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Biomedical subjects

M L Thomas

Publications and source records attributed to M L Thomas.

At least 235 records · Page 13Linked to original sources
PubMed1978

Clinical pharmacology of cefadroxil in infants and children.

The pharmacokinetics of cefadroxil suspension were studied in 30 children, 13 months to 12 years of age (mean age, 5.7 years). Average peak concentrations in serum of 11 to 14 mug/ml and of 7 to 10 mug/ml after 15- and 10-mg/kg doses, respectively, were not substantially affected by the feeding status. The serum half-life values were 1.3 to 1.5 h. Cefadroxil was detected in saliva of all children 2 h after 15-mg/kg doses: the levels ranged from 0.17 to 2.6 mug/ml (mean, 0.46 mug/ml). The average concentrations in urine were 1,700 and 2,620 mug/ml at 0 to 2 and 2 to 4 h, respectively, after 15-mg/kg doses. In a randomized controlled study of 50 children with impetigo, cefadroxil was as effective as penicillin G in curing existing lesions and in preventing development of new lesions. Cefadroxil may be useful for therapy of mucocutaneous and urinary tract infections in infants and children.

Biological Availability↗
PubMed1978

Coronary artery ectasia--a variant of occlusive coronary arteriosclerosis.

In a study of 1000 consecutive coronary arteriograms, 12 patients (all men) had coronary artery ectasia. Ectasia was found most frequently in the circumflex or right coronary artery. Only 1 patient had ectasia in the left anterior descending coronary artery. In 11 patients, ectasia of one artery was associated with severe stenosis or occlusion of other vessels, typical of arteriosclerosis. Histology from an ectatic segment in one of this group showed changes of severe arteriosclerosis with extensive intimal fibrosis and destruction of the media. One patient had a mixed collagen vascular disease. Measurement of coronary sinus flow in 2 patients with coronary artery ectasia showed flows in the range of patients with non-ectatic coronary artery disease. At cardiac surgery flows down the graft to ectatic arteries were in the same range as in grafts to non-ectatic vessels. Patients with coronary artery ectasia should be anticoagulated.

Adult↗
PubMed1978

Arteriomegaly of persistent sciatic arteries.

Angiographic findings are described in a patient with enlarged persistent sciatic arteries and a ruptured sciatic artery aneurysm. The left persistent sciatic artery was patent and dilated to a width of 10 cm throughout its length. It had ruptured in the lower thigh. The common iliac, internal iliac, and both sciatic arteries were dilated and tortuous, with generally smooth outlines. Some patchy calcification in the arterial wall was noted. Arterial flow was extremely slow in the dilated arteries, requiring very delayed films to show the right sciatic artery as far as its bifurcation at the knee.

Aneurysm↗
PubMed1978

A phlebographic study of the incidence and significance of venous thrombosis in the foot.

A total of 188 foot phelbograms in 100 patients with suspected venous thrombosis or pulmonary embolism were studied. Thrombus was demonstrated in 59 (31%) of the foot phlebograms. It is concluded that foot vein thrombosis is common, that it may be a source of pulmonary embolism, and that venous thrombus may start in the foot veins and spread into the calf. Foot phlebography should become part of the routine examination of patients with suspected deep venous thrombosis or pulmonary embolism.

Foot↗
PubMed1978

Pharmacologic evaluation of orally administered antibiotics in infants and children: effect of feeding on bioavailability.

The clinical pharmacology of orally administered antibiotics was investigated in 106 infants and children. The antibiotic suspensions studied were ampicillin, cephalexin, erythromycin estolate, erythromycin ethylsuccinate, penicillin G, and penicillin V. The feeding status of the patients was evaluated in relation to the concentrations of drugs in serum, saliva, and tears. Peak concentrations and area-under-the-curve values of cephalexin, penicillin V, and penicillin G were reduced 40% to 60% in patients given milk and drug concurrently. Absorption was enhanced when erythromycin ethylsuccinate was given milk. After administration of both erythromycin formulations, penicillin V and ampicillin, salivary concentrations exceeded the minimal inhibitory concentrations for most pneumococci and group A streptococci and for many meningococci. The clinical implications of these pharmacokinetic data are discussed.

Administration, Oral↗
PubMed1977

Doppler examination vs clinical and phlebographic detection of the location of incompetent perforating veins: a prospective study.

Accuracy in excess of 80% has been claimed both for ultrasound and for phlebographic localization of incompetent perforating veins (ICPVs). To test these claims, a blind prospective study was carried out to compare three methods of simultaneous ICPV detection with operative findings. ICPV localization on the medial side of 39 legs was made by clinical examination, ultrasound, and ascending phlebography, each by a different observer. The ICPVs were confirmed at operation. All three methods were comparable in their accuracy in predicting the anatomical site of ICPVs. Phlebography produced fewer (seven) and ultrasound more (49) false-positive results than clinical examination did. There was no specific advantage of ultrasound over clinical examination. The advantages of phlebography, (1) fewer unnecessary explorations and (2) assessment of the status of the deep venous sytem, must be weighed against its cost and morbidity.

Humans↗
PubMed1977

The accuracy of bolus ascending phlebography in demonstrating the ilio-femoral segment.

The phlebograms of the ilio-femoral segment obtained by a bolus technique in 100 patients were reviewed. The technique of bolus phlebography from bipedal injections is described in detail. In 92% of the phlebograms the ilio-femoral segment was considered to be sufficiently well opacified to exclude thrombus. Follow-up of the patients confirmed the accuracy of the method.

