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Biomedical subjects

L Whitaker

Publications and source records attributed to L Whitaker.

At least 37 records · Page 2Linked to original sources
PubMed1993

Late functional results after surgical closure of acquired ventricular septal defect.

To assess the longer term outlook for patients who have undergone surgery for acquired (postinfarction) ventricular septal defect, we interviewed and studied 60 survivors from a single regional cardiac center between 3 and 144 months after the operation. Including the patients who died within 1 month of the operation, the 5-, 10-, and 14-year survivals (with standard errors) were 69% (65% to 74%), 50% (44% to 57%), and 37% (27% to 46%). Eighty-two percent of patients were in New York Heart Association class I or II. Ten patients (17%) had a persisting but not hemodynamically significant ventricular septal defect. Mean left ventricular ejection fraction was reduced at 0.39 (standard deviation 0.15), but this did not correlate with either New York Heart Association class or exercise tolerance. Twenty-eight patients (47%) had asymptomatic arrhythmias (17 with ventricular premature beats). Angina and other medical problems were not prevalent.

Aged↗
PubMed1992

A theoretical problem of interpreting the recently reported increase in homosexual gonorrhoea.

There has been considerable interest recently in using the occurrence of gonorrhoea infection as an indicator of sexual behaviour relevant to the transmission of human immunodeficiency virus. Mathematical models of gonorrhoea transmission can predict increasing incidence with decreasing sexual activity in the population, due to a resultant concentration of sexual activity in an active 'core' group. Increases in the incidence of gonorrhoea reported recently should therefore be interpreted with caution.

Gonorrhea↗
PubMed1992

Concordance of auxotype/serovar classes of Neisseria gonorrhoeae between sexual contacts.

One hundred and three known sexual-contact pairs of patients with culture-proven gonorrhoea who attended St Mary's Hospital, London between May 1989 and February 1991 were identified. All isolates from these patients were serotyped and auxotyped and compared for type concordance within sexual-contact pairs. Serotype was concordant in 80 (78%) of 103 sexual-contact pairs, auxotype in 88 (85%) and auxotype/serovar (A/S) class in 66 (64%) on the first screening. All pairs of isolates showed concordance in both serotype and auxotype when typing was repeated using a single set of serotyping reagents and of auxotyping media. Seventeen serovars, 9 auxotypes and 36 A/S classes were found in this population. Our results suggest that both serotyping and auxotyping may be used as markers to allow tracing of sexual-contact pairs, but that a single set of reagents should be used to ensure maximum reliability.

Contact Tracing↗
PubMed1992

Soft-tissue reconstruction of the face: a comparison of dermal-fat grafting and vascularized tissue transfer.

Eight patients treated with dermal-fat grafts and 8 patients treated with vascularized tissue transfer were retrospectively reviewed to determine the efficacy of the two methods in the treatment of the soft-tissue defects in Romberg's disease, clefting syndromes including hemifacial microsomia, and traumatic defects. Follow-up averaged 4 years and ranged from 1 to 9 years for the vascularized transfers and 1.5 to 11 years for the dermal-fat grafts. Both techniques were able to provide enduring augmentation. The vascularized transfers were able to provide a greater amount of augmentation. We conclude that dermal-fat grafting is a satisfactory technique for mild to moderate defects, but that vascularized transfers are required for moderate to severe defects.

Adolescent↗
PubMed1987

Diagnosis of gestational diabetes by capillary blood samples and a portable reflectance meter: derivation of threshold values and prospective validation.

