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Biomedical subjects

S E King

Publications and source records attributed to S E King.

At least 19 recordsLinked to original sources
PubMed2000

The effects of gap size and disturbance type on invasion of wet pine savanna by cogongrass, Imperata cylindrica (Poaceae).

Cogongrass is a nonindigenous species perceived to threaten native communities of the southeastern United States through modification of species composition and alteration of community processes. To examine how gap size and disturbance type influence the invasion of wet pine savannas by cogongrass, we performed three field experiments to evaluate the response of cogongrass seeds and transplanted seedlings to four different gap sizes, four types of site disturbance, and recent burning of savanna vegetation. Cogongrass germinated, survived, and grew in all gap sizes, from 0 to 100 cm in diameter. Similarly, disturbance type had no effect on germination or seedling and transplant survival. Tilling, however, significantly enhanced transplanted seedling growth, resulting in a tenfold increase in biomass over the other disturbance types. Seedling survival to 1 and 2 mo was greater in burned savanna than unburned savanna, although transplant survival and growth were not affected by burning. Results of this study suggest that cogongrass can germinate, survive, and grow in wet pine savanna communities regardless of gap size or type of disturbance, including burning. Burning of savanna vegetation may enhance establishment by improving early seedling survival, and soil disturbance can facilitate invasion of cogongrass by enhancing plant growth.

Journal Article↗
PubMed1999

Distribution coefficients (Kd's) for use in risk assessment models of the Kara Sea.

As a prerequisite for most evaluations of radionuclide transport pathways in marine systems, it is necessary to obtain basic information on the sorption potential of contaminants onto particulate matter. Kd values for use in modeling radionuclide dispersion in the Kara Sea have been determined as part of several international programs addressing the problem of radioactive debris residing in Arctic Seas. Field and laboratory Kd experiments were conducted for the following radionuclides associated with nuclear waste: americium, europium, plutonium, cobalt, cesium and strontium. Emphasis has been placed on two regions in the Kara Sea: (i) the Novaya Zemlya Trough (NZT) and (ii) the mixing zones of the Ob and Yenisey Rivers (RMZ). Short-term batch Kd experiments were performed at-sea on ambient water column samples and on samples prepared both at-sea and in the laboratory by mixing filtered bottom water with small amounts of surficial bottom sediments (particle concentrations in samples = 1-30 mg/l). Within both regions, Kd values for individual radionuclides vary over two to three orders of magnitude. The relative particle affinities for radionuclides in the two regions are americium approximately equal to europium > plutonium > cobalt > cesium > strontium. The values determined in this study agree with minimum values given in the IAEA Technical Report [IAEA, 1985. Sediment Kd's and Concentration Factors for Radionuclides in the Marine Environment. Technical Report No. 247. International Atomic Energy Agency, Vienna.]. Given the importance of Kd's in assessments of critical transport pathways for radionuclide contaminants, we recommend that Kd ranges of values for specific elements rather than single mean values be incorporated into model simulations of radionuclide dispersion.

Americium↗
PubMed1998

An in vitro validation of a commercially available metabolic cart using pediatric ventilator volumes.

Our objective was to determine the validity of the SensorMedics 2900 Metabolic Measurement Cart (SensorMedics Corp., Yorba Linda, CA) for use at pediatric ventilator volumes by designing an in vitro validation study. The study was performed using a previously described nitrogen dilution, carbon dioxide infusion technique in which known amounts of nitrogen (N2) and carbon dioxide (CO2) are infused while a test lung is ventilated. Metabolic measurements were made at tidal volumes (Vt) varying from 50-500 mL at a peak end-expiratory pressure (PEEP) of 0 and 12 cm H2O and at inspiratory oxygen fractions (Fi,O2s) ranging from 0.21-0.60. Each study was repeated six times to assess reproducibility of measurements. At a PEEP of 0 cm H2O, the measurement of oxygen consumption (V'O2), carbon dioxide production (V'CO2), and minute ventilation (V'E) were all within +/-10% of predicted values at all Fi,O2S except when Vt(t) was 50 mL. When PEEP was increased to 12 cm H2O, error in measurement of V'O2 increased and became unacceptably large as Fi,O2 was increased. Each study consisted of six trials, and results showed acceptable reproducibility as demonstrated by narrow 95% confidence intervals. For V(t)s of 100-500 mL, the metabolic monitor provided accurate and reproducible results under in vitro testing conditions when PEEP was low. Accurate results could not be obtained with a Vt of 50 mL or at elevated PEEP.

Calorimetry, Indirect↗
PubMed1996

Isolation of tetranucleotide repeat polymorphisms flanking the BRCA1 gene.

Large pools of cosmids from the BRCA1 region of human chromosome 17 were screened for tetranucleotide repeat polymorphisms by hybridizing shotgun subcloned pools with a mixture of 25 oligonucleotides. Identified subclones were PCR amplified and directly sequenced to design PCR primers for short tandem repeat polymorphism (STRP) analysis of family DNAs. With the identification of the BRCA1 gene and the observation that most mutations in this > 100-kb gene are unique, haplotyping and linkage analysis may play a significant role in diagnosis and carrier detection of BRCA1-associated breast and ovarian cancers. We report the characterization of 15 new STRPs flanking the BRCA1 locus.

