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Biomedical subjects

S M Smith

Publications and source records attributed to S M Smith.

At least 181 records · Page 10Linked to original sources
PubMed1995

IgA nephropathy in renal allografts: increased frequency in Native American patients.

We investigated the frequency of IgA nephropathy in transplanted kidneys in 2 ethnic groups in New Mexico (USA). A total of 80 renal graft biopsies were obtained from 66 patients when clinically indicated for the differential diagnosis of graft dysfunction. Glomerulonephritis was present in 16 patients, in biopsies obtained after the first posttransplantation month. The frequency of IgAN in allografts was not the same in Native Americans and in Caucasians: Nondonor IgAN was observed in 4/18 biopsies from Native American patients (22.2%) but only in 4/48 biopsies from Caucasians (8.3%) (p < 0.01). This study demonstrates that in New Mexico the frequency of IgAN in transplanted kidneys in Native American patients is 2.7 times higher than in Caucasian graft recipients.

Biopsy↗
PubMed1995

Current management of acute myocardial infarction.

Acute myocardial infarction is a devastating cardiac clinical event, which is the result of progressive coronary arteriosclerosis. Coronary heart disease is a major health concern that accounts for a significant number of hospitalizations, health care expenditures, and deaths. Recent advancements in the nature and pathophysiology of progressive coronary disease and infarction have allowed us to curb the natural course of the disease, shorten hospital stays, and improve patient outcomes. Focused history taking and physical examination, with the assistance of the appropriate laboratory studies and an electrocardiogram, facilitate the rapid identification of a patient with myocardial infarction. Overall clinical results will be improved by minimizing the time from diagnosis to therapy. Several initial measures are readily available to the physician at the time of the patient's arrival in the hospital emergency room. Consideration regarding relief of pain, anticoagulation, and contraindications for thrombolytic therapy should accompany the initial evaluation. For patients in whom the diagnosis is in doubt, adjunctive confirmatory testing and imaging studies should be urgently sought. Elderly patients have a higher mortality rate from infarction, so an aggressive approach in this group of patients is warranted. Administration of thrombolytic therapy or primary angioplasty will be most efficacious in a majority of patients. The evolution of adjunctive medications will further improve efficacy and avoid reinfarction. Proper dosage and timing of adjunctive medications, along with dosage titration based on hemodynamic response, will facilitate the best possible results. Rapid restoration of flow down a suddenly occluded epicardial coronary vessel is the primary end point in therapy. With this in mind, there has been an increasing trend toward mechanical restoration of flow by means of primary angioplasty in centers where this technologic capability is available. Close attention to the patient's hemodynamic status along with rapid identification and therapy of peri-infarction arrhythmias will help to avoid clinical complications. When peripheral perfusion is compromised, hemodynamic monitoring, inotropic medications, and mechanical assistance may become necessary. Subsequent severe pump failure is usually the result of a devastating mechanical complication. Patients with mechanical complications have a high associated event-related mortality rate. Urgent identification of the nature of the complication with the use of invasive and noninvasive imaging studies, mechanical and inotropic assistance, and emergency surgical correction may be lifesaving.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1994

Treatment of septic shock with human monoclonal antibody HA-1A. A randomized, double-blind, placebo-controlled trial. CHESS Trial Study Group.

