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Biomedical subjects

S L Smith

Publications and source records attributed to S L Smith.

At least 127 records · Page 7Linked to original sources
PubMed1995

Pattern profile analysis of hominid and chimpanzee hand bones.

In a study designed to complement morphological research on hominid hand bones, length and width measurements of the thumb, index, and middle rays were obtained from radiographs of modern human hands. These rays are primary in precision-gripping postures and are therefore the ones most relevant for investigating evolutionary changes in fine manipulation. Pattern profile analysis allows individuals or samples to be plotted against a reference sample in standard deviation units, or Z-scores. It provides an indication of how different measurements are from modern human averages, while taking into consideration the degree of variation present within modern human samples. A pattern profile for chimpanzees is clearly distinct from humans but quite similar to that of a bonobo, demonstrating the promise of pattern analysis. Partial pattern profiles of several of the more complete early hominid bones from Hadar, Swartkrans, and Olduvai (O.H. 7) are presented and compared. Hadar bones are long and wide at midshaft relative to articular widths; both body-size effects and functional differences are likely. Thumb distal phalanges from Swartkrans and Olduvai both have relatively small base widths, but they differ in other proportions. Two first metacarpals from Swartkrans show distinct patterns. The profiles of La Ferrassie I and Shanidar IV show the characteristically large Neanderthal distal phalanges. Profiles of Skhul IV and Predmost III are alike in some regions with reference to modern North American white males, though they are less similar overall than are those of the two Neanderthals.

Adult↗
PubMed1995

Dynamic monitoring of total-body absorption by 19F NMR spectroscopy: one hour ventilation of HFA-134a in male and female rats.

Six male and six female Sprague-Dawley rats were ventilated head-only for 1 h on a 15% atmosphere of 1,1,1,2-tetrafluoroethane (HFA-134a) in air in a magnetic resonance imaging spectrometer. Results from these dynamic 19F NMR studies suggest that a steady-state in vivo concentration of HFA-134a was approached at approximately 25 min into the exposure. Quantitative integration analysis using an external standard estimated this plateau to be 58.3 +/- 11.9 mg of absorbed HFA-134a per rat. The HFA-134a 19F NMR signal disappeared rapidly following removal of the test atmosphere, with an elimination half-life of 4.6 +/- 0.6 min in the male rats and 4.9 +/- 1.5 min in the female rats. The data suggest that there was no statistical difference between the sexes in amount absorbed or in elimination half-lives.

Absorption↗
PubMed1995

Effects of perioperative analgesic technique on rate of recovery after colon surgery.

BACKGROUND: Choice of perioperative analgesia may affect the rate of recovery of gastrointestinal function and thus duration and cost of hospitalization after colonic surgery. METHODS: Fifty-four patients undergoing partial colectomy surgery were randomized into four groups. All groups received a standardized general anesthetic. Group MB received a preoperative bolus of epidural bupivacaine and morphine followed by an infusion of morphine and bupivacaine. Group M received a preoperative bolus of epidural morphine followed by an infusion of morphine. Group B received a preoperative bolus of bupivacaine followed by an infusion of bupivacaine. Group P received a preoperative bolus of intravenous morphine followed by intravenous patient-controlled morphine postoperatively. All patients participated in a standardized recovery program to minimize the influence of nonanalgesic factors on recovery of gastrointestinal function. All epidural groups were double-blinded. All patients were deemed ready for discharge according to prospectively defined criteria. RESULTS: Groups B and MB reported superior analgesia with activity (P < 0.01). Group M had a greater incidence of pruritus (P < 0.05). Group B had a greater incidence of orthostatic hypotension (P = 0.04). Groups B and MB recovered gastrointestinal function and fulfilled discharge criteria approximately 1.5 days earlier than groups M and P (P < 0.005). CONCLUSIONS: Epidural analgesia with bupivacaine and morphine provided the best balance of analgesia and side effects while accelerating postoperative recovery of gastrointestinal function and time to fulfillment of discharge criteria after colon surgery in relatively healthy patients within the context of a multimodal recovery program.

Analgesia, Epidural↗
PubMed1995

Molecular characterization of the 3' terminus of the simian hemorrhagic fever virus genome.

The 3' end of the simian hemorrhagic fever virus (SHFV) single-stranded RNA genome was cloned and sequenced. Adjacent to the 3' poly(A) tract, we identified a 76-nucleotide noncoding region preceded by two overlapping reading frames (ORFs). The ultimate 3' ORF of the viral genome encodes the capsid protein, and the penultimate ORF encodes the smallest SHFV envelope protein. These two ORFs overlap each other by 26 nucleotides. Northern (RNA) blot hybridization analyses of cytoplasmic RNA extracts from SHFV-infected MA-104 cells with gene-specific probes revealed the presence of full-length genomic RNA as well as six subgenomic SHFV-specific mRNA species. The subgenomic mRNAs are 3' coterminal. In its virion morphology and size, genome structure and length, and replication strategy, SHFV is most similar to lactate dehydrogenase-elevating virus, equine arteritis virus, and porcine reproductive and respiratory syndrome virus.

