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Biomedical subjects

R Davis

Publications and source records attributed to R Davis.

At least 415 records · Page 23Linked to original sources
PubMed1981

Technical factors important to dorsal column stimulation.

A series of 101 patients with weakened neurological conditions (including multiple sclerosis and other demyelinating diseases) were augmented with dorsal column stimulation (DCS) over a 5 1/2-year period. 65 patients were implanted with an RF-linked system while 36 had a fully implantable programmable stimulator inserted. 20% failure occurred in the radio receiver series while none occurred in the latter, except for routine battery depletion. After 5 years, 23% of the patients using the RF system continued to use DCS, while after 4 years of using the fully implantable units, 81% of the patients continued to use DCS. Electrode displacement occurred in 27 patients, with breakage in a further 6 patients early in the series. Cathodal stimulation is more efficient that anodal stimulation when compared in 21 patients undergoing DCS.

Electric Stimulation Therapy↗
PubMed1980

Chronic cerebellar stimulation for cerebral palsy--five-year study.

Two hundred sixty-two patients were implanted with cerebellar stimulator systems since February 1974. Cerebral Palsy (CP) patients constituted 88% (230) of this series. The age range was 3 to 53 years with 70% under 20 years of age. Half the CP series were severely affected with the rest being moderately to mildly involved. Athetosis was present in 50%. The primary effect of CCS has been a lowering of spastic muscle tone in 90% of the patients. Improvements in control of immature reflexes such as startle response, head control, scissoring, balance and sitting occur in the first month. Athetosis progressively decreases to a 50% level. In the moderate mild CP group abilities improve over the first six months leading to better feeding, dressing, and ambulation with clearer speech and less drooling. After six months, 25 of 48 patients were out of wheelchairs, walking. A further 47 patients were ambulating better. No deaths from surgery. Five have died during the 5 years from other causes. Eleven patients (4%) have had infected systems. Equipment problems especially with malfunctioning radio receivers (40%) have served as blind controls--spasticity returning and abilities decreasing. Replacements with another receiver or with a totally implantable lithium powered pacemaker (May 1979) have lead to a return of benefits. Post-mortem findings indicate the low current levels (0.8 uC/sqcm) applied intermittently produced no appreciable damage to the cerebellar cortex.

Adolescent↗
PubMed1980

Technical problems and advances in the cerebellar-stimulating systems used for reduction of spasticity and seizures.

A series of 300 patients were implanted for chronic cerebellar stimulation (CCS) from February 1974 to June 1980. The charge density was in the range of 0.7-1.6 microCi/cm2/phase. There is a very narrow range of stimulation in which CCS is effective. Increasing above the range, clinical benefits cease; at levels over 10 microCi/cm2/phase, damage to the underlying conducting elements occurs which renders the prosthesis ineffective. Periodic monitoring of the implanted equipment is mandatory for a successful clinical program. Scalp recordings and radiography have detected a 53% failure rate in the I-108 RF linked system. The failed receivers were replaced with more reliable I-110 receivers and later with a fully implantable pulse generator. No change has been detected in the electrode button-cortex interface when measuring the access resistance up to 5 years later.

Cerebellum↗
PubMed1980

Should autologous blood transfusion be rediscovered?

With a greater appreciation and understanding of reactions to homologous blood transfusion there has been a renewed interest in autologous blood transfusion. The techniques and indications for preoperative banked autologous blood, perioperative haemodilution and recycled salvaged autologous blood transfusion are described. When circumstances permit, autologous blood transfusion is a safe, economical and efficient alternative to homologous blood.

Blood Preservation↗
PubMed1980

Hopelessness, depression, and suicide intent.

Seventy-three inpatients completed Beck's Suicide Ideator Scale, Beck's Hopelessness Scale and the MMPI Depression Scale. As hypothesized, suicide intent was significantly more correlated with hopelessness than with depression. When the effect of hopelessness was removed statistically, there was no relationship between suicide intent and depression.

Adult↗
PubMed1980

Echocardiographic and surgical correlations in bacterial endocarditis.

