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Biomedical subjects

J M Thompson

Publications and source records attributed to J M Thompson.

At least 37 records · Page 2Linked to original sources
PubMed2000

Phytoestrogens decrease brain calcium-binding proteins but do not alter hypothalamic androgen metabolizing enzymes in adult male rats.

Phytoestrogen [plant estrogenic-like molecule(s)] research has grown rapidly in recent years due to their potential health benefits. However, little is known about phytoestrogen's effects on the CNS. Androgen metabolizing enzymes are known to regulate neuroendocrine functions and reproductive behaviors, while calcium-binding proteins are associated with protecting against neurodegenerative diseases. Therefore, we examined aromatase and 5alpha-reductase enzyme activities in the medial basal hypothalamic and preoptic area (mbh-poa) and characterized mbh-poa and amygdala (amy) calbindin and calretinin levels (via Western analysis) from animals fed a phytoestrogen-free (P-free) vs. a phytoestrogen-containing diet [(P-600); that had 600 microg/g of phytoestrogens]. After approximately 5 weeks on the diets, the male rats were killed at 105 days. P-600 plasma phytoestrogen levels were 78-fold higher than the P-free values and the mbh-poa phytoestrogen content was 8-fold higher than the P-free group, demonstrating the passage of phytoestrogens into brain. In general, brain aromatase or 5alpha-reductase activity levels were not significantly altered by the experimental diets. However, independent of brain site (i.e., mbh-poa or amy) the abundance of calbindin from male P-600 rats was significantly lower than P-free animals. Conversely, for calretinin there were no significant alterations in the mbh-poa tissue site, while in the amy a similar pattern of expression was seen to that of the calbindin results. These data suggest that consumption of phytoestrogens via a soy diet for a relatively short interval can significantly: (1) elevate plasma and brain phytoestrogens levels and (2) decrease brain calcium-binding proteins without altering brain androgen metabolizing enzymes.

Androgens↗
PubMed2000

Relationship between disease severity and responses by blood mononuclear cells from patients with rheumatoid arthritis to human heat-shock protein 60.

The hypothesis that T-cell responses to the 60 000 MW family of heat-shock proteins (hsp) may be related to the severity of rheumatoid arthritis (RA) was examined. Peripheral blood mononuclear cells (PBMC) from most normal individuals and both early and established RA patients proliferated in vitro in response to human hsp 60 and mycobacterial hsp 65 as well as tetanus toxoid (TT) and mycobacterial purified protein derivative (PPD). PBMC from some patients with established RA gave responses to hsp 60 that were above the normal range and/or peaked earlier than PBMC from normal individuals. The responses of PBMC from established RA to hsp 65, but not PPD or TT, were also higher than those from normal individuals, but the peak responses to all three antigens appeared delayed. Thus a selective increase in responsiveness to hsp 60 develops with disease duration in many RA patients. Six assessments of disease activity and severity were made but apart from rheumatoid factor titre, they were unrelated to the proliferative response. Similarly, disease activity and severity did not differ between those RA patients whose hsp 60 stimulated cells produced interferon-gamma and those who did not, although patients whose hsp 60-stimulated T cells produced interleukin-4 (IL-4) and/or IL-10, appeared to have less disease activity and severity than those who did not. Significant negative correlations were found between IL-10 production by hsp 60-stimulated cells and disease assessments. It is considered that RA is less severe in those patients whose hsp 60-stimulated cells produce T-helper 2 type cytokines.

Adult↗
PubMed2000

Does early hospital discharge with home support of families with preterm infants affect breastfeeding success? A randomized trial.

