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Biomedical subjects

S Baker

Publications and source records attributed to S Baker.

At least 55 records · Page 3Linked to original sources
PubMed2000

Radiation exposure from outpatient radioactive iodine (131I) therapy for thyroid carcinoma.

CONTEXT: In May 1997, the US Nuclear Regulatory Commission (NRC) revised its patient release regulations, allowing for outpatient administration of larger activities of sodium iodide 131I than previously permitted. OBJECTIVE: To measure the radiation exposure to household members from patients receiving outpatient 131I therapy for thyroid carcinoma in accordance with the new regulations. DESIGN: Consecutive case series from October 1998 to June 1999. SETTING AND PATIENTS: Thirty patients who received outpatient 131I therapy following thyroidectomy for differentiated thyroid carcinoma were enrolled, along with their 65 household members and 17 household pets. MAIN OUTCOME MEASURE: Radiation exposure to household members and 4 rooms in each home, as monitored with dosimeters for 10 days following 131I administration. RESULTS: The patients received 131I doses ranging from 2.8 to 5.6 GBq (mean, 4.3 GBq). The radiation dose to 65 household members ranged from 0.01 mSv to 1.09 mSv (mean, 0.24 mSv). The dose to 17 household pets ranged from 0.02 mSv to 1.11 mSv (mean, 0.37 mSv). The mean dose to the 4 rooms ranged from 0.17 mSv (kitchen) to 0.58 mSv (bedroom). CONCLUSION: In our study, 131I doses to household members of patients receiving outpatient 131I therapy were well below the limit (5.0 mSv) mandated by current NRC regulations.

Adolescent↗
PubMed2000

Using thresholds based on risk of cardiovascular disease to target treatment for hypertension: modelling events averted and number treated.

OBJECTIVE: To estimate the impact of using thresholds based on absolute risk of cardiovascular disease to target drug treatment to lower blood pressure in the community. DESIGN: Modelling of three thresholds of treatment for hypertension based on the absolute risk of cardiovascular disease. 5 year risk of disease was estimated for each participant using an equation to predict risk. Net predicted impact of the thresholds on the number of people treated and the number of disease events averted over 5 years was calculated assuming a relative treatment benefit of one quarter. SETTING: Auckland, New Zealand. PARTICIPANTS: 2158 men and women aged 35-79 years randomly sampled from the general electoral rolls. MAIN OUTCOME MEASURES: Predicted 5 year risk of cardiovascular disease event, estimated number of people for whom treatment would be recommended, and disease events averted over 5 years at different treatment thresholds. RESULTS: 46 374 (12%) Auckland residents aged 35-79 receive drug treatment to lower their blood pressure, averting an estimated 1689 disease events over 5 years. Restricting treatment to individuals with blood pressure >/=170/100 mm Hg and those with blood pressure between 150/90-169/99 mm Hg who have a predicted 5 year risk of disease >/=10% would increase the net number for whom treatment would be recommended by 19 401. This 42% relative increase is predicted to avert 1139/1689 (68%) additional disease events overall over 5 years compared with current treatment. If the threshold for 5 year risk of disease is set at 15% the number recommended for treatment increases by <10% but about 620/1689 (37%) additional events can be averted. A 20% threshold decreases the net number of patients recommended for treatment by about 10% but averts 204/1689 (12%) more disease events than current treatment. CONCLUSIONS: Implementing treatment guidelines that use treatment thresholds based on absolute risk could significantly improve the efficiency of drug treatment to lower blood pressure in primary care.

Adult↗
PubMed2000

Comparison of clinical outcome in black and white women treated with radiotherapy for cervical carcinoma.

