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Biomedical subjects

J S Smith

Publications and source records attributed to J S Smith.

At least 91 records · Page 5Linked to original sources
PubMed1999

Posttraumatic stress disorder after injury: impact on general health outcome and early risk assessment.

OBJECTIVE: To evaluate prospectively components of general health outcome after trauma and to report on the further validation of the Michigan Critical Events Perception Scale (MCEPS), an instrument that predicts increased risk for posttraumatic stress disorder (PTSD). METHODS: Adults without neurologic injury admitted to a Level I trauma center in 1997 were interviewed during hospitalization. Baseline data included demographics, injury mechanism, Injury Severity Score, the Short Form 36 (SF36), and the MCEPS, which measures peri-traumatic dissociation (the sense of depersonalization or derealization during an injury event). Surveys sent by mail and completed 6 months later included the SF36 and civilian Mississippi Scale for PTSD. RESULTS: A total of 140 patients were interviewed; the 70% (n = 100 patients) who completed the 6-month assessment form the study group. Injuries were categorized as 71% blunt, 13% penetrating, and 16% burn. Mean Injury Severity Score was 13.7+/-0.52. PTSD at 6 months occurred in 42% of the patients and was directly related to MCEPS dissociation (p = 0.001; odds ratio = 3.1; 95% confidence interval, 1.6, 5.9). A stepwise linear regression explains 40% of the variance in 6-month SF36 general health outcome (adjusted R2 = 0.402). The model controls for individual factors related to dissociation, PTSD, and general health outcome. Development of PTSD was independently and inversely related to general health outcome as measured by the SF36 at 6 months (p < 0.001, beta = -0.404). The R2 change of 0.132 for PTSD (vs. 0.082 for 6-month physical function) illustrates that PTSD contributes more to the patient's perceived general health at 6 months than the degree of physical function or injury severity. CONCLUSIONS: Within hours of injury, the MCEPS identifies patients who are three times more likely to develop PTSD. PTSD compromises self-reported general health outcome in injured adults independent of baseline status, Injury Severity Score, or degree of physical recovery. These data suggest that psychological morbidity is an important part of the patient's perceived general health.

Adult↗
PubMed1999

Posttraumatic stress disorder in injured adults: etiology by path analysis.

OBJECTIVE: Posttraumatic Stress Disorder (PTSD) impairs outcome from injury. We present a path analysis of factors related to the development of PTSD in injured adults. METHODS: A prospective cohort of 250 patients without severe neurotrauma was evaluated by interview during admission and by mailed self-report 6 months later. Data were gathered from the trauma registry (age, injury mechanism, and Injury Severity Score), social history (gender, income, education, and social support), and survey instruments. Baseline assessment used the Michigan Critical Events Perception Scale (peritraumatic dissociation and subjective threat to life), the Life Experience Survey (stressful exposure history), and the SF36 (general and mental health). PTSD at 6 months was identified with the civilian Mississippi Scale for PTSD. Data are listed as mean +/- SEM or percent (%). Path analysis was conducted by linear regression and significant (p<0.05) variables are shown. Factors are listed with the standardized beta. A negative beta suggests a protective effect. RESULTS: The 176 patients (72%) who completed the 6-month follow-up were 37.7+/-0.88 years old; 75% were men; and blunt (70%), penetrating (13.5%), and burn (16.4%) mechanisms caused the injuries. Assault was involved in 14.5% of the cases. Average income was $44,300+/-2,700/yr, education was 13.0+/-0.15 years, and Injury Severity Score was 13.9+/-0.50. A total of 42.3% of the patients developed PTSD. The 39.7% of the variance in PTSD explained by the model was due to intentional injury (beta = 0.27), male gender (beta = -0.21), age (beta = -0.20), peritraumatic dissociation (beta = 0.174), baseline mental health (beta = -0.21), and prior life-threatening illness (beta = -0.29). Peritraumatic dissociation was due to the patient's sense of threat to life (beta = -0.47), and threat was related to Injury Severity Score (beta = 0.2), assault(beta = 0.14), education (beta = -0.15), and age (beta = -0.19). Baseline SF36 mental health was related to social support (beta = 0.27) and income (beta = 0.21). Income was contingent on education (beta = 0.21). CONCLUSION: PTSD occurred in 42.3% of injured adults 6 months after trauma and was related to assault, dissociation, female gender, youth, poor mental health, and prior illness. By modeling PTSD, we may learn more of the etiology, risk stratification, and potentials for the treatment of this common and important morbidity of injury.