OBJECTIVE: To compare the effectiveness of 100 mg of HA-1A and placebo in reducing the 14-day all-cause mortality rate in patients with septic shock and gram-negative bacteremia in the Centocor: HA-1A Efficacy in Septic Shock (CHESS) trial, and to assess the safety of 100 mg of HA-1A given to patients with septic shock who did not have gram-negative bacteremia. DESIGN: Large, simple, group-sequential, randomized, double-blind, multicenter, placebo-controlled trial. SETTING: 603 investigators at 513 community and university-affiliated hospitals in the United States. PATIENTS: Within 6 hours before enrollment, the patients had been in shock with a systolic blood pressure of less than 90 mm Hg after adequate fluid challenge or had received vasopressors to maintain blood pressure. These episodes of shock began within 24 hours of enrollment. A presumptive clinical diagnosis of gram-negative infection as the cause of the shock episode and a commitment from the patients' physicians to provide full supportive care were required. MEASUREMENTS: Blood cultures were obtained within 48 hours of enrollment, and death at day 14 after treatment was recorded. Adverse events occurring within 14 days after enrollment were also tabulated. RESULTS: 2199 patients were enrolled; 621 (28.2%) met all enrollment criteria, received HA-1A or placebo, and had confirmed gram-negative bacteremia. Mortality rates in this group were as follows: placebo, 32% (95 and HA-1A, 33% (109 of 328) (P = 0.864, Fisher exact test, two-tailed; 95% CI for the difference, -6.2% to 8.6%). Mortality rates in the patients without gram-negative bacteremia were as follows: placebo, 37% (292 of 793) and HA-1A, 41% (318 of 785) (P = 0.073, Fisher exact test, one-tailed; CI, -0.8% to 8.8%). CONCLUSIONS: In this trial, HA-1A was not effective in reducing the 14-day mortality rate in patients with gram-negative bacteremia and septic shock. These data do not support using septic shock as an indication for HA-1A treatment. If HA-1A is effective in reducing the mortality rate in patients dying from endotoxemia, these patients must be identified using other treatment criteria.

Adult↗
PubMed1994

Geographic patterns of fatal abuse or neglect in children younger than 5 years old, United States, 1979 to 1988.

OBJECTIVE: To examine geographic patterns of fatal child abuse or neglect (CAN) among children younger than 5 years old. DESIGN: A death certificate-based model to estimate the occurrence of fatal CAN. SETTING: United States, 1979 to 1988. PARTICIPANTS: The population of children younger than 5 years old. INTERVENTIONS: None. MAIN RESULTS: We estimate that from 868 to 1815 deaths annually occur among children younger than 5 years old from CAN. The lower figure is the estimate of confirmed CAN, and the higher is the estimate of the sum of confirmed, probable, and possible CAN. Death rates were highest in the South and West, intermediate in the North Central, and lowest in the Northeast. A threefold difference was noted between rates in the lowest- and highest-ranking states (ie, Connecticut, 2.9 to 5.2 per 100,000, and Nevada, 6.7 to 15.4 per 100,000, respectively). When the 39 largest metropolitan areas were ranked, a similar variation between the lowest and the highest was observed (ie, Boston, Mass, 2.7 to 5.5 per 100,000, and Phoenix, Ariz, 6.6 to 15.5 per 100,000, respectively). CONCLUSION: Understanding the sizable geographic variation in CAN deaths rates could lead to effective interventions. If the US fatality rate were reduced to that of Connecticut, between 434 and 908 fewer CAN deaths might occur annually.

Cause of Death↗
PubMed1994

Retinoic acid receptor isoform beta 2 is an early marker for alimentary tract and central nervous system positional specification in the chicken.

In this study I describe the distribution of one variant of retinoic acid receptor-beta (RAR-beta), the RAR-beta 2 isoform, during the stages before organogenesis of the chick embryo. Unlike the situation in older embryos, at these stages its distribution does not differ qualitatively from that of all RAR-beta transcripts. During the presomite headfold stage, RAR-beta 2 transcripts are simultaneously upregulated in two different locations. These locations define positional identities within the anlage of the chick alimentary tract and within the central nervous system (CNS). As development proceeds the transcript expression maintains its spatial restriction within those two regions. At presomite stages RAR-beta 2 transcripts are enriched within the proamnion, which contains the presumptive foregut and precardiac cells; somewhat later it is present within the foregut endoderm at the site where foregut and the lateral amniocardiac vesicles fuse to form the coelom and cardiac tube. As the foregut continues its caudal extension, RAR-beta 2 expression defines an anteroposterior boundary at the level of the pharynx within the alimentary tract. The second expression site of RAR-beta 2 mRNA first appears within the posterior neural plate at the level where Hensen's node commences its caudal regression. This boundary lies at the border between the future rhombomeres 5 and 6 within the hindbrain. Expression of RAR-beta 2 transcripts is also spatially restricted within some migrating cranial neural crest cells. The expression of RAR-beta 2 in cranial neural crest cells is consistent with what is known about the mechanisms by which cranial neural crest cell fate is determined. These data support the hypothesis that retinoids may contribute to positional specification of anteroposterior body axis, and perhaps also to the formation and identity of the developing alimentary tract and heart tube.

