Biomedical subjects
Publications and source records attributed to R S Smith.
Laparoscopy has been used in the evaluation of injuries secondary to blunt and penetrating trauma. In this case report, we describe the use of a new gasless laparoscopic technique using conventional instruments to successfully evaluate and repair a traumatic gastric perforation.
Salvage of intraperitoneal blood with autotransfusion is a well-accepted practice. Laparoscopic examination is gaining popularity and holds diagnostic promise for the evaluation of trauma patients. We describe herein the successful combination of these techniques in a patient who sustained blunt abdominal trauma, facilitating splenic salvage, autotransfusion, and avoidance of laparotomy.
OBJECTIVE: The authors evaluated the neuropsychological correlates of temporal lobe abnormalities in schizophrenic patients. METHOD: Fifteen schizophrenic patients underwent assessment of memory, by the Wechsler Memory Scale--Revised, and abstraction/categorization, by the similarities subtest of the Wechsler Adult Intelligence Scale--Revised and the Wisconsin Card Sorting Test. Neuropsychological tests of motor and constructional functions were used as control tasks. The patients also underwent magnetic resonance imaging (MRI) studies in which new neuroimaging techniques were used to derive measurements of volume and three-dimensional surface renderings of temporal lobe structures. RESULTS: Spearman rank-order correlations indicated significant associations between poor scores on tests of verbal memory, abstraction, and categorization and reduced volume in temporal lobe structures, including the parahippocampal gyrus and posterior superior temporal gyrus (left and right). By contrast, performance on tests of visual memory and on control tasks was not correlated with MRI temporal lobe abnormalities. CONCLUSIONS: These findings suggest a significant but modest relation between reduced volume in specific temporal lobe regions and neuropsychological deficits in abstraction, categorization, and verbal memory, all of which may reflect a dysfunctional semantic system in schizophrenia.
Surprisingly few quantitative studies have addressed the question of whether visually impaired individuals evidence, perhaps in compensation for their loss of vision, increased acuteness in their other senses. In this experiment we sought to determine whether blind subjects outperform sighted subjects on a number of basic tests of chemosensory function. Over 50 blind and 75 sighted subjects were administered the following olfactory and gustatory tests: the University of Pennsylvania Smell Identification Test (UPSIT); a 16-item odor discrimination test; and a suprathreshold taste test in which measures of taste-quality identification and ratings of the perceived intensity and pleasantness of sucrose, citric acid, sodium chloride, and caffeine were obtained. In addition, 39 blind subjects and 77 sighted subjects were administered a single staircase phenyl ethyl alcohol (PEA) odor detection threshold test. Twenty-three of the sighted subjects were employed by the Philadelphia Water Department and trained to serve on its water quality evaluation panel. The primary findings of the study were that (a) the blind subjects did not outperform sighted subjects on any test of chemosensory function and (b) the trained subjects significantly outperformed the other two groups on the odor detection, odor discrimination, and taste identification tests, and nearly outperformed the blind subjects on the UPSIT. The citric acid concentrations received larger pleasantness ratings from the trained panel members than from the blind subjects, whose ratings did not differ significantly from those of the untrained sighted subjects. Overall, the data imply that blindness, per se, has little influence on chemosensory function and add further support to the notion that specialized training enhances performance on a number of chemosensory tasks.
A retrospective review of 525 consecutive exploratory celiotomies for abdominal trauma occurring between January 1987 and June 1990 in an urban trauma center was conducted. One hundred-fifteen patients sustained blunt abdominal trauma (21%), and 410 patients sustained penetrating abdominal trauma (78%). Penetrating injuries included 260 gunshot wounds and 150 stab wounds. Patients were divided into three groups: Group A (16%), no visceral injuries identified at exploration (true negative); Group B, positive operative findings at celiotomy requiring no operative repair (10%) (nontherapeutic celiotomy); and Group C (74%), injuries encountered requiring operative repair (true positive). A positive exploration rate of 90 per cent with blunt trauma is acceptable using diagnostic techniques currently available. Similarly, a positive exploration rate of 85 per cent in gunshot wounds warrants our continued use of mandatory celiotomy. A 36 per cent combined incidence of true negatives and nontherapeutic celiotomies (Group A and B) is unacceptably high. To reduce this high incidence will require improved clinical surveillance and the controlled implementation of newer diagnostic techniques.
