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Biomedical subjects

K Wallace

Publications and source records attributed to K Wallace.

At least 37 records · Page 2Linked to original sources
PubMed1994

Influence of aging on oral-pharyngeal bolus transit and clearance during swallowing: scintigraphic study.

The aim of the study was to determine the influence of normal aging on regional transit and the efficiency of bolus clearance during the oral and pharyngeal phases of swallowing. We compared scintigraphically derived oral-pharyngeal transit times and isotope clearance during swallowing in 21 healthy aged volunteers (mean age 68 +/- 8 yr) and 9 young controls (mean age 28 +/- 7.5 yr). Subjects swallowed 5- and 10-ml water boluses mixed with 30 MBq 99mtechnetium tin colloid. Oral and pharyngeal transit times, pharyngeal clearance time, and postswallow residual counts in each region were derived from time-activity curves. Pharyngeal residual counts were significantly greater in the aged than in controls (P = 0.0008), but age did not influence oral residual. Aging significantly prolonged oral transit time (P = 0.02), pharyngeal transit time (P = 0.0004), and pharyngeal clearance time (P = 0.0001). We conclude that normal impairs the efficiency of pharyngeal clearance during swallowing, prolongs scintigraphic measures of oral-pharyngeal transit, and increases the exposure time of the glottis to the swallowed bolus.

Adult↗
PubMed1994

Female pelvic floor functions, dysfunctions, and behavioral approaches to treatment.

This article has reviewed normal pelvic floor function and the type of evaluation and treatment programs that should be offered to the woman who presents with pelvic floor dysfunction. Pelvic floor muscle contraction is an acquired function. It is not innate. Development of pelvic floor muscle strength requires specificity training and dedication to an exercise program. It is imperative that women be educated about the functions and dysfunctions of the pelvic floor complex in order to promote preventive rather than restorative benefits of pelvic floor exercise. Exercise programs should be specific to the type of pelvic floor muscle dysfunction and its causes. Behavioral treatment options focus on traditional physical therapy techniques of education, therapeutic exercise, and the use of physical modalities that aid in the restoration of muscle function. Exercises for the pelvic floor should be part of every woman's fitness regime. Health care providers, health educators, and fitness personnel need to ask women more questions about pelvic floor function, encourage women to exercise these muscles, and to seek medical care for their dysfunctions. Only then will the magnitude and prevalence of pelvic floor muscle dysfunctions receive the attention that they need.

Biofeedback, Psychology↗
PubMed1993

Double-outlet single ventricle and an abdominal vascular mass: in utero diagnosis with pathological confirmation.

A fetal echocardiographic scan was performed when routine prenatal ultrasound screening failed to identify four cardiac chambers. The scan showed a single ventricle with an associated circoid varicosity. Because of these anomalies, amniocentesis was suggested and trisomy 18 confirmed. The presence of major cardiac structural anomaly should prompt careful and specific review of all fetal anatomy to screen for syndrome identification and consideration of amniocentesis.

Abnormalities, Multiple↗
PubMed1993

Cytotoxicity of tacrine and velnacrine metabolites in cultured rat, dog and human hepatocytes.

Clinical trials with tacrine (THA) and its principal (1-OH) metabolite (velnacrine) for the treatment of Alzheimer's disease have been hampered by adverse hepatic events that were undetected in preclinical studies. As part of integrated in vivo/in vitro efforts to characterize the role of metabolites in these events, cultured cells were evaluated for their suitability for further mechanistic studies. The relative cytotoxic potentials of THA, three monohydroxy metabolites of THA (including velnacrine, a racemate), the two velnacrine enantiomers, and several known and suspected dihydroxy velnacrine metabolites were determined. Cytotoxicity was evaluated in 24-hour cultures by morphology and by the Neutral Red Uptake Assay. All test articles were evaluated in primary rat hepatocytes and in a human hepatoma cell line (HepG2). THA and velnacrine were also tested in a rat hepatoma cell line (H4) and in primary dog hepatocytes. The metabolic competency of each cell type was determined. Sensitivity to THA and velnacrine was greatest in H4 cells, followed by primary rat and HepG2 cells; dog cells were least sensitive. In HepG2 cells, THA was clearly more cytotoxic (LC50:54 micrograms/ml) than its monohydroxy metabolites (LC50 values: 84 to 190 micrograms/ml); dihydroxy velnacrine metabolites were the least cytotoxic (LC50 values:251 to 434 micrograms/ml); the relative order was comparable in primary rat hepatocytes. Roles for reactive metabolites and/or altered metabolic capabilities of Alzheimer's patients are suggested.

Alanine Transaminase↗
PubMed1991

Pediatric poisoning from over-the-counter imidazoline-containing products.

We present two instructive cases of imidazoline poisoning in young children. Imidazoline decongestants, readily available in numerous non-prescription preparations, can rapidly produce toxicity from oral ingestion and topical application. Signs and symptoms depend on whether peripheral or central alpha 2-adrenergic receptor stimulation predominates. Timely diagnosis depends on a high index of suspicion and careful questioning about the availability of these over-the-counter products. Standard toxicologic management will prevent significant morbidity. No specific antidote exists.

