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J A Barrett

Publications and source records attributed to J A Barrett.

At least 37 records · Page 2Linked to original sources
PubMed1999

Fracture risk in the U.S. Medicare population.

Using data from the 5% U.S. Medicare sample, we estimated the actuarial (life table) risk that a person aged 65 will fracture the upper or lower limbs or the pelvis, by age 75, 80, 85, and 90, taking into account the chance of dying in the interval. The actuarial risk of a 65-year old white woman sustaining a fracture by age 90 is 16% for the hip, 9% for distal forearm, 5% for proximal humerus, and 4% for ankle. Black women and white men have substantially lower risks, and the risks for black men are very low. Although hip fractures pose the single greatest risk, the risk of all other fractures combined is greater. White women have particularly high risks for all fractures, because of their longevity as well as their high fracture rates. It is important to adjust for the probability of dying when estimating risks in an elderly population.

Actuarial Analysis↗
PubMed1998

Effects of short heat exposure on human red and white blood cells.

BACKGROUND: The infusion of warm intravenous fluid (IVF) is a simple and effective method used to maintain or restore core body temperature. At present, 40 degrees C is believed to be the highest temperature that can be safely administered. There is concern that temperatures greater than 40 degrees C may harm blood cells. The mixing time of IVF infused into a high-flow vein such as the superior vena cava is very short, however, approximately 300 milliseconds. We will determine the maximum temperature and exposure time tolerated by human red and white blood cells without producing injury. METHODS: Whole blood and isolated neutrophils were exposed to temperatures (40-80 degrees C) for short time intervals (150-1,200 milliseconds). Lethal injury to red and white blood cells was measured by the plasma free hemoglobin and percent viability, respectively. Neutrophil viability was measured by trypan blue staining. Sublethal injury to red and white cells was measured by osmotic fragility and oxidative burst, respectively. Neutrophil oxidative burst was measured by chemiluminescence. Control values were compared with postexposure values using analysis of variance with p < 0.05 indicating significance. RESULTS: Lethal injury to red blood cells did not occur until exposure at 70 degrees C for 300 milliseconds (plasma free hemoglobin, 116.3 +/- 34.7 mg%; p < 0.05). Lethal injury to neutrophils did not occur, even at exposure at 80 degrees C for 1,200 milliseconds. Sublethal injury to red blood cells did not occur until exposure at 60 degrees C for 1,200 milliseconds. Sublethal injury to neutrophils did not occur until exposure at 60 degrees C for 600 milliseconds (percent change in oxidative burst = 28.9 +/- 0.96%; p < 0.05). CONCLUSIONS: The exposure of human red blood cells and neutrophils to temperatures up to 60 degrees C for up to 600 milliseconds does not cause lethal or sublethal injury. These findings contribute to the body of evidence supporting the use of centrally infused IVF at temperatures greater than 40 degrees C for active core rewarming.

Erythrocytes↗
PubMed1998

Treatment of hairy cell leukemia with 2-chlorodeoxyadenosine via the Group C protocol mechanism of the National Cancer Institute: a report of 979 patients.

PURPOSE: To provide cladribine (CdA) to physicians for the treatment of patients with previously treated or untreated hairy cell leukemia (HCL), and to determine the response rate, response duration, survival, and toxicity with this agent. PATIENTS AND METHODS: This Group C phase II study was open to all eligible patients whose primary physician obtained written permission from the National Cancer Institute (NCI) to register patients onto this protocol. Of 979 patients registered, 861 were assessable for response and 895 for toxicity. RESULTS: The complete remission (CR) rate was 50% and the partial remission (PR) rate was 37%. At a median follow-up of 52 months, 12% of patients were reported to have progressed and 62 (7%) have died of disease. CONCLUSION: This large experience confirms the excellent response rates and remission duration of CdA in patients with HCL. Nevertheless, the response rates in this setting, which approximates general clinical practice, were lower than in other series. In general, CdA was well tolerated, but the potential increased risk for secondary malignancies requires additional follow-up evaluation. CdA can now be considered as one of the best agents for the treatment of HCL.