Femoral Vein↗
PubMed1977

Clinical pharmacology of methicillin in neonates.

The pharmacokinetic properties of methicillin were investigated in 59 newborn infants. Concentrations of methicillin in serum were approximately 58 and 80 microng/ml at one hour after 25 and 50 mg/kg doses, respectively. The average serum half-life values ranged from one to three hours and were inversely correlated with birth weight and chronologic age. The half-life values, volumes of distribution, and plasma clearances of methicillin are shown in relationship to gestational age and chronologic age. A dosage of 25 mg/kg is recommended for therapy of most neonatal staphylococcal diseases; the frequency of administration is altered on the basis of birth weight and chronologic age.

Birth Weight↗
PubMed1977

Site of origin of deep vein thrombus in the calf.

A phlebographic technique is described for demonstrating as fully as possible the stem and muscle veins of the calf. The findings in 103 examinations containing calf thrombus demonstrated by this method are presented. It is concluded that calf vein thrombosis is as likely to originate in stem veins as from the soleal muscle veins.

Clinical Trials as Topic↗
PubMed1977

The relative importance of incompetent communicating veins in the production of varicose veins and venous ulcers.

To investigate the possible anatomic and hemodynamic reasons for the variability in response to surgery for venous insufficiency (a 50% ulcer recurrence rate following ligation of incompetent perforating veins), we performed phlebography and venous pressure measurements in 109 legs of 77 patients and in 30 healthy volunteers. Patients were divided into five groups: saphenofemoral incompetence alone (group 1), saphenopopliteal incompetence (group 2), incompetent lower leg communicating veins alone (group 3), calf communicating veins and saphenous incompetence (group 4), and postthrombotic limbs (group 5). Patients in groups 1 through 4 had phlebographically normal deep veins. As compared to the normal controls (68%), preoperative pressure measurements revealed a significantly smaller pressure fall during exercise (deltaVPex) in all groups, which was the least marked in groups 3 (26%) and 5 (17%). These latter two groups failed to increase their pressure fall with thigh tourniquet. deltaVPex 3 months after operation demonstrated normalization in groups 1, 2, and 4 (52%, 57% and 59% respectively). Groups 3 and 5 improved little following surgical ligation. Whenever saphenous vein incompetence coexists with lower leg communicating vein incompetence, the former appears to be the dominant cause of the pressure abnormalities. Based on venous pressure measurements and phlebography, patients with normal deep veins and who increase their deltaVPex with a thigh tourniquet should respond favourably to orthodox surgical ligation of the saphenofemoral or saphenopopliteal junction. By contrast, if no change in deltaVPex is noted in patients with incompetent perforating veins and the deep veins look abnormal on the phlebogram, then ligation of the incompetent communicating veins would appear to be associated with a high recurrence rate.

Adult↗
PubMed1977

Intravenous administration of kanamycin and gentamicin in newborn infants.

The pharmacokinetics of kanamycin and gentamicin were studied after intramuscular (IM) and intravenous (IV) (constant infusion over 20 minutes) administration in newborn infants. The serum concentrations, half-lives, area-under-the-curve values, and volumes of distribution were similar for each drug after both routes of administration. Based on these pharmacological similarities, it is likely that these aminoglycosides can be given safely and effectively as constant IV infusions to neonates in whom IM injections are not feasible.

Female↗
PubMed1976

Relation between postphlebitic changes in the deep veins and results of surgical treatment of venous ulcers.

41 patients with venous ulceration, investigated by ascending phlebography, had operations to ligate incompetent calf perforating veins. Recurrent ulceration developed within five years of operation in all 23 patients with evidence of deep-vein damage on the initial phlebograms. Only 1 of the seventeen patients with normal deep veins had a recurrent ulcer during the same period of follow-up. Thus local surgery to the perforating veins in postphlebitic limbs was shown to be ineffective.

Adult↗
PubMed1976

Mixed vascular deformities of the lower limbs, with particular reference to lymphography and surgical treatment.

A series of patients with congenital blood and lymph anomalies of the lower limb investigated and treated at St Thomas's Hospital, London, are reviewed. They fell into three classes: (1) those in which the venous element predominated (Klippel and other syndromes), (2) those with arteriovenous shunts and (3) those with angiomas of blood or lymph vessels scattered through the limb (diffuse mixed angiomas). Most of the patients were investigated by angiography (of blood or lymph systems) as well as by plethysmography, dermal temperature measurements and other techniques in the thermal laboratory. Phlebography showed most abnormalities in the Klippel group and was useful in delineating them before operation. The importance of confirming the existence of an adequate deep venous circulation prior to ablation of abnormal superficial vessels is emphasized. Arteriography showed most abnormalities in the group with suspected arteriovenous shunts. The most commonly performed operations in this group were for control of overgrowth of the limb or for ulceration. Lymphography showed many of the Klippel group to suffer from insufficiency of the main pathways, either aplasia or hypoplasia. In addition many had vesicles, fistulas and lymph cysts. Patients in the arteriovenous shunt group had large hyperplastic lymph pathways, which were possibly either congenital or a hypertrophic response. One hundred and thirty-eight operations were performed in 46 patients for a variety of lesions and disabilities. These are reviewed. The scope and benefit of surgery in these children are greater than has been accepted in the past. Three patients required amputation of a limb. There were 5 deaths in the series, 4 of these being in the scattered angioma group and in patients in whom the deformities extended beyond the limb into the trunk.

Adolescent↗