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Biomedical subjects

M Reed

Publications and source records attributed to M Reed.

At least 37 records · Page 2Linked to original sources
PubMed1989

Effect of cytoskeletal geometry on intracellular diffusion.

A method is presented for determining the retardation of diffusion of particles inside cells owing to cytoskeletal barriers. The cytoskeletal meshwork is treated as a repeating periodic two-dimensional or three-dimensional lattice composed of elements of given size, shape, and spacing. We derive an analytic expression for the diffusion coefficient relative to that of the cytosol. This expression is evaluated by solving numerically an appropriate boundary-value problem for the Laplace equation. For the two-dimensional case, e.g., diffusion in a membrane, the results are quantitatively similar to those obtained by Saxton (1987. Biophys. J. 52:989-997) using Monte Carlo methods. The three-dimensional results are quantitatively similar to experimental results reported by Luby-Phelps et al. (1987. Proc. Natl. Acad. Sci. USA. 84:4910-4913) for the diffusion of dextran and Ficoll particles in Swiss 3T3 cells. By accounting for geometrical factors, these results allow one to assess the relative contributions of geometrical hindrance and of binding to the cytoskeletal lattice from measurements of intracellular diffusion coefficients of proteins.

Cytoskeleton↗
PubMed1989

Intubation with low-dose atracurium in children.

The objective of this study was to compare intubating conditions and neuromuscular effects using smaller doses of atracurium (0.25 mg/kg and 0.3 mg/kg) with the recommended dose of 0.4 mg/kg for intubation in children anesthetized with halothane, N2O and oxygen undergoing strabismus repair. All patients (10 in each group) had good or excellent intubating conditions at 80% depression of twitch height [T1 of train-of-four (TOF) stimulation]. Mean times to intubation were 2.6 +/- 0.2 minutes following 0.25 mg/kg and 2.2 +/- 0.2 minutes following 0.3 mg/kg. These times were significantly longer (P less than 0.05) than the mean intubation time of 1.5 +/- 0.2 minutes following 0.4 mg/kg. Mean times to recovery, defined as times from injection of atracurium to return of T1 of TOF to 10%, 25%, and 95% of control measurements, were significantly shorter with the smaller doses. Atracurium at these low doses may provide an alternative to succinylcholine for intubating children during halothane anesthesia for surgical procedures lasting 20-30 min.

Anesthesia↗
PubMed1988

A new autosomal recessive lethal chondrodystrophy with congenital hydrops.

Two sibs, the offspring of consanguineous parents, presented with severe short-limb dwarfism and distinct chondro-osseous, radiologic, and histologic appearance. The first sib presented at 30 wk with severe hydrops following fetal death; the second was detected by ultrasonography at 20 wk. Radiologic abnormalities included an unusual "moth-eaten" appearance of the markedly short long bones, bizzare ectopic ossification centers, and marked platyspondyly with unusual ossification centers. Marked extramedullary erythropoiesis was present in both fetuses, and chondro-osseous histology was characterized by marked disorganization of tissue with interspersed masses of cartilage, bone, and mesenchymal tissue. These sibs appear to have a distinct previously unreported autosomal recessive skeletal dysplasia, which can present as hydrops fetalis.

Adult↗
PubMed1988

VP-16 + adriamycin vs. adriamycin alone in advanced adenocarcinoma of the breast, phase II, a randomized trial: a Southwest Oncology Group Study.

One hundred twenty-two patients with advanced adenocarcinoma of the breast were randomized to receive adriamycin (AD) alone or a combination of VP-16 plus lower dose adriamycin (VAD). The patients were stratified to good and poor risk. The starting dose (day 1) of AD was 60 mg/m2 for good risk and 45 mg/m2 for poor risk. The starting dose of the VAD combination for the good-risk patient was VP-16, 75 mg/m2 daily x 5 plus adriamycin 35 mg/m2. The poor-risk dose for VAD was VP-16, 50 mg/m2 daily x 5 plus adriamycin, 30 mg/m2 on day 1. The total dose of AD was 450 mg/m2 on both arms. The patients who were on the VAD arm continued on VP-16 maintenance. Both arms were repeated every 21 days. There were 54 evaluable patients on the adriamycin arm and 52 evaluable patients on the VAD arm. Both arms were similar with regard to age, menopausal status, performance status, and prior hormonal therapy. More hematologic toxicity was seen in the adriamycin arm. Complete responses were observed on both arms, three (5%) with adriamycin and three (5%) with combination. Eleven (19%) and ten (18%) partial responses were observed with the adriamycin and VP-16 plus adriamycin, respectively. AD produced more stable disease than VAD (41% vs. 29%). Complete responses were seen only in the good-risk patients. Time to progression was delayed on the combination arm (P = 0.02). The survival in both arms was similar. The addition of VP-16 to adriamycin does not offer an important clinical advantage.

