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Biomedical subjects

C Adams

Publications and source records attributed to C Adams.

At least 181 records · Page 10Linked to original sources

Ferriprotoporphyrin IX mediated oxygen activation/insertion reactions: the anerobic reduction of the aniline-Fe3+-microperoxidase-8 complex by NADH.

A spectrophotometric study of the reduction of the Fe3+ microperoxidase-8-aniline (Fe3+-MP-8-An) complex has been carried out. Addition of NADH to a solution of Fe3+-MP-8-An under strictly anerobic conditions results in the formation of a species with lambda max = 414 nm (Fe3+-MP-8-An lambda max 407 nm). The kinetics of formation of this species show an induction period (tau) which follows saturation kinetics with respect to [aniline] with Km(app) = 2.2 x 10(-3) mol dm-3, i.e., close to that obtained in the preceding paper from O2 consumption kinetics mediated by MP-8. Addition of an anerobic solution of the NADH reduced MP-8-An complex, to a saturated O2 solution at pH 12 in the presence of 0.5 mM NADH and aniline 10 mM results in the virtual elimination of the induction phase, which has previously characterized O2 consumption kinetics in ferriprotoporphyrin IX oxygen activation systems. The Arrhenius activation energy for the reduction of the Fe3+-MP-8-An complex is close to that observed for the first reductive step in the cyt P-450 O2 activation cycle. Anerobic reduction of Fe3+-MP-8 by sodium dithionite in 20% MeOH/Aq at pH 8 followed by anerobic titration of the Fe2+-MP-8 (lambda max 420.5 nm) with aniline at pH 12 gives rise to a species lambda max 415 with KD for the process = 4.4 x 10(-3) mol dm-3 (+/- 1.2 x 10(-3) mol dm-3).

Aniline Compounds↗

The effect of Goldmann applanation tonometry on automated static threshold perimetry.

Automated static threshold perimetry was performed in both eyes of 10 normal and 12 ocular hypertensive subjects treated with a topical beta-blocker, before and after Goldmann applanation tonometry of their right eyes. Both objective statistical comparison and subjective evaluation of the resultant visual fields showed no detrimental effect on visual field test results after applanation tonometry.

Adrenergic beta-Antagonists↗

Pelvic-floor musculature exercises in treatment of anatomical urinary stress incontinence.

The purpose of this study was to investigate the effects of pelvic-floor musculature exercises in the treatment of women with anatomical urinary stress incontinence. Fourteen female subjects, ranging in age from 33 to 67 years, participated in a four-week pelvic-floor musculature exercise program. Subjects underwent a pretraining urodynamic evaluation and were reexamined after four weeks of exercise training. Paired t tests of subjects' pretraining and posttraining values of bladder capacity, functional urethral length, and static urethral pressure profile showed no significant differences. Multivariate regression analysis demonstrated that the covariates of weight, motivation, and age did not significantly influence subjects' bladder capacity, functional urethral length, or static urethral pressure profile. Nine of the 14 subjects had a negative result on the posttraining urinary stress test (R = 0, p less than .01). The urinary stress test result was the only variable to change significantly from pretraining to posttraining measurements. All subjects reported posttraining improvement in control of urinary incontinence. A short-term exercise program for pelvic-floor musculature produced positive changes in subjects with anatomical urinary stress incontinence.

Adult↗

Neurogenic arthrogryposis multiplex congenita: clinical and muscle biopsy findings.

Thirteen cases of arthrogryposis multiplex congenita without evidence of spinal muscular atrophy, congenital muscular dystrophy, or structural myopathy were reviewed. Family history, consanguinity, pregnancy, delivery, number and severity of contractures, and outcome were evaluated. Laboratory investigations had been performed and a biopsy of muscle from an affected limb had been examined histochemically and by electron microscopy. Five biopsies showed fiber type 1 predominance and three had type 2 predominance. Patterns of fiber-type predominance may have resulted from altered neural influence leading to impaired maturation of type 1 or 2 motor units. Nine patients had been followed up for 3-8 years. Two were still not walking at age 8 years. For the 6 who were walking, the mean age at ambulation was 4.7 years. There was no deterioration in power. Muscle biopsy is recommended in arthrogryposis multiplex congenita. Identification of a probable neurogenic arthrogryposis multiplex congenita is important because the condition is not progressive and is apparently not transmitted genetically.

Arthrogryposis↗

A comparison of clinical and judicial procedures for reviewing requests for involuntary medication in New York.

The Rivers v. Katz decision substituted judicial review for administrative review of requests for involuntary medication of patients in New York State mental hospitals. This change, prompted by concern for the rights of involuntarily committed patients, did not delay or diminish the use of involuntary medication in a large state hospital. Advantages of judicial review include a better understanding by clinicians of the legal basis for involuntary medication and greater patient participation in the review procedure. Disadvantages include lack of an independent clinical review and increased costs.