Animals↗
PubMed1994

Expression of a single gene encoding microbody NAD-malate dehydrogenase during glyoxysome and peroxisome development in cucumber.

A full-length cDNA clone encoding microbody NAD(+)-dependent malate dehydrogenase (MDH) of cucumber has been isolated. The deduced amino acid sequence is 97% identical to glyoxysomal MDH (gMDH) of watermelon, including the amino terminal putative transit peptide. The cucumber genome contains only a single copy of this gene. Expression of this mdh gene increases dramatically in cotyledons during the few days immediately following seed imbibition, in parallel with genes encoding isocitrate lyase (ICL) and malate synthase (MS), two glyoxylate cycle enzymes. The level of MDH, ICL and MS mRNAs then declines, but then MDH mRNA increases again together with that of peroxisomal NAD(+)-dependent hydroxypyruvate reductase (HPR). The mdh gene is also expressed during cotyledon senescence, together with hpr, icl and ms genes. These results indicate that a single gene encodes MDH which functions in both glyoxysomes and peroxisomes. In contrast to icl and ms genes, expression of the mdh gene is not activated by incubating detached green cotyledons in the dark, nor is it affected by exogenous sucrose in the incubation medium. The function of this microbody MDH and the regulation of its synthesis are discussed.

Amino Acid Sequence↗
PubMed1994

Molecular cloning of cucumber phosphoenolpyruvate carboxykinase and developmental regulation of gene expression.

A cDNA library from RNA of senescing cucumber cotyledons was screened for sequences also expressed in cotyledons during post-germinative growth. One clone encodes ATP-dependent phosphoenolpyruvate carboxykinase (PCK; EC 4.1.1.49), an enzyme of the gluconeogenic pathway. The sequence of a full-length cDNA predicts a polypeptide of 74,397 Da which is 43%, 49% and 57% identical to bacterial, trypanosome and yeast enzymes, respectively. The cDNA was expressed in Escherichia coli and antibodies raised against the resultant protein. The antibody recognises a single polypeptide of ca. 74 kDa, in extracts of cotyledons, leaves and roots. The cucumber genome contains a single pck gene. In the seven-day period after seed imbibition, PCK mRNA and protein steady-state levels increase in amount in cotyledons, peaking at days 2 and 3 respectively, and then decrease. Both accumulate again to a low level in senescing cotyledons. This pattern of gene expression is similar to that of isocitrate lyase (ICL) and malate synthase (MS). When green cotyledons are detached from seedlings and incubated in the dark, ICL and MS mRNAs increase rapidly in amount but PCK mRNA does not. Therefore it seems unlikely that the glyoxylate cycle serves primarily a gluconeogenic role in starved (detached) cotyledons, in contrast to post-germinative and senescing cotyledons where PCK, ICL and MS are coordinately synthesised. While exogenous sucrose greatly represses expression of icl and ms genes in dark-incubated cotyledons, it has a smaller effect on the level of PCK mRNA.

Amino Acid Sequence↗
PubMed1994

Hypertensive effect of polyunsaturated dietary fat.

Male Sprague-Dawley rats were fed a diet high in either saturated fat (lard) or polyunsaturated fat (corn oil) beginning at 10 weeks of age. After 10 weeks of diet treatment, blood pressure (BP) was 17% higher in rats fed saturated fat and 8% higher in rats fed polyunsaturated fat than in rats fed a low-fat control diet. Rats fed the lard diet became obese, and their fasting insulin levels were elevated (38% above control). These data demonstrate that both saturated and polyunsaturated dietary fats induce hypertension.

