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Biomedical subjects

D David

Publications and source records attributed to D David.

At least 199 records · Page 11Linked to original sources
PubMed1979

Inefficacy of digitalis in the control of heart rate in patients with chronic atrial fibrillation: beneficial effect of an added beta adrenergic blocking agent.

The role of digoxin and the new beta adrenergic blocking agent, timolol, in controlling heart rate at rest and during exercise was investigated in 28 patients with chronic atrial fibrillation. Digoxin failed to prevent excessively rapid heart rates during mild to moderate exercise. Increasing digoxin blood levels from a mean of 0.6 to 1.8 ng/ml had no effect on heart rate either at rest or during exercise. The addition of timolol, 20 to 30 mg/day, resulted in a satisfactory and significant attenuation of the rapid heart rates both at rest and during exercise. Heart rates at rest were 91 and 98 beats/min in the patients with low and high digoxin dosage and rose to 135 and 139 beats/min, respectively, during exercise. Timolol reduced the heart rate to 67 at rest and to 92 beats/min during exercise. The effect of beta adrenergic blockade at rest was less pronounced in patients whose initial heart rates were below 90 beats/min. Digoxin alone may not suffice to control excessive heart rate in patients with chronic atrial fibrillation. The additional beta adrenergic blockade actually normalizes the heart rate response in these patients.

Adrenergic beta-Antagonists↗
PubMed1979

The importance of the genetic picture and globin synthesis in determining the clinical and haematological features of thalassaemia intermedia.

Twelve carriers of thalassaemia intermedia were studied. Their clinical and haematological picture was distinctly different from that in both heterozygotes and homozygotes for beta thalassaemia. Several genetic patterns were found responsible for thalassaemia intermedia: beta/delta beta thalassaemia, alpha 2 beta/beta thalassaemia-heterocellular HPFH. In a few subjects the genetic picture indicated that the patients were homozygous for beta thalassaemia, in spite of the mildness of the clinical situation. The lack of genetic uniformity was refelcted in very wide Hb A2 (2.5--8.7%) and Hb F (7.5--96.9%) ranges, as opposed to the noticeable degree of biochemical uniformity indicated by the very similar imbalance of globin chain synthesis: 0.33-0.54 for the non-alpha/alpha chain ratio in the peripheral blood. The mean for this parameter (0.43 +/- 0.05) was significantly different (P less than 0.001) from that observed in heterozygous carriers (0.60 +/- 0.10) and homozygous carriers (0.11 +/- 0.05) for beta thalassaemia. The marrow blood displayed a comparable pattern. It is therefore suggested that the severity of thalassaemia is attributable to the degree of chain synthesis imbalance.

Adolescent↗
PubMed1979

The beneficial effects of verapamil in chronic atrial fibrillation.

Digitalis preparations frequently fail to control heart rate in many patients who have chronic atrial fibrillation, particularly during physical exertion. The effects of orally administered verapamil, 160 to 240 mg/day, on the heart rate at rest and during mild exercise were studied in 23 digitalized patients with chronic atrial fibrillation of various causes. Verapamil substantially reduced the excessive heart rate response to exercise in well-digitalized patients who had chronic atrial fibrillation.

Aged↗
PubMed1978

Transtelephone adjustment of antiarrhythmic therapy in ambulatory patients.

The electrocardiograms of 80 ambulatory patients receiving antiarrhythmic therapy were supervised with the help of a transtelephone monitoring system. The patients used a pocket-size modulator and reported several times daily to the receiving center integrated into the intensive cardiac care unit. The surveillance lasted for 5-28 days during which various drugs in varying dosages were administered to suppress or prevent dysrhythmias. In 94% of the patients, a satisfactory therapeutic achievement was obtained. The transtelephone system provides easy diagnosis, immediate pattern recognition, direct and frequent contact with the ambulatory patient and long periods of follow-up. During this time, the proper antiarrhythmic agent can successfully be defined, its effective dose can safely be determined and unnecessary hospitalization can thus be prevented.

Adult↗
PubMed1978

Immune reactions associated with practolol therapy.

A review of adverse reactions following practolol therapy is presented. The appearance of antinuclear antibodies seems to herald the clinical manifestations. Antinuclear antibodies were found in 30% of patients treated with practolol for prolonged periods. It is suggested that patients who develop an immune reaction following practolol metabolize the drug differently than those who do not.

