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Biomedical subjects

K Hayden

Publications and source records attributed to K Hayden.

14 recordsLinked to original sources
PubMed2006

Conversion to dementia from mild cognitive disorder: the Cache County Study.

OBJECTIVE: To examine 3-year rates of conversion to dementia, and risk factors for such conversion, in a population-based sample with diverse types of cognitive impairment. METHODS: All elderly (aged 65 or older) residents of Cache County, UT, were invited to undergo two waves of dementia screening and assessment. Three-year follow-up data were available for 120 participants who had some form of mild cognitive impairment at baseline. Of these, 51 had been classified at baseline with prodromal Alzheimer disease (proAD), and 69 with other cognitive syndromes (CS). RESULTS: Three-year rates of conversion to dementia were 46% among those with cognitive impairment at baseline. By comparison, 3.3% without impairment converted to dementia in the interval. Among converters, AD was the most common type of dementia. In individuals with at least one APOE epsilon4 allele, those with proAD or CS exhibited a 22- to 25-fold higher risk of dementia than cognitively unimpaired individuals (vs 5- to 10-fold higher risk in those without epsilon4). CONCLUSIONS: Individuals with all types of mild cognitive impairment have an elevated risk of dementia over 3 years, more so in those with an APOE epsilon4 allele. These results suggest value in dementia surveillance for broad groups of cognitively impaired individuals beyond any specific category, and utility of APOE genotyping as a prognostic method.

Aged↗
PubMed2006

Composting is an effective treatment option for sanitization of Phytophthora ramorum-infected plant material.

AIMS: To determine the effects of heat and composting treatments on the viability of the plant pathogen Phytophthora ramorum grown on both artificial and various natural substrates. METHODS AND RESULTS: Phytophthora ramorum was grown on V8 agar, inoculated on bay laurel leaves (Umbellularia californica) and on woody tissues of coast live oak (Quercus agrifolia). Effects on growth, viability and survival were measured as a result of treatment in ovens and compost piles. Direct plating onto PARP medium and pear-baiting techniques were used to determine post-treatment viability. No P. ramorum was recovered at the end of the composting process, regardless of the isolation technique used. By using a PCR assay designed to detect the DNA of P. ramorum, we were able to conclude the pathogen was absent from mature compost and not merely suppressed or dormant. CONCLUSIONS: Some heat and composting treatments eliminate P. ramorum to lower than detectable levels on all substrates tested. SIGNIFICANCE AND IMPACT OF THE STUDY: Composting is an effective treatment option for sanitization of P. ramorum-infected plant material. Assaying for pathogen viability in compost requires a direct test capable of differentiating between pathogen suppression and pathogen elimination.

Pest Control, Biological↗
PubMed2002

Therapy of circadian rhythm disorders in chronic fatigue syndrome: no symptomatic improvement with melatonin or phototherapy.

BACKGROUND: Patients with chronic fatigue syndrome (CFS) show evidence of circadian rhythm disturbances. We aimed to determine whether CFS symptoms were alleviated by melatonin and bright-light phototherapy, which have been shown to improve circadian rhythm disorders and fatigue in jet-lag and shift workers. DESIGN: Thirty patients with unexplained fatigue for > 6 months were initially assessed using placebo and then received melatonin (5 mg in the evening) and phototherapy (2500 Lux for 1 h in the morning), each for 12 weeks in random order separated by a washout period. Principal symptoms of CFS were measured by visual analogue scales, the Shortform (SF-36) Health Survey, Mental Fatigue Inventory and Hospital Anxiety and Depression Scale. We also determined the circadian rhythm of body temperature, timing of the onset of melatonin secretion, and the relationship between these. RESULTS: Neither intervention showed any significant effect on any of the principal symptoms or on general measures of physical or mental health. Compared with placebo, neither body temperature rhythm nor onset of melatonin secretion was significantly altered by either treatment, except for a slight advance of temperature phase (0.8 h; P = 0.04) with phototherapy. CONCLUSION: Melatonin and bright-light phototherapy appear ineffective in CFS. Both treatments are being prescribed for CFS sufferers by medical and alternative practitioners. Their unregulated use should be prohibited unless, or until, clear benefits are convincingly demonstrated.

Adult↗
PubMed2000

Radioimmunoassay for the measurement of thrombospondin in plasma and breast cyst fluid: validation and clinical application.

Thrombospondin is an adhesive protein that has been implicated in malignancy, specifically in tumour progression and angiogenesis. We developed a radioimmunoassay for the measurement of thrombospondin in plasma and breast cyst fluid. The assay exhibited high accuracy, with recoveries of 102-136% and acceptable imprecision, with an intra-assay coefficient of variation (CV) of <7.5% across the analytical range 30-1000 ng/mL and inter-assay CV of 4.4% and 7.7% at 152 and 224 ng/mL, respectively. Thrombospondin measured in the breast cyst fluid of patients with gross cystic disease of the breast showed that patients with type II (Na+) cysts had significantly higher concentrations than type I (K+) cysts. The plasma thrombospondin reference range was determined as 131-274 ng/mL. Patients with breast cancer had significantly higher plasma thrombospondin concentrations than normal individuals or patients with benign breast disease. Plasma thrombospondin was higher in breast cancer patients with lymph node involvement.