Adaptation, Psychological↗
PubMed1999

RNase H requirements for the second strand transfer reaction of human immunodeficiency virus type 1 reverse transcription.

Retroviral reverse transcriptase (RT) enzymes are responsible for transcribing viral RNA into double-stranded DNA. An in vitro assay to analyze the second strand transfer event during human immunodeficiency virus type 1 (HIV-1) reverse transcription has been developed. Model substrates were constructed which mimic the viral intermediate found during plus-strand strong-stop synthesis. Utilizing wild-type HIV-1 RT and a mutant E478Q RT, the requirement for RNase H activity in this strand transfer event was analyzed. In the presence of Mg2+, HIV-1 RT was able to fully support the second strand transfer reaction in vitro. However, in the presence of Mg2+, the E478Q RT mutant had no detectable RNase H activity and was unable to support strand transfer. In the presence of Mn2+, the E478Q RT yields the initial endoribonucleolytic cleavage at the penultimate C residue of the tRNA primer yet does not support strand transfer. This suggests that subsequent degradation of the RNA primer by the RNase H domain was required for strand transfer. In reactions in which the E478Q RT was complemented with exogenous RNase H enzymes, strand transfer was supported. Additionally, we have shown that HIV-1 RT is capable of supporting strand transfer with substrates that mimic tRNAHis as well as the authentic tRNA3Lys.

Base Sequence↗
PubMed1999

A genetic screen for ribosomal DNA silencing defects identifies multiple DNA replication and chromatin-modulating factors.

Transcriptional silencing in Saccharomyces cerevisiae occurs at several genetic loci, including the ribosomal DNA (rDNA). Silencing at telomeres (telomere position effect [TPE]) and the cryptic mating-type loci (HML and HMR) depends on the silent information regulator genes, SIR1, SIR2, SIR3, and SIR4. However, silencing of polymerase II-transcribed reporter genes integrated within the rDNA locus (rDNA silencing) requires only SIR2. The mechanism of rDNA silencing is therefore distinct from TPE and HM silencing. Few genes other than SIR2 have so far been linked to the rDNA silencing process. To identify additional non-Sir factors that affect rDNA silencing, we performed a genetic screen designed to isolate mutations which alter the expression of reporter genes integrated within the rDNA. We isolated two classes of mutants: those with a loss of rDNA silencing (lrs) phenotype and those with an increased rDNA silencing (irs) phenotype. Using transposon mutagenesis, lrs mutants were found in 11 different genes, and irs mutants were found in 22 different genes. Surprisingly, we did not isolate any genes involved in rRNA transcription. Instead, multiple genes associated with DNA replication and modulation of chromatin structure were isolated. We describe these two gene classes, and two previously uncharacterized genes, LRS4 and IRS4. Further characterization of the lrs and irs mutants revealed that many had alterations in rDNA chromatin structure. Several lrs mutants, including those in the cdc17 and rfc1 genes, caused lengthened telomeres, consistent with the hypothesis that telomere length modulates rDNA silencing. Mutations in the HDB (RPD3) histone deacetylase complex paradoxically increased rDNA silencing by a SIR2-dependent, SIR3-independent mechanism. Mutations in rpd3 also restored mating competence selectively to sir3Delta MATalpha strains, suggesting restoration of silencing at HMR in a sir3 mutant background.

Chromatin↗
PubMed1999

Body composition of preterm infants during infancy.

