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Biomedical subjects

P C O'Brien

Publications and source records attributed to P C O'Brien.

At least 163 records · Page 9Linked to original sources
PubMed1995

Insulin therapy for diabetic ketoacidosis. Bolus insulin injection versus continuous insulin infusion.

OBJECTIVE: Despite widespread acceptance of continuous insulin infusion (CII) over bolus insulin injection (BII) for treatment of diabetic ketoacidosis (DKA), there are no population-based studies demonstrating whether CII has resulted in lower morbidity and mortality. RESEARCH DESIGN AND METHODS: We addressed this issue using a provider-linked database and retrospectively reviewing the complete medical records of all incidence cases of diabetes among Rochester, Minnesota, residents from 1950 to 1989 with a discharge diagnosis of DKA. This population-based study describes the consequences of the widespread change in treatment modality outside the confines of a controlled clinical trial. RESULTS: Among the diabetes incident cohort, there were 59 subjects with confirmed first episodes of DKA during 1950-1992; 29 of 30 subjects treated with BII occurred before 1970. All 29 CII cases occurred between 1976 and 1992. Sex, etiology, diabetes duration, and age at DKA were similar for the two groups. The proportion of obese individuals (BII = 2/28, CII = 8/21; P = 0.01) differed between groups. The CII group exhibited higher glucose values (BII = 24.9 +/- 8.5 mmol/l, CII = 37.1 +/- 15.1 mmol/l; P = 0.002) and lower bicarbonate values (BII = 7.7 +/- 3.0 nmol/l, CII = 6.2 +/- 2.9 nmol/l; P = 0.04) upon admission. The mean quantity of insulin administered was higher in the BII group than in the CII group (179 +/- 140 and 99 +/- 70 U, P < 0.006). The outcome of hypoglycemia occurred more frequently in the BII group than in the CII group (BII = 8/30, CII = 1/29; P = 0.03). The proportion with hypokalemia, neurological deficit, myocardial arrhythmia, or mortality did not differ significantly between groups. CONCLUSIONS: Our findings suggest the introduction of CII was accompanied by a decreased incidence of hypoglycemia.

Adult↗
PubMed1995

Salvage radiotherapy following chemotherapy failure in Hodgkin's disease--what is its role?

Radiotherapy is rarely used as salvage therapy following chemotherapy failure in Hodgkin's disease. Analysis of our experience identified only 11 cases from over 400 patients treated, and data from other centres are similarly sparse. Three (43%) of 7 patients with relapse confined to nodal sites were salvaged with radiotherapy alone. Actuarial relapse free survival at 5 years was 27% (+/- 12 SE) with survival 45% (+/- 15 SE). These data were then combined with four other detailed series in the literature to delineate the patient and disease characteristics of 60 patients, and better assess the role of salvage radiotherapy. This confirms that radiotherapy has an important role in salvaging a small proportion of cases, who can be spared the risk of more aggressive regimens, such as high dose chemotherapy. Patients with relapse confined to one or two nodal sites, and having a disease free interval greater than 12 months, have the best prospects for salvage. Initial stage IV disease seems to have little bearing, provided relapse is confined to nodal sites.

Actuarial Analysis↗
PubMed1995

Value of autonomic testing in reflex sympathetic dystrophy.

OBJECTIVE: To attempt to characterize reflex sympathetic dystrophy (RSD) and to determine factors that would predict a response to sympathetic block. DESIGN: We undertook a retrospective analysis on 396 patients with chronic limb pain referred for autonomic testing during a 5-year period. MATERIAL AND METHODS: Clinical endpoints were relief of pain after sympathetic block and a composite RSD diagnostic probability score, based on the clinical attributes of allodynia, protopathia, swelling, and vasomotor alterations. We compared the results of three autonomic tests--resting sweat output (RSO), resting skin temperature (RST), and quantitative sudomotor axon reflex test (QSART). RESULTS: Increased RSO predicted the diagnosis of RSD with 94% specificity, and the specificity was 98% when RSO was considered in conjunction with an abnormal QSART result, the best laboratory correlate (P = 0.003) of the clinical diagnosis. Shorter duration of pain correlated with a warmer limb (P < 0.001), even in the absence of RSD. Response to a single sympathetic block did correlate with the diagnosis (P = 0.031) but correlated most significantly with short duration of pain in the arm (P = 0.001) and laboratory findings in the leg, where increased RST (P < 0.001) and QSART (P < 0.001) were near-perfect predictors of response. CONCLUSION: Sweating abnormalities correlate strongly with the clinical syndrome of RSD, and alterations in RST may be superior to clinical findings in predicting the response to sympathetic block. The findings provide physiologic support for the unproven view of a natural disease progression ("stages"), with better treatment response and a warmer extremity initially. Because certain physiologic trends occur in all patients, general alterations of autonomic function with pain are suggested.