UNLABELLED: The aim of the present study was to determine if earlier discharge of preterm infants (<37 wk) from hospital is safe and if it affects breastfeeding rates. In a pilot observational study, premature infants received full oral (sucking) feeds for a mean (SD) 7.7 +/- 7.9 d before discharge. In the main study, 308 preterm infants were randomly assigned to either Early Discharge (148 infants) when fully orally fed but not yet gaining weight or Routine Discharge (160 infants) when fully orally fed and also gaining weight before discharge. A further 122 mothers declined randomization. The Early Discharge group was followed by Visiting Nurse Specialists who were available 24 h a day, while the Routine group was followed by the Home Care Nurses available on week days. There were no significant differences between the groups in birthweight or gestational age. The Early Discharge group were discharged 2.5 +/- 2 d after full oral feeding compared to 4.4 +/- 2.7 d for the Routine group (p < 0.001) and 6.1 +/- 5 d for those who declined. However, there was no significant difference between the Early and Routine groups for breastfeeding either at discharge (80 vs 83%), or 6 wk (55 vs 60%) or 6 mo after discharge (36 vs 36%), or for weight gain, or rates of re-hospitalization (8.8% vs 11.9% at 6 wk, p = 0.37). CONCLUSION: Early discharge from hospital once a preterm infant can take full oral feeds does not alter later breastfeeding rates when adequate visiting nursing support is available.

Age Factors↗
PubMed2000

Previous breastfeeding does not alter thymic size in infants dying of sudden infant death syndrome.

The relationship between thymic weights and previous feeding histories was examined in 294 infants of 37 wk gestation or more dying of sudden infant death syndrome (SIDS). One hundred and sixty-five infants had been breastfed exclusively, 89 had been partially breastfed and 40 had never been breastfed. We found no relationship between thymic weight and type of previous feeding. The difference between these findings in SIDS and the substantially greater thymic size previously reported in 4-mo-old breastfed living infants deserves further study.

Age Factors↗
PubMed2000

Diagnosis and prevention of hyponatremia at an ultradistance triathlon.

OBJECTIVE: To evaluate a method of medical care at an ultradistance triathlon, with the aim of reducing the incidence of hyponatremia. DESIGN: Descriptive research. SETTING: New Zealand Ironman triathlon (3.8 km swim, 180 km cycle, 42.2 km run). PARTICIPANTS: 117 of 134 athletes seeking medical care after the triathlon (involving 650 race starters). INTERVENTIONS: A prerace education program on appropriate fluid intake was undertaken. The number of support stations was decreased to reduce the availability of fluid. A body weight measurement before the race was introduced as a compulsory requirement, so that weight change during the race could be included in the triage assessment. An on-site laboratory was established within the race medical tent. MAIN OUTCOME MEASURES: Numbers of athletes and diagnoses, including the incidence of symptomatic hyponatremia (defined as symptoms of hyponatremia in association with a pretreatment plasma sodium concentration [Na] < 135 mmol/L); weight changes; and changes in [Na]. RESULTS: The common diagnoses in the 117 athletes receiving attention were exercise-associated collapse (27%), musculoskeletal complaints (26%), and dehydration (12%). There was a significant reduction in the number of athletes receiving medical care for hyponatremia, from 25 of the 114 athletes who received care in 1997 (3.8% of race starters) to 4 of the 117 athletes who received care in 1998 (0.6% of race starters). Mean weight change among athletes in the 1998 race was -3.1 kg, compared with -2.6 kg in 1997. CONCLUSION: A preventive strategy to decrease the incidence of hyponatremia, including education on fluid intake and appropriate placement of support stations, was associated with a decrease in the incidence of symptomatic hyponatremia.

Bicycling↗
PubMed2000

Exercise-induced hyponatremia in ultradistance triathletes is caused by inappropriate fluid retention.

