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Biomedical subjects

S Bennett

Publications and source records attributed to S Bennett.

At least 217 records · Page 12Linked to original sources
PubMed1983

Effect of anion exchange inhibitors and para-aminohippurate on the transport of urate in the rat proximal tubule.

The present studies were designed to examine the effect of some anion exchange inhibitors and para-aminohippurate (PAH) on urate transport in the proximal tubule of the rat utilizing microperfusion techniques. The addition of SITS, DIDS, or furosemide to the luminal perfusion solution resulted in a decreased rate of absorption of water and 2-14C-urate. In addition, the presence of PAH in the luminal microperfusion solution resulted in a lower rate of urate absorption. The absorptive flux of urate was significantly higher, however, when PAH was added to the solution microperfusing the capillaries. The capillary to lumen secretory flux of urate was significantly higher when PAH or unlabeled urate was added to the luminal perfusion solution and significantly lower when PAH was added to the capillary perfusion solution. The addition of SITS to either the capillary or luminal microperfusion solution resulted in lower secretory and absorptive fluxes of urate. These studies suggest that both the secretion and reabsorption of urate in the proximal convoluted tubule of the rat is influenced by some anion exchange inhibitors and PAH. The results are considered in conjunction with recent in vitro data suggesting that urate transport is mediated by a process of anion exchange.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1983

A 3-year longitudinal study of school-aged children's fundamental frequencies.

This report describes the longitudinal changes that took place in the average fundamental frequencies (fo) of 25 boys and girls over a 3-year period (means age range = 8:2-11:2). Results showed that developmental changes in the central tendency of fo can be detected over a 1-year period. For the group, the amount of decrease per 12-month interval averaged about 12 Hz, with a standard deviation of about 8 Hz. Cross-sectional observations of 7-11-year-old children's fundamental frequency characteristics do not reflect accurately the developmental course of fo, in large part because the between-subject standard deviations are larger than the age-related changes that occur in children's voices at this stage of development.

Age Factors↗
PubMed1983

Pharmacokinetics and tissue penetration of ticarcillin combined with clavulanic acid.

A combination of 3 g of ticarcillin and 200 mg of clavulanic acid was administered intravenously to six healthy male volunteers, after which the concentrations of these agents in serum and blister fluid were measured. The ratio of the two drugs in serum varied from 15:1 (ticarcillin-clavulanic acid) at the time of administration to 28:1 at 30 min and 62:1 at 5 h after injection. Both agents penetrated blister fluid rapidly, the ratio being 33:1 at 1 h and 66:1 at 3 h. The elimination rates of these agents were different, but for each compound they were similar in serum and blister fluid.

Adult↗
PubMed1983

Penetration of sulbactam and ampicillin into peritoneal fluid.

Twenty-five patients undergoing elective intraabdominal surgery received either 1 or 2 g of ampicillin together with 1 g of sulbactam intravenously before surgery. The peritoneal levels of the agent were measured. Both compounds penetrated peritoneal fluid readily; the mean percentage of penetration by ampicillin was 92%; that of sulbactam was 96%. After 1 g of each agent, the peritoneal levels of sulbactam were 47% greater than those of ampicillin. Our results suggest that 2 g of ampicillin plus 1 g of sulbactam should provide peritoneal levels that would inhibit most susceptible beta-lactamase-producing pathogens encountered in intraabdominal sepsis.

Aged↗
PubMed1983

Semantic generalization investigated using second-order conditioned visual afterimages.

A series of experiments is reported during which three subjects were initially classically conditioned to produce visual percepts to a sound only, second-order conditioned to transfer that response to an animal name, and finally taught a "foreign language". The results suggest that semantic generalization occurs whether the semantic relationships are formed either before or after the conditioned response is established.

Afterimage↗
PubMed1982

Preparation and evaluation of 2-substituted anthraquinones based on the anthracyclines.

Anthraquinones substituted at the 2 position with a basic side chain were prepared, and their binding to DNA was evaluated. All compounds showed an intercalative mode of binding to DNA; 1,4-dihydroxy derivatives bound more strongly than 1-hydroxy or nonhydroxylated compounds. Greatest DNA-binding activity was found where there were five atoms between the anthraquinone ring and the basic nitrogen.

Animals↗
PubMed1982

An effective paradigm for conditioning visual perception in human subjects.

