmH2O in 68% and 73% of cases, respectively. Coughs were present before filling in 94%, during filling in 95%, before voiding in 72% and after voiding in 87% of cases. The cough-test frequency was sufficient in 30% of traces. In 11 the intravesical pressure line fell out during voiding.

CONCLUSION

Most of the traces assessed met the quality criteria defined, but significant defects were not uncommon. Some of the problems identified suggest areas of urodynamic technique which should be studied in more detail. We intend to modify our quality control practices, and hope to show an improvement on re-audit. We hope that other urodynamic departments will be encouraged to review their practice, and we aim to improve our results.

Dental fluorosis: variability among different inbred mouse strains

Concurrent with the decline in dental caries has been an increase in the prevalence of dental fluorosis, a side-effect of exposure to greater than optimal levels of fluoride during amelogenesis. The mechanisms that underlie the pathogenesis of dental fluorosis are not known. We hypothesize that genetic determinants influence an individual's susceptibility or resistance to develop dental fluorosis. We tested this hypothesis using a mouse model system (continuous eruption of the incisors) where genotype, age, gender, food, housing, and drinking water fluoride level can be rigorously controlled. Examination of 12 inbred strains of mice showed differences in dental fluorosis susceptibility/resistance. The A/J mouse strain is highly susceptible, with a rapid onset and severe development of dental fluorosis compared with that in the other strains tested, whereas the 129P3/J mouse strain is least affected, with minimal dental fluorosis. These observations support the contribution of a genetic component in the pathogenesis of dental fluorosis.

Surviving uncertainty and projecting recovery: a qualitative study of patients' and family members' experiences with acute spinal cord injury

The purpose of this grounded theory study (Glaser & Strauss, 1967) was to explore, identify, and describe patients' and family members' experiences during the acute phase of spinal cord injury (SCI). The study sample consisted of 14 patients with acute spinal cord injury and 11 associated family members. Data sources included: unstructured interviews, participant observation, document analysis, and field notes. Level I (substantive), Level II (categorical), and Level III (theoretical constructs) codes were developed during data analysis. The substantive grounded theory generated in this study described how patients and family members defined and managed physiological and psychological uncertainty of acute SCI by mobilizing family resources and projecting recovery in the sociocultural context of the acute hospital environment.

Associations between phenylalanine-to-tyrosine ratios and performance on tests of neuropsychological function in adolescents treated early and continuously for phenylketonuria

Phenylketonuria (PKU) is a genetic disorder characterized by hyperphenylalaninemia. Treatment involves dietary phenylalanine restriction to prevent mental retardation. Because phenylalanine is involved in tyrosine synthesis and tyrosine is a catecholamine precursor, low tyrosine may lead to brain dopamine deficiencies. Because dopamine is involved in the modulation of prefrontally orchestrated executive functions, deficiencies may lead to executive impairments. Despite treatment, impairments in executive cognitive functions have been reported in young children with PKU. Outcome beyond middle childhood has not been extensively investigated. In this study, PKU-affected adolescents (N = 18) with normal-range IQ scores completed neuropsychological tests, and their performance was compared with unaffected peers (N = 16) and chronically ill controls (N = 17). Results demonstrated that the overall performance of the PKU group did not differ from that of the other two groups, but that performance of the PKU proband was associated with phenylalanine and tyrosine levels, and most strongly with phenylalanine-to-tyrosine ratios at several points in development. These findings provide a preliminary test of the dopamine hypothesis of PKU as it applies to adolescents and young adults.

Phylogeography of the red-tailed chipmunk (Tamias ruficaudus), a northern Rocky Mountain endemic

The northern Rocky Mountains have experienced a complex history of geological events and environmental fluctuation, including Pleistocene glaciation. To provide an initial assessment of the genetic impact of this history on the regional biota we estimated phylogenetic relationships within Tamias ruficaudus, a regional endemic, from cytochrome b sequence variation using parsimony, maximum likelihood, and nested clade analysis. Analyses of sequence variation in 187 individuals from 43 localities across the distribution of T. ruficaudus indicate a history of vicariance events and range fluctuation consistent with successive periods of extensive Pleistocene glaciation in the northern Rocky Mountains. Intraspecific divergence levels (c. 4.7% uncorrected) and phylogenetic structure are consistent with a genealogical vicariance initiated prior to the Late Pleistocene, whereas nested clade analyses indicate more recent population history structured by both fragmentation and range expansion. A comparison of sequence variation with bacular morphology indicates that the two genetically and morphologically differentiated entities exhibit a zone of differential character introgression. Sequence data support a multiple refugia hypothesis and provide a phylogeographical case study for the ongoing synthesis of regional biogeography for northern Rocky Mountain endemics.