OBJECTIVE: To study fluid and sodium balance during overnight recovery following an ultradistance triathlon in hyponatremic athletes compared with normonatremic controls. CASE CONTROL STUDY: Prospective descriptive study. SETTING: 1997 New Zealand Ironman Triathlon (3.8 Km swim, 180 Km cycle, 42.2 Km run). PARTICIPANTS: Seven athletes ("subjects") hospitalized with hyponatremia (median sodium [Na] = 128 mmol L(-1)). Data were compared with measurements from 11 normonatremic race finishers ("controls") (median sodium = 141 mmol L(-1)). INTERVENTIONS: None. MAIN OUTCOME MEASURES: Athletes were weighed prior to, immediately after, and on the morning after, the race. Blood was drawn for sodium, hemoglobin, and hematocrit immediately after the race and the following morning. Plasma concentrations of arginine-vasopressin (AVP) were also measured post race. RESULTS: Subjects were significantly smaller than controls (62.5 vs. 72.0 Kg) and lost less weight during the race than controls (median -0.5% vs. -3.9%, p = 0.002) but more weight than controls during recovery (-4.4% vs. -0.8%, p 0.002). Subjects excreted a median fluid excess during recovery (1,346 ml): controls had a median fluid deficit (521 ml) (p = 0.009). Estimated median sodium deficit was the same in subjects and controls (88 vs. 38 mmol L(-1), p = 0.25). Median AVP was significantly lower in subjects than in controls. Plasma volume fell during recovery in subjects (-5.9%, p = 0.016) but rose in controls (0.76%, p = NS). CONCLUSIONS: Triathletes with symptomatic hyponatremia following very prolonged exercise have abnormal fluid retention including an increased extracellular volume, but without evidence for large sodium losses. Such fluid retention is not associated with elevated plasma AVP concentrations.

Adult↗
PubMed2000

HMO Web sites: what do they tell consumers?

Despite the growth of managed care, little is known about health plans' web sites. This paper reports on a review of the web sites of the 25 largest HMOs in the United States to identify whether their content included information deemed important by consumers: quality, price, provider network, personal health information, and customer service features. Findings show variation in the content of HMO web sites, with sites emphasizing customer service features, the provider network, and personal health information. Two-thirds of HMOs offer information on quality; however, pricing information is offered by only four plans. Implications for future differentiation of HMO web sites are discussed.

Consumer Behavior↗
PubMed1999

Cognitive properties of sedation agents: comparison of the effects of nitrous oxide and midazolam on memory and mood.

OBJECTIVES: To compare the effects of nitrous oxide and midazolam on cognition and mood. DESIGN: A three-way, counterbalanced, cross-over study, using patients receiving conscious sedation for routine dental treatment. METHODS: On each of three separate visits, patients performed a computerised test battery to determine baseline cognitive performance. Then, following administration of either midazolam, nitrous oxide, or no drug, patients re-performed the test battery. Finally, patients completed visual analogue scales assessing their subjective mood state. RESULTS: Relative to baseline performance, midazolam administration produced significantly slower reaction times compared with nitrous oxide and no-drug conditions. Furthermore, patients receiving midazolam were impaired in accuracy relative to the other conditions on many of the cognitive tasks, particularly those assessing the recall of information. Patient performance in nitrous oxide and control conditions did not significantly differ. These results could not be explained by differences in mood between the conditions, as subjective mood ratings during midazolam or nitrous oxide administration were very similar. CONCLUSIONS: It is important for clinicians to be aware that peri-operative recall of information is reduced in patients who have undergone midazolam sedation. This is an advantage for patients who are anxious, and do not wish to be aware of the operative treatment being performed. However, as the cognitive impairment is enduring, an adult escort and written post-operative instructions should be mandatory for midazolam sedation patients. In contrast, the use of nitrous oxide sedation does not significantly impair higher cognitive tasks and thus patients receiving nitrous oxide sedation can resume normal activities in the post-operative period.

Adolescent↗
PubMed1999

Water fluoridation and the sudden infant death syndrome.

AIMS: To determine whether exposure to fluoridated water supplies prenatally or postnatally at the time of death increases the risk of sudden infant death syndrome (SIDS). METHODS: A nationwide, case-control study, with infant's water fluoridation status determined from census area unit information for mother's usual address at the time of the infant's birth, infant's usual address at the time of death / nominated sleep and address where infant died / was at nominated sleep. SIDS risk associated with fluoride exposure postnatally was assessed according to method of infant feeding (breast or reconstituted formula), for the two days prior to infant's death / nominated sleep. RESULTS: Infants exposed to fluoridated water supplies during pregnancy were not at increased risk for SIDS, adjusted odds ratio (OR) 1.19 (95% confidence interval (CI) 0.82, 1.74). For breast-fed infants at the time of death / nominated sleep, fluoridated water exposure was not associated with an increased risk for SIDS, adjusted OR 1.09 (95% CI 0.66, 1.79). Similarly, 'fluoridated' formula feeding, when compared with 'unfluoridated' formula feeding, showed no increased risk of SIDS, adjusted OR 1.25 (95% CI 0.73, 2.13). There was no evidence of an interaction between fluoridation and infant feeding for the last two days (chi2 = 0.171, df = 1, p = 0.68). CONCLUSION: Exposure to a fluoridated water supply prenatally or postnatally at the time of death did not affect the relative risk for SIDS.