AIMS: To examine body composition in preterm infants. METHODS: Body composition was measured by dual energy x-ray absorptiometry (DEXA) at hospital discharge, term, 12 weeks, and at 6 and 12 months corrected age in 125 infants (birthweight < or = 1750 g, gestational age < or = 34 weeks). RESULTS: Body weight derived by DEXA accurately predicted that determined by conventional scales. In both sexes lean mass (LM), fat mass (FM), %FM, bone area (BA), bone mineral mass (BMM), and bone mineral density (BMD) increased rapidly during the study; significant changes were detectable between discharge and term. At 12 months, LM, BA, and BMM, but not FM, %FM, or BMD were greater in boys than in girls. Corrected for age, LM was less than those of the reference term infant; FM and %FM were similar; BMM was greater. Corrected for weight, LM was similar to those of the reference infant, while the FM and %FM of study infants were slightly greater. CONCLUSIONS: DEXA accurately measures body mass. Body composition in preterm boys and girls differs. Interpretation of DEXA values may depend on whether age or body weight are regarded as the appropriate reference.

Absorptiometry, Photon↗
PubMed1999

Iron nutritional status in preterm infants fed formulas fortified with iron.

AIMS: To prospectively evaluate the iron nutritional status of preterm infants fed either a term (0.5 mg/dl iron) or preterm (0.9 mg/dl) formulas fortified with iron after hospital discharge. METHODS: Healthy low birthweight preterm infants were randomly assigned into three groups at the time of hospital discharge. Group A were fed an iron fortified preterm formula (0.9 mg/dl iron) until 6 months corrected age; group B, a fortified term formula (0.5 mg/l iron) until 6 months corrected age group C, the preterm formula between hospital discharge and term, then the term formula until 6 months corrected age. RESULTS: Seventy eight infants were followed up to 6 months corrected age. Iron intake from formula differed significantly between the groups (A, 1.17 mg/kg/day (SD 0.32) > C, 0. 86 mg/kg/day (SD 0.40) = B, 0.81 mg/kg/day (SD 0.23); p < 0.0001). Haemoglobin concentrations were similar to those of iron sufficient preterm infants of the same postnatal age, and term infants of the same postmenstrual age (after 3 months of age). There were no significant differences in haemoglobin concentration (p = 0.391), plasma ferritin (A vs B, p = 0.322), or in the incidence of iron deficiency (A vs B, p = 0.534). CONCLUSIONS: Iron fortified formulas containing between 0.5 and 0.9 mg/dl iron seem to meet the iron nutritional needs of preterm infants after hospital discharge.

Analysis of Variance↗
PubMed1999

Laboratory investigation of human deaths from vampire bat rabies in Peru.

In the spring of 1996, multiple cases of an acute febrile illness resulting in several deaths in remote locations in Peru were reported to the Centers for Disease Control and Prevention (CDC). The clinical syndromes for these cases included dysphagia and encephalitis. Because bat bites were a common occurrence in the affected areas, the initial clinical diagnosis was rabies. However, rabies was discounted primarily because of reported patient recovery. Samples of brain tissue from two of the fatal cases were received at CDC for laboratory confirmation of the rabies diagnosis. An extensive array of tests on the formalin-fixed tissues confirmed the presence of both rabies viral antigen and nucleic acid. The virus was shown to be most closely related to a vampire bat rabies isolate. These results indicate the importance of maintaining rabies in the differential diagnosis of acute febrile encephalitis, particularly in areas where exposure to vampire bats may occur.

Animals↗
PubMed1999

Molecular characterization of rabies virus isolates from Mexico: implications for transmission dynamics and human risk.

Twenty-eight samples from humans and domestic and wild animals collected in Mexico between 1990 and 1995 were characterized by using anti-nucleoprotein monoclonal antibodies and limited sequence analysis of the nucleoprotein gene. The variants of rabies viruses identified in these samples were compared with other isolates from Mexico and the rest of the Americas to establish epidemiologic links between cases and outbreaks and to increase the understanding of rabies epidemiology in the Western Hemisphere. Antigenic and genetic diversity was found in all samples from dogs and dog-related cases, suggesting a long-term endemic situation with multiple, independent cycles of virus transmission. Two isolates from bobcats were antigenically and genetically homologous to the rabies variant circulating in the Arizona gray fox population, indicating a wider distribution of this variant than previously reported. Rabies isolates from skunks were unrelated to any variant analyzed in this study and represent a previously unrecognized cycle of rabies transmission in skunks in Baja California Sur. Two antigenic and genetic variants co-circulating in southern and eastern Mexico were found in viruses obtained from cases epidemiologically related to vampire bats. These results serve as a baseline for the better understanding of the molecular epidemiology of rabies in Mexico.