Cyclophosphamide plus topotecan in children with recurrent or refractory solid tumors: a Pediatric Oncology Group phase II study

PURPOSE

To determine the response rate of the combination of cyclophosphamide and topotecan in pediatric patients with recurrent or refractory malignant solid tumors.

PATIENTS AND METHODS

A total of 91 pediatric patients, 83 of whom were fully assessable for response and toxicity, received cyclophosphamide (250 mg/m2/dose) followed by topotecan (0.75 mg/m2/dose), each given as a 30-minute infusion daily for 5 days. All patients received filgrastim (5 mcg/kg) daily until the absolute neutrophil count (ANC) was > or = 1,500 microL after the time of the expected ANC nadir.

RESULTS

A total of 307 treatment courses were given to the 83 fully assessable patients. Responses (complete response plus partial response) were seen in rhabdomyosarcoma (10 of 15 patients), Ewing's sarcoma (six of 17 patients), and neuroblastoma (six of 13 patients). Partial responses were seen in two of 18 patients with osteosarcoma and in one patient with a Sertoli-Leydig cell tumor. Twenty-three patients had either minor responses (n = 6) or stable disease (n = 17); the median number of courses administered to patients with partial or complete response was six (range, two to 13 courses), and the median administered to those with stable disease was three (range, one to 11 courses). The toxicity of the combination was limited principally to the hematopoietic system. Of 307 courses, 163 (53%) were associated with grade 3 or 4 neutropenia, 84 (27%) with grade 3 or 4 anemia, and 136 (44%) with grade 3 or 4 thrombocytopenia. Despite the severe myelosuppression, only 34 (11%) of 307 courses were associated with grade 3 or 4 infection. Nonhematopoietic toxicity of grades > or = 3 was rare and consisted of nausea and vomiting (two courses), perirectal mucositis (one course), transaminase elevation (one course), and hematuria (two courses).

CONCLUSION

The combination of cyclophosphamide and topotecan is active in rhabdomyosarcoma, neuroblastoma, and Ewing's sarcoma. Stabilization of disease was seen in osteosarcoma, although objective responses were rare in this disease. The therapy can be given with acceptable hematopoietic toxicity with the use of filgrastim support.

Sustained dysfunction of antiviral CD8+ T lymphocytes after infection with hepatitis C virus

Hepatitis C virus (HCV) sets up persistent infection in the majority of those exposed. It is likely that, as with other persistent viral infections, the efficacy of T-lymphocyte responses influences long-term outcome. However, little is known about the functional capacity of HCV-specific T-lymphocyte responses induced after acute infection. We investigated this by using major histocompatibility complex class I-peptide tetrameric complexes (tetramers), which allow direct detection of specific CD8+ T lymphocytes ex vivo, independently of function. Here we show that, early after infection, virus-specific CD8+ T lymphocytes detected with a panel of four such tetramers are abnormal in terms of their synthesis of antiviral cytokines and lytic activity. Furthermore, this phenotype is commonly maintained long term, since large sustained populations of HCV-specific CD8+ T lymphocytes were identified, which consistently had very poor antiviral cytokine responses as measured in vitro. Overall, HCV-specific CD8+ T lymphocytes show reduced synthesis of tumor necrosis factor alpha (TNF-alpha) and gamma interferon (IFN-gamma) after stimulation with either mitogens or peptides, compared to responses to Epstein-Barr virus and/or cytomegalovirus. This behavior of antiviral CD8+ T lymphocytes induced after HCV infection may contribute to viral persistence through failure to effectively suppress viral replication.