Analysis of Variance↗
PubMed1999

Changing infants' sleep position increases risk of sudden infant death syndrome. New Zealand Cot Death Study.

OBJECTIVE: To examine whether the prone sleeping position may increase the risk for sudden infant death syndrome (SIDS), particularly in infants unused to prone sleep. DESIGN: A 3-year (1987-1990) case-control study. SETTING: Nationwide study in New Zealand. SUBJECTS: Four hundred eighty-five infants who died of SIDS and 1800 controls. MAIN OUTCOME MEASURES: Infants were classified as unaccustomed to prone if their usual sleep position was nonprone and they were placed prone for the last sleep. Secondary prone was used to describe infants placed nonprone but found prone. RESULTS: Infants usually and last placed nonprone were at the lowest risk for SIDS (odds ratio [OR], 1.0); those usually and last placed prone were at increased risk (adjusted OR, 4.6; 95% confidence interval, 3.4-6.3). Risk was greatly increased among infants unaccustomed to the prone position (adjusted OR, 19.3; 95% confidence interval, 8.2-44.8). These infants accounted for 8% (31/ 386) of all SIDS deaths. Ninety percent (28/ 31) of infants in this group were found prone, and 71% (20/28) of those found prone were found with their faces turned down into bedding-a position in which asphyxia has been implicated as a mechanism of death. In addition, 138 infants who died of SIDS were last placed nonprone. Forty-seven infants (34%) in this group were found prone (secondary prone), and 60% (28/47) of those found prone were found with their faces turned down into the bedding. This group accounted for 12% of all SIDS deaths. Most of these infants (91% [43/47]) were usually placed nonprone. CONCLUSIONS: Infants placed supine to sleep were at the lowest risk of SIDS, which supports the recommendation that this is the preferred sleeping position for healthy infants. In New Zealand, 20% of SIDS deaths involved lack of experience with the prone sleeping position. Our findings suggest the possibility that an infant's competence in escaping from potentially lethal situations during prone sleep (eg, the face-down position) may be impaired by inexperience in prone sleeping. Great caution should be exercised in placing infants unaccustomed to the prone sleeping position in the prone position.

Case-Control Studies↗
PubMed1999

A comparison of midnight versus early morning removal of urinary catheters after transurethral resection of the prostate.

PURPOSE: This article describes a study that compares the outcomes of midnight versus early morning urethral catheter removal after transurethral resection of the prostate. SUBJECTS AND SETTING/METHODS: The research setting was a large, metropolitan hospital in Sydney, Australia. Forty-eight patients who had undergone transurethral resection of the prostate were randomly assigned to either group A, catheter removal at 2400 hours (n = 20), or group B, catheter removal at 0600 hours (n = 28). MAIN OUTCOME MEASURES: Data collected included time to first void, volume of first void, time between catheter removal and discharge from hospital, weight of prostatic resection, and tissue pathology. RESULTS: There was no significant difference between the 2 groups with respect to pathology, weight of prostatic resection, mean volume of first void, or time to first void after catheter removal. There was a significant difference in the time between catheter removal and discharge from hospital. Eighty-five percent of those having catheters removed at 2400 hours were discharged on the same day as catheter removal, as compared with 65% of those who underwent catheter removal at 0600 hours (chi 2 = 12.684; P < 0.005). CONCLUSION: After transurethral resection of the prostate, removal of the urethral catheter at 2400 hours reduced the length of hospital stay, but did not significantly affect the time to first void or the volume of the first void.