Antibodies, Antinuclear↗
PubMed1977

[Detection of DDT in quail eggs: quantitative analysis].

Significant residues of DDT have been found in the albumin and vitellus of Quail eggs, after external treatment of the shell with an aqueous suspension of commercial DDT. The rate of pesticide crossing varies according to the shell porosity and thickness. Residues of DDT have also been found in the control eggs and in the Quail industrial food.

Age Factors↗
PubMed1977

Humoral factors in shock causing bradycardia and myocardial depression.

Hypovolemic shock was maintained for 6 hours in dogs in which the heart was hemodynamically protected by a biological model described earlier. Blood of these dogs was exchanged with that of healthy dogs in which myocardial tension and heart rate were continuously monitored. It was found that rate and force of decline in the recipient dog in a fashion similar to the drop in the animal in shock. If, however, the pH of the infused blood was raised to normal, the bradycardia in the recipient dog was prevented but the myocardial depression was not abolished. Administration of aprotinin alone did not prevent the bradycardia or depression of contractility, whereas correction of the pH and treatment with aprotinin not only prevented the decline in both but led also to a transient increase in myocardial tension of the recipient animal. The results seem to indicate that 1) in shock myocardial depression and cardiac slowing are induced by humoral factors transferable by blood to a normal animal, 2) acidity caused the bradycardia but not drop of tension, 3) aprotinin prevents the depression of contractility only in a normal pH medium, and 4) aprotinin may prevent the action of a preformed myocardial depressant factor rather than inhibit its formation.

Animals↗
PubMed1977

[Action of DDT on colonization of the chick embryonic genital ridges, by primordial germ cells (author's transl)].

Colonization of the genital ridges by primordial germ cells was quantitatively studied, at stages 18-24, in Chick embryos issued from eggs treated with commercial DDT before incubation. The pesticide provokes, dating from the 4th day of development (stage 24), a significant reduction in the gonadal germ population. This deficit may be due to 3 different actions of DDT on the primordial gonocytes: an inhibition of their gonadic colonizing capacity, a failure of proliferation and, at last, an excessive rate of cell death. However, the DDT modifies neither the initial number of blastodermal germ cells nor their migratory capacity toward the gonadal region.

Animals↗
PubMed1977

Thrombosis on Björk-Shiley aortic valve prosthesis. A case report and review of the literature.

A patient who developed thrombosis on a Björk-Shiley aortic valve prosthesis is reported. The patient presented with severe angina pectoris and the main physical findings were absence of the closing click of the prosthetic valve and the presence of systolic and diastolic aortic murmurs. Echocardiography showed early closure of the mitral valve and depressed left ventricular function. An emergency operation was performed and the clot was removed. The patient's recovery was uneventful and he is well one year after surgery. Awareness of the possibility of valve thrombosis is necessary in view of the need for emergency surgical treatment. The literature on the subject is reviewed.

Adult↗
PubMed1976

Diagnostic and therapeutic assessment by telephone electrocardiographic monitoring of ambulatory patients.

The electrocardiograms of ambulatory patients have been monitored over the telephone by staff of the intensive cardiac care unit using equipment in the unit. Telephone monitoring is a useful way of diagnosing transient symptomatic arrhythmias and a reliable aid in supervising the patient's rhythm at the beginning or end of treatment. The doctor has direct contact with the patient at the time of his symptoms so that he can reassure or instruct him. This system costs relatively little in manpower and equipment and permits relatively long periods of follow-up. It is effective, however, only in symptomatic cases in which the rate or rhythm disturbances last long enough to be transmitted. Also important are the negative findings when the patient complains of symptoms and abnormal findings during routine telephone transmissions. Accurate detection of transient ischaemic changes seems to be less reliable, and further technical improvements are required.

Adult↗
PubMed1976

[Comparative effects of intravitellin injections of p, p'-DDT and of commercial DDT on the germ cells of embryonic gonads of birds].

The p, p'-DDT present in the composition of commercial DDT, is responsible for the germ deficit in the gonads of bird embryos. Administered into the vitellus or on the shell, before incubation, the pesticide exerts the same reduction of the Quail germ population. While, for the Chick, the germ decrease is less significant after injection than after immersion.

Animals↗