Racial variation in prostate specific antigen in a large cohort of men without prostate cancer

Several studies have reported racial variation in serum prostate specific antigen (PSA) levels. Many of these studies, however, have included a significant number of men without a documented digital rectal examination (DRE) result or without prostate biopsies if abnormalities in PSA or DRE were detected. Thus, it is not clear that men with prostate cancer have been excluded in these analyses. In this report, data from 9,162 men (3,786 African-American men and 5,376 white men) are reviewed. All men had both serum PSA and DRE testing. Every man in this study had either a documented normal DRE and PSA (< 4 ng/mL) (3,422 African-American men and 4,795 white men) or a negative prostate biopsy (364 African-American men and 581 white men). Data were analyzed in age-matched decades. African-American men and white men had no difference in serum PSA levels between 30 and 39 years of age. At 40-49, 50-59, 60-69 and 70-79 years of age, African-American men had a statistically higher serum PSA level than white men. From these data, we conclude that racial variation in serum PSA is present in all decades above 40 years of age. Our data are unique in that this cohort included a substantial number of men between 30 and 39 years of age. In this group of young men, no racial differences in serum PSA were detected. These studies indicate, for the first time, that the onset of racial variation in PSA occurs after the fourth decade of life.

Time acts as a conditioned stimulus to control behavioral sensitization to amphetamine in rats

Repeated exposure to the psychostimulant drug, amphetamine, results in a persistent increase in the ability of the drug to elicit behavioral activation.(14,19) The development of sensitized responses to amphetamine involves long-lasting neuroadaptations within defined circuitry.(3,6,12,15,23) The behavioral expression of sensitization, however, can come under the control of specific environmental cues. Thus, the sensitized locomotor response to a challenge injection of amphetamine is greater if the drug is given in the environment previously associated with intermittent injections than if given in a different environmental context.(2,13,16,18,20,21) Contrary to the wealth of information on the significance of contextual cues, little is known about the importance of time cues in the expression of sensitized responding to amphetamine. In the present study we, therefore, asked whether time of injection might influence the expression of amphetamine sensitization. We found that time can readily act as a conditioned stimulus to control the expression of behavioral sensitization to amphetamine in rats. This finding is important for understanding the mechanisms underlying sensitization to psychostimulant drugs and its impact on behavior.

Functional analysis of cis-regulatory elements within the promoter of the tobacco late pollen gene g10

The tobacco gene g10 is preferentially and maximally expressed in mature pollen, shows homology to pectate lyases, and is the putative homologue of the tomato gene lat56. Analysis of regulatory elements within the g10 promoter was carried out to verify the importance of putative regulatory sequence motifs. Analysis of transgenic plants showed that 1190 bp of g10 5' sequence directed preferential expression of GUS in pollen, with bimodal peaks of expression just before and during pollen mitosis I, and in mature anthers. This was confirmed by northern analysis of native g10 transcripts in isolated spores. Transient expression analysis defined the minimal g10 promoter region capable of directing expression in pollen as -86 to +217. Three upstream regions within -427 bp modulate the expression from g10. Gain-of-function analyses showed that the region from -106 to -53 could enhance pollen-specific expression of a minimal CaMV 35S promoter. These analyses further showed that sequences upstream of -86 modulate expression in pollen, but are not essential for preferential pollen expression. The function of a conserved GTGA motif shared between the tobacco g10 and tomato lat56 promoters was demonstrated in g10. Thus, further functional evidence is provided for the conservation of mechanisms for the regulation of late pollen genes across species.

Phylogeography of the tailed frog (Ascaphus truei): implications for the biogeography of the Pacific Northwest

Tailed frogs are distributed in high-gradient streams within the disjunct mesic forests of the Pacific Northwest and represent the basal lineage of the anurans. We sequenced 1,530 nucleotides of the mitochondrial cytochrome b and NADH dehydrogenase subunit two genes from 23 populations and used parsimony, maximum-likelihood, and nested-clade analyses to estimate relationships among populations and infer evolutionary processes. We found two divergent haplotype clades corresponding with inland Rocky Mountain populations and coastal populations and separated by up to 0.133 substitutions per site. Within the coastal assemblage, haplotypes formed clades by mountain range with 0.010-0.024 substitutions per site divergence among populations. Inland haplotypes exhibited minimal genetic structure, with the exception of 0.021 substitutions per site distance between populations from the East Fork of the South Fork of the Salmon River and all other inland haplotypes. The magnitude of divergence between inland and coastal populations, as well as the paleobotanical record, suggest isolation of these lineages occurred during the late Miocene to early Pliocene, probably in response to the rise of the Cascade Mountains. Genetic structure within coastal and inland populations is consistent with isolation in refugia during the late Pliocene and early Pleistocene. Closely related inland haplotypes reflect range expansion following glaciation. The depth of divergence between inland and coastal populations supports the persistence of mesic forests within the inland Pacific Northwest throughout the Pleistocene and is congruent with patterns found in several other mesic forest species. Based on mitochondrial divergence and previous allozyme and morphological data, we recommend recognition of inland populations as a distinct species, Ascaphus montanus.