Repeated pairing of an auditory conditioned stimulus with a weak visual unconditioned stimulus produced extended image sequences and visual responses conditioned to the tone alone. The experiment is set into the context of Pavlov's view of Helmholtz's "unconscious inference" thus providing experimental evidence linking the higher mental process of perception with classical conditioning.

Adolescent↗
PubMed1981

Vowel formant frequency characteristics of preadolescent males and females.

This report describes the vowel formant frequency characteristics (F1-F4 of five vowels produced in a fixed phonetic context) of 42 seven and eight year old boys and girls and the relationship of vocal tract resonances to several indices of body size. Results showed that the vowel resonances of male children were consistently lower than those of females, and that the extent of the sexual differences varied as a function of formant number and vowel category. Average across all measured formants of all five vowels, the overall sexual distinction was approximately 10%. The range of differences extended from about 3% for F1 of /i/ to 16%for F1 of /ae/. Measures of body size were always significantly related to these children's formant frequencies (range in multiple r's -0.506 to -0.866). The origin of the sexual differences in vocal tract resonance characteristics is discussed with reference to differences in vocal tract size and articulatory behaviors.

Adult↗
PubMed1981

Accelerated hypertriglyceridemia in patients on continuous ambulatory peritoneal dialysis - a preventable abnormality.

Increasing hypertriglyceridemia is a recognised complication of CAPD. To investigate the etiology lipid clearance studies using the intravenous fat tolerance test were performed in control subjects and in uremic patients before and after six months CAPD treatment. Oral carbohydrate intake was restricted and the use of hypertonic dialysate kept to a minimum. Although serum triglycerides were elevated in the uremic patients before CAPD (3.1 +/- 0.3 mMol/L) no further increase occurred during therapy. Oral carbohydrate intake was restricted to 240-250 Gms/24 hrs and hypertonic dialysate to 5.7 +/- 4.1% of the total. There were no significant changes in fractional removal rate of lipid. Therefore further increases in serum triglycerides in CAPD may be prevented by simple dietary manoeuvres.

Adult↗
PubMed1980

Mosaic and hypermodal cells in amniotic fluid cell cultures.

Karyotypic results from a series of 975 consecutive amniotic fluid specimens studied for prenatal diagnosis are reported. In only 32% of specimens were all cells analyzed euploid. Two thirds (63%) of the specimens studied were hypomodal in at least one cell; 25% of the studies were hypomodal in three or more cells. In contrast, only 3.5% of the studies were hypermoidal in one or more cells. Most frequently an additional chromosome 2 was present in these hypermodal cells. Cells with other than a diploid chromosome constitution may be mistakenly identified as evidence of mosaicism. This is especially likely when the involved chromosome is one associated with a clinically defined syndrome.

Amniotic Fluid↗
PubMed1980

Radioimmunodetection of cancer with radiolabeled antibodies to alpha-fetoprotein.

Sixteen patients with histologically proven malignant neoplasia were investigated by radioimmunodetection, using goat anti-alpha-fetoprotein (AFP) antibody radiolabeled with 131I. Images of the chest and abdomen were made with a scintillation camera, usually at 24 and 48 hr following injection of 1 to 2.5 mCi of radioiodinated antibody. Computer-assisted processing for the subtraction of 99mTc background radioactivity was used to enhance the detection and localization of tumors visualized by immune scintigraphy. All 12 sites involved by five AFP-producing tumors could be demonstrated by radioimmunodetection, while normal goat immunoglobulin G labeled with 131I failed to show similar results in one of the patients in whom the radioactive AFP antibody achieved tumor radiolocalization. Five patients in whom the tumors were not expected to produce AFP also had their large tumors demonstrated by immune scintigraphy in 6 of 16 tumor sites. The average tumor to non-tumor 131I image count density ratios were 3.20 and 1.96 for the AFP-containing and putatively AFP-deficient tumors, respectively. The image contrast was significantly greater for the AFP-containing tumors, and the subtraction technique enhanced the image contrast more than 2-fold. Based upon these initial results, the sensitivity of the method (true-positive rate) was 100%, its specificity (true-negative rate) was 80%, and the accuracy of the technique was 85%. This study thus indicates that radioimmunodetection of cancer with radioactive AFP antibodies can be useful in the evaluation of patients with AFP-containing neoplasms.

Adult↗
PubMed1980

Radioimmunodetection of primary and metastatic ovarian cancer using radiolabeled antibodies to carcinoembryonic antigen.