Adenocarcinoma↗
PubMed1988

A statistical approach to the discrimination of the cranial form.

In a study of lateral cephalographic dimensions, their multivariate statistical analysis was shown to discriminate between patients with gross cranial anomalies and controls exhibiting no abnormal morphology. Although the degree of discrimination depended upon the group of dimensions included in the analysis, discrimination was more consistent than when compared using univariate statistical techniques. As cephalographic dimensions combine both size and shape parameters together, however, the interpretation of such contrasts must await more specific analytic techniques development.

Cephalometry↗
PubMed1988

Surgical intensive care unit pneumonia.

With use of an objective numerical rating system for the assessment of the presence or absence of pneumonia on a chest x-ray film, 81 patients in the surgical intensive care unit with positive sputum cultures were assigned to either colonization (C; 39 patients) or pneumonia (P; 42 patients) groups. Respiratory failures preceding the first positive sputum culture and hepatic and/or renal failure were more frequent in the P group. Escherichia coli and Pseudomonas species, as well as polymicrobial sputa, were more common in the P group. Positive blood or pleural cultures with the same organism found in the sputum were noted in 10 of 11 P patients and only 3 of 10 C patients. Broad-spectrum antibiotic therapy directed at all sputum pathogens decreased mortality in the P group but not in the C group. We conclude that an objective rating system for chest x-ray diagnosis provides a reasonable method for separating patients with pneumonia from those with colonization. We recommend antibiotic therapy directed at all sputum pathogens in patients in surgical intensive care units. For such therapy to be successful, however, diagnostic criteria must be precise and exclude patients with colonized pathogens.

Bacteria↗
PubMed1987

Blood donation by the elderly. Clinical and policy considerations.

At present, healthy potential blood donors older than the age of 66 years often leave the donor pool for reasons of age alone, despite the fact that this demographic group is growing, is a potentially willing source of blood products, and constitutes the cohort with highest per capita use of blood and its derivatives. There is no clinical or physiological rationale for this. We performed a controlled study to measure the feasibility and safety of blood donation by healthy elderly donors aged 66 years and older, compared with a younger cohort aged 55 to 65 years of age. A study group of prior donors aged 66 years and older and a control group of prior donors between the ages of 50 and 65 were sent letters inviting them to donate blood. The volume donated did not differ between the two groups. In the older group, there were eight immediate reactions, seven mild and one moderate. The control population experienced seven immediate reactions, six mild and one severe. We conclude that it is both clinically feasible and efficient to recruit healthy prior donors older than the age of 66 years for blood donation. As a group, this population is potentially able to donate large volumes of blood and do so without any difference in immediate or short-term reactions. Further study of hemodynamic variables as more objective markers of safety is needed.

Adult↗
PubMed1987

Cardiac embryogenesis: a three-dimensional approach.

In order to aid students in the understanding of cardiac embryogenesis, seven three-dimensional fiberglass models depicting stages eleven to eighteen of cardiac embryogenesis, and one model of a mature heart were constructed. The details of these models, and a review of cardiac embryogenesis is presented. The results we have had with these models in the teaching of cardiac embryogenesis to medical students, cardiac technologists, and nurses have been encouraging, and this approach to teaching is highly recommended.

Heart↗
PubMed1986

Rheumatic diseases in an Inuit population.