A phase I study of irinotecan in pediatric patients: a pediatric oncology group study

A Phase I trial of irinotecan was performed to determine the maximum tolerated dose (MTD), the dose-limiting toxicities (DLTs), and the incidence and severity of other toxicities in children with refractory solid tumors. Thirty-five children received 146 courses of irinotecan administered as a 60-min i.v. infusion, daily for 5 days, every 21 days, after premedication with dexamethasone and ondansetron. Doses ranged from 30 mg/m2 to 65 mg/m2. An MTD was defined in heavily pretreated and less-heavily pretreated (i.e., two prior chemotherapy regimens, no prior bone marrow transplantation, and no radiation to the spine, skull, ribs, or pelvic bones) patients. Myelosuppression was the primary DLT in heavily pretreated patients, and diarrhea was the DLT in less-heavily pretreated patients. The MTD in the heavily pretreated patient group was 39 mg/m2, and the MTD in the less-heavily pretreated patients was 50 mg/m2. Non-dose-limiting diarrhea that was well controlled and of brief duration was observed in approximately 75% of patients. A partial response was observed in one patient with neuroblastoma, and in one patient with hepatocellular carcinoma. Stable disease (4-20 cycles) was observed in seven patients with a variety of malignancies including neuroblastoma, pineoblastoma, glioblastoma, brainstem glioma, osteosarcoma, hepatoblastoma, and a central nervous system rhabdoid tumor. In conclusion, the recommended Phase II dose of irinotecan administered as a 60-min i.v. infusion daily for 5 days, every 21 days, is 39 mg/m2 in heavily treated and 50 mg/m2 in less-heavily treated children with solid tumors.

Transurethral resection of the prostate: failure patterns and surgical outcomes in patients with symptoms refractory to alpha-antagonists

BACKGROUND

alpha-Antagonists (AAs) are ineffective in some men with lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH). Transurethral resection of the prostate (TURP) may be required. Reasons for AA failure and surgical outcomes in these patients have not been reported.

METHODS

We retrospectively reviewed cases of TURP for LUTS due to bladder outlet obstruction from 1995 to 1998. The TURP patients in whom AA therapy had failed (group 1) were compared with those who had symptomatic BPH but were not taking AAs (group 2). Comorbid conditions that might influence treatment results were considered, as were sizes of resection and pathologic results.

RESULTS

No differences occurred between groups 1 (n = 38) and 2 (n = 25) in age, length of postoperative follow-up, or resection size. However, outcomes were poorer in group 1 than in group 2. A trend toward greater comorbidity that might lead to voiding dysfunction, though not statistically significant, was seen in group 1.

CONCLUSIONS

Postoperative results of TURP may be less successful after AA therapy failure. This may be due to preoperative risk factors that affect voiding function rather than to prostatic size.

Role of stored iron in atherosclerosis

Myocardial infarction remains the No. 1 killer of American men and women, with a death rate of 225,000 per year, and stroke, the third leading cause of death in the United States, afflicts about 600,000 per year. The combined financial burden of these diseases is approximately $134 billion per year. Therefore, interventions that reduce mortality and suffering will have a significant impact on the health care system. This article summarizes research conducted during the last 2 decades that addresses the idea that stored iron plays a role in the pathogenesis of atherosclerosis and that iron reduction through phlebotomy may play a role in the treatment or prevention of atherosclerosis. Body iron stores rise after adolescence in men and menopause in women. This rise has been linked to the pathogenesis of atherosclerosis through iron-induced oxidation of low-density lipids and foam cell formation. However, the available evidence on the iron hypothesis remains circumstantial. Reduction of body iron stores in the setting of a controlled, prospective intervention trial is necessary to determine whether the amount of stored iron is related to clinically meaningful vascular disease. Such a study is feasible because reduction in iron stores can be achieved safely and predictably without induction of iron deficiency by graded phlebotomy. The Iron and Atherosclerosis Study (FeAST), a Veteran's Administration Cooperative Study, is under way to test this concept.