The incidence of recurrent injury requiring evaluation and treatment at an urban trauma center was assessed by examination of data from the registry of an urban trauma unit. A subgroup of 342 recidivists sustained 711 traumatic injuries. This represented 6.4% of trauma service activations or consultations. The rates of recurrence in random groups of 100 patients with trauma and 50 patients with traumatic deaths were 5% and 12%, respectively. These rates of recurrent injury are lower than those of several previous reports. Comparison of patients with recurrent episodes of trauma with patients who experience a single episode of trauma revealed significant differences in age, sex distribution, mechanism of injury, and fatal outcomes. Recidivists averaged only 7.9 months between episodes of injury. In patients with recurrent trauma with fatal outcomes, the mean interval between initial injury and death was 18.8 months. Early identification of patients at high risk for recurrence may provide an opportunity for behavior modification.
The present study examined the effect of varying dietary linoleate intake (0.01, 0.24, 2.4, 24, 80 or 160 g/kg diet) for 24 weeks on the distribution of triacylglycerol (TG) molecular species in rat epididymal adipose tissue. Adipose TG fractions were purified by thin-layer chromatography and separated into different molecular species by reverse-phase high-performance liquid chromatography. The identification of TG species was based on fatty acid composition, retention time and the theoretical carbon number. When the dietary 18:2n-6 content was equal to or less than 24 g/kg, no significant amounts of n-6 fatty acids (mainly 18:2n-6) were observed in adipose tissue TG despite the fact that the levels of 20:4n-6 in liver phospholipids increased significantly. There were 12 major molecular species in adipose tissue when the dietary 18:2n-6 content was less than 2.4 g/kg. When the dietary 18:2n-6 content reached 24 g/kg, an additional six TG species containing one, two or three molecules of 18:2n-6 were observed. The levels of TG molecules containing two or three 18:2n-6 residues were further increased when the diet contained very large amounts of linoleic acid (160 g/kg). Conversely, those TG species containing only one 18:2n-6 residue became less abundant. It is suggested that the accumulation of these linoleate-rich TG molecular species in adipose tissue, particularly di- and trilinoleoyl containing TG, is the result of an adequate or an excessive intake of linoleic acid.
Schizophrenic patients have low concentrations of PGE-1, n-6 fatty acids, vitamin C and zinc, elevated brain levels of dopamine and high plasma levels of interleukin-2 receptors (IL-2R). IL-2R plasma titers can be raised in celiac patients by administering wheat. These findings are both consistent with and supportive of the GI T-lymphocyte theory of schizophrenia.
Chronic macrophage activation with subsequent failure of activated macrophages to properly control T-lymphocyte secretion of interleukin-2 and interleukin-2 receptors is proposed as the basic biological mechanism of schizophrenia. Fundamental to this theory are the clinical observations on interleukin-2 provoking the active phase symptoms of schizophrenia in psychiatrically normal human volunteers and macrophage cytokines producing the prodromal and residual phase symptoms. This theory provides a completely new and unified mechanisms for the antipsychotic action of typical and atypical neuroleptics, bromocriptine, naloxone and DMSO. Furthermore, this hypothesis reveals why the dopamine theory of schizophrenia was a false lead. The effects of prolactin, estrogens and androgens are consistent with the model. Age of onset, male/female incidence, course of the disease from prodromal to active to residual phase, the protection afforded by rheumatoid arthritis and the close relationship between depression and schizophrenia can be explained by this theory. The gastrointestinal tract is suggested as the preferred site to investigate for the cause of the immune activation in schizophrenia.
Immune cell cytokines are proposed as the common mediators of headache. This unifying concept can not only account for headache, but also the prostaglandins, leukotrienes, platelet activating and vasoactive substances linked with headache, the varied symptoms associated with headache and the high incidence of headache with depression, infectious disease, trauma and in premenopausal women. The immune system as the central mediator of headache is consistent with the promoting effect of estrogen, the abortive activity of cortisol and the prophylactic properties of fish oil and evening primrose oil. This hypothesis provides a unified mechanism to explain headache triggered by food, infectious disease or trauma.