BACKGROUND: The purpose of this investigation was to evaluate the significance of race on the cancer-specific survival outcome of women treated with radiotherapy for advanced-stage cancer of the uterine cervix. METHODS: Data from 922 women with cancer of the uterine cervix treated with radiotherapy were reviewed. Patients were treated at the Mallinckrodt Institute of Radiology from 1959 through 1993. There were 576 women with clinical Stage II cancer and 346 women with clinical Stage III cancer. All women were treated following standard medical care treatment policies according to the stage of their disease. Data were analyzed by race and known treatment-related prognostic factors. Overall and cancer-specific survivals were evaluated. RESULTS: The 5-year cancer-specific survivals for clinical Stage II were 66 and 61% (P = 0.56) for white and black women, respectively. The corresponding 5-year overall survivals were 60 and 51% (P = 0.02). The 5-year cancer-specific survivals for clinical Stage III were 38 and 47% (P = 0.34) for white and black women, respectively. The associated 5-year overall survivals were 32 and 40% (P = 0.37). No differences in treatment-related factors were identified. CONCLUSIONS: In a cancer treatment system where black and white women with clinical Stage II and III cancer of the uterine cervix are all treated with radiotherapy alone, following standard treatment policies, no significant difference in cancer-specific survival outcome is shown. Multivariate analysis revealed that clinical stage and overall treatment time are significant variables affecting the control of tumor by radiotherapy. Overall survivals for the two racial groups are different and may be related to other non-cancer-related factors.

Black People↗
PubMed2000

Clinical value of real-time tertiary fetal ultrasound consultation by telemedicine: preliminary evaluation.

Congenital fetal abnormalities are major causes of perinatal mortality and morbidity. The performance of ultrasound in the diagnosis and assessment of fetal anomalies varies enormously between tertiary referral centers and general units. Telemedicine offers a chance for tertiary realtime ultrasound consultations using standard telephone lines for remote sites. Preliminary investigations by our group have shown that real-time transmission of fetal ultrasound images over long distances via telephone (integrated systems digital network [ISDN]) lines is technically feasible. A live link of up to 2 Mb/s was established between Mater Mothers Hospital in Brisbane and Kirwan Hospital for Women in Townsville, which are 1,500 km apart. The objective of the current study was to evaluate the clinical value of a tertiary teleultrasound consultation service. Patients requiring tertiary ultrasound consultations were recruited from North Queensland. Clinicians from the referral site established an initial diagnosis and management plan. Using standard ISDN lines, the real-time ultrasound images were transmitted to the maternal fetal medicine subspecialists in Brisbane. The ultrasound examination was completed under the direction of the subspecialist. The subspecialist explained the findings to the patient at the end of the session, and discussed the diagnosis and management plans with the clinicians involved. Any diagnosis and management variations were classified into minor and major upon agreement by the two teams of clinicians involved. The clinicians and patients in Townsville rated the value of the consultation, and the subspecialists rated the confidence of their diagnoses on five-point scales. Pregnancy outcomes were obtained and the data analyzed. Over a 3-month period, 24 teleultrasound consultations were carried out. The indications for referral were: assessment of growth restriction/fetal wellbeing in the third trimester (6); detailed assessment for high-risk patients (5); evaluation of markers for anomalies (5); isolated fetal anomalies (1); and complex fetal problems such as twin/twin transfusion, multiple anomalies, etc. (7). Overall, the consultations resulted in some modifications to the clinical diagnosis in 45.8% of the cases, and modifications to the management plan in 33.3% of the cases (about half of which were minor variations). The clinicians rated the teleconsultations highly (mean rating 4.7, SD 0.44). The patients also rated the consultations highly, and were comfortable that their privacy and confidentiality were maintained during the consultation. The subspecialists were confident in making their diagnoses by telemedicine (mean score for confidence 4.2, SD 0.43). All the pregnancies have now been completed, with all antenatal diagnoses confirmed to be correct postnatally. Tertiary real-time ultrasound consultation by telemedicine is not only technically feasible, it is welcomed by the clinicians and patients involved. It also contributes to diagnostic and management differences. Larger scale clinical trials are needed to evaluate the true benefits and costs involved. The social benefits in bridging the healthcare gap between the country and the city, and in enabling patients in remote areas to stay close to their family under times of stress is well recognized by all involved.

