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Biomedical subjects

R Fink

Publications and source records attributed to R Fink.

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

Analysis of optimal design configurations for a multiple disk centrifugal blood pump.

A multiple disk centrifugal pump was analyzed as a blood pump for use in cardiac assistance or as a bridge to transplant device. The original configuration consisted of 6 parallel disks with 0.016 inch spacing between disks. This pump suffered from a degradation of flow with increasing afterload. A study was conducted to analyze flow performance as a function of afterload, preload, and motor speed. Configurations were examined including 4, 5, and 6 disks each with spacings of 0.15, 0.20, and 0.25 inches. Flow rates were examined for variations in afterload from 60-130 mm Hg, in preload from 0-20 mm Hg and for motor speeds of 1,250, 1,500, and 1,750 rpm. Analyses of afterload effects were intended to determine those configurations that produced less flow degradation with increasing afterload. Analyses of motor speed effects were intended to determine any configurations that produced greater flow increases with increasing motor speed. A hemolysis study was also performed. Both plasma free hemoglobin and the index of hemolysis were compared to data reported for other centrifugal blood flow devices. Results indicated that a 5 disk configuration with a 0.15 inch spacing produced optimal flow results with minimal degradation at higher afterloads. No optimal configuration based upon motor speed was indicated. Preload effects on pump performance were minimal. Hemolysis results indicated minimal blood damage with levels below those of many other centrifugal blood pump designs.

Animals↗
PubMed1998

Localized fibrous nodular mesothelioma of the pelvis.

We present a case of localized fibrous nodular mesothelioma of the pelvis. There is one previously reported case of this uncommon pelvic tumor. We review and discuss the diagnostic and pathologic findings and relevant literature.

Adult↗
PubMed1998

Approach to the seriously ill or terminal cancer patient who has a poor appetite.

Lack of appetite is a frequent complaint of patients with serious illness and is particularly bothersome to cancer patients and their families. As patients enter the terminal phase of their illness, poor appetite becomes an even more distressing problem that affects not only physical symptoms but also functional, social, and psychological aspects of a patient's quality of life. Family and friends frequently relate a patient's poor appetite as a specific contributor to their perception of lack of health. We have investigated a number of ways to approach the seriously ill or terminal cancer patient who has a poor appetite with education, dietary changes (including the use of smaller, more frequent meals but still providing the patient's favorite foods), and at times dietary supplements. Appetite stimulants such as Megace Oral Suspension (Bristol-Myers Squibb, Princeton, NJ) are used not so much for facilitating weight gain as for adding to the quality of life, including social and psychological well-being, by allowing patients to enjoy foods they like in a social family setting.

Appetite Stimulants↗
PubMed1998

HMO data systems in population studies of access to care.

OBJECTIVES: A review of the current status of HMO data sets and their applicability to population studies of access to care. DATA SOURCES: Publications and reports based on research among different models of HMOs; reviews of HMO quality of care by national organizations; and HMO industry profiles. STUDY DESIGN: Design was a literature review of the content of HMO data sets: completeness of reporting, processing, and reporting. DATA COLLECTION: Publications and publicly available reports were reviewed. PRINCIPAL FINDINGS: Most HMOs are able to aggregate the number of services provided but demonstrate little ability to provide patient profiles. While their content is limited, HMO data sets are significant improvements over indemnity plan data, and where available, their accuracy in measuring health services utilization is superior to that of surveys. There are important differences among HMO delivery systems in their ability to provide useful data for population studies. CONCLUSIONS: A valuable resource, HMO data are limited by their content and the relative inaccessibility to IPAC-HMO information. This could be improved through new financial and technical support to HMOs interested in research.

Community Health Planning↗
PubMed1997

Can gas exchange measurements be used for calculation of nutrient oxidation in mink (Mustela vison) exposed to short-term changes in energy supply?