Adolescent↗
PubMed1994

Treatment of subdiaphragmatic Hodgkin's disease: is radiotherapy alone appropriate only for inguino-femoral presentations?

PURPOSE: Evaluate the role of staging laparotomy, and the impact of disease subsites on treatment outcome, for sub-diaphragmatic Hodgkin's Disease. METHODS AND MATERIALS: Between 1966 and 1989, 23 patients with Hodgkin's disease limited to sites below the diaphragm were treated at the Royal Adelaide Hospital. The high male:female ratio (2:8), low proportion of nodular sclerosis subtype (26%), and older age (mean = 40) relative to supra-diaphragmatic Hodgkin's disease is consistent with most other series. Thirteen patients underwent staging laparotomy. Initial treatment consisted of radiation therapy alone in 11, chemotherapy alone in 7, and combined modality therapy in 4 patients. This data was then combined with other published series over the last decade, to analyse relapse patterns and treatment results in relation to initial site(s) of disease. RESULTS: The overall, disease specific, and progression free 5 (and 10) year survival rates were 69%, 81%, and 58% respectively. There was no statistically significant effect of staging laparotomy on any of these parameters. Combining these results with those in the literature revealed an unacceptable relapse rate for patients with disease outside of the inguino-femoral region treated with inverted-Y radiation therapy alone. CONCLUSIONS: For the majority of patients with sub-diaphragmatic Hodgkin's disease, staging laparotomy can be avoided. Inverted-Y radiation therapy should only be used for inguino-femoral presentations.

Adolescent↗
PubMed1994

Incidence and prevalence of Huntington's disease in Olmsted County, Minnesota (1950 through 1989).

OBJECTIVE: To calculate average annual incidence rates for Huntington's disease (HD) from 1950 through 1989 and to estimate prevalence rates of the disease for January 1, 1960, and January 1, 1990. DESIGN: Health care records from all sources, including hospitals, outpatient clinics, and long-term care institutions, are readily available for all inhabitants of Olmsted County, Minnesota. The diagnoses entered in these records have been coded and indexed. All health care records containing a diagnosis that might suggest HD were reviewed, and those patients for whom the symptoms of HD began between January 1, 1950, and December 31, 1989, were identified. We used specific criteria for diagnosing HD. PARTICIPANTS: Health care records were reviewed; residence in Olmsted County during the year of symptom onset was required. MAIN OUTCOME MEASURES: Average annual incidence rates and prevalence rates for January 1, 1960, and January 1, 1990. RESULTS: Overall incidence rates were 0.4 (95% confidence interval [CI], 0.1 to 0.8) for women and 0.2 (95% CI, 0.04 to 0.6) for men per 100,000 person-years. Estimated prevalence rates for January 1, 1960, per 100,000 person-years were 6 (95% CI, 0.7 to 21.5) for women and 6.6 (95% CI, 0.8 to 23.8) for men. For January 1, 1990, the prevalence rates were 1.8 (95% CI, 0.04 to 10.2) for women and 2 (95% CI, 0.05 to 10.9) for men. CONCLUSIONS: Incidence and prevalence rates of HD in this community are similar to those reported in other communities. The small numbers of affected persons do not allow an estimate of variation over time.

Female↗
PubMed1994

A plasma exchange versus immune globulin infusion trial in chronic inflammatory demyelinating polyradiculoneuropathy.