Adult↗
PubMed1997

Technetium-99m-labeled chemotactic peptides in acute infection and sterile inflammation.

UNLABELLED: Chemotactic peptides have been proposed as vehicles to image infection and inflammation. Previous studies have shown high uptake at the site of infection soon after injection, most likely because of specific binding to receptors on locally present leukocytes. To investigate this hypothesis, the in vivo behavior of a synthetic chemotactic peptide was compared to a control peptide of similar molecular weight with low receptor binding affinity. In addition, the potential to target to different infections and sterile inflammation was tested. METHODS: Twenty-four hours after induction of Escherichia coli, Staphylococcus aureus and zymosan abscesses, rabbits were i.v. injected with either 1 mCi of 99mTc-labeled formyl-methionyl-leucyl-phenylalanyl-lysine-hydrazinonicotinamid e (99mTc-fMLFK-HYNIC) or 99mTc-labeled hydrazinonicotinamide-methionyl-leucyl-phenylalanyl-OMe (99mTc-HYNIC-MLFOMe, control peptide). Gamma camera images were obtained at 5 min and 1, 4, 8 and 20 hr postinjection. Biodistribution was determined at 20 hr postinjection. RESULTS: The blood clearances of 99mTc-fMLFK-HYNIC and 99mTc-HYNIC-MLFOMe were similar. With time, 99mTc-fMLFK-HYNIC was retained in the abscess (E. coli), whereas the control agent 99mTc-HYNIC-MLFOMe was cleared from the abscess (0.049 +/- 0.011 versus 0.005 +/- 0.0003% 1D/g at 20 hr postinjection; p < 0.0005). Abscess-to-contralateral muscle ratios of 99mTc-fMLFK-HYNIC rose to 36.8 +/- 4.3 at 20 hr postinjection. E. coli, S. aureus and zymosan abscesses were clearly visualized from 4 hr postinjection onward. Abscess-to-background ratios increased to values varying from 4.4 +/- 0.2 (zymosan) to 7.1 +/- 0.6 (S. aureus) at 20 hr postinjection. The uptake in S. aureus and zymosan abscesses did not differ significantly from the uptake in E. coli abscesses. CONCLUSIONS: fMLFK-HYNIC is retained in both acute infection and sterile inflammation by means of specific receptor binding if sufficient cellular infiltration is present.

Abscess↗
PubMed1996

MDR1 and multidrug resistance-associated protein (MRP) gene expression in epithelial ovarian tumors.

Clinical drug resistance poses a major problem in the successful treatment of ovarian cancer. Two genes, MDR1 and MRP, have been found to play a role in the multidrug resistance phenotype of a number of human tumors. Using a sensitive semiquantitative PCR assay we examined 53 primary untreated ovarian tumors for expression of both MDR1 and MRP genes. Approximately one-third of the tumors expressed MDR1 while all the tumors expressed varying levels of the MRP gene.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

Heterogeneity of hip fracture: age, race, sex, and geographic patterns of femoral neck and trochanteric fractures among the US elderly.

To explore potential etiologic differences in the two major types of hip fracture, the authors computed the incidence rates of fractures of the femoral neck and trochanteric region of the proximal femur using a 5 percent sample of the US Medicare population aged 65-99 years. For the period they examined, July 1, 1986, through June 30, 1990, the rates of both hip fracture types increased with age in all race and sex categories. The proportion of hip fractures that occurred in the trochanteric region rose steeply with age among white women, but not among black women, white men, or black men. Within the United States, a north-to-south gradient in rates of both fracture types was observed among women, while no clear pattern was found for men. These findings raise the possibility of etiologic differences in the two fracture types, and the results provide further evidence of sex and racial differences in the risk of osteoporotic fractures.

Black or African American↗
PubMed1996

Patterns of fracture among the United States elderly: geographic and fluoride effects.