Amino Acid Sequence↗
PubMed1995

Assessing and treating anxiety in elderly persons.

Although anxiety disorders appear to occur less frequently in elderly persons, subsyndromal anxiety and anxiety associated with other medical and psychiatric disorders are significant sources of morbidity. Theories of etiology of anxiety range from the psychodynamic to the neurobiologic. Treatment of anxiety syndromes hinges on a thorough diagnostic evaluation, with attention to the tendency of older adults to prefer somatic descriptors and to view psychiatric illness as stigmatizing. The efficacy of nonpharmacologic treatment strategies such as relaxation training and psychotherapy for elderly anxious patients has not been well researched, but these interventions have been reasonably successful with younger adult populations and avoid the potential for harmful side effects of medication. Pharmacologic treatment strategies can be effective when used with appropriate caution.

Aged↗
PubMed1994

Direct measurement of hydroxyl radicals, lipid peroxidation, and blood-brain barrier disruption following unilateral cortical impact head injury in the rat.

We present data correlating the time courses of hydroxyl radical (.OH) production, lipid peroxidation, and blood-brain barrier (BBB) damage following unilateral head injury in the rat. Using a controlled cortical impact device to inflict head injury, we have directly measured brain .OH levels via the salicylate trapping method, and phosphatidylcholine hydroperoxide (PCOOH) levels via the HPLC-chemiluminescence technique, at 5, 30, and 60 min postinjury. These results were then correlated with the time course of BBB disruption, as measured by the extravasation of Evans blue dye (EB) into the injured cortex, over the same time period. In the present study, .OH levels were 62% higher than sham at 5 min postinjury, 25% higher at 15 min (both p < or = 0.05), and no different from sham at 60 min. PCOOH, on the other hand, increased linearly between 5 and 60 min postinjury. Whereas PCOOH levels were 25% greater than sham at 5 min, they were 35% and 52% higher than sham at 30 and 60 min, respectively (both p < or = 0.05 vs sham). Blood-brain barrier disruption followed a similar time course to PCOOH generation, except that the magnitude of the effect was much greater. Whereas EB extravasation was only slightly elevated in the injured cortex at 5 min postinjury, there was nearly an 8-fold increase at 30 min and an 11-fold increase at 60 min (all p < or = 0.05 vs sham). An additional experiment demonstrated that BBB damage can be attenuated by treatment with the 21-aminosteroid lipid peroxidation inhibitor, tirilazad mesylate (U-74006F). Rats were given a single i.v. injection of 3 or 10 mg/kg of U-74006F 5 min postinjury and killed 30 min postinjury. The 10 mg/kg dose of U-74006F reduced EB extravasation 52% (p < 0.025) in comparison to vehicle-treated controls. This is the first study to correlate the time courses of .OH formation, lipid peroxidation, and BBB disruption in injured brain. The results suggest that there is an immediate, posttraumatic burst in .OH formation, followed by a progressive increase in lipid peroxidation and a similar, although slightly delayed, time-related opening of the BBB. The attenuation of BBB damage by U-74006F suggests that this chain of events can be interrupted by administration of an antioxidant/lipid peroxidation inhibitor.

Animals↗
PubMed1994

The impact of previous sexual abuse on children's adjustment in adoptive placement.

This article explores the effects of previous sexual abuse on the adjustment of children in adoptive placement. A conceptual model is used to interpret the findings of a study comparing the adoptive placements of 35 sexually abused children with the placements of 113 children who had no identified history of sexual abuse. Data were gathered from the children's case records. Results indicate that sexually abused children experienced more moves when in care, increased frequency of disrupted adoptive placements, greater behavioral difficulties, and more attachment problems than the comparison group. This article examines the interaction of sexual abuse and adoption issues and discusses the implications of the findings for social work practice with sexually abused children and their adoptive families.

Adoption↗
PubMed1994

Sharing the tools of primary care.

Emphasizing community-based primary care as the dominant mode of clinical practice presents an opportunity for greater self determination among retirees, dependents, and active duty personnel. Physician certification of patients' knowledge of personal profiles, problem lists, medication lists, and plans--described as the tools of primary care--permits patient and doctor agreement on mutual agendas of prevention as well as treatment. This opening for primary care involves interaction among all three of the variables in classic medicine--doctors, illnesses, and patients.

Female↗
PubMed1994

Auditory evoked potentials in Rett syndrome.

This study was designed to assess auditory function in subjects with Rett syndrome, a rare neurologic disorder that is characterized by progressive symptoms of dementia, ataxia, respiratory disorder, and communication disorder. Auditory evoked potentials, including the auditory brainstem response (ABR), middle latency response (MLR), and late vertex response (LVR), were recorded in 36 subjects with Rett syndrome. Results showed a systematic decline in auditory function from the peripheral to the central auditory system, with normal ABR in all subjects, normal MLR in 50 percent of subjects, and normal LVR in 36 percent of subjects. Results suggest that hearing sensitivity and the functional integrity of eighth nerve and auditory brainstem pathways are not affected in subjects with Rett syndrome. However, abnormality of both the MLR and LVR suggest the presence of central auditory disorder.