Emergency Service, Hospital↗
PubMed1989

Orbital neoplasia with enophthalmos in a cat.

A 9-year-old cat was evaluated for left-sided enophthalmos and protrusion of the third eyelid. A primary orbital fibrosarcoma was diagnosed. During the orbital exploration, normal periorbital fascia could not be identified in the lateral and ventral region, thus accounting for the enophthalmos.

Animals↗
PubMed1989

Reinfection of virus free mice with mouse mammary tumour virus.

BR6/Icrf mice carrying a milk-transmitted mammary tumour virus (MMTV) develop tumours after several pregnancies. If the mice are freed from MMTV, no tumours develop. In the experiments described in this paper, MMTV was reintroduced into MMTV-free mice by foster nursing, which was least effective if the pups were exposed to the virus only during the first week of life. Exposure for even a short time after that age led to a tumour incidence similar to that found in normally infected mice. Reinfection was also achieved by injection of MMTV-containing milk into weanling or pregnant mice, and was then transmitted naturally to the next generation.

Aging↗
PubMed1987

Localization of the monoclonal antibody HMFG2 after intravenous and intraperitoneal injection into nude mice bearing subcutaneous and intraperitoneal human ovarian cancer xenografts.

Xenografts (s.c. and i.p.) of human ovarian cancer, shown to express the tumor associated antigen defined by the monoclonal antibody HMFG2, were used to investigate in vivo localization of the radioiodinated antibody after i.p. and i.v. injection. Following i.v. injection, maximum uptake (31.4 +/- 3.5%/g s.c. tumor) was seen in s.c. tumors at 48 h after injection. Tumor:normal tissue ratios increased with time to 240 h. Uptake by ascites and i.p. tumors was less, with a maximum of 10.0 +/- 8%/g ascites reached at 16 h and 11.4 +/- 3.2%/g i.p. tumor at 96 h. After i.p. injection uptake in s.c. xenografts was maximal (14.8 +/- 2.0%/g) at 20 h. For ascites, the i.p. route of administration resulted in high uptake (27.7 +/- 5.8%/g) early (2 h) with an ascites:normal tissue ratio of 69.3 and a specific antibody:nonspecific antibody ratio of 30.8. Except for data at one time point, uptake by i.p. solid tumor was similar to that seen for s.c. tumor. These data strongly suggest that large concentration advantages can be achieved in ascites cells by regional i.p. injection, but that i.p. solid tumor may rely on i.v. delivery of antibody before uptake.

Animals↗
PubMed1987

Intraperitoneal xenografts of human epithelial ovarian cancer in nude mice.

Using continuous human ovarian cancer cell lines, i.p. xenografts were successfully established in nude mice from four of four attempts. When primary tumor material was used, xenografts grew in 8 of 10 attempts. From these eight, three passageable xenograft cell lines have been established. To our knowledge, this is the first report published of such xenografts. I.p. xenografts closely mimic the clinical behavior of human ovarian cancer, and those developed from primary tumor material maintain close morphological similarity to the parent primary tumor. When expression of placental alkaline phosphatase and the tumor associated antigens defined by the monoclonal antibodies HMFG1, HMFG2, AUA1, and F36/22 by these models was determined, those i.p. xenografts derived from primary tumor material exactly matched the original tumor, while none of the xenografts derived from the cell lines expressed these antigens. These models will be useful for investigating the biology and treatment of ovarian cancer.

Animals↗
PubMed1984

A possible mechanism for diisopropylfluorophosphate-induced memory loss in rats.

Passive avoidance retention and cortical [H3]-quinuclidinyl benzilate (QNB) binding were examined in rats that were chronically treated with diisopropylfluorophosphate (DFP), an irreversible acetylcholinersterase inhibitor. Retention of a passive avoidance response in DFP-treated rats was significantly lower when compared to vehicle-treated controls. Passive-avoidance retention decreased from 93% in control animals to 68% in DFP-treated rats. QNB binding studies revealed the density of muscarinic receptors in cortical homogenates was significantly reduced from 0.95 +/- 0.04 pmole/mg protein in controls to 0.72 +/- 0.04 pmole/m protein in DFP-treated rats. Scatchard analysis of QNB binding curves did not reveal a decrease in affinity of muscarinic receptors for QNB. Based on data that DFP causes a reduction in cholinergic receptors, this study supports the hypothesis that central cholinergic receptors are associated with mechanisms involved in memory storage.

Animals↗
PubMed1983

Grass-skirt burns in Papua New Guinea.

A retrospective survey of burn cases admitted to Alotau Hospital, Papua New Guinea, over a four-year period showed that 48% were due to grass-skirt burns. Most of these occurred in young girls and usually caused full-thickness burns of the buttocks and thigh. The commonest long-term complications were contractures of the hips and knees. The next most common cause of burns was a fall into a fire during an epileptic fit (24%). None of the patients were on anticonvulsants. The population needs to be informed of the dangers of leaving children near open fires, of the value of bundling up children whose grass-skirts catch fire to smother the flames, of the importance of anticonvulsants to chronic epileptics, and of the advantages of seeking medical treatment when burns occur.