The purpose of this study was to examine whether geographic area or water fluoride were related to the occurrence of fractures among the elderly in the United States. We used a 5% sample of the white U.S. Medicare population, aged 65 to 89 years during the period 1986-1990, to identify fractures of the hip, proximal humerus, distal forearm, and ankle. The association of geographic region and fluoridation status with fracture rates was assessed using Poisson regression. We found that rates of hip fracture were generally lower in the northern regions of the United States and higher in the southern regions. For fractures of the distal forearm and proximal humerus, lower rates were found in the Western states, and higher rates in the East. No discernible geographic pattern was found for ankle fractures. Adjustment for water fluoridation did not influence these results. Independent of geographic effects, men in fluoridated areas had modestly higher rates of fractures of the distal forearm and proximal humerus than did men in nonfluoridated areas; no such differences were observed among women, nor for fractures of the hip or ankle among either men or women. In conclusion, our data suggest that fractures of the distal forearm and proximal humerus have etiologic determinants distinct from those of fractures of the hip or ankle.

Aged↗
PubMed1996

The epidemiology of peripheral fractures.

Although much is known about hip fracture epidemiology, there are relatively little data regarding fractures at other peripheral sites. Epidemiological differences between fractures are important, since they imply that an understanding of the consequences and clinical expression of osteoporosis requires the study of many different fracture types. Recent data regarding the basic epidemiology of limb fractures among the elderly in industrialized countries have made some patterns clear. Fractures outside the hip are relatively common events, and before age 70 to 75, ankle and distal forearm fractures occur more commonly than fractures of the hip. Among the elderly, fractures at the most proximal and most distal ends of the limbs have the highest incidence. Thus, in the upper extremity, fractures of the proximal humerus and distal forearm are the most common, while in the lower extremity, those at the hip and ankle predominate. Outside the axial skeleton, females have higher rates for most fracture types, and at most fracture sites whites have higher rates than blacks. In each limb, the most proximal fractures tend to have the most pronounced age-related increases in risk.

Aged↗
PubMed1996

Safety of 65 degrees C intravenous fluid for the treatment of hypothermia.

BACKGROUND: To demonstrate the safety and efficacy of 65 degrees C (149 degrees F) centrally administered intravenous fluid (CIVF) compared to conventional 40 degrees C (104 degrees F) CIVF in the treatment of hypothermia. METHOD: Ten beagles (9-13 kg) were prospectively randomized to receive 65 degrees C or 40 degrees C CIVF. They were anesthetized and data were collected at baseline, during hypothermia, and after 1 and 2 hours of rewarming. The plasma free/total hemoglobin (PFHb/THb) was measured to detect hemolysis. Each subject was cooled to 30 degrees C (86 degrees F) and then received either 65 degrees C or 40 degrees C CIVF through a specialized catheter in the superior vena cava for 2 hours in addition to conventional rewarming techniques. All subjects survived 7 days, after which they were sacrificed and a complete autopsy was performed. RESULTS: The rewarming rate was 3.7 degrees C/hr in the 65 degrees C CIVF group and 1.75 degrees C/hr in the 40 degrees C CIVF group. Core temperatures were significantly different after 1 hour (33.4 degrees +/- 0.77 degrees versus 31.7 degrees +/- 0.57 degrees, P < 0.01) and 2 hours (37 degrees +/- 1.03 degrees versus 33.4 degrees +/- 0.89 degrees, P < 0.001). PFHb/THb was not different. Two intimal injuries occurred in each group but these were remote from the infusion site. Blinded examination by two pathologists could not differentiate the etiology of these injuries from mechanical trauma. CONCLUSION: CIVF at 65 degrees C is a safe and effective means of treating hypothermia.

Animals↗
PubMed1996

Intestinal permeability and orocaecal transit time in elderly patients with Parkinson's disease.

The aetiology of weight loss in patients with Parkinson's disease is likely to be multifactorial. We studied 15 patients with Parkinson's disease and 15 age- and sex-matched controls and looked for evidence of malabsorption due to small bowel bacterial overgrowth or alteration of intestinal permeability. There was a marked increase in orocaecal transit time in the patients with Parkinson's disease, although lactulose hydrogen breath testing did not show evidence of small bowel bacterial contamination. Intestinal permeability measured by the differential sugar absorption test was also deranged. There was reduced absorption of mannitol in patients with Parkinson's disease while lactulose absorption was similar in both groups, suggesting decreased non-mediated uptake across the enterocyte brush border membrane in patients with Parkinson's disease.

