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Biomedical subjects

D Harris

Publications and source records attributed to D Harris.

At least 199 records · Page 11Linked to original sources
PubMed1991

Magnitude estimation and cross-modal matching of auditory and lingual vibrotactile sensation by normal speakers and stutterers.

The present experiment was a preliminary attempt to employ the psychophysical scaling methods of magnitude estimation and cross-modal matching to investigate suprathreshold auditory and lingual vibrotactile sensation magnitude responses for normal-speaking young adults (N = 20) and young adult stutterers (N = 7). A 1000-Hz binaural auditory stimulus and a 250-Hz lingual vibrotactile stimulus were employed for both procedures. Results indicated that the stutterers tended to use more restricted response ranges than the normal speakers for auditory magnitude scaling, and lower response ranges than the normal speakers for lingual vibrotactile magnitude scaling.

Adolescent↗
PubMed1991

The effects of two anti-vertigo drugs (betahistine and prochlorperazine) on driving skills.

1. The effects of betahistine 72 mg three times daily, prochlorperazine 5 mg three times daily and placebo taken for 3 days before testing were compared on two actual driving tasks (weaving and gap estimation) and two psychomotor tasks (reaction time and kinetic visual acuity) in normal subjects in a double-blind prospectively randomised cross-over study. 2. The psychomotor effects of betahistine could not be distinguished from those of placebo. 3. Prochlorperazine impaired driving performance causing increased carelessness and slowing on the weaving test. 4. There was little subjective appreciation of impairment whilst taking prochlorperazine.

Adult↗
PubMed1991

Differences between OK and LLC-PK1 cells: cystine handling.

Cultured opossum kidney (OK) and porcine kidney (LLC-PK1) cells were compared for biochemical characteristics and cystine transport systems. The cell lines differ in amount of protein per cell, with OK cells having approximately one-half the amount found in LLC-PK1. Both cell lines contain 19 micrograms DNA/10(6) cells. As cells reach confluence, cystine uptake increases in OK and decreases in LLC-PK1 cells. Throughout the growth period, only lysine inhibits cystine uptake in OK, whereas glutamate is the inhibitor in LLC-PK1. The predominant site of cystine transport in OK cells is across the apical membrane, and the basolateral membrane is the corresponding site of transport in LLC-PK1 cells. Although the intracellular reduced glutathione pool is the same, the cysteine pool in OK cells is approximately one-fourth that found in LLC-PK1 cells. The ability of OK cells to reflect the shared cystine-dibasic amino acid transport system and LLC-PK1 to exhibit the cystine-glutamate antiporter system makes available two models for investigation of the development and structure of cystine transport systems.

Animals↗
PubMed1991

Osseointegrated implants for single tooth replacement: a 1-year report from a multicenter prospective study.

One hundred seven dental implants were inserted to support single tooth restorations in 92 patients participating in a prospective multicenter investigation. Only three implants (2.8%) were lost after 1 year of clinical function. Most of the remaining restorations were esthetically successful by using modified components. The gingival condition was healthy around the single crowns and coincided well with the clinical situation around the permanent teeth. The most obvious problem experienced during the first year was related to loose abutment screws. Twenty-six percent of the screws retaining crowns were retightened during the observation period, but the frequency of loose screws had a tendency to decrease as the study progressed.

Adult↗
PubMed1991

DNA flow cytometry of colorectal carcinoma: correlation of DNA stemlines with other prognostic indices.

DNA flow cytometry (FCM) was performed on paraffin-embedded tissue blocks of 38 surgically resected colorectal carcinomas (CRC). Forty-seven percent of tumors exhibited aneuploidy and 53% were diploid. Seventy-two percent of patients in the aneuploid but only 35% in the diploid group were alive after a mean follow-up of 30.7 and 28.8 months (p = 0.01), and 5-yr survival of 56.7% and 11.7%, respectively (p less than 0.05). The site of tumor location, Dukes' stage, and serum CEA level did not predict a certain DNA stemline. However, irrespective of the ploidy pattern, a serum CEA level greater than 5.0 was associated with a higher mortality and poor 5-yr survival (p less than 0.005). Similarly, advanced Dukes' stage was associated with higher mortality (p less than 0.05). Forty-six percent of the patients with lesions that were Dukes' B2 or advanced stage received adjuvant therapy. Eighty-five percent of this subgroup of patients died; 18% of these patients had aneuploid tumors. The role of FCM in the assessment of prognosis of CRC deserves further clinical evaluation in a randomized control trial.

Adult↗
PubMed1990

Substrate specificity and inhibitor sensitivity of a trypanosomatid alkaline peptidase.

An alkaline peptidase of Trypanosoma cruzi and Crithidia fasciculata, previously shown to cleave on the carboxyl side of arginine and lysine residues, was examined for its ability to cleave various fluorogenic substrates and for its sensitive to peptidase inhibitors. The enzyme of both T. cruzi and C. fasciculata has a preference for cleavage of substrates with basic amino acids at the P2 as well as the P1 position of the peptide chain. Arginine and lysine are equally acceptable at P2, whereas the enzyme prefers arginine to lysine at P1. An influence of the P3 amino acid residue on substrate cleavability was also apparent. The peptidase was highly susceptible to inactivation by peptidylfluoromethanes, peptidyldiazomethanes and peptidylsulphonium salts that contained arginine or lysine at P1. Additionally, diisopropylfluorophosphate inhibited the enzyme, whereas trans-epoxysuccinylleucylamido(4-guanidino)butane and iodoacetic acid were relatively weak inhibitors. Various reversible inhibitors of the enzyme were also examined. Inhibition by members of the primary aliphatic amine series, methylamine to n-heptylamine, showed a peak of inhibition at n-butylamine, which most closely resembles the lysine side chain. Agmatine, which resembles the arginine side chain, also strongly inhibited the peptidase. The kinetics of inhibition by these basic compounds were of the competitive type. Pentamidine and hirudonin, which resemble two arginine side chains joined together, were more effective inhibitors of the trypanosomatid peptidase than bases resembling only one arginine or lysine side chain.