Congenital Abnormalities↗
PubMed2000

Factors affecting morbidity, mortality, and survival in patients undergoing Ivor Lewis esophagogastrectomy.

OBJECTIVES: To examine the safety of transthoracic esophagogastrectomy (TTE) in a multidisciplinary cancer center and to determine which clinical parameters influenced survival and the rates of death and complications. SUMMARY BACKGROUND DATA: Although the incidence of cancer at the gastroesophageal junction has been rising rapidly in the United States, controversy still exists about the safety of surgical procedures designed to remove the distal esophagus and proximal stomach. Alternatives to TTE have been proposed because of the reportedly high rates of death and complications associated with the procedure. METHODS: Data from 143 patients treated by TTE by one author (1989-1999) were entered into a computerized database. Preoperative clinical parameters were tested for effect on death, complications, and survival. RESULTS: The patient population consisted of 127 men and 16 women. One hundred twenty-one patients had a history of tobacco abuse, and 118 reported the regular ingestion of alcohol. One hundred fifteen patients had adenocarcinoma, 16 had squamous cell cancer, 6 had another form of esophageal tumor, and 6 had high-grade dysplasia associated with Barrett epithelia. Fifty-six patients had adenocarcinomas arising in Barrett epithelium. Twenty-eight patients were treated with neoadjuvant chemoradiation before surgery. Three patients died within 30 days of surgery (mortality rate 2.1%). Five patients (3.5%) had a documented anastomotic leak; three died). Overall, 42 patients had complications (29%). Twenty-six had pulmonary complications (19%). The mean length of stay in the intensive care unit was 3.35 days; the mean hospital length of stay was 13.54 days. The overall 3-year survival rate was 29.6%. CONCLUSIONS: A high ASA score and the development of complications predicted an increased length of stay. The presence of diabetes predicted the development of complication and an increased length of stay. None of the other parameters tested predicted perioperative death or complications. Only disease stage, diabetes, and blood transfusion affected overall survival. From these results with a large series of patients with gastroesophageal junction cancers, TTE can be performed with a low death rate (2.1%), a low leak rate (3. 5%), and an acceptable complication rate (29%).

Adenocarcinoma↗
PubMed2000

Emergency department discharge of patients with a negative cranial computed tomography scan after minimal head injury.

OBJECTIVE: To determine the negative predictive value of cranial computed tomography (CT) scanning in a prospective series of patients and whether hospital admission for observation is mandatory after a negative diagnostic evaluation after minimal head injury (MHI). SUMMARY BACKGROUND DATA: Hospital admission for observation is a current standard of practice for patients who have sustained MHI, despite having undergone diagnostic studies that exclude the presence of an intracranial injury. The reasons for this practice are multifactorial and include the perceived false-negative rate of all standard diagnostic tests, the belief that admission will allow prompt diagnosis of occult injuries, and medicolegal considerations about the risk of early discharge. METHODS: In a prospective, multiinstitutional study during a 22-month period at four level I trauma centers, all patients with MHI were evaluated using the following protocol: a standardized physical and neurologic examination in the emergency department, cranial CT scanning, and then admission for observation. MHI was defined as either a documented loss of consciousness or evidence of posttraumatic amnesia and an emergency department Glasgow Coma Scale score of 14 or 15. Outcomes were measured at 20 hours and at discharge and included clinical deterioration, need for craniotomy, and death. RESULTS: Two thousand one hundred fifty-two consecutive patients fulfilled the study protocol. The CT was interpreted as negative for intracranial injury in 1,788, positive in 217, and equivocal in 119. Five patients with CT scans initially interpreted as negative required intervention. There was one craniotomy in a patient whose CT scan was initially interpreted as negative. This patient had facial fractures that required surgical intervention and elevation of depressed intracranial fracture fragments. The negative predictive power of a cranial CT scan based on the preliminary reading of the CT scan and defined by the subsequent need for neurosurgical intervention in the population fully satisfying the protocol was 99.70%. CONCLUSIONS: Patients with a cranial CT scan, obtained on a helical CT scanner, that shows no intracerebral injury and who do not have other body system injuries or a persistence of any neurologic finding can be safely discharged from the emergency department without a period of either inpatient or outpatient observation. Implementation of this practice could result in a potential decrease of more than 500,000 hospital admissions annually.