Aged↗
PubMed1996

Indispensable amino acid deficiency and increased seizure susceptibility in rats.

Repeated subthreshold stimulation of limbic brain areas increases seizure susceptibility in experimental models of epilepsy. In addition, acute dietary indispensable amino acid (IAA) deficiency activates the anterior piriform cortex (APC), a seizure-prone limbic brain area in the rat. Based on these two findings, we hypothesized that activation of the APC by chronic exposure to IAA-deficient diets might increase seizure susceptibility. Several nonessential amino acid neurotransmitters are important in seizures, but deficiencies of nontransmitter IAAs have not been well studied in seizure models. In four trials, we made injections of pentylenetetrazole intraperitoneally or of bicuculline into the APC in histidine-, isoleucine-, or threonine-deficient rats and controls. Increased susceptibility to seizures in the deficient animals was observed as increased severity of the seizures, decreased threshold for the dose of the chemostimulant and time to seizure, or a combination thereof. Pair-fed controls showed that this effect was not due to an energy deficit. This novel but robust finding suggests that IAA deficiency may increase vulnerability to seizures by repeated activation of the APC.

Amino Acids↗
PubMed1995

Inhibition of chemotactic peptide-induced neutrophil adhesion to vascular endothelium by cAMP modulators.

An early event associated with neutrophil-dependent tissue damage involves the adhesion of neutrophils to the vascular endothelium and the subsequent release of oxygen-derived free radicals and granule constituents. Elevations in intracellular cAMP are known to inhibit free radical release but not lysosomal enzyme release. The role of cAMP in FMLP-induced neutrophil adhesion was examined in this study by using an in vitro model of neutrophil-endothelial cell adhesion. FMLP stimulated a time- and concentration-dependent increase in human neutrophil adhesion to HUVEC. FMLP-mediated adhesion was inhibited by a diverse group of cAMP modulators: forskolin, isoproterenol, phosphodiesterase IV inhibitors (rolipram and Ro 20-1724), but not phosphodiesterase III inhibitors (milrinone and bemoradan). Endogenous adenosine has previously been shown to mediate FMLP-induced increases in cAMP enhanced in the presence of Ro 20-1724. In this study, adenosine deaminase prevented the inhibitory effects observed with rolipram and Ro 20-1724, implicating endogenous adenosine as a co-modulator of inhibition. FMLP stimulated neutrophil shape change and the surface expression of the beta 2 integrins CD11b/CD18 and CD11a/CD18. Both these responses were inhibited by rolipram but not bemoradan. With the use of 4,4'-diisothiocyanostilbene-2,2'disulfonic acid, we showed that mobilization of the intracellular pool of CD11b/CD18 paralleled adhesion. We conclude that neutrophil-endothelial cell adhesion is attenuated by elevating neutrophil intracellular cAMP and that inhibition of neutrophil CD11b/CD18 surface expression by cAMP accounts for this observed inhibition of adhesion.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1995

Use of inferior vena cava filters in the Medicare population.

To examine the use of inferior vena cava (IVC) filters, we performed a population-based study using a 5% random sample of the United States Medicare population (1.25 million persons). Filter placement and its timing relative to diagnosis of venous thromboembolism (VTE) were determined using both hospital and physician Medicare billing codes after detailed review of large samples of complete individual claims records. Comorbid conditions and mortality were also noted. From July 1986 through June 1989, a total of 806 patients in the sample population received IVC filters. Mortality rates after filter placement were high: 16% during initial hospitalization, 32% within 6 months of filter placement, and 48% after 2 years. However, only 3 (1%) of 423 patients who underwent filter placement without the diagnosis of pulmonary embolism (PE) suffered PE within 1 year of filter placement. Use of IVC filters increased significantly over the study period (p < 0.001). Rates of filter placement among the nine census divisions of the United States differed significantly (p < 0.001). An East-West trend was notable with the highest rate (37 filters/100,000 enrollees/yr) in New England, as compared with 14 filters/100,000 enrollees/yr in the Pacific Division. No explanation for these regional differences was evident after patient demographics and comorbidity were examined. Vena cava filters prevent PE for at least 1 year after placement. The frequency of IVC filter use in elderly patients is increasing and varies substantially by region. Although reasons for these trends are unclear, these findings suggest the need for uniform practice guidelines for IVC filter placement.