Aged↗
PubMed1999

Matched-pair analysis of hematopoietic progenitor cell mobilization using G-CSF vs. cyclophosphamide, etoposide, and G-CSF: enhanced CD34+ cell collections are not necessarily cost-effective.

Using matched-pair analysis, we compared two popular methods of stem cell mobilization in 24 advanced-stage breast cancer patients who underwent two consecutive mobilizing procedures as part of a tandem transplant protocol. For the first cycle, 10 microg/kg/day granulocyte colony-stimulating factor (G-CSF) was given and apheresis commenced on day 4 and continued for < or =5 days (median 3 days). One week after the first cycle of apheresis, 4000 mg/m2 cyclophosphamide, 400 mg/m2 etoposide, and 10 microg/kg G-CSF were administered for < or =16 days (cycle 2). Apheresis was initiated when the white blood cell (WBC) count exceeded 5000 cells/microL and continued for < or =5 days (median 3 days). Mean values of peripheral blood WBC (31,700+/-3200 vs. 30,700+/-3300/microL) were not significantly different between cycles 1 and 2. Mean number of mononuclear cells (MNC) collected per day was slightly greater with G-CSF mobilization than with the combination of chemotherapy and G-CSF (2.5+/-0.21x10(8) vs. 1.8+/-0.19x10(8) cells/kg). Mean daily CD34+ cell yield, however, was nearly six times higher (12.9+/-4.4 vs. 2.2+/-0.5x10(6)/kg; p = 0.01) with chemotherapy plus G-CSF. With G-CSF alone, 13% of aphereses reached the target dose of 5x10(6) CD34+ cells/kg in one collection vs. 57% with chemotherapy plus G-CSF. Transfusions of red blood cells or platelets were necessary in 18 of 24 patients in cycle 2. Three patients were hospitalized with fever for a median of 3 days after cycle 2. No patients received transfusions or required hospitalization during mobilization with G-CSF alone. Resource utilization (cost of drugs, aphereses, cryopreservation, transfusions, hospitalization) was calculated comparing the median number of collections to obtain a target CD34+ cell dose of 5x10(6) cells/kg: four using G-CSF vs. one using the combination in this data set. Resources for G-CSF mobilization cost $7326 vs. $8693 for the combination, even though more apheresis procedures were performed using G-CSF mobilization. The cost of chemotherapy administration, more doses of G-CSF, transfusions, and hospitalizations caused cyclophosphamide, etoposide, and G-CSF to be more expensive than G-CSF alone. A less toxic and less expensive treatment than cyclophosphamide, etoposide, and G-CSF is needed to be more cost-effective than G-CSF alone for peripheral blood progenitor cell mobilization.

Adult↗
PubMed1999

Hematopoietic growth factor after autologous peripheral blood transplantation: comparison of G-CSF and GM-CSF.

Autologous peripheral blood stem cell (PBSC) transplantation results in rapid hematologic recovery when sufficient numbers of CD34+ cells/kg are infused. Recent studies suggest that filgrastim (G-CSF) administration following transplantation leads to more rapid neutrophil recovery and lower total transplant costs. This study compares the use of G-CSF (5 microg/kg/day) with sargramostim (GM-CSF) 500 microg/day from day 0 until neutrophil recovery (ANC >1500/mm3) in patients with breast cancer or myeloma who had PBSC mobilized with the combination of cyclophosphamide, etoposide, and G-CSF. Twenty patients (13 breast cancer and seven myeloma) received GM-CSF and 26 patients (14 breast cancer and 12 myeloma) received G-CSF. The patients were comparable for age and stage of disease, and received stem cell grafts that were not significantly different (CD34+ x 10(6)/kg was 12.5 +/- 11.1 (mean +/- s.d.) for GM-CSF and 19.8 +/- 18.5 for G-CSF; P = 0.10). The use of red cells (2.8 vs 2.3 units), and platelet transfusions (2.5 vs 3.1) was similar for the two groups, as was the use of intravenous antibiotics (4.3 vs 4.6 days) and the number of days with temperature >38.3 degrees C (2.3 vs 1.8). Platelet recovery was also similar in both groups (platelets >50,000/mm3 reached after 11.8 vs 14.9 days). The recovery of neutrophils, however, was faster using G-CSF. ANC >500/mm3 and >1000/mm3 were reached in the GM-CSF group at 10.5 +/- 1.5 and 11.0 +/- 1.7 days, respectively, whereas with G-CSF only 8.8 +/- 1.2 and 8.9 +/- 2.2 days were required (P < 0.001). As a result, patients given G-CSF received fewer injections than the GM-CSF patients (10.9 vs 12.3). Resource utilization immediately attributable to the use of growth factors and the duration of pancytopenia, excluding hospitalization, were similar for the two groups. This study suggests that neutrophil recovery occurs more quickly following autologous PBSC transplant using G-CSF in comparison to GM-CSF, but the difference is not extensive enough to result in lower total cost.