Animals↗
PubMed1999

Scintigraphic, sonographic, and histologic evaluation of renal autotransplantation in cats.

OBJECTIVE: To determine scintigraphic, sonographic, and histologic changes associated with renal autotransplantation in cats. ANIMALS: 7 adult specific-pathogen-free cats: 5 males, 2 females, 1 to 9 years old. PROCEDURE: Renal autotransplantation was performed by moving a kidney (5 left, 2 right) to the left iliac fossa. Before and at multiple times after surgery, for a total of 28 days, cats were evaluated by B-mode and Doppler ultrasonography, scintigraphy, and renal biopsy. RESULTS: By 24 hours after surgery, a significant decrease (42%) in mean glomerular filtration rate (GFR) and an increase in mean renal size (81% increase in cross-sectional area) were evident in the transplanted kidney, compared with preoperative values. By postsurgery day 28, reduction in GFR was 23%. Significant changes in renal blood flow velocity were identified in both kidneys. Consistent changes in resistive index or pulsatility index for either kidney could not be identified. When all postoperative histologic data were combined, the histologic score, indicating degree and numbers of abnormalities detected, for the transplanted kidney was significantly higher than that for the control kidney. CONCLUSIONS: Significant changes in renal function, size, and histologic abnormalities develop secondary to acute tubular necrosis in cats after uncomplicated renal autotransplantation. CLINICAL RELEVANCE: Evaluation of renal size and function may be of benefit for clinical evaluation of feline renal transplant patients, whereas measurement of the resistive index may be of little clinical value.

Animals↗
PubMed1999

QOL and outcomes research in prostate cancer patients with low socioeconomic status.

The VA Cancer of the Prostate Outcomes Study (VA CaPOS) is collecting quality-of-life (QOL) information from prostate cancer patients, spouses, and physicians at six VA medical centers. Currently, 601 men with prostate cancer are included in the study, most of whom are of low socioeconomic status and over half of whom are African-American. Quality-of-life responses were most favorable for newly diagnosed patients, intermediate for those with stable metastatic disease, and poorest for those with progressive metastatic disease. Patients could not provide reliable estimates of their own preferences for future QOL states but responded reliably to questions phrased as a comparison of the preferences of two hypothetical patients. High out-of-pocket costs for hormonal therapies, lack of health insurance, and a belief that the non-VA system offered poorer services were the most common reasons for patient transferral to the VA system. Satisfaction with medical care was generally high. While African-American patients were more likely to have advanced prostate cancer at diagnosis, after adjustment for differences in health literacy, race was no longer a significant predictor of advanced disease. The VA CaPOS provides useful information on health status and patient satisfaction of VA prostate cancer patients. Long-term evaluations are needed to detect clinically meaningful QOL information as the disease progresses.

Adult↗
PubMed1999

Bedside manners.

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Emergency Medical Technicians↗
PubMed1998

Rabies surveillance in the United States during 1997.