Nutrient oxidation was calculated from gas exchange measurements for 6 control and 12 flush fed female mink, measured in six consecutive, one week periods. The energy supply to controls and flushed animals in periods 1 and 6 was ca 850 kJ ME/day, and during restriction and flush feeding, it was ca 450 kg ME/day and ca 1300 kJ ME/day, respectively. Over the total experimental period the energy intake was similar in both groups, but it differed significantly between periods in the flushed group. Protein, fat, and carbohydrate oxidation averaged 39, 38, and 21%, of the total heat production (HP), respectively in the control group. During restriction, protein oxidation was ca 35% of HP in flushed animals, then increasing to 55% of HP during the first period of refeeding. High values for fat oxidation were recorded during restriction because of fat mobilization and values were low when feed supply was ample. It was concluded that the calculation method was a good indicative method, but some short-comings were discussed.

Animals↗
PubMed1997

Evaluation of awakening and recovery characteristics following anaesthesia with nitrous oxide and halothane fentanyl or both for brief outpatient procedures in infants.

This study compared recovery characteristics and postoperative ventilatory function when halothane, fentanyl or combination of halothane and fentanyl in addition to N2O were used for intraoperative anaesthesia in term infants undergoing hernia repair as outpatients. Sixty-six full term ASA PS I infants ages 1-12 months were studied. All received inhalation induction with N2O, O2 and halothane, followed by intravenous atropine and atracurium, tracheal intubation, and controlled ventilation. For anaesthesia maintenance, patients were randomized into one of three groups. Group I received 70% N2O, 30% O2 and halothane. Group II received 70% N2O, 30% O2, halothane and 2 micrograms.kg-1 fentanyl. Group III received 70% N2O, 30% O2 and 10 micrograms.kg-1 fentanyl. Awakening times were similar in all three groups, however, Group I patients had significantly shorter recovery and discharge times than those of Group II and III. None of the patients experienced postoperative apnoea or periodic breathing. One patient in Group III experienced two brief episodes of bradycardia not associated with apnoea or arterial desaturation (SpO2 > 90% for greater than 30 s). Decreased SpO2 occurred less frequently in Group I (5.9%) compared to Group II (22.7%) and Group III (19.0%) patients, however, the group differences were not significant. Transcutaneous CO2 (TcCO2) values were not statistically different among the three groups. Pain scores were initially lower in Groups II and III, but at 120 min the differences were not significant. Postoperative apnoea was not observed in this study. SpO2 < 90% and TcCO2 > 9 kPa (70 mmHg) was more common in infants receiving 2 and 10 micrograms.kg-1 fentanyl than in infants receiving halothane and nitrous oxide anaesthesia. Infants < 3 months old did not have a higher incidence of SpO2 < 90% or significantly higher TcCO2 values when compared to infants > 3 months old. Fentanyl in doses used in this study did not prolong awakening time but did prolong recovery and discharge times in outpatient infants.

Ambulatory Surgical Procedures↗
PubMed1996

Anal pathology in patients with Crohn's disease.

BACKGROUND: A distinctive feature of patients suffering from Crohn's disease is a predisposition to develop a variety of anal complications. The aetiology of such conditions is unclear, and the reported incidence of anal involvement in Crohn's disease varies party due to the various criteria used for classification. This study aims to review the management of patients with symptomatic anal pathology associated with Crohn's disease at St Vincent's Hospital, Melbourne. METHODS: A database of 306 patients with Crohn's disease referred to the department between January 1978 and October 1994 was reviewed to identify those patients with symptomatic anal disease. The anal pathology was recorded and classified. Demographic data and the clinical and surgery history of the patient were recorded. RESULTS: Of the 306 patients with Crohn's disease, 129 (42.4%) were identified as having symptomatic anal pathology. Patients were likely to present with anal symptoms after they had been diagnosed as having intestinal Crohn's disease (46.1%). The commonest presentations were perianal abscess (29.5%), anal fissure (27.6%), and low anal fistula (26.7%). A minority of patients presented with high/complex anal fistulae (3.8%), or recto-vaginal fistulae (5.2%). Five per cent of patients had Crohn's disease localized to the anal area. The pattern of intestinal disease in the remaining patients was small bowel 21.1%. small bowel and colon 31.9%, and colon 43.0%. A total of 244 local anal and surgical procedures were performed on these patients; the commonest of these were drainage of an abscess (38.5%), examination under anaesthetic (29.1%), and laying open of a low anal fistula (22.5%). Following surgical treatment, the recurrence rate for perianal abscesses was 13%, and for low anal fistulae 6%. CONCLUSIONS: The majority of patients with Crohn's disease who develop anal pathology have an excellent prognosis. A minority of patients develop complex anal complex anal fistulae and these remain a therapeutic challenge.

