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Biomedical subjects

H M Hudson

Publications and source records attributed to H M Hudson.

16 recordsLinked to original sources

Combining components of quality of life to increase precision and evaluate trade-offs.

Methods for combining measurements on multiple dimensions of quality of life can reduce the dimensionality of the data and increase the precision of estimation. When the dimensions are weighted according to their importance to patients, the resulting estimate is clinically useful and provides a step towards a true utility estimate. We derive two such weighting methods using linear regression on a measure of overall quality of life and demonstrate their usefulness in the analysis of quality of life data from two clinical trials of cancer therapies. Procedures for transforming the quality of life measures into utility measures are demonstrated.

Antineoplastic Combined Chemotherapy Protocols↗

The interdependency of protein-energy malnutrition, aging, and dysphagia.

Advancing age is increasingly associated with confounding chronic and acute ailments, predisposing elderly individuals to conditions such as malnutrition and swallowing dysfunction. This enhanced susceptibility to malnutrition and dysphagia in this aging demographic lends itself to exacerbating, disabling conditions that may result in increased morbidity and mortality in the event of an aspiration episode. Early identification of substandard nutritional status and subsequent interventiion in the elderly dysphagic population may circumvent the deleterious effects of malnutrition.

Acute Disease↗

Rheological and physical properties of derivitized whey protein isolate powders.

Pregelatinized starch is employed in many food applications due to the instantaneous nature of thickening and stability imparted by modification. Proteins, however, have been excluded as a viscosifying agent due to requisite thermal treatments required to create structure. Whey protein isolate gels were produced while manipulating heating time, pH, and mineral type/content, producing a variety of gel types/networks. Gels were frozen, freeze-dried, and ground into a powder. Once reconstituted in deionized water, gel powders were evaluated based on solubility studies, rotational viscometry, and electrophoresis. The protein powder exhibiting the largest apparent viscosity, highest degree of hydrolysis, and greatest solubility was selected for pH and temperature stability analyses and small amplitude oscillatory rheology. This processing technique manipulates WPI into a product capable of forming cold-set weak gel structures suitable for thickening over a wide range of temperature and pH food systems.

Milk Proteins↗

A clinical perspective of accelerated statistical reconstruction.

Although the potential benefits of maximum likelihood reconstruction have been recognised for many years, the technique has only recently found widespread popularity in clinical practice. Factors which have contributed to the wider acceptance include improved models for the emission process, better understanding of the properties of the algorithm and, not least, the practicality of application with the development of acceleration schemes and the improved speed of computers. The objective in this article is to present a framework for applying maximum likelihood reconstruction for a wide range of clinically based problems. The article draws particularly on the experience of the three authors in applying an acceleration scheme involving use of ordered subsets to a range of applications. The potential advantages of statistical reconstruction techniques include: (a) the ability to better model the emission and detection process, in order to make the reconstruction converge to a quantitative image, (b) the inclusion of a statistical noise model which results in better noise characteristics, and (c) the possibility to incorporate prior knowledge about the distribution being imaged. The great flexibility in adapting the reconstruction for a specific model results in these techniques having wide applicability to problems in clinical nuclear medicine.

Algorithms↗

Fisher's method of scoring in statistical image reconstruction: comparison of Jacobi and Gauss-Seidel iterative schemes.

Many algorithms for medical image reconstruction adopt versions of the expectation-maximization (EM) algorithm. In this approach, parameter estimates are obtained which maximize a complete data likelihood or penalized likelihood, in each iteration. Implicitly (and sometimes explicitly) penalized algorithms require smoothing of the current reconstruction in the image domain as part of their iteration scheme. In this paper, we discuss alternatives to EM which adapt Fisher's method of scoring (FS) and other methods for direct maximization of the incomplete data likelihood. Jacobi and Gauss-Seidel methods for non-linear optimization provide efficient algorithms applying FS in tomography. One approach uses smoothed projection data in its iterations. We investigate the convergence of Jacobi and Gauss-Seidel algorithms with clinical tomographic projection data.

Algorithms↗

Vesico-diverticular fistula: a rare complication of Meckel's diverticulum.

Enterovesical fistulas usually result from diverticulitis, Crohn's disease, or colorectal cancer. A perforated Meckel's diverticulum can also result in an vesico-diverticulum fistula, as noted in three previously reported cases. In all three cases, bladder or bowel disease was associated with the fistula. Herein, the authors describe a previously healthy, 23-year-old man who presented with an enterovesical fistula. Exploratory laparotomy revealed a vesico-diverticular fistula resulting from a perforated Meckel's diverticulum. Pathologic examination revealed that the diverticulum did not contain ectopic gastric or pancreatic tissue and that the perforation was secondary to an enterolith. The patient underwent a diverticulectomy and had an uneventful postoperative course. Unlike any of the three previously reported cases, the authors' patient had no coexisting bowel or bladder disease occurring with his vesico-diverticular fistula. To the authors' knowledge, this is only the third reported case of a vesico-diverticular fistula resulting from a perforated Meckel's diverticulum that did not contain ectopic tissue. It represents the first case where the perforation was secondary to an enterolith.

Adult↗

Intraaortic balloon pump entrapment.

Catheter entrapment is a rare complication of intraaortic balloon counterpulsation caused by the formation of hard blood clot within the balloon itself. We present two cases of intraaortic balloon pump entrapment seen at the University Hospital, Boston. This phenomenon usually presents as a limb threatening vascular emergency. The entrapped catheter becomes stuck fast within the iliac system during withdrawal of the device, occluding arterial flow at that level. The etiology of this phenomenon, and a proposed management scheme is discussed. Preoperative radiographic determination of the level of entrapment may be necessary. We feel it is necessary to control the abdominal aorta prior to removal of an entrapped intraaortic balloon.