Aged↗
PubMed1995

Tumour marker CA15-3: possible uses in the routine management of breast cancer.

Tumour markers are a potentially powerful means of obtaining information about cancers whilst causing minimal morbidity, inconvenience and cost. CA15-3 has been suggested as a marker of distant metastasis (M+ disease) in breast cancer. We have measured CA15-3 in 77 patients with carcinoma of the breast in order to determine whether routine assay of this tumour marker would be useful in the oncology unit of a district general hospital. A highly significant correlation existed between elevated CA15-3 levels (> or = 30 U/ml) and M+ disease. The CA15-3 assay was found to have a sensitivity of 70%, a specificity of 96% and a predictive value of 87%, in agreement with previous studies. There was evidence that CA15-3 levels frequently increased in advance of otherwise detectable distant metastases. 70 patients had a 99m Tc bone scan close to the date on which CA15-3 was measured. All patients with a positive bone scan and raised levels of CA15-3 were subsequently confirmed as having bony metastases; no patient with normal bone scan and normal CA15-3 developed M+ disease (to the date of follow-up). CA15-3 levels were raised in 83% of patients who developed non-bony distant metastases. In clinical practice it may be possible to exploit the high specificity of CA15-3, in order to provide additional information to that already determined by current investigations. For example, CA15-3 might be assayed alongside a bone scan to confirm positive or negative results. Another role might be as a screen for breast cancer metastases in departments with limited access to bone scans and other imaging facilities. CA15-3 might also be used in monitoring patients for the development of distant metastases during follow-up. It is, however, unlikely that CA15-3 can substitute directly for a bone scan or other imaging currently used routinely by a department. Clinical trials are now necessary to determine the effect of using tumour markers such as CA15-3 on patient morbidity and mortality.

Biomarkers, Tumor↗
PubMed1995

Demographics of civilian cranial gunshot wounds: devastation related to escalating semiautomatic usage.

The demographics and outcome of patients with gunshot wounds to the head over the past 10 years at Chicago's Cook County Hospital was examined. The study group consisted of 476 consecutive patients admitted to this urban level I trauma center with a diagnosis of penetrating craniocerebral missile injury. All patients followed a protocol that included aggressive surgical management when indicated. The Glasgow Outcome Score was used to assess outcome. There is an alarming rise in firearm violence in general and craniocerebral injury in particular. Some patients with severe neurologic deficits and massive cerebral damage can benefit from aggressive treatment and make a good recovery. A large proportion of this violence is most likely attributable to gang activity. Factors correlating with poor outcome included hypotension, apnea, bihemispheric injuries, or ventricular penetration. Although aggressive surgical and medical management improves the outcome of these patients, much more stringent preventative measures are required to control this violent epidemic.

Adolescent↗
PubMed1995

Buckshot colic: case report and review of the literature.

Three weeks after a shotgun wound to the chest and abdomen, a patient developed acute ureteral colic caused by a migrating shotgun pellet. The pellet passed spontaneously. A search of the literature revealed 25 similar cases of this unusual complication of missile injuries to the abdomen. These cases are reviewed and analyzed. Ureteral obstruction from migrating retained missiles is an unusual complication of missile injuries to the abdomen. Cases have been described occurring after shotgun, gunshot, and shrapnel wounds. Cases involving bullets and shrapnel fragments usually have had long latent periods after the initial injury and required surgery to remove the obstructing projectile. In contrast, cases of "buckshot colic" from shotgun pellets present earlier and often resolve with spontaneous passage of the pellet. The following report illustrates how conservative management can be successful in cases of "buckshot colic."

Abdominal Injuries↗