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Biomedical subjects

D Allen

Publications and source records attributed to D Allen.

At least 253 records · Page 14Linked to original sources
PubMed1986

An analysis of medical care at mass gatherings.

Emergency medical care at public gatherings is haphazard at best and dangerous at worst. The Arizona chapter of the American College of Emergency Physicians, through the Chapter Grant Program, studied the level of medical care provided at public gatherings in order to develop guidelines for emergency medical care at mass gatherings. The study consisted of a survey of medical care at 15 facilities providing events for the public. The results of these surveys showed a wide variation of medical care provided at mass events. Of the 490 medical encounters reviewed, 52.2% were within the realm of care of paramedics, but not basic emergency medical technicians. The most common injuries/illnesses were lacerations, sprains, headaches, and syncope. Problems noted included poor documentation and record keeping of medical encounters, a tendency for prehospital care personnel to make medical evaluations without transport or medical control, and variability of care provided. Based on this survey and a literature review, guidelines for medical care at mass gatherings in Arizona were determined using an objective-oriented approach. It is our position that event organizers have the responsibility of ensuring the availability of emergency medical services for spectators and participants. We recommend that state chapters or National ACEP evaluate the role of emergency medical care at mass gatherings.

Arizona↗
PubMed1986

Electrophysiological assessment of contrast sensitivity in human infants.

Contrast sensitivity functions (CSF's) were measured for a group of 6-month-old infants using the visual evoked potential (VEP). Sine-wave luminance gratings were counterphase modulated at 12 contrast reversals per s and simultaneously swept in contrast. Each contrast sweep lasted 10 s, spanning a range of 0.5 to 40% contrast in 19 equal logarithmic steps. The amplitude and phase of the response at the second harmonic were determined by a discrete Fourier transform. Contrast thresholds were estimated from a linear extrapolation to zero-amplitude of the VEP amplitude vs. log-contrast function. Contrast sensitivity was found to be nearly adult-like at 1 c/deg, but was not yet mature at higher spatial frequencies.

Child Development↗
PubMed1986

Comparative study of electrophysiological and psychophysical measurement of the contrast sensitivity function in humans.

We measured the human contrast sensitivity function (CSF) both electrophysiologically with the steady-state visual evoked potential (VEP) and psychophysically using a method of ascending limits. VEP contrast thresholds were determined using a rapid recording technique in which the contrast of a counterphase modulated sine wave grating was swept logarithmically from 0.5 to 40% over a period of 10 s. For this pattern reversal stimulus the amplitude and phase of the second harmonic response as a function of contrast were measured using a discrete Fourier transform (DFT). Psychophysical thresholds were determined on the same trials used to record the VEP. Near threshold the VEP amplitude vs. contrast function was approximately linear and VEP contrast thresholds were estimated by a linear extrapolation to zero amplitude. The contrast thresholds obtained by the two methods correlated at 0.914 for 5 observers, with a mean discrepancy of only 12%. At higher contrasts, the VEP amplitude vs. contrast function often became nonmonotonic, sometimes showing two amplitude peaks.

Electrophysiology↗
PubMed1986

Growth of severely impaired children: neurological versus nutritional factors.

Nineteen children with cerebral palsy who have had gastrostomies since 1981 and who have been followed for at least six months postoperatively were reviewed to assess the effects of gastrostomy feeding on their growth and to determine whether growth failure was due to neurological or nutritional dysfunction. The children's ages ranged from five to 168 months (mean 60.4 months) and follow-up extended from six to 41 months (mean 23.1 months). All were profoundly handicapped, with involvement of all four limbs. 11 also had seizures and all 19 were severely to profoundly retarded. Heights and weights were recorded during the visit immediately before surgery and at most recent follow-up. Data were recorded as a standard deviation score (Z-score). Before surgery the mean weight/height was -2.71 Z. Postoperatively this improved to -1.18 Z. 16 of the 19 children increased their weight/height ratio. Three children had a weight/height ratio greater than 10th percentile preoperatively. 11 achieved this on follow-up. Seven children were greater than 25th percentile for weight/height. Improvement in weight/height did not correlate with length of follow-up. For severely neurologically impaired children, nutritional factors play a major rôle in growth. By ensuring adequate caloric intake via gastrostomy, a significant number of children achieved adequate growth and better nutritional status.