BRCA1 Protein↗
PubMed1996

Changes in glucose and lipid metabolism following weight loss produced by a very low calorie diet in obese subjects.

OBJECTIVE: To study the effects of a very low calorie diet (VLCD) on glucose and lipid metabolism in obese subjects, in particular, the effects on insulin sensitivity and the activities of the key enzymes of glucose disposal, glycogen synthase (GS) and the pyruvate dehydrogenase complex (PDHC). DESIGN: Clinical dietary intervention study (1.67 MJ (400 kcal)/day) until weight loss of > 10%. SUBJECTS: 11 (seven male, four female) non-diabetic, obese subjects (age: 27-62 y; BMI: 40.5 +/- 1.4 kg/m2). MEASUREMENTS: Whole body glucose disposal (by euglycemic hyperinsulinemic clamp), respiratory quotient (RQ), resting energy expenditure (REE), glucose and lipid oxidation (by indirect calorimetry), insulin-stimulated PDHC and GS activity (in muscle biopsies) both before and immediately after VLCD (i.e. while still in a hypocaloric state), serum hormone and metabolite levels throughout the dietary period. RESULTS: Weight loss was accompanied by reduced insulin and elevated NEFA levels, improved insulin sensitivity due to increased nonoxidative glycolysis with no increase in PDHC or GS activities. The rate of weight loss was inversely related to the initial RQ. PDHCa was strongly age-related. CONCLUSION: A low RQ may be used as a predictor of the efficacy of VLCD treatment and that while VLCD improves nonoxidative glycolytic flux, changes in oxidative glucose disposal and muscle glucose storage are prevented by high NEFA availability during this catabolic phase of dietary intervention.

Adult↗
PubMed1996

The "epidemic" of breast cancer in the U.S.--determining the factors.

Breast cancer incidence rates in the United States rose by 24% between 1973 and 1991. Mortality during this period, however, remained stable. Both the 5-year relative survival rate and the rates of in situ and stage I breast cancers have been increasing, while the incidence of later-stage cancers has been decreasing. Increased mammography screening may explain the documented jump in breast cancer incidence rates during the mid-1980s. Differences in the distribution of breast cancer risk factors may account, in part, for the temporal trends in breast cancer incidence. In particular, breast cancer risk factors may vary by birth cohort, including age at menarche, age at first birth, physical activity, obesity, diet, alcohol intake, estrogen therapy, and exposure to environmental organochlorines. After decades of epidemiologic research, a preventive approach to breast cancer that focuses on the physiologic effects of the sex steroid hormones, and their potential interactions with family history, is being carefully formulated.

Adult↗
PubMed1995

A YAC-, P1-, and cosmid-based physical map of the BRCA1 region on chromosome 17q21.

A familial early-onset breast cancer gene (BRCA1) has been localized to chromosome 17q21. To characterize this region and to aid in the identification of the BRCA1 gene, a physical map of a region of 1.0-1.5 Mb between the EDH17B1 and the PPY loci on chromosome 17q21 was generated. The physical map is composed of a yeast artificial chromosome (YAC) and P1 phage contig with one gap. The majority of the interval has also been converted to a cosmid contig. Twenty-three PCR-based sequence-tagged sites (STSs) were mapped to these contigs, thereby confirming the order and overlap of individual clones. This complex physical map of the BRCA1 region was used to isolate genes by a number of gene identification techniques and to generate transcript maps of the region, as presented in the three accompanying manuscripts of Brody et al. (1995), Osborne-Lawrence et al. (1995), and Friedman et al. (1995).

BRCA1 Protein↗
PubMed1995

Intraperitoneal fluid collections following liver transplantation in a paediatric population.

Reduced-size liver transplant techniques are now widely used in paediatric liver transplantation programmes. An argument against their use is the potential for an increased incidence of post-operative fluid collections arising from the cut surface of the liver. The distribution and management of fluid collections after 70 paediatric liver transplants (18 whole and 52 reduced), performed over a 3 year period is reported. Fluid collections occurred in seven of the whole liver transplant (WLT) group and in 23 of the reduced-size liver transplant (RLT) group. The incidence of fluid collections in the two groups was therefore similar (39% and 44%). Intervention was required in 20 collections: in the RLT group, seven of these were due to biliary anastomosis leaks or bowel perforation, the incidence of the remaining collections requiring intervention was similar in the two groups. In conclusion the overall incidence of fluid collections was not increased by the use of reduced-size liver transplants, and the increased rate of intervention in the RLT group was not related to the cut surface.

Adolescent↗
PubMed1993

The human NME2 gene lies within 18kb of NME1 in chromosome 17.