Acoustic Stimulation↗
PubMed1993

Transfection of human astrocytoma cells with glial fibrillary acidic protein complementary DNA: analysis of expression, proliferation, and tumorigenicity.

Glial fibrillary acidic protein (GFAP) is a M(r) 50,000 intracytoplasmic filamentous protein that constitutes a portion of, and is specific for the cytoskeleton of the astrocyte. GFAP appears to stabilize the astrocyte's cytoskeleton, and helps maintain normal astrocyte cell shape through complex interactions between it and the nuclear and plasma membranes. A critical observation from histopathological studies is that there is progressive loss of GFAP expression with increasing astrocytic anaplasia. To determine how GFAP expression affects human malignant astrocytoma cells that are GFAP-deficient, we have stably transfected GFAP-negative SF-126 human astrocytoma cells with a eukaryotic expression vector into which a complementary DNA for the entire coding sequence of the human GFAP protein has been inserted. Positive transformants were selected for neomycin resistance, and GFAP-positive astrocytoma cells have been identified by indirect immunofluorescence using anti-GFAP antibodies. Upon successful transfection, 5 stably transfected SF-126 astrocytoma cell clones were selected that produced GFAP, formed elongated processes in cell culture, and demonstrated decreased proliferation in a tritiated thymidine uptake assay when compared to the control. In addition, the 5 astrocytoma cell clones demonstrated marked reduction in the number and growth of colonies in soft agar when compared to the control. Southern analysis revealed extra copies of the GFAP complementary DNA that had become integrated into the SF-126 astrocytoma cell genome. Northern analysis revealed variable expression of a 3.5-kilobase GFAP mRNA transcript among the 5 cell clones. The amount of GFAP mRNA expression and immunoreactivity by the stably transfected SF-126 astrocytoma cell clones was found to correlate inversely with astrocytoma proliferation and growth in soft agar. The restoration of GFAP expression to GFAP-negative human astrocytoma cells has affected tumor cell morphology, proliferation, and growth in soft agar in this experimental cell system.

Astrocytoma↗
PubMed1993

Effects of plant flavonoids and other allelochemicals on insect cytochrome P-450 dependent steroid hydroxylase activity.

The plant flavonoids flavone, chrysin, apigenin, kaempferol, morin, quercetin, myricetin and phloretin were found to inhibit in a dose-dependent manner the cytochrome P-450 dependent ecdysone 20-monooxygenase activity associated with adult female Aedes aegypti, wandering stage larvae of Drosophila melanogaster, and fat body and midgut from prewandering and wandering stage last instar larvae of Manduca sexta. The concentrations of these flavonoids required to elicit a 50% inhibition of the steroid hydroxylase activity in all the insects ranged from ca 1 x 10(-5) to 1 x 10(-3) M. In addition, lower concentrations (1 x 10(-6) to 1 x 10(-5) M) of the flavonols kaempferol, morin, quercetin and myricetin significantly stimulated (50-100% above control) M. sexta fat body ecdysone 20-monooxygenase activity. Other plant allelochemicals examined and found to significantly inhibit insect ecdysone 20-monooxygenase activity include corynanthine, quinidine, and quinine; whereas, indican and mimosine were found to significantly stimulate M. sexta fat body steroid hydroxylase activity. Several allelochemicals were without effect at all concentrations tested. Although none of the compounds tested in this study elicited effects at very low concentrations (1 x 10(-9) to 1 x 10(-8) M), the in vitro monooxygenase radioassay does hold considerable promise as a screening tool for the detection and identification of plant allelochemicals which may function as biopesticides affecting insect ecdysteroidogenesis.

Aedes↗
PubMed1993

Early clinical experience with the Baerveldt 350-mm2 glaucoma implant and associated extraocular muscle imbalance.

PURPOSE: The Baerveldt glaucoma implant is a new commercially available aqueous drainage device. Clinical data on the performance of the implant are relatively limited. The purpose of this investigation is to explore potential advantages and disadvantages of this implant over the more widely used Molteno implant. METHODS: Retrospective analysis was performed on 37 eyes of 36 patients with refractory glaucoma who underwent placement of a mid-sized Baerveldt 350-mm2 implant. Patient selection was based on previous failure of conventional medical, laser, and surgical management, with poor prognosis for further glaucoma surgery and adjunctive antifibrosis therapy. RESULTS: Significant postoperative extraocular motility restriction and heterotropia were found in the operated eyes. Twenty-three (77%) of 30 eyes measured have significant heterotropia in primary gaze and restriction of gaze into the quadrant of the implant. As a result, 11 (65%) of 17 functionally binocular patients have diplopia in primary gaze. CONCLUSIONS: Pending further study, the authors are avoiding placement of the Baerveldt 350-mm2 implant in both binocular and monocular patients due to the high frequency of induced heterotropia and motility restriction.

Adolescent↗