The results of preoperative echocardiography were compared with the pathologic findings at the time of surgery in 24 patients undergoing valve surgery for endocarditis. Of the 32 valves involved by vegetations, 27 (84%) were identified preoperatively. Valve destruction was correctly predicted in 16 of 18 cases. Myocardial abscess formation was detected in only one of the five patients in whom it occurred. Overall, the echocardiograms satisfactorily predicted the pathologic anatomy in 20 cases. In the remaining four patients, the echocardiographic description was seriously incomplete or misleading. Thus, surgery can be recommended on the basis of the clinical and echocardiograhic findings for patients with endocarditis. Cardiac catheterization is reserved for patients in whom significant coronary artery disease or intracardiac shunts are suspected or in whom a satisfactory echocardiogram cannot be obtained.

Adult↗
PubMed1979

Treatment of chronic congestive heart failure with captopril, an oral inhibitor of angiotensin-converting enzyme.

The renin-angiotensin system is thought to maintain elevated systemic vascular resistance in heart failure. The hemodynamic effects of captopril (SQ 14225), an oral inhibitor of angiotensin-converting enzyme, were measured in 10 patients with stable congestive heart failure poorly controlled by digitalis and diuretics. At single daily doses of 25 to 150 mg, the cardiac index rose from 1.75 +/- 0.18 to 2.27 +/- 0.39 (mean +/- S.D.) liters per minute per square meter (P less than 0.001), and pulmonary-wedge pressure fell from 26.5 +/- 7.5 to 17.3 +/- 6.1 mm Hg (P less than 0.01). Systemic vascular resistance decreased from 2006 +/- 300 to 1393 +/- 238 dyne seconds per centimeter (P less than 0.001), and mean arterial pressure fell from 83.7 +/- 7.0 to 70.3 +/- 9.9 mm Hg (P less than 0.001) (mean +/- S.D.). Heart rate did not change appreciably. Hemodynamic alterations peaked at 90 minutes and persisted for three to four hours. Control plasma renin activity ranged from 1.1 to 7.3 ng per milliliter per hour and did not correlate with changes in hemodynamic values. Three patients on long-term treatment maintained clinical improvement. Although its mechanism of action has not been completely elucidated, captopril may prove useful in the treatment of chronic congestive heart failure.

Administration, Oral↗
PubMed1979

No place on the NHS menu for à la carte and candlelight.

The problems facing the catering manager are so multifarious they include the kitchen sink. Not only has he the whole spectrum of modern management skills to grapple with but tired appetites to tempt and the out-dated image of institutional 'gruel' to overcome. A catering manager for Birmingham Health District, describes the ways in which catering can improve the image of hospital food.

Food Service, Hospital↗
PubMed1979

Photolytic decomposition of indapamide.

Photolytic decomposition of indapamide (I) in nitrogen-flushed methanol yields 3-sulfamoyl-4-chlorobenzamide (II), 2-methylindoline (III), semicarbazide (IV), and 1-(N-formamido)-2-methylindoline (V); in oxygen-flushed methanol, II--V, 1-aminocarboxymethyl-2-methylindoline (VI), 3-sulfamoyl-4-chlorobenzoic acid (VII), methyl-3-sulfamoyl-4-chlorobenzoate (VIII), and 2-(N-acetamido)-benzoic acid (IX) are formed. A comparison is made with thermal decomposition of I.

Chemical Phenomena↗
PubMed1979

Evaluating the performance of a computer-based consultant.

The performance of a computer-based clinical consultation system is evaluated. The program, called MYCIN, is designed to function as an aid for infectious disease diagnosis and therapy selection, with an initial emphasis on bacteremias. The evaluation methodology is discussed, as well as the difficulties encountered in attempting to evaluate clinical judgments. Specialists in infectious diseases judged MYCIN's final therapy recommedation, and intermediate conclusions about the significance of the infection and identity of infecting organisms. The evaluation techniques described may be useful in assessing the performance of other clinical decision aids. Results of the evaluation show that the program's therapy recommedations meet Stanford experts' standards of acceptable practice 90.9% of the time (table 2), with some variation noted both among individual experts and between Stanford experts and others (tables 1, 2).

Animals↗