In 1997, 49 states, the District of Columbia, and Puerto Rico reported 8,509 cases of rabies in nonhuman animals and 4 cases in human beings to the Centers for Disease Control and Prevention. Nearly 93% (7,899) were wild animals, whereas 7% (610) were domestic species. The total number of reported cases increased 19.4% from that of 1996 (7,128 cases). Increases were apparent in each of the major species groups, with the exception of cattle. The relative contributions of these groups to the total reported for 1997 were as follows: raccoons (50.5%; 4,300 cases), skunks (24.0%; 2,040), bats (11.3%; 958), foxes (5.3%; 448), cats (3.5%; 300), dogs (1.5%; 126), and cattle (1.4%; 122). The 958 cases of rabies reported in bats represented a 29.3% increase over the total reported for 1996 and the greatest number reported since 1984, with cases reported by 46 of the 48 contiguous states. The epizootic of rabies in raccoons expanded into Ohio in 1997 and now includes 19 states and the District of Columbia. Thirteen states, where rabies in raccoons is enzootic, reported increases over 1996 in total numbers of reported cases. New York (1,264 cases), North Carolina (879), Virginia (690), and Maryland (619) reported the greatest numbers of cases [corrected]. Five states reported increases that exceeded 50%, compared with cases reported in 1996: Ohio (673.3%; 15 cases in 1996 to 116 in 1997). Massachusetts (144.3%; 115 to 281), South Carolina (97.9%; 96 to 190), Connecticut (97.4%; 274 to 541), and Maine (86.3%; 131 to 244). Cases of rabies associated with foci of rabies in foxes in west central Texas and in dogs and coyotes in southern Texas continued to decline, with this state reporting 78.3% fewer rabid foxes (13 cases), 26.7% fewer rabid dogs (11), and 63.2% fewer rabid coyotes (7) during 1997, compared with 1996. Reported cases of rabies in cats (300) and dogs (126) increased 12.8% and 13.5%, respectively, whereas cases in cattle (122) decreased by 6.9%. Thirty states, the District of Columbia, and Puerto Rico reported increases in rabies in animals during 1997, compared with decreases reported by 31 states and the District of Columbia in 1996. One state (Mississippi; 5 cases) remained unchanged. Hawaii was the only state that did not report a case of rabies in 1997. Four indigenously acquired cases of rabies reported in human beings were the result of infection with rabies virus variants associated with bats.

Animals↗
PubMed1998

NMR structure and dynamics of an RNA motif common to the spliceosome branch-point helix and the RNA-binding site for phage GA coat protein.

The RNA molecules that make up the spliceosome branch-point helix and the binding site for phage GA coat protein share a secondary structure motif in which two consecutive adenine residues occupy the strand opposite a single uridine, creating the potential to form one of two different A.U base pairs while leaving the other adenine unpaired or bulged. During the splicing of introns out of pre-mRNA, the 2'-OH of the bulged adenine participates in the transesterification reaction at the 5'-exon and forms the branch-point residue of the lariat intermediate. Either adenine may act as the branch-point residue in mammals, but the 3'-proximal adenine does so preferentially. When bound to phage GA coat protein, the bulged adenine loops out of the helix and occupies a binding pocket on the surface of the protein, forming a nucleation complex for phage assembly. The coat protein can bind helices with bulged adenines at either position, but the 3'-proximal site binds with greater affinity. We have studied this RNA motif in a 21 nucleotide hairpin containing a GA coat protein-binding site whose four nucleotide loop has been replaced by a more stable loop from the related phage Ms2. Using heteronuclear NMR spectroscopy, we have determined the structure of this hairpin to an overall precision of 2.0 A. Both adenine bases stack into the helix, and while all available NOE and coupling constant data are consistent with both possible A.U base pairs, the base pair involving the 5'-proximal adenine appears to be the major conformation. The 3'-proximal bulged adenine protonates at unusually high pH, and to account for this, we propose a model in which the protonated adenine is stabilized by a hydrogen bond to the uridine O2 of the A.U base pair. The 2'-OH of the bulged adenine adopts a regular A-form helical geometry, suggesting that in order to participate in the splicing reaction, the conformation of the branch-point helix in the active spliceosome may change from the conformation described here. Thus, while the adenine site preferences of the spliceosome and of phage GA may be due to protein factors, the preferred adenine is predisposed in the free RNA to conformational rearrangement involved in formation of the active complexes.

Adenine↗
PubMed1998

Impact of a nurse practitioner on the cost of managing inpatients with heart failure.

We examined the impact on hospital costs of having a nurse practitioner manage uncomplicated patients hospitalized for decompensated heart failure. This strategy was associated with a significant decrease in total hospital costs ($6,659+/-5,843 vs $5,211+/-4,137 [p < 0.03]), a trend toward decreased length of stay (4.0+/-3.0 vs 3.4+/-2.4 days [p = 0.13]), and no significant change in the 30-day readmission rate (13% of patients vs 16% of patients [p = NS]).