Slow rehydration of bacteria from dried inoculant formulations provided higher viable counts than did rapid rehydration. Estimates were higher when clay and peat powder formulations of Rhizobium meliloti, Rhizobium leguminosarum biovar trifolii, and Pseudomonas putida, with water activities between 0.280 and 0.650, were slowly rehydrated to water activities of approximately 0.992 before continuing the dilution plating sequence. Rhizobium meliloti populations averaged 6.8 x 10(8) cfu/g and 1328 cfu/alfalfa seed greater when slowly rehydrated from bulk powder and preinoculated seeds, respectively. Bulk powder samples were slowly rehydrated to 0.992 water activity by the gradual addition of diluent, followed by a 10-min period for moisture equilibration. Preinoculated seed samples were placed in an environmental chamber at 24 degrees C with relative humidity greater than 80% for 1 h to allow moisture absorption. "Upshock," osmotic cellular stresses that occur during rehydration, was reduced when dried microbial formulations were slowly rehydrated and equilibrated before becoming fully hydrated in the dilution plating sequence. These procedures may also be applicable when estimating total viable bacterial populations from dried soil or other dry formulations.
Military weapons produce massive traumatic injuries. Multiple organ system failure can be expected to occur frequently as a result of such injuries. This case report from the recent conflict with Iraq is representative of wartime injuries and complications and the positive impact of modern intensive care capability on such injuries. Availability of critical care in future conflicts is essential.
Contact lens fenestration can increase tear exchange. We describe a case in which a patient with 15 D of against-the-rule astigmatism was fit with a Softperm contact lens but was unable to wear it for more than 1 hour because of corneal edema. After fenestrating the Softperm lens with an argon laser the patient was able to wear her lens for 10 hours without signs of corneal decompensation.
Apolipoprotein (apo) A-I, the major apoprotein of human high density lipoprotein, is a vital cofactor for lecithin-cholesterol acyltransferase (LCAT), the plasma enzyme responsible for esterification of free cholesterol associated with high density lipoprotein. This esterification is an important component of the reverse cholesterol transport process. An immunochemical approach was used to test the hypothesis that a discrete region of apoA-I was important for LCAT activation. Three human apoA-I-specific monoclonal antibodies were found to inhibit LCAT activation in vitro in a manner directly proportional to their ability to bind to apoA-I-proteoliposomes in fluid phase immunoassays. This relationship was not observed with another four apoA-I-specific antibodies that also were able to bind to the apoA-I proteoliposomes. The use of synthetic peptides representing short amino acid sequences of the apoA-I molecule facilitated the identification of discrete but overlapping apoA-I epitopes for those antibodies that interfered with LCAT-mediated cholesterol esterification. These epitopes spanned amino acid residues 95-121 of mature apoA-I. Therefore, this region is most likely involved in the activation of LCAT by apoA-I.
Plasma apolipoprotein E (apoE) is a ligand for the cellular uptake of cholesterol-rich plasma lipoproteins. ApoE also inhibits mitogen-stimulated lymphocyte proliferation and gonadotropin-stimulated ovarian theca/interstitial cell androgen production. To address the mechanism(s) by which apoE is active and to understand its interaction with the target cells, we prepared and examined the inhibitory activity of a series of apoE synthetic peptides. ApoE peptides representing amino acid residues 93-112, 141-155, 161-171, 172-182, and 174-193 were not active in either bioassay. However, specific inhibition of both lymphocyte proliferation and ovarian androgen production was observed with a self-conjugate of peptide-(141-155). Furthermore, a synthesized dimeric peptide representing two repeats of sequence-(141-155) (i.e. (141-155)-(141-155] was active as well. In both bioassays, the inhibition observed was not a result of direct cell killing. Furthermore, these apoE peptides exhibited activities with characteristics that were shared with those of native apoE. The results indicate that amino acid residues 141-155 of apoE are responsible for the biological activity of apoE. Furthermore, the results suggest that dimers or multimers of native apoE may be a biologically important species.