Adult↗
PubMed1995

Effect of activated oxygen species in human lymphocytes.

The cytogenetic effectiveness of activated oxygen species (AOS) generated by the superoxide forming xanthine-xanthine oxidase (X/XO) system was studied in human lymphocyte cultures. The observed chromosome damage was exclusively of the chromatid type. In the experiments a clear dependence of aberration induction on XO concentration and exposure time could be demonstrated. While using anti-AOS agents, the H2O2 antagonist catalase and the hydroxyl radical scavenger formate reduced X/XO induced chromosome damage whereas superoxide dismutase (SOD) did not. In the presence of SOD, aberration frequency was even enhanced. The results indicate that the chromosome damage is caused indirectly via H2O2 formation from spontaneous dismutation of superoxide, whereas H2O2 might be reduced intracellularly giving rise to the highly reactive hydroxyl radical. This effect might be enhanced by SOD, possibly by raising the intracellular amount of easily membrane passing H2O2. Thus, referring to chromosome aberrations, SOD, which is generally reported to protect from AOS, is capable of increasing oxygen mediated biological damage. This observation might be explained by the involvement of DNA associated transition metal, like iron or copper ions, in reducing H2O2. DNA bound copper ions, thought to be necessary for maintenance of DNA quaternary structure, might represent a generator complex for the hydroxyl radical by reduction of X/XO derived hydrogen peroxide. This might cause 'site specific damage' to the DNA which is subsequently converted into chromatid-type aberration by S-dependent misreplication and/or misrepair. This is different to the formation of radiation induced chromosome aberrations which arise by an S-phase independent mechanism.

Antioxidants↗
PubMed1995

Crohn's disease: a colon and rectal department experience.

This study reviewed a series of patients with Crohn's disease managed by surgeons of the Department of Colon and Rectal Surgery, St Vincent's Hospital, Melbourne, since 1978. There were 306 patients: 171 males and 135 females. The mean age at diagnosis was 33.4 years (ranger 11-93). The distribution of the disease was small bowel 32.3%, small bowel and colon 26.5%, colon 39.9%, and anal disease alone 1.6%. A total of 416 abdominal operations were performed on 204 patients. The commonest indications for surgery were failed medical therapy (21.9%), small bowel obstruction (15.9%), enteric fistula (10.1%), and intra-abdominal abscess (10.1%). The most frequently performed procedures were ileocolic resection with anastomosis (28.8%), small bowel resection (9.4%), and total colectomy and ileostomy (7.0%). Postoperative complications included anastomotic leaks in 4.0%, intra-abdominal abscess formation in 3.6%, and enterocutaneous fistulae developed in 6%. Three patients died during the review period. During follow up (mean 84.4), 30% of patients developed recurrence requiring further surgery at a mean of 72.7 months postoperatively. The most frequent site for a recurrence was the pre-anastomotic terminal ileum (61.7%). In conclusion, the majority of patients with Crohn's disease will require resectional surgery at some stage. This can be performed with a low mortality and morbidity, and a recurrence rate of around 5% per year.

Adolescent↗
PubMed1995

A preliminary flow visualization study in a multiple disk centrifugal artificial ventricle.

Flow patterns in a multiple disk centrifugal pump were analyzed so that the device could be incorporated as a ventricular assist or a bridge-to-transplant device. The pump operates either in pulsatile or steady flow modes with the ability to change modes within a fraction of a second. The pump was tested on a mock circulatory system consisting of an arterial fluid capacitor, a systemic resistor, and a venous capacitor. Arterial volume flow rate, arterial pressure, inlet (venous) pressure, and pump rotation speed are continually monitored. A glycerin/water solution is used as a blood analog. Flow visualization was performed with a 3 mW yellow laser, sheet lens, neutrally buoyant amberlite particles, and both still and motion picture photography. Flow patterns matched theoretical predictions very well; inlet flow spread radially outward through the disk annular spaces while propelled by shear and centrifugal forces.