Aged↗

The management of traumatic aortic tear in the multiply-injured patient.

Patients with traumatic aortic tears and severe life-threatening associated injuries require early and expeditious evaluation and treatment in order to improve survival. Diagnostic and treatment priorities, however, are not clearly established in this subset of patients. The purpose of this retrospective analysis was to help identify successful diagnostic and treatment priorities in this group of patients. Between 1979-1989 the medical records of all patients sustaining blunt chest trauma resulting in a traumatic aortic tear were reviewed. There were 11 patients with multiple injuries and this diagnosis was treated at Boston University Medical Center. Five patients had diagnostic peritoneal lavage or an exploratory laparotomy prior to a thoracotomy. Four patients had only a thoracotomy. Two patients in this series had a thoracotomy prior to treatment of suspected intraabdominal injuries. One of these two patients died. Our overall survival rate was 82%. This series suggests that the management sequence in patients with coexistent injuries should include treatment of severe associated injuries prior to treatment of the aortic injury and that initial treatment of traumatic aortic tears is appropriate if there is no evidence of severe life-threatening trauma.

Adult↗

Do symptoms of gastric ulcer become less frequent with time?

It has been claimed that gastric and duodenal ulcer (GU and DU) symptoms decrease in frequency with time, indicating 'burn out' of ulcer. The present study was undertaken to investigate further this phenomenon in GU. The prevalence of symptom experience during 1 year was examined in 447 medically treated patients with GU diagnosed 2-20 or more years previously. When ulcer history length was measured from either first symptom onset or first ulcer diagnosis, reporting of symptoms did not become less frequent as history length increased. This remained true after adjustment for GU location, sex, age, smoking, and analgesic and non-steroidal anti-inflammatory drug ingestion. It is concluded that GU symptoms do not decrease in frequency with time.

Duodenal Ulcer↗

Evaluation of trends in middle ear disease among Australian aborigines.

The Gompertz hazard model of age incidence of disease is applied to estimation of disease trends in a community. The trend estimate is based on proportions of individuals with disease experience in different age groups at one point of time, and may be used as an indicator of the changing health of a community. A major application of the method is to ear health data collected among Australian aboriginal children by the National Trachoma and Eye Health Program of the Royal Australian College of Ophthalmologists.

Adolescent↗

Factors relevant to the prognosis of chronic duodenal ulcer.

The aim of the study was to define the effects of sex, age, smoking, alcohol, analgesic ingestion, and treatment method whereby healing was initially induced on the prognosis of patients with a chronic duodenal ulcer (DU). 122 patients were assessed 1 year after the endoscopic demonstration of a DU. Two outcome variables for this 1-year period were studied - freedom from symptoms, and proven recurrence of the DU. Additionally, the outcome groups were compared to a community control population as regards the exposure variables. The results of the study indicate that each increase in smoking by 10 cigarettes daily increased the risk of DU recurrence within 1 year by 40%. Comparisons between patients and community controls revealed that smoking was significantly associated with DU and this association was present whether the ulcer was in exacerbation or in remission.

Age Factors↗

An environmental and demographic analysis of otitis media in rural Australian aborigines.

Otitis media (OM) and tympanic scarring prevalence among rural Australian Aboriginal children is examined in relation to age, sex, community size and 34 environmental variables pertaining to living conditions and climate. The environmental variables are reduced to a smaller set of underlying factors via Principal Components Analysis. With age and sex standardized, a multivariate analysis is performed. OM prevalence is profoundly age-dependent, and is related negatively to community socioeconomic status and the presence of swimming facilities. Scarring prevalence is shown to be subject to substantial inter-observer variation, and with the appropriate adjustment manifests an inverse relationship with winter warmth. The data were collected under the National Trachoma and Eye Health Program.

Adolescent↗

Laparoscopic cholecystectomy in a renal transplant recipient.

Laparoscopic cholecystectomy is a viable and safe alternative for the treatment of symptomatic gallstones and biliary colic. As surgeons gain more experience with this procedure, contraindications become fewer and indications increase. Well-documented advantages of this approach include less patient discomfort, less surgical scarring, and earlier return to employment. Not previously discussed in the literature, however, are the additional advantages that this procedure holds for a specific subset of patients--namely, those patients that have undergone successful organ transplantation and are receiving immunosuppressive drugs. We report a case of a laparoscopic cholecystectomy in such a patient.

Cholecystectomy↗

Mortality among Vietnam veterans compared with non-veterans and the Australian population.

A retrospective cohort study of mortality was conducted to assess whether the military service of young Australian men in Vietnam has influenced their overall death rates, or those from specific causes. The study was of all national servicemen who were conscripted during the conflict and served in the Army for at least 12 months. Of these, 19 205 served in Vietnam (veterans) while 25 677 served only in Australia (non-veterans). These men were traced from the end of their national service (between 1966 and 1973) until the beginning of 1982. For most causes of death, the observed number of deaths of veterans and of non-veterans was less than expected from Australian population death rates, and for no cause was there a statistically significant excess of deaths compared with that of the Australian population. Similarly, when veterans were compared with non-veterans, there was no statistically significant difference in deaths for all causes combined, for diseases of the circulatory system, for deaths in motor vehicle accidents, for suicide and for all external causes after adjustment for the different subsequent death rates of men who had served in different Army corps. All seven deaths from diseases of the digestive system were of veterans. There was no excess of deaths among veterans from cancer or from atypical causes of death in this group of young men. Three-quarters of deaths of both veterans and non-veterans were from external causes, often involving motor vehicle accidents.

Adult↗