The NME1 gene, localized to human chromosome 17 at q22, shows reduced expression in tumors of high metastatic potential. A homologous gene, NME2, with similar reduced expression in breast carcinoma, has recently been reported. We have isolated and characterized five yeast artificial chromosome (YAC) clones and three cosmid clones that contain both genes, demonstrating that the NME2 gene is also located on chromosome 17 and is separated by not more than 18 kb from the NME1 gene. The two putative tumor suppressor genes, encoding the two polypeptide chains of nucleoside diphosphate (NDP) kinase, are thus quite close to each other on chromosome 17, indicating that they may well have arisen by a tandem duplication. Both genes now appear to be excluded as candidates for the early-onset breast cancer (BRCA1) locus.

Animals↗
PubMed1986

Quantitative comparisons of healing in cranial fresh autografts, frozen autografts and processed autografts, and allografts in canine skull defects.

Adult dog skull defects larger than 17 mm do not spontaneously heal. A quest for a potentially viable, cosmetically, mechanically, and technically acceptable template for human cranial reconstruction prompted a comparison of processed autogeneic and allogeneic bone implants with a fresh autograft control in the dog. Quantitative reproducible observations demonstrated that fresh calvarial bone autografts were superior to the nonviable implants in volume percent defect filled, mm2 new cortical bone, mm2 new and old cortical bone, and cortical bone porosity. Frozen autografts achieved 75%, antigen-extracted, autolyzed, partially demineralized auto- and allografts, 50% of the overall efficiency of fresh autografts. Fresh cancellous bone added to allografts did not improve long-term repair. Remodeling of all grafts appeared consistent with osteoconductive invasion by peripheral host endosteal and diploic elements; host external periosteum and dura contributed less. Central osteoinductive recruitment of mesenchymal cells from muscle or dura seemed not to occur in the adult dog. Partially demineralized dog calvarial grafts were resorbed without acting as a template for new bone formation. Surface demineralization, antigen extraction, and autolytic digestion of autografts and allografts, with or without fresh iliac bone, did not improve calvarial bone regeneration in adult dogs.

Animals↗
PubMed1983

Calmodulin infused intracerebroventricularly enhances food intake in the cat.

In the fasted cat, calmodulin (CaM) infused into the cerebral ventricle produces an increase in the normal intake of food in a dose-dependent manner. The enhancement of feeding by CaM seems to be functionally specific since the response was: (1) abolished by the simultaneous intraventricular infusion of calcineurin, a specific CaM antagonist; (2) not mimicked by another calcium binding protein, troponin C; and (3) independent of the CaM's lack of effect on body temperature and water intake. This finding opens up the dual possibility that this Ca2+ binding protein may affect receptors other than intracellularly and that CaM is involved in specific functions controlled by the brain.

Animals↗
PubMed1982

Unique contribution of catecholamine receptors in the brain of the cat underlying feeding.

After a Collison cannula was implanted bilaterally in the cat for intracerebroventricular (ICV) injection, individual patterns of food intake were determined. A mixture of dry and canned cat food was provided to the animal every morning at the same time for 1.0 hr. Once intakes had stabilized, either norepinephrine (NE) or an adrenoreceptor blocking agent was infused in one lateral ventricle by gravity flow over an interval of 30-60 sec. NE given ICV in a dose of 25-75 micrograms 15 min before the period of feeding enhanced both the amount of food consumed by the cat and the duration of its feeding for up to 1.0 hr. When phentolamine in a dose of 25-100 micrograms was infused 15 min prior to the feeding interval, the cat's intake of food was attenuated in a dose-dependent manner, again in terms of both the quantity consumed and the interval of eating. Propranolol was essentially without effect on food intake. In the fully satiated cat, NE infused ICV 15-45 min following the termination of its morning feeding episode tended to augment food intake at the highest 100 micrograms dose, but the effect was not significant. The dose-dependent hypothermia typically observed after NE is given ICV to the cat was found to be entirely independent of the feeding response. Overall, these findings show that noradrenergic pathways in the cat's feeding system apparently bias or otherwise modulate the amount of food consumed. As in other species, the feeding mechanism appears to be mediated through alpha-adrenergic receptors presumed to be in the diencephalon of the cat.

Animals↗
PubMed1981

Bovine salmonellosis attributed to Salmonella anatum-contaminated haylage and dietary stress.

An epizootic of salmonellosis in a dairy herd started 2 days after the feeding of a new shipment of medicinal-smelling soybean meal. Clinical findings consisted of diarrhea or fever (greater than 39 C), or both, and markedly decreased milk production. The attack rate was 73% in lactating cows, 3% in calves, and 0% in nonlactating cows. There were no deaths, but 1 cow aborted a late-term fetus. Salmonella anatum was isolated from feces, milk, pharynx, uterine fluid, haylage, and bird droppings from a hayfield. The epidemiologic findings suggested that haylage contaminated by wild birds and improperly stored in a silo was the source of infection and that the precipitating event was ingestion of spoiled soybean meal.

Animal Feed↗