Adult↗
PubMed1994

Expansion/deletion of mature T cells exposed to endogenous superantigens in vivo.

Previous studies have shown that in thymectomized hosts exposure of mature T cells to Mlsa (mtv-7) Ag in vivo leads to specific tolerance and the disappearance of Mlsa-reactive V beta 6+ T cells after an initial phase of T cell expansion. To investigate the factors controlling postthymic elimination of mature T cells, we examined T cell responses to Mlsa and other endogenous superantigens in a number of different strain combinations. The results show that the extent of T cell expansion/deletion is influenced by various factors, including the H-2 haplotype of the host and the particular V beta studied. Collectively, the results suggest that the extent of elimination of mature T cells is variable and may be a function of high avidity interactions with APC.

Animals↗
PubMed1994

Phase II study of carboplatin (CBDCA) in refractory multiple myeloma. A Southwest Oncology Group study.

Nineteen patients with multiple myeloma resistant to standard alkylating agent therapy or to the VAD regimen received carboplatin at a planned daily dose of 100 mg/M2 on four successive days. Two patients erroneously received a four-fold higher drug dose resulting in bone marrow aplasia and death without antitumor effect in one patient with post-mortem examination. No anti-tumor effect was observed among 15 patients evaluable for response (two lacked follow-up examination of tumor markers). Major toxicities were hematologic and included grade > or = III, leukopenia in 9, thrombocytopenia in 6 and anemia in 3 of the 17 evaluable patients. Their median survival was 9 months. These results indicate that carboplatin is inactive in refractory multiple myeloma.

Adult↗
PubMed1993

A phase I study of escalating interferon alpha-2a combined with 5-fluorouracil and leucovorin in patients with gastrointestinal malignancies.

On the basis of preclinical data showing synergy between 5-fluorouracil (5-FU), leucovorin (LV) and IFN-alpha-2a, a phase I study was carried out to determine the maximum tolerable dose (MTD) of IFN-alpha-2a with this combination in patients with gastrointestinal malignancies. The treatment consisted of 370 mg/m2 5-FU and 200 mg/m2, LV on days 1 to 5, and IFN-alpha-2a on days 1 to 5 of the first week of chemotherapy and on days 1, 3, 5 of each subsequent week, on a 28-day cycle. Six patients with colorectal, 3 with pancreas, 2 with oesophagus, 2 with hepatocellular and one with gastric cancer were treated. At level III (5 x 10(6) U/m2) all patients experienced grade 3 or 4 toxicity during the first 56 days of treatment and the MTD was declared level II. Grade 3 toxicity comprised of anorexia, mucositis, diarrhoea, and fatigue; in one instance, grade 4 neutropenia occurred. Ten patients were evaluable for response, one patient with an oesophageal cancer had a minor response and one patient with rectal cancer and liver metastases had a radiological complete response lasting 3 months. The recommended dose for this schedule in phase II studies is 5-FU 370 mg/m2, LV 200 mg/m2, and IFN-alpha-2a 4 x 10(6) U/m2.

Adult↗
PubMed1984

Hemoptysis following Mustard repair: a late complication.

Hemoptysis was the presenting symptom in a 4-year, 11-month-old male who had had a Mustard operation for hemodynamic correction of transposition of the great vessels at the age of five months. Chest roentgenography demonstrated hyperlucency of the left lung and tomography showed compression and narrowing of left main stem bronchus. Angiography documented the absence of antegrade flow in the left pulmonary artery and no pulmonary venous drainage on the left. The left lung was supplied by bronchial collateral arteries which drained by retrograde filling of the left pulmonary artery. It is surmised that pulmonary venous drainage on the left was compromised at surgery and that the dilated main pulmonary artery compressed the left main stem bronchus. This combination promoted bronchial collateral ingrowth. Hemoptysis is a complication of enlargement of bronchial collateral vessels.

Child, Preschool↗
PubMed1981

Link between caudal regression and Vater syndromes.

A variant between caudal and regression and Vater syndromes is presented which was significant anomalies of the genitourinary tract. The patient has a normal 46XX karyotype with the following urogenital anomalies: solitary pelvic kidney with megacalycosis, high ureteral bud or diverticulum, and ectopic insertion of the ureter into the proximal urethra; as well as, sacral agenesis, vaginal atresia, aberrant gonadal tissue, and uterine agenesis.

Abnormalities, Multiple↗