Adolescent↗
PubMed2000

Inhibition of neutrophil apoptosis after severe trauma is NFkappabeta dependent.

BACKGROUND: Systemic inflammation may inhibit neutrophil (PMN) apoptosis and promote multiple organ dysfunction syndrome. We hypothesize that severe trauma causes dysregulation of PMN apoptosis. METHODS: Neutrophils were isolated from trauma patients (24-72 hours after injury; n = 16) and controls (healthy volunteers) and incubated for 18 hours. In separate experiments, control cells were treated +/- the nuclear factor kappa beta (NFkappabeta) inhibitor pyrrolidinithiocarbamate then incubated with 25% patient or control plasma. Apoptosis was quantified by enzyme-linked immunosorbent assay for histone-associated DNA and annexin V fluorescence-activated cell sorter. NFkappabeta activation was determined by Western blot for phosphorylated I kappabeta. RESULTS: Apoptosis was inhibited in trauma patient PMN. Neutrophil apoptosis correlated with multiple organ dysfunction syndrome score, Acute Physiology and Chronic Health Evaluation II, and platelet count. Patient plasma inhibited apoptosis and induced phosphorylation of I kappabeta in control cells. Inhibition of PMN apoptosis by patient plasma was blocked by pretreatment with pyrrolidinithiocarbamate. CONCLUSION: NFkappabeta-dependent inhibition of neutrophil apoptosis occurs after trauma. Early inhibition of PMN apoptosis is dependent on the magnitude of injury.

Apoptosis↗
PubMed2000

Tenure in supportive housing for homeless persons with severe mental illness.

OBJECTIVE: The study examined the long-term effectiveness of approaches to housing homeless persons with serious mental illness. METHODS: A total of 2,937 persons placed in high-, moderate, -and low-intensity housing were followed for up to five years. Intensity reflected on the amount of structure and degree of clients' independence. The outcome variable was tenure in housing. Cox stepwise regression was used to calculate risk ratios of becoming discontinuously housed. RESULTS: Thirty percent of the sample were initially placed in high-intensity settings, 18 percent in moderate-intensity settings, and 52 percent in low-intensity settings. Those in high-intensity settings tended to be younger, to be referred from hospitals, and to have a history or diagnosis of substance abuse. Individuals in moderate-intensity settings were more likely to be female and were least likely to have substance abuse problems. Individuals in low-intensity settings were more likely to be referred by municipal shelters and to have lived in municipal shelters for four or more months. After one, two, and five years, 75 percent, 64 percent, and 50 percent, respectively, of the sample were continuously housed. Older age was associated with longer tenure, and having a history of substance abuse was associated with shorter tenure. Individuals referred from a state psychiatric center had a greater risk of shorter tenure than other types of referrals. CONCLUSIONS: Results show that homeless persons with serious mental illness can remain in stable housing for periods of up to five years, supporting the premise that long-term residential stability can be enhanced by providing access to safe and affordable supportive housing.

Adult↗
PubMed2000

Clinical evaluation of the non-invasive cardiac output (NICO) monitor in the intensive care unit.