Adult↗
PubMed1998

Genomic organization and mutation analysis of p73 in oligodendrogliomas with chromosome 1 p-arm deletions.

p73, a protein having substantial structural and functional similarity to p53, has recently been identified and demonstrated to be a potential tumor suppressor. Its location on human chromosome 1p36.33 implicates p73 as a candidate for neuroblastoma. Like neuroblastoma, oligodendrogliomas also show a high frequency of deletions in chromosome 1p36.3. To determine whether p73 is a potential tumor suppressor gene involved in the development of oligodendrogliomas, we performed mutation analysis of p73 in oligodendrogliomas with chromosome 1 p-arm deletions. We first determined the genomic organization and the intron-exon boundary sequences of the p73 gene by long PCR, vectorette PCR, and Southern hybridization. This gene spans about 65 kb with a large first intron. Primer pairs for the amplification of each of the 13 p73 encoding exons were designed in corresponding introns. The amplicons were then analyzed using the denaturing high-performance liquid chromatography system for mutations in the p73 gene. Twenty oligodendroglioma samples with 1p36.3 deletions were screened, but no mutations were detected except for several polymorphisms. It is thus clear that p73 is not a candidate gene for oligodendroglioma despite its location in the frequently deleted 1p36.3 region.

Chromosomes, Human, Pair 1↗
PubMed1998

Epidemiology of human rabies in the United States, 1980 to 1996.

PURPOSE: To summarize the epidemiologic, diagnostic, and clinical features of the 32 laboratory-confirmed cases of human rabies diagnosed in the United States from 1980 to 1996. DATA SOURCES: Data were obtained from case reports of human rabies submitted to the Centers for Disease Control and Prevention by state or local health authorities. STUDY SELECTION: All cases of human rabies reported in the United States from 1980 to 1996 in which infection with rabies virus was confirmed by laboratory studies. DATA EXTRACTION: Patients were reviewed for demographic characteristics, exposure history, rabies prophylaxis, clinical presentation, treatment, clinical course, diagnostic laboratory tests, identification of rabies virus variants, and the number of medical personnel or family members who required postexposure prophylaxis after coming in contact with an exposed person. DATA SYNTHESIS: 32 cases of human rabies were reported from 20 states. Patients ranged in age from 4 to 82 years and were predominantly male (63%). Most patients (25 of 32) had no definite history of an animal bite or other event associated with rabies virus transmission. Of the 32 cases, 17 (53%) were associated with rabies virus variants found in insectivorous bats, 12 (38%) with variants found in domestic dogs outside the United States, 2 (6%) with variants found in indigenous domestic dogs, and 1 (3%) with a variant found in indigenous skunks. Among the 7 patients with a definite exposure history, 6 cases were attributable to dog bites received in foreign countries and 1 was attributable to a bat bite received in the United States. In 12 of the 32 patients (38%), rabies was not clinically suspected and was diagnosed after death. In the remaining 20 cases (63%), the diagnosis of rabies was considered before death and samples were obtained specifically for laboratory confirmation a median of 7 days (range, 3 to 17 days) after the onset of clinical signs. Of the clinical differences between patients in whom rabies was diagnosed before death and those in whom it was diagnosed after death, the presence of hydrophobia or aerophobia was significantly associated with antemortem diagnosis (odds ratio, 11.0 [95% CI, 1.05 to 273.34]). The median number of medical personnel or familial contacts of the patients who received postexposure prophylaxis was 54 per patient (range, 4 to 179). None of the 32 patients with rabies received postexposure prophylaxis before the onset of clinical disease. CONCLUSIONS: In the United States, human rabies is rare but probably underdiagnosed. Rabies should be included in the differential diagnosis of any case of acute, rapidly progressing encephalitis, even if the patient does not recall being bitten by an animal. In addition to situations involving an animal bite, a scratch from an animal, or contact of mucous membranes with infectious saliva, postexposure prophylaxis should be considered if the history indicates that a bat was physically present, even if the person is unable to reliably report contact that could have resulted in a bite. Such a situation may arise when a bat bite causes an insignificant wound or the circumstances do not allow recognition of contact, such as when a bat is found in the room of a sleeping person or near a previously unattended child.

Age Distribution↗