Adolescent↗
PubMed1986

A prospective study of mammographic parenchymal patterns and risk of breast cancer.

Breast parenchymal patterns have been assessed by the method of Wolfe in a prospective study in Guernsey. Women with P2 or DY grades had approximately four times the risk of developing breast cancer compared with those with N1 or P1 grades. Age, weight, parity and age at birth of first child are all related to the distribution of mammographic patterns. The combination of these variables with Wolfe grades may identify subsets of the population at very high risk.

Adult↗
PubMed1986

Physicians' attitudes toward pain in children.

Physicians' attitudes toward pain in children were assessed in an attempt to explain why adults are administered more analgesics than children while in the hospital. A survey was conducted of all pediatricians, family practitioners, and surgeons in Hartford. Fifty-seven percent of the sample responded (112/195). Seventy-five percent of the sample felt that children experienced adult-like pain by age 2. Thirty-eight percent of the physicians were somewhat or significantly concerned about the risk of addiction when using narcotics in their young patients. Pediatricians were significantly more likely than surgeons or family practitioners to see younger children as having adult-like pain and to prescribe analgesics for children at an earlier age. Many other attitudinal differences were also related to specialty. Other demographic variables (age, sex, mode of practice, and personal experience with pain) had little effect on attitudes. These findings suggest possible explanations for the discrepancy between child and adult analgesic prescribing practices.

Adult↗
PubMed1986

Crystalloids versus colloids: implications in fluid therapy of dogs with intestinal obstruction.

Responses of jejunal transcapillary and transmucosal fluid fluxes to IV infusion of crystalloid or colloid solutions were evaluated in 12 dogs. One isolated intestinal segment in each dog was used as the control segment, and 2 segments were distended to a intraluminal hydrostatic pressure of 10 cm of H2O. The artery supplying 1 of the 2 distended (autoperfused) segments was cannulated and perfused with blood from the femoral artery. One of the 2 distended segments was autoperfused from the femoral artery. Intraluminal pressure was increased in the autoperfused segment and in 1 other segment for three, 20-minute periods after administration of the crystalloid or colloid solution. Net transmucosal fluid flux was estimated, using a volume recovery method. In each autoperfused segment, blood flow, capillary pressure, lymph flow, and plasma protein and lymph protein concentrations were measured during each 20-minute distention period. Systemic arterial pressure was monitored throughout the procedure. Plasma and tissue oncotic pressures were calculated from the plasma protein and lymph protein concentrations. Total vascular resistance and precapillary and postcapillary resistances were determined. Capillary pressure increased after infusion with colloids and crystalloids, with the effects being more prolonged in the colloid group. Plasma oncotic pressure transiently increased after infusion with colloids and decreased after infusion with crystalloids. Lymph flow increased only in crystalloid-treated dogs. Due to alterations in transcapillary fluid filtration, crystalloids induced a net loss of fluid into the intestinal lumen, whereas the fluid absorptive capacity of the jejunum was unaltered by colloid treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Interaction of test protocol and horizontal run training on maximal oxygen uptake.

Twenty-seven untrained college-age males (mean age = 23.1 yr) volunteered for this 12-wk training study, which investigated potential interactions between training specificity and treadmill protocol specificity. The study was designed to analyze the interaction between a subject's maximal oxygen uptake (VO2max) on an inclined protocol (IP) vs a horizontal protocol (HP) before and after training exclusively on flat terrain. Experimental subjects (E, N = 17) trained by running on flat terrain for 12 wk, 4 d/wk, 37 min/d at an intensity equal to 65 to 85% of their heart rate reserve while control subjects (C, N = 10) remained sedentary. All subjects underwent a minimum of four maximal treadmill tests (two with an IP and two with a HP) prior to training and two maximal treadmill tests (one IP and one HP) post-training. Multivariate analysis of variance and post-hoc t-tests using a pooled variance-covariance matrix were used to analyze the data. Alterations in E, consequent to training, included significant increases in VO2max [mean IP = 53.6 to 58.4 (+8.9%) and mean HP = 51.7 to 56.2 ml. kg-1 . min-1 (+8.7%)]. C showed a significant pre- to post-training decrease on the HP for VO2max [mean HP = 52.4 to 50.7 ml . kg-1 . min-1 (-3.2%)], but showed no significant change on the IP. There was no significant pre- to post-training interaction between protocols for VO2max. It was concluded that the post-training results do not support the concept of protocol specificity when evaluating VO2max in subjects trained exclusively on flat terrain.

