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Biomedical subjects

B Smith

Publications and source records attributed to B Smith.

At least 415 records · Page 23Linked to original sources
PubMed1983

First report of intramyocardial pH in man. II. Assessment of adequacy of myocardial preservation.

Intramyocardial pH and temperature were continuously measured in the anteroseptal region in 40 patients undergoing aortic cross-clamping during cardiac operations. Myocardial protection was achieved with systemic cooling (25 degrees C) and multidose potassium cardioplegia (4 degrees C). A clinical myocardial preservation score was devised based on intraoperative and postoperative need for inotropic support, postoperative creatine kinase isoenzyme (CK-MB) and electrocardiographic changes, and radionuclide ventriculography. The patients were divided into three groups according to their preservation scores. Group I (n = 17) with good preservation (scores 0 to 2), Group II (n = 15) with fair preservation (scores 3 to 8), and Group III (n = 8) with poor preservation (scores 9 to 15). Baseline intramyocardial pH was similar in all groups (mean +/- SEM = 6.77 +/- 0.03). With the administration of cold potassium cardioplegia, intramyocardial pH rose above baseline in all three groups. The magnitude of this rise related directly to the adequacy of preservation and to the duration of the cross-clamp period. Patients with lowest preservation scores and shortest cross-clamp periods had the highest intramyocardial pH. In contrast, there was no relationship between myocardial temperature during cross-clamp and either intramyocardial pH or the preservation score. The integrated mean intramyocardial pH during cross-clamp was found to be the parameter that correlated most with the adequacy of preservation. The correlation between intramyocardial pH and myocardial temperature during the period of cross-clamping related to the length of this period; it was good (r = 0.76, p less than 0.01) in periods of 40 minutes or less and very poor in periods exceeding 60 minutes (r = 0.27, p greater than 0.10). It is concluded that (1) the magnitude of rise in intramyocardial pH during the period of aortic cross-clamping is a good indicator of the adequacy of myocardial preservation; (2) during periods of aortic cross-clamping exceeding 40 minutes, myocardial temperature is a poor indicator of adequacy of preservation, since progressive tissue acidosis may occur despite low myocardial temperatures; and (3) techniques and solutions that can effectively reduce the progression of tissue acidosis will, in most likelihood, enhance our ability to protect the ischemic myocardium during cardioplegic arrest.

Adult↗
PubMed1982

Comparison of questionnaire and laboratory tests in the detection of excessive drinking and alcoholism.

A comparison was made between the efficacy of eight laboratory tests and three rapid interviews in the detection of excessive drinking and alcoholism among 385 psychiatric patients. gamma-glutamyl transpeptidase, the best of the laboratory tests, detected only a third of those consuming more than 16 "drinks" per day or independently diagnosed as alcoholic. In contrast, the Brief MAST, the Cage, and the Reich interviews each identified nine out of ten alcoholics, and the Cage and Reich interviews detected 93% and 98% of excessive drinkers respectively. The three interviews, each of which takes less than 1 min to administer, have considerable potential for use in the routine screening of high-risk groups, such as hospital patients.

Adolescent↗
PubMed1982

Naso-orbital fractures, complications, and treatment.

Naso-orbital fractures designate a backward displacement of the bones of the nasoskeletal framework into the interorbital space. This anatomical disruption results in deformities, lacrimal dysfunction, medial canthal deformities, ptosis, blow-out fractures, ocular complication, and most severely, penetration of bony fragments into the anterior cranial fossa. Early and late treatment methods are considered. Restoration of the bony contour of the nose and medial canthoplasty procedures are discussed.

Blepharoptosis↗
PubMed1982

Reactivation of contraction in detergent-lysed teleost retinal cones.

Teleost retinal cones contract in the light and elongate in the dark. In the green sunfish, Lepomis cyanellus, the necklike myoid region of the cone contracts from as much as 120 micrometers (midnight dark-adapted) to 6 micrometers in fully light-adapted state. When dark-adapted fish are exposed to light (1.4 lux), cone myoids contract with a linear rate of 1.5 +/- 0.1 micrometers/min. We report here that detergent-lysed motile models of teleost retinal cones exhibit calcium- and ATP-dependent reactivated contraction, with morphology and rate comparable to that observed in vivo. For reactivation studies isolated dark-adapted retinas were lysed with nonionic detergent Brij-58 (0.1-1.0%). In reactivation medium containing 10(-5) M free calcium and 4 mM ATP, the lysed cones contracted with normal morphology at in vivo rates (1.4 +/- 1 micrometer/min). Little contraction was observed if ATP or detergent was deleted from the medium or if free calcium levels were less than 10(-8) M. Ultrastructural examination of cone models lysed with 1% Brij-58 revealed that, in spite of extensive extraction of the cytoplasmic matrix, cytoskeletal components (thin filaments, intermediate filaments, microtubules) were still present. Thus we have produced extensively extracted motile models of teleost retinal cones which undergo calcium- and ATP-dependent reactivated contraction with normal morphology at physiological rate.