Chronic inflammatory demyelinating polyradiculoneuropathy is a paralytic syndrome, causing considerable disability and even death. In controlled clinical trials, plasma exchange prevented or ameliorated neurological deficits, but the efficacy of immune globulin infusion remains unproved. Also unknown is whether immune globulin infusion is as effective, or more effective, than plasma exchange and what dosages and frequencies are best. In this observer-blinded study, using some objective end points not subject to bias (e.g., summated compound muscle action potential), 20 patients with progressive or static polyneuropathy were randomly assigned to receive either of the two treatments for 6 weeks, followed by a washout period, and then were assigned to receive the other treatment. Plasma exchange (twice a week for 3 weeks then once a week for 3 weeks) and immune globulin infusion (0.4 gm/kg once a week for 3 weeks, then 0.2 gm/kg once a week for the next 3 weeks) were used. End points assessed before and after treatment schedules were neurological disability score; muscle weakness of the neurological disability score; summated compound muscle action potentials of ulnar, median, and peroneal nerves; summated sensory nerve action potentials of ulnar and sural nerves; and vibratory detection threshold of the great toe using CASE IV. Observers were masked as to treatment used. Of 20 patients, 13 received both treatments whereas 4 did not worsen sufficiently to receive the second treatment--1 patient left the study during and 2 after the first treatment to receive unscheduled treatment elsewhere.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Liver iron stores in patients with non-insulin-dependent diabetes mellitus.

BACKGROUND: Iron overload such as that in idiopathic hemochromatosis is a well-established, albeit rare, cause of non-insulin-dependent diabetes mellitus (NIDDM). Most patients with NIDDM have no recognized cause of their disease. Investigators have proposed that subclinical iron overload may cause diabetes mellitus in a substantial number of patients with NIDDM. OBJECTIVE: The aim of the current study was to evaluate hepatic iron stores in autopsy specimens from a group of community residents with NIDDM. METHODS: Fifteen patients with NIDDM and 17 age-matched control subjects were identified from a review of medical records of decreased residents of Olmsted County, Minnesota. Formalin-fixed liver tissue was analyzed for iron concentration by flameless atomic absorption spectrophotometry, and distribution of hepatic iron was determined histochemically. RESULTS: No significant difference was found in either the distribution or the mean amount of hepatic iron between the diabetic and the control group (1,303 versus 1,349 micrograms Fe/g dry weight; P = 0.87). Thus, the mean difference was -46 micrograms Fe/g dry weight (confidence interval, -631 to 540). CONCLUSION: Because hepatic iron quantification is the definitive means of assessing total body iron stores, our results suggest that NIDDM is typically not associated with a substantial level of iron overload.

Aged↗
PubMed1994

Pseudomyxoma peritonei. Long-term patient survival with an aggressive regional approach.

OBJECTIVE: The aims of this study were to analyze the natural history of patients with pseudomyxoma peritonei (PMP), evaluate clinical and pathologic variables as prognostic indicators, and review the authors' experience with different treatments. SUMMARY BACKGROUND DATA: PMP is an unusual form of intra-abdominal neoplasm that presents with large amounts of extracellular mucin. Diffuse peritoneal spread occurs in most patients with PMP, and distant metastasis is infrequent. Debulking surgery, radiation therapy (radioisotope and external beam), and chemotherapy (both intraperitoneal and systemic) have all been advocated for optional patient management, but the variability of patients studied, the small patient numbers, and the prolonged course of this disease make the evaluation of results difficult. METHODS: Fifty-six patients were treated for PMP at the Mayo Clinic between 1957 and 1983. The data were collected retrospectively. Univariate (log-rank test) and multivariate (Cox regression model) analyses were performed for disease recurrence and patient survival. RESULTS: Most patients with PMP had carcinomas of the appendix (52%) or ovary (34%). All gross tumor could be removed only in the 34% of patients with limited disease. Although tumor progression occurred in 76% of patients, the 1-, 5-, and 10-year survival rates were 98%, 53%, and 32%, respectively. Adverse predictors of patient survival included weight loss (p = 0.001), abdominal distention (p = 0.004), use of systemic chemotherapy (p = 0.005), diffuse disease (p = 0.038), and invasion of other organs (p = 0.04). Intraperitoneal chemotherapy (p = 0.009) and radioisotopes (p = 0.0043) both were effective in prolonging the recurrence time of symptomatic PMP. CONCLUSIONS: Although PMP is an indolent disease, aggressive surgical debulking followed by intraperitoneal radioisotopes and/or chemotherapy should be considered because of the diffuse peritoneal involvement.

Adolescent↗
PubMed1994

Radiotherapy alone for early stage Hodgkin's disease: a 16 year experience at the Royal Adelaide hospital.