Amines↗
PubMed1990

Stereochemistry of carbon monoxide binding to normal human adult and Cowtown haemoglobins.

The structures of carbonmonoxyhaemoglobins A and Cowtown (His146 beta----Leu) have been refined at 2.2 A (1 A = 0.1 nm) and 2.3 A resolution, respectively. The least squares fit to the Fe-C-O line makes an angle to the haem normal of about 6 degrees. The Fe-C-O group is bent from linearity by about 7 degrees. The porphyrins in the CO liganded haemoglobins are ruffled. This deformation of the haem and the distortion of the Fe-C-O group may explain the low CO affinity of haemoglobin. The electron density for the C-terminal residues is low but sufficient to distinguish the histidyl and leucyl residues clearly. The similarity between these two structures, apart from 146 beta, means that the reduced alkaline Bohr effect is due solely to the replacement of histidine by a leucine.

Carbon Monoxide↗
PubMed1990

Bioadhesive polymers in peptide drug delivery.

A frequently encountered problem with the peptide-based drugs which are becoming available is that these agents must generally be administered by injection. There is therefore considerable research interest in alternative delivery routes, such as the buccal and nasal mucosae, and the conjunctiva. This paper reports some quantitative considerations of peptide delivery via the buccal, nasal, ocular and gastrointestinal routes, based on estimates of permeability coefficients and other necessary parameters. Rates of delivery and the resulting systemic levels are calculated for some peptide drugs, and compared to therapeutic levels: situations are identified in which bioadhesive formulations may be of benefit.

Adhesiveness↗
PubMed1990

Inhibition of binding of anti-CD3 antibodies to paternal lymphocytes correlates with failure of immunotherapy for treatment of recurrent spontaneous abortions.

A two color flow cytometry crossmatch (FCXM) was used to evaluate the induction of anti-lymphocyte antibodies in 34 women undergoing immunotherapy for recurrent spontaneous abortions. All women had anti-lymphocyte antibodies that reacted with T-cells when analyzed by FCXM. However, inhibition of the binding of anti-CD3 to paternal CD3 lymphocytes in the presence of maternal antipaternal lymphocyte antiserum was found for some couples following lymphocyte immunotherapy for spontaneous recurrent abortions. Ten couples who had another spontaneous abortion following immunotherapy showed inhibition. In contrast, eight couples who did not show inhibition of the binding of anti-CD3 T lymphocytes to paternal lymphocytes by maternal anti-lymphocyte antiserum had live births. Women of the remaining 16 couples were either pregnant and awaiting birth or not pregnant. Thus, by FCXM it may be possible to predict those couples who will have successful pregnancies following this treatment.

Abortion, Habitual↗
PubMed1990

Metastatic salivary pleomorphic adenoma.

Pleomorphic adenomas of the salivary gland are usually regarded as benign tumours. We report a case in which a solitary pulmonary metastasis arose from a pleomorphic adenoma of the right parotid gland. The mechanism of metastasis is discussed.

Adenoma, Pleomorphic↗
PubMed1990

Timing of intensive care unit admission in relation to ICU outcome.

This study assessed the relationship between admission time (from hospital admission to ICU admission) and mortality predicted by the Mortality Prediction Model (MPM), actual mortality, and resource use. All admissions, except elective surgery patients, to the general medical/surgical ICU of a tertiary care hospital during a 24-month period were studied (n = 1,889). Patients admitted to the ICU within 1 day of hospital admission had lower predicted and actual mortality, and used fewer resources than patients admitted later. Predicted mortality was higher than actual mortality for patients admitted to the ICU early and was lower than actual mortality for later ICU admissions. Transfers had higher predicted and actual mortality, and used more resources than nontransfer patients. Time from hospital admission to ICU admission can be a potentially useful variable in models of ICU outcome.

Adult↗
PubMed1990

Axillary block anaesthesia in acute and elective hand surgery: a report on 300 procedures.

A total of 300 consecutive anaesthetic axillary blocks was performed over a period of 18 months in 291 patients. These blocks were carried out for emergency and elective hand surgery. Patients did not require any preparation or starving; 20-30 ml of 1% prilocaine according to the size of the patient is used for the block. A minimum induction time of 45 min is needed and patients are able to leave the hospital 20 min-2 h after operation, depending on the nature of the operation. No operation had to be abandoned due to failure of the block. Eleven patients required further injection of local anaesthetic during the operation. The duration of operations ranged from 10 to 130 min. Only 20% needed postoperative analgesia. The technique is easy to perform, it is safe and has long-lasting analgesic effect. It is an efficient, economical method of treatment, well tolerated and often preferred by patients. We think axillary block anaesthesia should be more generally used in hand and orthopaedic units.

Adolescent↗