Blood Cells↗
PubMed1994

Reversal of Hartmann's procedure: effect of timing and technique on ease and safety.

PURPOSE: The optimal time for reversal of Hartmann's procedure is controversial. Significant operative difficulty and morbidity have been reported for Hartmann's reversal. The purpose of this study was to examine 11 years' experience with Hartmann's reversal, with particular attention to rate of reversibility, operative difficulty, and timing of reversal. METHODS: Case records of all patients undergoing either Hartmann's procedure or Hartmann's reversal at St. Vincent's Hospital between 1981 and 1991 were examined. Patients having Hartmann's reversal were divided into an early group (before 15 weeks) and a late group (after 15 weeks). These groups were compared in terms of morbidity and mortality, bed stay, and operative difficulty. RESULTS: Hartmann's procedure was performed on 111 patients, mostly for advanced cancer and complicated diverticular disease. Of 96 patients who survived, 50 (52 percent) underwent reversal. Of those with diverticular disease, 40 of 48 (83 percent) underwent reversal. Mortality for Hartmann reversal was 2 percent; anastomotic leak rate 4 percent; and overall complication rate 26 percent. Early reversal was performed in 13 patients and late reversal in 37 patients. There was no difference between these groups in mortality, morbidity, or anastomotic leakage. However, bed stay was longer in the early group and graded operative difficulty greater. In particular, cases in which adhesion density was most severe and in which accidental enterotomy occurred were more common in the early group (P = 0.02, Miettinen's modification of Fisher's exact test). CONCLUSIONS: Hartmann's reversal can be performed with an acceptable morbidity and mortality in most survivors of complicated diverticular disease. Operative difficulty appears to be less after a delay of 15 weeks.

Anastomosis, Surgical↗
PubMed1994

Safety assessment of data management in a clinical laboratory.

This paper briefly reviews work undertaken within the DTI-sponsored MORSE project. The Clinical Biochemistry Department of the West Middlesex University Hospital, one of the five project partners, provides clinical and laboratory services to a wide range of users. The Laboratory Information Management System used within the department has been developed using a range of commercially available hardware and software together with software that has been designed and developed within the laboratory. This paper reports on the first stages of safety analysis of the overall operations in the laboratory. This is a pre-cursor to the systematic re-development of the information system in the light of the findings of the safety analysis.

Clinical Laboratory Information Systems↗
PubMed1994

Development of immune responses to Aspergillus at an early age in children with cystic fibrosis.

Although the ability of Aspergillus organisms to colonize the respiratory tract in patients with cystic fibrosis (CF) is well recognized, the contribution of Aspergillus to the disease process is poorly understood. Using sera from 147 CF patients (age 5 to 43 yr), we measured IgE antibody (ab) to Aspergillus fumigatus and five common inhalant allergens with a radioallergosorbent test (RAST). Total IgE levels and IgG ab to radio-labeled Asp f I, an allergen purified from A. fumigatus and a potent inhibitor of protein synthesis, were also measured. Thirty (20%) of the patients had IgE ab to A. fumigatus, and 22 (15%) of these patients had developed total IgE levels > or = 400 IU/ml, raising the consideration of a diagnosis of allergic bronchopulmonary aspergillosis (ABPA). Five of the 22 patients developed these IgE responses by age 5 yr and 14 by age 10 yr. The proportion of patients with IgE ab to one or more of the other allergens tested was not significantly different from that of control subjects without respiratory symptoms. A striking proportion (84%) of CF sera contained IgG ab to Asp f I, compared with 6% of sera from control patients and 20% of sera from allergic children with asthma (n = 25), only one of whom had IgE ab to A. fumigatus. In an examination of additional sera from young CF patients, IgG anti-Asp f I ab was detected in 41% of these sera from patients 5 yr of age or older, increasing to 98% of 89 sera from patients older than age 10.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