Breast Neoplasms↗
PubMed1999

Specialty care for patients with epilepsy must become standard of care. Promotion of Specialty Care for Epilepsy Group.

Epilepsy is a complex, common disorder with severe consequences for patients. The authors believe that a significant percentage of patients are receiving suboptimal care. The national standard of care needs to be upgraded to include the notion that patients with less than total seizure control or those suffering from any medication side-effects should be given the opportunity to receive specialty care by physicians with specific expertise in the field of epilepsy.

Epilepsy↗
PubMed1999

Human factors in telesurgery: effects of time delay and asynchrony in video and control feedback with local manipulative assistance.

This paper presents the results of experiments examining the performance of a telesurgeon and an assistant local to the patient performing simulated laparoscopic tasks under a variety of time-delay conditions. Of particular interest is a comparison between the surgeon provided with audio/video and force feedbck synchronously with various time delays, and the surgeon performing asynchronously, where video is delayed relative to force feedback. These conditions are relevant since current telecommunication systems have limited bandwidth, and video signals must be compressed for efficient transmission. This produces a time lag between the video camera and the surgeon's monitor, Force feedback and position commands from a surgical teleoperator require much lower bandwidth, and can be transmitted in near-real time. In the first of two series of experiments, two laparoscopic training tasks were performed under different time-delay conditions, with force and video feedback delayed by equal amounts. In the second series, using the same tasks, the force feedback was more immediate, while the video delay lagged by the time required for compression and decompression. In both experiments, there were various role assignments in terms of whether the telesurgeon or the assistant controlled the laparoscope and/or the various surgical tools required. The three most striking results are that (1) nontrivial time delays significantly degraded the performance of the surgical tasks, (2) asynchronous force feedback resulted in significantly faster task-performance than did synchronous performance when the surgeon operated the laparoscopic tools, and (3) there was no difference between synchrony and asynchrony when the remote surgeon operated the laparoscope and gave commands while the local assistant operated the surgical tools.

Humans↗
PubMed1999

Revisiting employee benefits managers.

This article presents a case study of health purchasing practices of a sample of Employee Benefits Managers (EBMs) in a medium-size metropolitan area who were interviewed in 1991 and again in 1998. Findings show that employers have become less paternalistic in their health benefits; shifted plan options from indemnity coverage to managed care; increased employee cost-sharing; and placed greater decision-making on employees. EBMs embrace choice in health plans, have influenced the provider networks of plans, and have specified requirements for plan performance, however, use of quality information is limited.

Administrative Personnel↗
PubMed1999

Absorbed dose from traversing spherically symmetric, Gaussian radioactive clouds.

If a large radioactive cloud is produced, sampling may require that an airplane traverse the cloud. A method to predict the absorbed dose to the aircrew from penetrating the radioactive cloud is needed. Dose rates throughout spherically symmetric Gaussian clouds of various sizes, and the absorbed doses from traversing the clouds, were calculated. Cloud size is a dominant parameter causing dose to vary by orders of magnitude for a given dose rate measured at some distance. A method to determine cloud size, based on dose rate readings at two or more distances from the cloud center, was developed. This method, however, failed to resolve the smallest cloud sizes from measurements made at 1,000 m to 2,000 m from the cloud center.

Absorption↗