Adenosine Triphosphate↗
PubMed1982

Dynamics of breathing in infants.

Passive compliance (C) has been measured in 10 infants at 10--90 min after birth and in 10 infants at a few days of life by recording mouth pressure after airways occlusions at end inspiration. From the slope of the expiratory flow-volume curve, the passive time constant (tau) and resistance (R = tau/C) have been also computed. Examination of the changes of C with time and of the expiratory flow-volume curves indicates that the end-expiratory volume is maintained above functional residual capacity at both ages, but significantly more so at a few days (7.6 ml) than at 10--90 min (3.5 ml). The passive time constant (tau = C . R) is shorter at the early age due to the smaller C. The active compliance (C') and resistance (R') values have been estimated from the pressure generated by the infant when the airways are occluded at end expiration. The active time constant of the respiratory system (tau' = C' . R') is less than tau, due to a smaller active compliance, particularly at a few days. The active resistance is on the contrary similar to R. The active stiffening of the respiratory system provides more stability of the infant's respiratory system and a more ready volume response for any given change in pressure; its price, however, is a higher work of breathing. At optimal breathing rates, in fact, the active work is 127% (10--90 min) to 183% (a few days) higher than that computed from the passive values. The inspiratory flow wave tends to be squared at both ages minimizing the energy losses due to friction.

Airway Resistance↗
PubMed1982

Exfoliative dermatitis during cefoxitin therapy.

An 84-year-old man was admitted to the hospital with a diabetic foot ulcer and osteomyelitis of the calcaneum. While being treated with cefoxitin sodium, he experienced generalized exfoliative dermatitis, which subsided on discontinuation of therapy. To our knowledge, this is the first report of exfoliative dermatitis with a cephalosporin or related drug.

Aged↗
PubMed1982

The neuropathology of pseudo-obstruction of the intestine.

Destruction of the myenteric plexus impairs ongoing peristalsis and produces dilatation of the gut lumen with thickening of the gut wall. Achalasia of the cardia, hypertrophic pyloric stenosis and non-Hirschsprung megacolon are well-known examples of damage to the bowel nerve supply. There are many causes, some of which are unknown, but the common ones can be divided into three groups. Congenital developmental failure may be total and incompatible with life, or less severe, in which case resection may be possible. Acquired inflammatory damage, other than Chagas' disease, can occur anywhere in the gut. Autonomic neuropathy may involve either the neurons or the Schwann cells. The former is often due to drugs because the autonomic ganglia are outside the blood-brain barrier. The latter is frequently associated with metabolic disease, such as diabetes mellitus.

Adult↗
PubMed1982

Preparation of split thickness auricular cartilage for use in ophthalmic plastic surgery.

Auricular cartilage can be used extensively in a number of procedures by the ophthalmic plastic surgeon. It is ideal for the lengthening of eyelids, and also has a place in eyelid reconstruction, surgery for trichiasis, and the anophthalmic socket. It is vital that the cartilage be prepared in a precise and meticulous manner in order to insure optimum results.

Ear Cartilage↗
PubMed1981

Effects of 17 beta-estradiol on the biosynthesis of collagen in cultured bovine aortic smooth muscle cells.

The effect of 17 beta-estradiol (E2) on the biosynthesis of collagen in cultured bovine aortic smooth muscle cells was explored. Cells treated with various concentrations of the hormone for 14 days following subcultivation were subjected to growth studies. The cultures were also evaluated for [14C]hydroxyproline formation, the presence of collagenase-susceptible protein, prolyl hydroxylase activity, and procollagen types. There were no effect of E2 on the growth of these cells. At 10(-8) M E2, the hydroxylation of proline when compared to control cultures was reduced by 25-30%; however, little difference in extractable prolyl hydroxylase activity or total [14C]proline incorporation into protein was observed. The effect on collagen synthesis appears to be dose dependent over concentrations of E2 ranging from 10(-6) to 10(-12) M when measured by collagenase susceptibility. Procollagen typing on diethylaminoethylcellulose displayed reduced amounts of procollagen type I and type III fractions as well as other collagenous components. More importantly, however, the ratio of these two procollagen types were also altered. Similar results were obtained from the medium or cell layer. It is concluded that aortic smooth muscle cells cultured in the presence of 17 beta-estradiol display a decreased production of collagen in addition to altering the ratio of type I to type III procollagen fractions produced.

Animals↗
PubMed1981

Lisuride in parkinsonism.

Lisuride is a soluble ergolene derivative with endocrine effects similar to but more potent than those of bromocriptine. In nine subjects with idiopathic, postencephalitic, or drug-induced parkinsonism, lisuride at a dosage of 0.05 to 0.15 mg intravenously caused an immediate improvement in tremor, rigidity, akinesia, and postural deformity, but also caused chorea and orofacial dyskinesia. Improvement lasted 2 to 3 hours. Lisuride had little or no effect in a single patient with progressively supranuclear palsy. Oral lisuride therapy, 0.8 to 4.8 mg daily, had similar effects but occasionally caused reduced awareness and hallucinations.

Administration, Oral↗