The hypothesis that the reversal of rapid axonal transport requires a proteolytic conversion of anterograde transport vesicles was examined using sciatic nerve preparations from Xenopus laevis and leupeptin as an inhibitor of proteolysis. The transport of newly synthesized 35S-labeled proteins was studied with a position-sensitive detector of radiation. Organelle transport in isolated myelinated axons was studied by video microscopy. Leupeptin (0.1-0.4 mM) reduced the anterograde-to-retrograde reversal of protein transport adjacent to an axonal lesion. In experiments in which organelle transport was observed close to lesions in axons maintained in a medium compatible with intracellular function, 1.0 mM leupeptin inhibited neither the anterograde-to-retrograde nor the retrograde-to-anterograde reversal of organelle transport. In addition, in experiments in which conditions approximated those used to study protein transport, organelle transport away from the lesion was not inhibited by 1.0 mM leupeptin. A comparison of the morphology of rapidly transported organelles that underwent anterograde transport to the morphology of those that returned from a lesion (with or without the presence of leupeptin) provided no evidence that a morphological conversion was a necessary step in transport reversal.
Membranes from 2 K1735 murine melanoma clones of high invasive capacity show increased amounts of pertussis toxin (PT) substrate when compared to a weakly invasive cellular counterpart. Using a panel of specific G-protein antibodies, we identified Gi alpha 2 as the PT-sensitive G-protein uniquely abundant in highly invasive cells. In addition, RNA hybridization results confirm the immunoblot observations that Gi alpha 2 is present at higher levels in strongly invasive cells. This result suggests that the elevated expression of Gi alpha 2 in highly invasive cells is not entirely due to differences in either translational efficiency or protein degradation but is related to altered RNA transcriptional initiation, processing and/or degradation. ADP-ribosylation of Gi alpha-subunits by PT inhibited the fibronectin, laminin and collagen type-IV-stimulated motility of the 2 highly invasive clones, while PT treatment of cells from a poorly invasive clone resulted in little or no reduction of the fibronectin, laminin or collagen type-IV-stimulated lower motility. Furthermore, PT treatment of highly or poorly invasive K1735 clones does not result in any alteration in cellular cAMP accumulation, suggesting that the PT substrate is not linked with the adenylyl cyclase enzyme complex. The data suggest that a PT-sensitive G-protein, probably Gi alpha 2 regulates second messenger pathways that contribute to elevated motility in highly invasive K1735 cells.
The effects of dietary supplementation of either alpha-linolenic acid (18:3(n-3)) or stearidonic acid (18:4(n-3)) in combination with either linoleic acid (18:2(n-6)) or gamma-linolenic acid (18:3(n-6)) on liver fatty acid composition in mice were examined. Essential fatty acid deficient male C57BL/6 mice were separated into four groups of seven each and were fed a fat-free semi-purified diet supplemented with 1% (w/w) fatty acid methyl ester mixture (1:1), 18:2(n-6)/18:3(n-3), 18:2(n-6)/18:4(n-3), 18:3(n-6)/18:3(n-3), or 18:3(n-6)/18:4(n-3). After 7 days on the diets, fatty acid compositions in liver phosphatidylcholine and phosphatidylethanolamine fractions were analyzed. In groups fed 18:4(n-3) (18:2(n-6)/18:4(n-3) or 18:3(n-6)/18:4(n-3)) as compared to those fed 18:3(n-3) (18:2(n-6)/18:3(n-3) or 18:3(n-6)/18:3(n-3)), the levels of 20:4(n-3), 20:5(n-3) and 22:5(n-3) were increased, whereas those of 20:3(n-6) and 20:4(n-6) were decreased. When 18:3(n-6) replaced 18:2(n-6) as the source of n-6 acids, the levels of 18:3(n-6), 20:3(n-6), 20:4(n-6) and 22:5(n-6) were increased, whereas those of 20:4(n-3) and 20:5(n-3) were reduced. Replacing 18:3(n-3) by 18:4(n-3) reduced the (n-6)/(n-3) ratio by approx. 30%, whereas replacing 18:2(n-6) by 18:3(n-6) increased the (n-6)/(n-3) ratio by approx. 2-fold. These findings indicated that delta 6-desaturase products were metabolized more readily than their precursors. Both products also competed for the subsequent metabolic enzymes. However, the n-6 fatty acids derived from 18:3(n-6) were incorporated more favourably into liver phospholipids than n-3 fatty acids derived from 18:4(n-3).