The Non-invasive Cardiac Output (NICO) monitor (Novametrix Medical Systems Inc., Wallingford, CT, U.S.A.) utilizes a minimally-invasive partial rebreathing method to determine cardiac output by means of a differential form of the Fick equation. We evaluated the NICO monitor by comparing its output to paired measurements obtained by the standard thermodilution (TD) technique in patients who had recently undergone cardiac surgery. Forty-two paired measurements were carried out in 12 patients. The correlation between the two methods was moderate with a correlation coefficient of 0.691. Repeated measures ANOVA showed that TD measures of cardiac output were significantly higher than those obtained by the NICO monitor (P = 0.0003). Comparison of the two techniques using the method described by Bland and Altman showed decreased correlation at higher values of cardiac output. We conclude that the NICO monitor may well have a place in intensive care monitoring, provided patients are not breathing spontaneously and are able to tolerate a 4 mmHg rise in PaCO2. It is less suitable for use in patients with a high cardiac output state.

Analysis of Variance↗
PubMed2000

Quantitative ultrasound: an indicator of osteoporosis in perimenopausal women.

The key to effective treatment of osteoporosis is early detection; however, the disease in perimenopausal women is frequently undiagnosed. To assess the utility of quantitative ultrasound (QUS) at the calcaneus in perimenopausal women, broadband ultrasound attenuation (BUA); speed of sound (SOS); quantitative ultra-sound index (QUI), an algorithm of BUA and SOS; and bone mineral density by dual X-ray absorptiometry (DXA) of the posteroanteiror spine, femoral neck, and total hip were measured in 420 women (ages 45-55 yr). Thirty (7.1%) of the women were found to be osteoporotic by DXA. All QUS measurements were predictors of osteoporosis. QUS values did not differ between postmenopausal women on estrogen replacement therapy (ERT) and those not on ERT. There were no differences among BUA, SOS, and QUI in the area under the receiver operating characteristic curves for predicting osteoporotic vs nonosteoporotic cases. At a QUI of 89, ultrasound had an 80% sensitivity for the diagnosis of osteoporosis, but only a 74% specificity. The use of QUS in perimenopausal women will facilitate the identification of women with osteoporosis. However, the high false-positive rate (26%) limits the utility of QUS as the sole diagnostic technique on which to base therapeutic decisions. Nevertheless, low QUS measurements may provide a means for targeting those women who would benefit most from more extensive evaluation (e. g., DXA).

Bone Density↗
PubMed2000

Nodal metastases with unknown primary--an unusual presentation of carcinoid tumor.

Carcinoid tumors arise from neuroendocrine cells and produce their symptoms mainly through secreted amines, and by a local desmoplastic response. The critical issue in the management of advanced carcinoid tumors is preservation of quality of life and symptomatic relief. This is because of the characteristic indolent growth which makes survival a secondary consideration, and the relative rarity of the condition. Although systemic therapy has been shown to improve symptoms, true survival benefit has not been established. We present a case of carcinoid tumor that has metastasized to mesenteric nodes, and probably other locations, with an occult primary site. The patient remains completely asymptomatic and continues to enjoy a normal lifestyle. No references were found in the literature concerning the management of asymptomatic, but metastatic carcinoids. This case thus constitutes a unique situation in which further treatment may not be beneficial and may even be harmful. Nevertheless, additional treatment is an important consideration in view of the known poor survival of those with metastatic disease versus localized, resectable tumor. However, the concept of medical therapy to improve survival in an asymptomatic individual, though theoretically attractive, has little precedence. In this article we have tried to address the therapeutic dilemma posed by this unusual clinical scenario.

Aged↗
PubMed1999

A phase I evaluation of multitargeted antifolate (MTA, LY231514), administered every 21 days, utilizing the modified continual reassessment method for dose escalation.