Commitment of Persons with Psychiatric Disorders↗

[Acquired systemo-pulmonary fistula after pleurectomy responsible for a continuous thoracic murmur].

Systemo-pulmonary fistulae are rare. The case of a 27 year-old man, hospitalized for exploration of a continuous thoracic murmur, is reported. A right pleurectomy had been performed 2 years previously because of a recurrent spontaneous pneumothorax, and no murmur was present at that time. Angiography showed a systemo-pulmonary fistula with the right internal mammary artery and branches of the right axillary artery as afferent vessels, and the right pulmonary arteries and veins as efferent vessels. Blood gases measurements demonstrated a left-right shunt. The acquired nature of the fistula was suspected because of the history of right pleurectomy and the acquired nature of the murmur. There was no indication for surgery because of the complexity of the fistula and the absence of symptoms.

Adult↗

[Annulo-ectasing disease of the aorta: apropos of 10 cases].

Ten patients were investigated and operated for severe aortic regurgitation due to dystrophic aortic dilatation. This is the third commonest cause of pure aortic regurgitation (18 p. 100) operated at Necker Hospital during the same period. This condition, comprising aneurysm of the ascending aorta, dilatation of the aortic ring and dystrophic aortic valves, is often responsible for severe aortic regurgitation and is noteworthy because of the associated risk of aortic dissection. Cardiovascular surgery is indicated and usually includes replacement of the ascending thoracic aorta with aortic valve replacement.

Adult↗

Contrast sensitivity after epikeratophakia.

Epikeratophakia is a rapidly evolving surgical procedure for the refractive correction of aphakia. Even when Snellen acuity after epikeratophakia is normal, patients often report a subjective degradation of the visual image through the surgically corrected eye. To further define visual performance in the patient with optically successful epikeratophakia, we examined contrast sensitivity in two patients surgically corrected for monocular aphakia. Contrast thresholds were measured over a range of spatial frequencies using both computer-generated sinusoidal gratings and a commercially available wall chart system. The eye with epikeratophakia in each case was compared with the opposite normal eye with comparable acuity. One patient was also tested prospectively in the same eye both before and after surgery. Data demonstrate a depression of the contrast sensitivity function in the middle and high spatial frequencies induced by the placement of an epikeratophakia lenticule when compared with the normal eye or contact lens-corrected, preoperative aphakic eye with comparable good acuity. These findings may explain the subjective experience of epikeratophakia patients.

Adult↗

Effect of isomers of swainsonine on glycosidase activity and glycoprotein processing.

The chemical synthesis of swainsonine [(1S,2R,8R,8 alpha R)-trihydroxyindolizidine] from trans-1,4-dichloro-2-butene was previously described [Adams, C. E., Walker, F. J., & Sharpless, K. B. (1985) J. Org. Chem. 50, 420-424]. A modification of that synthesis provided two other isomers, referred to here as "Glc-swainsonine" [(1S,2S,8R,8 alpha R)-trihydroxyindolizidine] and "Ido-swainsonine" [(1S,2S,8S,8 alpha R)-trihydroxyindolizidine]. To determine whether these new compounds had biological activity, they were compared to swainsonine as inhibitors of a number of commercially available glycosidases. While swainsonine is a potent inhibitor of jack bean alpha-mannosidase but does not inhibit other glycosidases, its two isomers were inactive on alpha-mannosidase but did inhibit other enzymes. Thus, Glc-swainsonine was an inhibitor of the fungal alpha-glucosidase amyloglucosidase, and this inhibition was of a competitive nature (Ki = 5 X 10(-5) M) with respect to the substrate p-nitrophenyl alpha-D-glucopyranoside. This alkaloid also inhibited beta-glucosidase, but much less effectively than alpha-glucosidase. On the other hand, Ido-swainsonine was more effective toward beta-glucosidase than toward alpha-glucosidase, and this inhibition was also of a competitive nature. None of these inhibitors were effective against beta-mannosidase or alpha- or beta-galactosidase. Glc-swainsonine was also tested against the glycoprotein processing glycosidases. Surprisingly, in this respect, the alkaloid was like swainsonine in that it inhibited mannosidase II but had no effect or only slight effect on glucosidase I, glucosidase II, and mannosidase I. Glc-swainsonine also inhibited glycoprotein processing in cell culture.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaloids↗

Contrast sensitivity after penetrating keratoplasty.

Contrast sensitivity testing in the corneal transplant patient may enhance our assessment of visual performance, which is traditionally evaluated using Snellen acuity only. To evaluate contrast sensitivity function after penetrating keratoplasty, we studied 29 patients with anatomically successful corneal grafts and a best corrected visual acuity of 20/50 or better. Graft patients were compared with an age-matched control group including persons with comparable visual acuities without ocular disease. In addition to a complete ophthalmic examination, all subjects underwent contrast sensitivity testing using a computer-generated sinusoidal grating system as well as a commercially available contrast sensitivity wall chart. Data indicate that, despite comparable Snellen visual acuity, the contrast sensitivity curves for graft patients were depressed overall compared with those of normal subjects except at the lowest spatial frequency. However, comparison of grafted eyes to contralateral eyes with corneal disease in a small subset of patients with bilateral disease shows a trend toward higher contrast sensitivity values in the eyes that had been operated on. These data suggest that despite an improvement in contrast sensitivity with penetrating keratoplasty, an eye with a corneal transplant is not entirely normal from a visual standpoint. Nonacuity parameters may be important indexes for assessing real-world visual function in the graft patient, although the clinical role of these tests is not yet completely defined.