Prevalence and incidence rates for rheumatic diseases were found to be minimal among the Inuit people in the Keewatin District of the Northwest Territories, Canada. Patient identification was achieved by a review of medical records. All identified patients were interviewed and examined by a participating rheumatologist. Among women, the prevalence of rheumatoid arthritis, adjusted for age of the Manitoba population, was 1,822 per 100,000 and was comparable with that observed in other populations; no cases of rheumatoid arthritis in men were confirmed. The age-adjusted prevalence of osteoarthritis, 1,219 per 100,000 in men and 2,144 per 100,000 in women, was apparently low. A moderately high incidence of Reiter's syndrome, 24.9 per 100,000, was found. The findings in children suggested a high frequency of seronegative spondylarthropathies (yearly incidence 60.1 per 100,000), although the adjusted yearly incidence for juvenile rheumatoid arthritis also appeared to be high, 23.6 per 100,000. The frequencies of HLA antigens in patient groups were compared with those found in 19 patients with musculoskeletal complaints but no rheumatic disease. Both HLA-B27 and HLA-DR4 appeared to be common in these controls, 36.8% and 63.2%, respectively. Nevertheless, there was a higher frequency of HLA-B27 in patients with seronegative spondylarthropathies (87%) than in controls (P = 0.001). Because of the small numbers of patients who had rheumatoid arthritis, no associations with HLA were made for this condition. Although the findings suggest differences in the distribution of rheumatic diseases compared with those found in other populations, more complete studies are required to confirm these observations.

Adult↗
PubMed1986

Basidiomycete mycelia and spore-allergen extracts: skin test reactivity in adults with symptoms of respiratory allergy.

One hundred fifty adults, with respiratory-allergic disease, and 14 control subjects, without symptoms of respiratory allergy, were skin prick tested with 16 common inhalant allergens, 12 extracts of mycelia from Basidiomycetes grown in vitro, and/or 10 to 15 basidiospore extracts. Eighty-three subjects (58%) had positive skin tests to two or more of the common inhalant allergens. Twenty-seven percent of the study subjects had positive skin reactions to one or more of the Basidiomycete mycelia extracts, and 32% demonstrated positive skin reactions to one or more basidiospore extracts. None of the 14 control subjects had positive skin reactivity to basidiospore extracts. Skin prick reactivity of study subjects to 15 different basidiospore extracts ranged from 5% for Cantharellus cibarius to 17% for Scleroderma sp. The prevalence of skin test reactivity to basidiospores did not differ significantly from the reactivity to commercial mold extracts of several common species of the Fungi Imperfecti (6% for Cladosporium herbarum or Penicillium notatum to 13% for Alternaria tenuis). These results demonstrate that a significant number of individuals reporting symptoms of respiratory allergy have skin test reactivity to basidiospores and suggest that these spores are important fungal aeroallergens in the New Orleans environment.

Adult↗
PubMed1986

Enterobacter bacteremia in surgical patients.

The records of 63 surgical patients with one or more positive blood cultures for Enterobacter organisms were reviewed to determine clinical, epidemiologic, and mortality risk factors. Enterobacter bacteremia occurred, on the average, on the twenty-third day of hospitalization, most frequently in male patients (47), after antibiotic therapy (48 patients), placement of central venous catheters (38 patients), gastrointestinal tract operations (36 patients), and respiratory failure (31 patients). Portals of entry were most commonly sputum (25 patients), open skin wounds (16 patients), and central venous lines (12 patients). Mortality risk (22 patients, 35%) was increased with Enterobacter bacteremia occurring after the fifteenth day of hospitalization (18 of 45 patients versus 4 of 28 patients, p less than 0.01), a preceding Enterobacter focus (13 of 22 patients versus 9 of 41 patients, p less than 0.05), preceding non-Enterobacter bacteremia (10 of 15 patients versus 12 of 48 patients, p less than 0.02), preceding total parenteral nutrition (11 of 21 patients versus 11 of 42 patients p less than 0.01), respiratory failure (19 of 36 patients versus 3 of 27 patients p less than 0.01), and renal failure (11 of 12 patients versus 11 of 51 patients p less than 0.01). The mortality risk was not diminished by specific antibiotic therapy. Enterobacter is emerging as an important pathogen in surgical patients. Prolonged antibiotic administration, particularly that of cephalosporins, may promote Enterobacter colonization of the tracheobronchial tree and skin with subsequent invasion enhanced by respiratory failure, open skin wounds, or central venous catheters traversing the skin. Mortality risk is determined primarily by factors associated with critical illness rather than effects of Enterobacter organisms and their specific treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Cross Infection↗
PubMed1985

Neurophysiological signs of brain damage due to glue sniffing.