Adult↗
PubMed1986

Interaction of test protocol and inclined run training on maximal oxygen uptake.

Twenty-two men, 17 to 27 years of age, volunteered to participate in an inclined terrain running program. Men were randomly assigned to a control (N = 10) or an experimental (N = 12) group. The experimental group ran on inclined terrain 4 times/wk for 35 min a session at an intensity of 65 to 85% of maximal aerobic power for 12 wk. The purpose of this study was to analyze the interaction between a subject's VO2max on an inclined protocol (IP) vs a horizontal protocol (HP) before and after training on incline terrain. VO2max, HRmax, VEmax, Rmax, and maximum treadmill time were evaluated on both treadmill protocols (IP and HP). Prior to training, results indicated no difference in VO2max values between protocols. Following training, VEmax, maximum treadmill time, and VO2max increased 8.7, 9.1, and 8.5%, respectively, on the IP and 5.8, 6.8, and 5.3% on the HP respectively. All increases were statistically significant at the 0.05 level. The post-training VO2max on the IP was significantly greater than the value on the HP. These results support the concept of specificity of training and indicate the importance of careful selection of both the test protocol as well as the test mode.

Adult↗
PubMed1985

A re-evaluation of the role of tracheostomy in Ludwig's angina.

Ten cases of Ludwig's angina that required surgical decompression in addition to intravenous antibiotic therapy are reviewed. The vocal cords were visualized in all ten patients following deep inhalational anesthesia to relieve trismus. Only one case required tracheostomy, which has previously been recommended as the treatment of choice for airway management; the other nine were intubated under direct vision.

Adult↗
PubMed1985

Bleomycin-induced lung injury in the rabbit. Analysis and correlation of bronchoalveolar lavage, morphometrics, and fibroblast stimulating activity.

We have used a rabbit model of bleomycin-induced lung injury to evaluate the chronological changes in the bronchoalveolar lavage fluid (BALF) constituents. The correlation of these changes with morphologic alterations and measured soluble mediators of fibrosis has also been assessed. Three groups of 8 treated and 8 control New Zealand white rabbits received 10 U/kg bleomycin in normal saline, or equal volumes of saline intratracheally. The animals underwent bronchoalveolar lavage with a balloon tipped catheter localized to the right lower lobe at 3, 8, or 12 wk. Total cell counts and differentials were performed on the BALF. The lungs were examined histologically for inflammatory cells in the interstitium, alveoli, and airways by morphometric techniques. The lungs were also assayed for total hydroxyproline content. Bronchoalveolar lavage fluid supernatants and supernatants from lavaged macrophages cultured for 24 h were assayed for fibroblast stimulating activity (FSA) by 3H-thymidine incorporation into rabbit lung fibroblasts. There was a significant increase in macrophages and neutrophils in the BALF at 3 wk only, although the elevation of macrophages was sustained for longer than that of neutrophils. The numbers of BALF macrophages correlated with the morphometric assessment of the number of intra-alveolar macrophages (p less than 0.001) and interstitial mononuclear cells (p less than 0.001), as well as the extent of airway inflammation (p less than 0.001). The numbers of BALF neutrophils correlated with morphometrically assessed alveolar (p less than 0.01) and interstitial neutrophils (p less than 0.01) but not with any airway inflammation scores.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Relationship of the redox state to muscle protein degradation.

With increasing muscle size, incubated or fresh-frozen leg muscles showed a more reduced redox state and slower proteolysis. The ln of these data gave a linear correlation showing faster proteolysis under more oxidized conditions. In incubated diaphragms, the inhibitory effects of insulin and catecholamines on proteolysis were associated with a more reduced state. Fasting, trauma or cortisol treatment led to accelerated proteolysis and a more oxidized state. Long term fasting and refeeding supported this relationship, as did streptozotocin diabetes. Like the NAD+ and NADP+ redox couples, the glutathione couple seemed to fit this relationship. Use of proteinase inhibitors showed that the redox state probably mediated the effects of the various factors on proteolysis rather than vice versa. Muscle contains thioltransferase which catalyzes the formation of glutathione-protein mixed disulfides. We propose that increased formation of oxidized glutathione and its interaction with muscle proteins may act as a signal for the initiation of proteolysis.

Adrenalectomy↗