Accidents, Home↗
PubMed1980

Dust levels in a riding stable.

Over a period of 4 months, in winter, the mean concentration of airborne particles in the ambient air of a riding stable was 0.41 mg/m3. This value was significantly higher than that found outdoors (0.04 mg/m3). During the day, levels of airborne particles were highest when stalls were cleaned and soiled bedding from the previous night replenished, and lowest when all stable activities had ceased. Fine particles, capable of entering the pulmonary alveoli, constituted 30 to 40 per cent of the total mass concentration of airborne particles.

Air↗
PubMed1980

Early-onset pauciarticular juvenile rheumatoid arthritis associated with human leukocyte antigen-DRw5, iritis, and antinuclear antibody.

Evidence has been sought for a genetically determined predisposition among children with juvenile rheumatoid arthritis (JRA) who are also at particular risk for the development of inflammatory eye disease.45 unrelated Caucasian patients (41 female) with early-onset pauciarticular JRA were human leukocyte antigen (HLA) types. 28 of the study group were found to be HLA-DRw5 compared with 16 of 84 controls (X(2), 24.3, P = <0.001). 9 patients were HLA-DRw8 compared with 4 of 84 controls (X(2), 7.51, P = <0.01). Iritis developed in 24 of the 45 children studied, 17 of whom were typed as HLA-DRw5 when compared to controls (X(2), 26.76, P = <0.001) and 6 with iritis typed as HLA-DRw8 (X(2), 9.10, P = <0.01). Antinuclear antibody was found in the serum of 17 of the 28 patients typing as HLA-DRw5 compared with 4 of the 17 who did not have this antigen (X(2), 5.88, P = <0.02). No such association was seen in patients with HLA-DRw8. In a study of linked genes, a delta value of 0.090 was found for HLA-DRw5 with HLA-B12, of 0.070 for DRw5 with HLA-Cw4, and a value of 0.050 for DRw5 and HLA-Bw35. This suggests a linkage disequilibrium between HLA-DRw5 and these two B series alleles, a conclusion which was supported by haplotype analysis in families of 11 of the disease probands. HLA-DRw5 has not previously been reported to be increased in any rheumatic disease group. It is proposed that HLA-DRw5 is a genetic marker defining those at risk for early-onset pauciarticular JRA with iritis.

Antibodies, Antinuclear↗
PubMed1976

Residues of 2, 4-D in air samples from Saskatchewan: 1966-1975.

Residues of 2,4-D (2,4-dichlorophenoxyacetic acid) in air samples from several sampling sites in central and southern Saskatchewan during the spraying seasons in the 1966-68 and 1970-75 periods were determined by gas-liquid chromatographic techniques. Initially, individual esters of 2,4-D were characterized by retention times and confirmed further by co-injection and dual column procedures. Since 1973, however, only total 2,4-D acid levels in air samples have been determined after esterification to the methyl ester and confirmed by gc/ms techniques whenever possible. Up to 50% of the daily samples collected during the spraying season at any of the locations and during any given year contained 2,4-D, with butyl esters being found most frequently. The daily 24-hr mean atmospheric concentrations of 2,4-D ranged from 0.01 to 1.22 mug/m3, 0.01 to 13.50 mug/m3, and 0.05 to 0.59 mug/m3 for the iso-propyl, mixed butyl and iso-octyl esters, respectively. Even when the samples were analysed for the total 2,4-D content, i.e. from 1973 onwards, the maximum level of the total acid reached only 23.14 mug/m3. In any given year and at any of the sampling sites, about 30% of the samples contained less than 0.01 mug/m3 of 2,4-D. In another 40% of the samples, the levels of 2,4-D ranged from 0.01 to 0.099 mug/m3. Only about 30% of the samples contained 2,4-D concentrations higher than 0.1 mug/m3, with only 10% or less exceeding 1 mug/m3. None of the samples, obtained with the high volume particulate sampler, showed any detectable levels of 2,4-D, indicating little or no transport of 2,4-D adsorbed on dust particles or as crystals of amine salts.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1975

Recent advances and controversies in the management of Hodgkin's disease.

Sifting the preceding factors, which may weigh for or against routine laparotomy and splenectomy as a staging procedure in Hodgkin's disease, we advocate that one be sure the diagnosis and histologic classification are confirmed by an experienced hematologic pathologist, that complete clinical studies for clinical staging with the exception of the lymphangiogram be performed, and that a laparotomy and splenectomy be performed in appropriate centers for clinical Stages I through III and unconfirmed Stage IV patients unless some contraindication is present. The subdiaphragmatic nodal areas should not be irradiated without evidence of the presence of disease in these areas. A minimum of 4,000 rads of supervoltage therapy should be delivered to the areas known to be involved with Hodgkin's disease plus the neighboring lymph node areas, using total nodal irradiation only on definite indication but not prophylactically.

Adult↗