Recordings of the brain electrical responses to pattern reversal (checkerboard) visual stimuli showed significantly increased latencies in a group of 12 young people who had been sniffing glue over a prolonged period. Only small improvements were observed in two people who had repeat recordings after 6 months' abstinence. These results show that chronic glue sniffing can lead to long lasting brain damage.

Adhesives↗
PubMed1985

Intestinal triglycerides are derived from both endogenous and exogenous sources.

Although studies have indicated that the small intestine is capable of utilizing endogenous substrates for triglyceride synthesis in the absence of dietary lipid, the importance of the endogenous contribution to total intestinal triglyceride production during absorption has not yet been defined. In this study we have examined the quantitative contribution of endogenous triglyceride production during different luminal lipid loads. By use of a mesenteric lymph fistula rat model with total parenteral nutritional support, mesenteric lymphatic triglyceride transport was investigated. Our results indicate that, during absorption, a substantial fraction (greater than 50%) of total triglyceride is derived from endogenous sources. Increased luminal fatty acid loads lead to an increase in both endogenous and exogenous triglyceride production. Incorporation of luminally infused oleic acid into triglyceride carried by chylomicrons is dependent on the luminal fatty acid load, while incorporation of oleic acid into very low-density lipoprotein (VLDL) triglyceride is saturable. We conclude that both chylomicron and VLDL are involved in transporting triglyceride derived from both endogenous and exogenous sources. The different patterns in the partition of endogenous and exogenous triglyceride into chylomicrons and VLDL suggest that these two lipid-carrying lipoproteins are probably packaged differently in the small intestine.

Animals↗
PubMed1985

Role of small intestine in pathogenesis of hyperlipidemia in diabetic rats.

The small intestine can utilize endogenous substrates for triglyceride synthesis. In diabetes mellitus, potential endogenous substrates are elevated. This study was designed to investigate whether intestinal triglyceride production utilizing endogenous substrates contributes to the pathogenesis of hyperlipidemia in diabetes. Intestinal fatty acid esterification as well as activities of acyl-CoA synthetase and acyl-CoA monoglyceride acyltransferase are the same in diabetic and control rats when the results are expressed per milligram protein. However, due to marked intestinal hypertrophy these activities are increased when the results are expressed as per centimeter gut length. In the mesenteric lymph fistula rat model, we found that during fasting diabetic rats have a greater than twofold increase in triglyceride output that is carried mainly by very low-density lipoproteins (VLDL). During lipid infusion, total triglyceride fatty acid output was not different between diabetic and control rats, although there were significant differences in the patterns of partition of endogenous and exogenous triglyceride into chylomicrons and VLDL. Endogenous triglyceride production did not increase in diabetic rats during lipid infusion. In contrast, there was a substantial increase in endogenous triglyceride production in the control group to a level comparable with that of the diabetic rats. There was a significant reduction in incorporation of exogenous triglyceride into chylomicrons in diabetic rats.

Animals↗
PubMed1985

Acquired hearing loss and psychiatric illness: an estimate of prevalence and co-morbidity in a geriatric setting.

Hearing impairment and mental disorders are common among residents of nursing homes and homes for the aged; however, the relationship between sensory deficit and psychiatric illness has been little investigated in this population. The prevalence of hearing impairment, psychiatric illness, and co-morbidity was investigated in a sample of 102 elderly residents from consecutive admissions to a home for the aged. Examining the coincidence of these disorders showed evidence of an association between hearing loss and paraphrenia, and hearing loss and dysphoric states, but not between hearing and cognitive impairment. The results of this survey provide only suggestive evidence regarding aetiology, but strongly support conjoint assessment of the elderly.

Aged↗