Adult↗

[Fitness for sports of patients with Wolff-Parkinson-White syndrome].

The fitness of patients with Wolff-Parkinson-White syndrome to indulge in sporting activities is a practical cardiology problem. The major risk is sudden death due to atrial fibrillation deteriorating to ventricular fibrillation. This risk is small or even theoretical, but signing a fitness certificate engages the clinician's responsibility. Non invasive complementary examinations are useful. Echocardiography may detect a heart disease that would preclude any sport. Exercise tests explore the behaviour of the accessory pathway and rarely trigger off arrhythmias. Holter recordings mainly investigate disorders of the atrial rhythm. The decision concerning fitness may be based on clinical symptoms. Exercise-induced tachycardia is a classical contra-indication to competitive sports. In patients whose tachycardia is unrelated to exercise, fitness may be discussed according to the results of exercise tests and of the electrophysiological study. A refractory period which would be considered as rather prolonged at rest does not protect against fast ventricular rate during passage to atrial fibrillation. If pre-excitation disappears during the exercise test in an asymptomatic patient, then competitive sports can be authorized without limitations. If not, only surgical excision or fulguration would provide full protection against a potentially dangerous fibrillation. It is concluded that Wolff-Parkinson-White syndrome contra-indicates competitive sports in most cases. Games played outside competitions remain possible in the absence of symptoms or when arrhythmias are well controlled by medical treatment.

Ajmaline↗

Aging and memory.

Although some age-related decline in memory probably occurs, most memory changes that result from normal aging are not as extensive within individuals or as representative within the population as previously had been believed (Zarit et al., 1981). Still, when older adults become aware of memory problems, they typically become quite alarmed (see Poon et al., 1980). One reason for this alarm is that memory loss has been found to be a reliable early sign of organic brain disease. Despite the sadness and severity of problems experienced by these patients and their families, the actual incidence of organic brain disease in older adults remains quite low. Unfortunately, it is possible that older adults' concern about less significant memory loss may compound or magnify problems that do exist. Therefore, when working with relatively healthy older adults, it is important first to consider possible transitory, nonmemory factors that could be contributing to memory problems and then to provide the clients with some perspective on their memory failures.

Aged↗

Late-onset hexosaminidase A and hexosaminidase A and B deficiency: family study and review.

Five children from two non-consanguineous Asian families with juvenile-onset hexosaminidase deficiency are presented. Two have juvenile Tay-Sachs disease with hexosaminidase A deficiency and three have juvenile Sandhoff disease with hexosaminidase A and B deficiency. The contributing factors in the spectrum of the hexosaminidase deficiency disease are outlined, and previously reported cases of late-onset Tay-Sachs and Sandhoff disease are reviewed. The heterogeneity of the effects of hexosaminidase deficiency is discussed, with the recommendation that the diagnosis be considered, in its various forms, when there is no other obvious explanation.

Age Factors↗

Review of the 12 years' activity of the International Committee for Prevention and Treatment of Depression.

The recognition and treatment of depressive states, as well as their prevention, call for special knowledge and experience. Therefore it was considered desirable that practising physicians with no specialised knowledge of psychiatry should be given more extensive opportunity for post-graduate instruction in the diagnosis and management of depression and also that they should be in a position to collaborate more closely with psychiatrists. Hence the idea of establishing an international committee, the members of which would in their turn set up national committees with the aim of promoting and intensifying post-graduate instruction in their respective countries.

Depressive Disorder↗

[Acute degenerative mitral insufficiency caused by rupture of the chordae in the elderly patient].

Five cases of degenerative mitral incompetence due to rupture of the chordae tendinae in patients over 70 years of age were reviewed to determine the clinical features of this pathology which is not rare in elderly patients. Chordal rupture usually involves the posterior leaflet and is a sign of generalised disease of the mitral apparatus of two main types: myxoid infiltration or pellucid degeneration. Although the clinical syndrome of rupture is rare (10 p. 100), the mechanism of the mitral regurgitation can be identified by 2D echocardiography with a sensitivity of 92 p. 100, and the consequences of regurgitation on the left ventricle can also be evaluated. Rapid progression to acute cardiac failure is often observed and early surgical cure may be necessary (valvular replacement with a bioprosthesis is more common than mitral valvuloplasty). Further justification for this surgical approach is the improved myocardial protection which has reduced the perioperative mortality rate to less than 10 p. 100.

Acute Disease↗