The records of all patients with stage I and II Hodgkin's disease treated with radiotherapy alone at the Royal Adelaide Hospital between 1970 and 1986 were reviewed. The aim was to ensure the results were equivalent to the best reported series, particularly as treating such patients with chemotherapy alone has been shown to produce equivalent overall survival figures with improved relapse-free survival. There were 104 patients of whom 67 had undergone staging laparotomy. Fifty-seven patients were stage I and 47 stage II. Nine patients had B symptoms. Overall survival at 10 years was 83% with disease-specific survival being 86% and relapse-free survival 68%. These results compare favourably with those in the world literature. Multivariate analysis only revealed stage as an independent predictor of improved relapse-free survival. The use of radiotherapy for most patients with early stage Hodgkin's disease is continued at Royal Adelaide Hospital. However, careful selection criteria need to be applied to minimize the incidence of relapse after radiotherapy.

Adolescent↗
PubMed1994

Intravenous immunoglobulin therapy in multiple sclerosis: progress from remyelination in the Theiler's virus model to a randomised, double-blind, placebo-controlled clinical trial.

No treatment has been found which reverses long-standing neurological dysfunction in patients with multiple sclerosis (MS). Observations in animal models of MS show that immunoglobulins directed against CNS components promote oligodendroglial proliferation and new myelin synthesis. Preliminary studies in inflammatory-demyelinating diseases of the human peripheral and central nervous system suggest that the repeated intravenous administration of polyclonal human immunoglobulin (IVIg) is sometimes followed by clinical improvement. A randomised, placebo-controlled, double-blind, clinical trial was designed to test the hypothesis that repeated administration of IVIg will result in a meaningful degree of recovery of apparently irreversibly lost neurological function (weakness). A total of 76 patients with MS will participate in the study. These patients had developed a fixed, apparently permanent weakness that had not improved in the preceding four to 18 months. If effective, IVIg administration may benefit the large proportion of patients with MS who have active disease by enhancing the potential for myelin repair in the evolution of the inflammatory-demyelinating lesion.

Animals↗
PubMed1994

Pneumothorax following thoracic radiation therapy for Hodgkin's disease.

Radiation therapy alone to the nodal drainage sites above the diaphragm, namely a "mantle" field, is often standard treatment for early stage Hodgkin's disease and may be used in combination with chemotherapy in more advance disease. Localised pneumonitis and fibrosis are recognised treatment related sequelae; however, other pulmonary complications, including pneumothorax, have been described. Two cases of spontaneous pneumothorax following mantle radiation therapy are presented.

Adolescent↗
PubMed1994

Diagnosis of mesial temporal sclerosis with conventional versus fast spin-echo MR imaging.

PURPOSE: To test the accuracy of fast spin-echo (FSE) imaging versus that of double-echo conventional spin-echo (CSE) imaging in identification of the increased hippocampal signal intensity associated with mesial temporal sclerosis (MTS). MATERIALS AND METHODS: Thirty-four subjects who subsequently underwent anterior temporal lobectomy for intractable seizures and in whom the presence or absence of MTS was ascertained with certainty were imaged with CSE and FSE. Three blinded reviewers evaluated the first and second CSE images (CSE1 and CSE2) and the FSE images. RESULTS: CSE1 imaging had lower accuracy than FSE (P = .038) and CSE2 (P = .006) imaging. CSE2 imaging was slightly more accurate than FSE imaging (P = .048). Contrast-to-noise ratios were lower for CSE1 imaging than for CSE2 or FSE imaging (P < .001). CONCLUSION: The FSE sequence evaluated was more time efficient than CSE imaging but slightly less accurate. Therefore, substitution of this sequence for a CSE sequence seems unwarranted.

Adolescent↗
PubMed1994

Are patients with Alzheimer's disease surviving longer in recent years?

We report the survival experience of the incidence cohort of Alzheimer's disease (AD) patients in Rochester, Minnesota, whose onset occurred during the years 1960 to 1984. Survival was evaluated relative to year of onset, age at onset, and gender. Survival was better among women than men and improved for those with AD with more recent onset. The relative hazard decreased by a factor of 0.82 for each decade. The effect of age at onset was nonlinear, indicating that the hazard of death does not change at a constant rate with age.

Age of Onset↗
PubMed1994

Intractable nonlesional epilepsy of temporal lobe origin: lateralization by interictal SPECT versus MRI.