Animals↗
PubMed1994

Colonization pattern of vancomycin-resistant Enterococcus faecium.

BACKGROUND: Vancomycin-resistant Enterococcus faecium is increasingly recognized as a serious problem by hospital epidemiologists. Understanding its colonization patterns may help in designing strategies to control its nosocomial spread in the hospital. METHODS: Twenty patients, selected at random, with vancomycin-resistant E. faecium isolated from cultures of various body sites were studied to determine sites of colonization. For 12 of these patients, cultures of environmental surfaces of their rooms and wards were also obtained. RESULTS: Eighteen patients (90%) had vancomycin-resistant E. faecium grown in stool cultures. In five patients (25%), vancomycin-resistant E. faecium was cultured from other sites: groins (four), popliteal fossae (three), mouth (one), and an open wound site (one). Patients with positive cultures from the groins and popliteal fossae also had growth of vancomycin-resistant E. faecium in cultures of diarrhea soiling those sites. No patients had the organism isolated from their nares. Vancomycin-resistant E. faecium grew in cultures obtained from bedside stand tables, over-bed tables, used linen, and bedside rails. CONCLUSIONS: In the 20 patients studied, colonization of vancomycin-resistant E. faecium was limited chiefly to the enteric tract. Absence of colonization of such a secluded area with poor antibiotic penetrability as the nares is encouraging. In our study, vancomycin-resistant E. faecium was isolated from various environmental surfaces from the rooms and wards of patients with vancomycin-resistant E. faecium in their stools.

Administration, Oral↗
PubMed1994

The effects of watercress growing on chalk headwater streams in Dorset and Hampshire.

Chalk stream headwaters are of high value for water supply, amenity, game fishing and fish farming. The water quality implications of modern watercress growing watercress beds are reflected in increasing concentrations of phosphorus and potassium downstream of the beds. Zinc concentrations in both suspended solids emanating from the beds and in sediments downstream of the watercress farms reach high levels in some cases. Ranunculus plants downstream of the watercress farms show elevated levels of zinc. Large amounts of suspended solids enter the receiving streams from watercress beds and in many cases the stream bed directly downstream of the farms has a high proportion of fine organic sediments derived from the watercress farms.

Journal Article↗
PubMed1994

Enteric eradication of vancomycin-resistant Enterococcus faecium with oral bacitracin.

The emergence of vancomycin-resistant Enterococcus faecium (VREF) has produced a therapeutic dilemma. The colonization of the intestinal tract with VREF may predispose patients to infections by this organism and may contribute to its nosocomial spread. It is reasonable to attempt to eradicate VREF from colonized patients. The optimal regimen, however, is unknown and this study was designed to evaluate the efficacy of oral regimens of vancomycin and bacitracin for the elimination of VREF from the enteric tract. Enterococcal isolates were tested for susceptibilities to vancomycin, bacitracin, and ampicillin with median minimum inhibitory concentrations of > 512 micrograms/ml, 10 units/ml, and 128 micrograms/ml, respectively. All patients were given an initial trial of oral vancomycin 125 mg every 6 h for 10 days. Those who failed oral vancomycin were then given oral bacitracin 25,000 units every 6 h for 10 days due to its favorable in vitro activity. VREF was eradicated from the stools of 42% of patients (eight of 19) receiving oral vancomycin as compared with all eight patients receiving oral bacitracin (P < 0.01). The organism recurred in two bacitracin patients (25%) 8 and 20 days after completion of therapy. Whether prior vancomycin therapy predisposed patients to colonization by VREF was also examined. Ten (53%) of 19 patients had received prior vancomycin therapy before isolation of VREF from the stool. Our data suggest that oral bacitracin may be an effective alternative to commercially available oral vancomycin for the eradication of VREF from the enteric tract.

Administration, Oral↗
PubMed1994

Magnetic resonance microscopy of water diffusion and edema during hypothermic preservation of rat kidneys.