131I-labeled goat immunoglobulin G (IgG) prepared against carcinoembryonic antigen (CEA) was administered at an average dose of 1.0 mCi (180 to 250 microgram IgG protein) to patients with ovarian tumors in order to evaluate this method of tumor detection and localization, termed the radioimmunodetection of cancer. All primary cancers in 13 patients could be localized, whereas the metastases in six of nine cases could be imaged by external scintigraphy. However, only two of these cases showed metastatic spread by more conventional diagnostic techniques, including computer-assisted tomography, ultrasonography, and angiography. Successful tumor radiolocalization appeared to depend on tumor size, with lesions smaller than 2 cm in diameter not being detected. Tumors containing a CEA concentration above 115 ng/g, including a benign neoplasm, could be localized with radioactive anti-CEA antibodies. Administration of radioiodinated normal goat IgG to four patients with malignant or benign ovarian tumors failed to show tumor radioimmunodetection. One of these cases subsequently demonstrated a 4- x 4-cm tumor after receiving specific radiolabeled anti-CEA IgG. This study shows that ovarian neoplasms containing CEA can be detected and localized by external photoscanning after the application of radioiodinated antibodies to CEA and that, in this small series of patients, primary and secondary tumors could be detected in 100 and 67% of the cases, respectively.

Adenocarcinoma↗
PubMed1979

Sexual characteristics of preadolescent childrens' voices.

This investigation was undertaken to enlarge current understanding of the acoustic properties which influence the perception of maleness and femaleness in the voices of prepubertal children. Perceptual judgments of sexual identity were obtained in response to tape recordings of whispered and normally phonated vowels, normally spoken sentences, and sentences spoken in a monotonous fashion. Seventy-three children provided recordings. The four utterance types were chosen to experimentally manipulate selected physical properties of speech thought to exert an influence on listener judgments of sexual identity. The results of this work suggest that cues stemming from differences in vocal tract dimensions and/or articulatory behaviors provided the primary cues about the sexual identity of these preadolescent children. Although laryngeal source cues could have provided relevant information about the sex of a few children, this variable was felt to play a relatively minor role in the sex recognition process. New information was uncovered about the role certain suprasegmental factors play in the identification of child sex.

Adolescent↗
PubMed1979

Acoustic correlates of perceived sexual identity in preadolescent children's voices.

This project was undertaken to provide information about the sexual characteristics of preadolescent children's voices. In one series of experiments, perceptual judgments of sexual identity were obtained in response to 73 children's productions of isolated whispered and normally phonated vowels, normally spoken sentences, and sentences spoken in a monotonous fashion (Bennett and Weinberg, 1978). The purpose of this portion of the project was to describe certain acoustic and temporal characteristics of these children's speech samples, and to assess the relationship of these variables to perceptual judgments of sexual identity. Sexual differences in the frequency location of vocal tract resonances were significantly correlated with listener judgments of child sex in all four utterance conditions. The origin of the observed differences in vocal tract resonance characteristics is discussed with reference to possible sexual differences in vocal tract size as well as certain articulatory behaviors. Average fundamental frequency was significantly related to listeners' sex identifications in two utterance conditions. However, the influence of this variable was considerably less pronounced when compared to vocal tract information. Although certain measures of fundamental frequency variability (mean duration of level inflections and the rate of frequency change associated with upward shifts) were significantly related to perceptual measures of sexual identity, these cues were also interpreted to play a secondary role in defining maleness and femaleness in these children's voices.

Child↗
PubMed1978

Use of radiolabeled antibodies to carcinoembryonic antigen for the detection and localization of diverse cancers by external photoscanning.

To determine whether tumors containing carcinoembryonic antigen could be detected by administration of a radiolabeled, affinity-purified, goat lgG having 70 per cent immunoreactivity against carcinoembryonic antigen, 18 patients with a history of cancer of diverse histopathology received an average total dose of 1.0 mCi of 131l-labeled lgG. Total-body photoscans were performed with a gamma scintillation camera at various intervals after administration of the radioactive antibody. Ordinary photoscans proved difficult to interpret because of blood-pool background radioactivity, thus necessitating the computer subtraction of radioactive blood-pool agents from the antibody's 131l activity. Tumor location could be demonstrated at 48 hours after injection in almost all cases studied. The scans were negative in patients without demonstrable tumors or with tumors apparently devoid of carcinoembryonic antigen. Circulating antigen levels of up to 350 ng per milliliter did not prevent successful tumor imaging after injection of the radioantibody.

Animals↗