We performed a retrospective study of 53 consecutive "nonlesional" temporal lobectomy patients to assess the relative utility of MRI versus interictal single-photon emission computed tomography (SPECT) in this patient population. We compared the seizure lateralizing properties of MRI and SPECT using multiple blinded expert reviewers for both SPECT and MRI with a test-retest reviewer paradigm and measurements of hippocampal volume from MRI. The criterion standard for seizure lateralization was satisfactory postoperative seizure control (n = 43). The rate of correct seizure lateralization was significantly greater for MRI than for SPECT (p < or = 0.01), and the rate of incorrect lateralization was significantly less for MRI than for SPECT. The most accurate MRI measure was hippocampal volume measurements, which correctly lateralized the seizures in 86.0% of cases. The correct lateralization rate for SPECT was 45.4%. The MRI and SPECT studies tended to be noncomplementary with respect to seizure lateralization, and SPECT was likely to give an incorrect or indeterminate result in patients who were not lateralized by MRI. Concordant MRI-EEG lateralization was a strong predictor of satisfactory postoperative seizure control, while no relationship between postoperative seizure control and SPECT findings was present.

Adult↗
PubMed1994

Referral selection bias in the Medicare hospital mortality prediction model: are centers of referral for Medicare beneficiaries necessarily centers of excellence?

OBJECTIVE: Although the Health Care Financing Administration (HCFA) uses Medicare hospital mortality data as a measure of hospital quality of care, concerns have been raised regarding the validity of this concept. A problem that has not been fully evaluated in these data is the potential confounding effect of illness severity factors associated with referral selection and hospital mortality on comparisons of risk-adjusted hospital mortality. We address this issue. DATA SOURCES AND STUDY SETTING: We analyzed the 1988 Medicare hospitalization data file (MEDPAR). We selected data on patients treated at the two Mayo Clinic-associated hospitals in Rochester, Minnesota, and a group of seven other hospitals that treat many patients from large geographic areas. These hospitals have had observed mortality rates substantially lower than those predicted by the HCFA model for the period 1987-1990. STUDY DESIGN: Using the multiple logistic regression model applied by HCFA to the 1988 data, we evaluated the relationship between distance from patient residence to the admitting hospital and risk-adjusted hospital mortality. PRINCIPAL FINDINGS: Among patients admitted to Mayo Rochester-affiliated hospitals, residence outside Olmsted County, Minnesota was independently associated with a 33 percent lower 30-day mortality rate (p < .001) than that associated with residence in Olmsted County. When patients at Mayo hospitals were stratified by residence (Olmsted County versus non-Olmsted County), the observed mortality was similar to that predicted for community patients (9.6 percent versus 10.2 percent, p = .26), whereas hospital mortality for referral patients was substantially lower than predicted (5.0 percent versus 7.5 percent, p = < .001). After incorporation of the HCFA risk adjustment methods, distance from patient residence to the hospitals was also independently associated with mortality among the Mayo Rochester-affiliated hospitals and seven other referral center hospitals. CONCLUSIONS: The HCFA Medicare hospital mortality model should be used with extreme caution to evaluate hospital quality of care for national referral centers because of residual confounding due to severity of illness factors associated with geographic referral that are inadequately captured in the extant prediction model.

Aged↗
PubMed1993

Characterization and mechanisms of thymic atrophy in protein-malnourished mice: role of corticosterone.

The purpose of this project was to characterize changes in murine T lymphocyte subpopulations during thymic atrophy induced by protein malnutrition and to determine the role of elevated serum corticosterone in this process. A suitable animal model was generated by placing mice on protein-sufficient (PS) and protein-deficient (PD) diets for 6 weeks. Body weight was monitored to determine the establishment and maintenance of malnutrition. Results obtained using PD mice indicated a direct correlation between serum corticosterone levels and thymic atrophy. Furthermore, results of the experiments using mice implanted with corticosterone-impregnated pellets indicated that corticosterone alone, at the levels observed in PD mice, induced thymic atrophy in normal mice. These results demonstrate that the thymic atrophy induced by protein malnutrition is primarily due to elevated serum corticosterone. As indicated by flow cytometric analysis, the number of cells in all thymocyte subpopulations decreased as protein malnutrition continued, possibly reflecting depletion of immature CD4-/CD8- and CD4+/CD8+ cells, ultimately resulting in loss of mature CD4+ and CD8+ cells. TCR expression by PD thymocytes, especially those with high levels of CD3, increased during the dietary period. Mice implanted with corticosterone pellets experienced severe losses of CD4+/CD8+ cells, resulting in thymocyte subpopulation and CD3 profiles more similar to those of hydrocortisone-injected mice than those of PD mice. Therefore, whereas thymic atrophy in protein-malnourished mice seems to be caused by elevated serum corticosterone, it appears that additional factors further modulate thymocyte proliferation, differentiation, and/or death in this system.

Animals↗