Kidney degradation during hypothermic storage was studied on rat kidneys, using magnetic resonance microscopy. Poor storage, modeled by storage with lactated Ringer's solution, resulted in rapid kidney swelling, together with increased signal intensity and water diffusion coefficient in the cortical and medullary regions. Storage of kidneys in Euro-Collins solution resulted in slower swelling and no significant change in signal intensity and in the water diffusion coefficient. Storage with Belzer's solution resulted in shrinkage of the kidneys and no significant change in the diffusion coefficient of water over time. These changes correlated well with kidney degradation observed by histology, and show the potential of magnetic resonance imaging in quality assessment of kidney transplants.

Animals↗
PubMed1994

Effects of practice on tip-of-the-tongue states.

Tip-of-the-tongue (TOT) states were examined in relation to acquisition manipulations, using named imaginary animals (TOTimals) as targets. High levels of TOT states were found in three experiments. In the first experiment an increase in the duration of initial exposure to target material improved recall and recognition, and reduced the number of unrecalled items not in TOT states (NTOTs), but did not affect TOT levels. In Experiment 2 practice at writing target names, as compared with only reading them, improved recall performance and decreased TOT levels, but did not reduce NTOTs. Experiment 3 replicated the finding that writing during practice reduced TOT states, but did not reduce NTOTs, and also found that more frequent practice trials increased recall without affecting TOT levels. The results suggest that practice writing target names prevents TOT states by strengthening otherwise deficient phonological connections in memory, a deficiency that can cause TOT states when visual-to-lexical connections give only partial access to a target in memory. The results also demonstrate the usefulness of the TOTimal technique for testing effects of acquisition variables on TOT experiences.

Analysis of Variance↗
PubMed1994

Nutrition in space: lessons from the past applied to the future.

From the basic impact of nutrient intake on health maintenance to the psychosocial benefits of mealtime, the role of nutrition in space is evident. In this discussion, dietary intake data from three space programs, Apollo, Space Shuttle, and Skylab, are presented. Data examination reveals that energy and fluid intakes are almost always lower than predicted. Nutrition in space has many areas of impact, including provision of required nutrients and maintenance of endocrine, immune, and musculoskeletal systems. Long-duration missions will require quantitation of nutrient requirements for maintenance of health and protection against the effects of microgravity. Psychosocial aspects of nutrition will also be important for more productive missions and crew morale. Realization of the full role of nutrition during spaceflight is critical for the success of extended-duration missions. Research conducted to determine the impact of spaceflight on human physiology and subsequent nutritional requirements will also have direct and indirect applications in Earth-based nutrition research.

Diet↗
PubMed1994

Nectar feeding by the early-spring mosquito Aedes provocans.

Nectar feeding by males and females of the mosquito Aedes provocans was studied at a site near Belleville, Ontario, Canada. Canada plum, Prunus nigra, and especially pin cherry, P. pensylvanica, bloomed contemporaneously with the emergence of Ae. provocans and were important nectar sources for adult mosquitoes during their first week of life. Blossoms of P. pensylvanica shielded for 24 h from foragers produced an average of 0.14 mg of sugar (approximately 2.3J). This nectar was avidly sought by both sexes of Ae. provocans; > 97% of the blossoms were visited by mosquitoes in the first few days of blooming. Young adult mosquitoes were found on blossoms at all hours of the day and night; feeding on P. nigra was strongly eocrepuscular, whereas on P. pensylvanica feeding was much less strongly periodic. Adults foraged for nectar in an energy-conserving, pedestrian strategy, devoting 56% (females) and 68% (males) of their time on blossoms to nectar feeding during foraging bouts that lasted a median of 5.3 min. Both sexes sought nectar soon after emergence--males before they had completed hypopygial rotation or swarmed, and females before mating or host seeking. Female Ae. provocans sought nectar in all stages of oogenesis, but primarily at the initiation of a gonotrophic cycle. Energy stores in the crop averaged 18J per female, with a distribution that depended on gonotrophic age and parity.

Aedes↗