PURPOSE: To determine toxicities, maximally tolerated dose (MTD), pharmacokinetic profile, and potential antitumor activity of MTA, a novel antifolate compound which inhibits the enzymes thymidylate synthase (TS), glycinamide ribonucleotide formyltransferase (GARFT), and dihydrofolate reductase (DHFR). METHODS: Patients with advanced solid tumors were given MTA intravenously over 10 min every 21 days. Dose escalation was based on the modified continual reassessment method (MCRM), with one patient treated at each minimally toxic dose level. Pharmacokinetic studies were performed in all patients. RESULTS: A total of 37 patients (27 males, 10 females, median age 59 years, median performance status 90%) were treated with 132 courses at nine dose levels, ranging from 50 to 700 mg/m(2). The MTD of MTA was 600 mg/m(2), with neutropenia and thrombocytopenia, and cumulative fatigue as the dose-limiting toxicities. Hematologic toxicity correlated with renal function and mild reversible renal dysfunction was observed in multiple patients. Other nonhematologic toxicities observed included mild to moderate fatigue, anorexia, nausea, diarrhea, mucositis, rash, and reversible hepatic transaminase elevations. Three patients expired due to drug-related complications. Pharmacokinetic analysis during the first course of treatment at the 600 mg/m(2) dose level demonstrated a mean harmonic half-life, maximum plasma concentration (Cpmax), clearance (CL), area under the curve (AUC), and apparent volume of distribution at steady state (Vdss) of 3.08 h, 137 microg/ml, 40.0 ml/min per m(2), 266 microg. h/ml, and 7.0 l/m(2), respectively. An average of 78% of the compound was excreted unchanged in the urine. Partial responses were achieved in two patients with advanced pancreatic cancer and in two patients with advanced colorectal cancer. Minor responses were obtained in six patients with advanced colorectal cancer. CONCLUSIONS: The MTD and dose for phase II clinical trials of MTA when administered intravenously over 10 min every 21 days was 600 mg/m(2). MTA is a promising new anticancer agent.

Adult↗
PubMed1999

Minimum requirements for remote realtime fetal tele-ultrasound consultation.

We studied the transmission bandwidth required for accurate diagnoses when performing realtime fetal tele-ultrasound consultations. The study was divided into three phases. In phase I, three experienced clinicians evaluated the quality of ultrasound images transmitted at various bandwidths (internally looped back within Brisbane) using eight commercially available codecs at random. The two codecs that performed best proceeded to phase 2, in which a realtime video-link of up to 2 Mbit/s was set up between Brisbane and Townsville (1,500 km apart). Testing with a standard video-tape was performed at seven different bandwidths selected at random, with four clinicians (who were blinded to the equipment and bandwidths used). The optimum line rates for transmission were determined, and testing was then performed using these line rates for fetuses with various anomalies (phase 3). The results showed significant differences in performance according to bandwidths used, but not according to observers. Bandwidths were grouped into three levels. At level I (256 kbit/s) the performance was significantly worse than at level II (384, 512 or 768 kbit/s), which was in turn worse than that at level III (1, 1.5 or 2 Mbit/s). However, within each level, performance at one bandwidth was not significantly different from that at the others. The most cost-effective transmission rates therefore appeared to be 384 kbit/s and 1 Mbit/s. Further testing with fetuses affected by various anomalies confirmed that the majority could be diagnosed using a 384 kbit/s link, with slight improvement in evaluation when the bandwidth was increased to 1 Mbit/s.

Analysis of Variance↗
PubMed1999

Patient monitor for small creatures.

A prototype patient monitor has been developed for monitoring various physiological parameters during surgery. The system displays ECG, Temperature and CO2 as well as the envelope of heart sounds in real time. Subsequent clinical studies will involve ferrets.

Animals↗
PubMed1999

Home care: addressing the needs of people living with AIDS and their caregivers.

Home care has become an important community resource for the care of people living with AIDS (PLWA). Another important resource to maintaining PLWAs in the home environment is the availability of informal caregivers who are willing to provide support and assistance in the home setting. Because of the stressful nature of AIDS care, home care nurses must anticipate and address the needs of both PLWAs and their caregivers.

Caregivers↗