Paired capillary-venous samples were obtained from 255 women undergoing a glucose challenge test and 116 women undergoing an oral glucose tolerance test. The capillary equivalents for the venous threshold values were calculated by regression analysis. The glucose challenge test predictions of either normal or abnormal agreed in 82%. The sensitivity, specificity, and positive and negative predictive values for the capillary oral glucose tolerance test were 89%, 90%, 62%, and 98%, respectively. These capillary equivalents were then applied prospectively to 147 women undergoing a glucose challenge test and 141 women undergoing an oral glucose tolerance test. The concurrence rate of the glucose challenge test in the prospective group was 90%. The sensitivity, specificity, and positive and negative predictive values for the capillary oral glucose tolerance test were 64%, 95%, 75%, and 92%. When the venous threshold recommendations of the American Diabetes Association were used instead of those standard at our institution, these values increased to 75%, 98%, 83%, and 96%, respectively. The recommended capillary values of the American Diabetes Association were 100% sensitive but had a positive predictive value of only 20%. Based on the prospective group, the cost per case of gestational diabetes identified would decline 63% if both a capillary glucose challenge test and an oral glucose tolerance test were used and 25% if the capillary glucose challenge test and venous oral glucose tolerance test were used. Combining the data set for new regression equations, the following venous-capillary threshold sets emerged: glucose challenge test, 140 mg/dl/150 mg/dl; fasting oral glucose tolerance test, 105 mg/dl/114 mg/dl; 1 hour, 190 mg/dl/211 mg/dl; 2 hours, 165 mg/dl/183 mg/dl; 3 hours, 145 mg/dl/157 mg/dl. The sensitivity, specificity, and negative predictive values for the capillary oral glucose tolerance test with these thresholds were 80%, 97%, 80%, and 97%. In conclusion, capillary glucose testing for diabetes during pregnancy is feasible and cost-effective.

Blood Glucose↗
PubMed1986

The relationship between capillary and venous glucose concentration during pregnancy.

Previous attempts to construct capillary equivalents of venous glucose values for prognostic purposes have failed. We examined the relationship between capillary and venous glucose concentration during pregnancy in 258 women who had samples taken at four different time intervals in relation to two different standardized meals. Capillary glucose concentration was determined with the Chemstrips bG and an Accu-Chek reflectance colorimeter and venous plasma glucose concentration was measured by the hexose kinase technique on an AutoAnalyzer. The capillary: venous relationship was constant over time for a given meal but the magnitude of the difference was affected by time. The capillary: venous relationship differed significantly between the two standard meals. The findings indicate that meal size and sampling time must be controlled for when one is attempting to construct capillary equivalents for venous derived norms. The failure of previous studies to control for these variables may explain their inability to construct useful capillary equivalents for venous glucose values. Our findings also indicate that attainment of venous norms with capillary specimens represent, in reality, tighter control.

Blood Glucose↗
PubMed1984

Ocular motility in craniofacial reconstruction.

Of 140 children undergoing major craniofacial reconstruction at The Children's Hospital of Philadelphia and examined preoperatively and postoperatively by the Ophthalmology Division, only 10 had surgically induced alteration in primary position horizontal alignment, 4 greater than 10 prism diopters. Only 2 patients had a new strabismus in primary position created by craniofacial surgery, both cranial nerve palsies. We believe early strabismus surgery is advantageous for attainment of binocularity and ease of tissue manipulation. Of 44 patients with craniofacial dysostosis (Crouzon), 20 had preoperative strabismus, and 12 required extraocular muscle surgery. Five of 12 had anomalies of extraocular muscle number and structure, usually involving the superior rectus muscle.

Adolescent↗
PubMed1980

The use of microvascular free flaps for soft tissue augmentation of the face in children with hemifacial microsomia.

The extent of facial deformity from hemifacial microsomia varies considerably. Minor degrees of asymmetry may be barely perceptible. Severe defects involve deficiencies and asymmetry of bone and soft tissue. Hence, reconstruction of both soft and hard tissues may be necessary. The authors have utilized a free flap based on the superior gluteal vessels to replace soft tissue deficits in three children with hemifacial microsomia. The flap, composed of fascia lata, adjacent muscle and fat (two patients) and overlying skin (one patient), is harvested through an incision high on the lateral thigh in the "bathing trunk" area. The vessels, measuring 0.5--1.0 mm. were anastomosed to the facial (one patient) and superficial temporal (two patients) vessels. In one child, simultaneous mandibular restructuring was done with bone grafts. The children ranged in age from four to eight years. Follow-up is for five to seven months. Although this microvascular procedure requires a prolonged anesthetic, it permits more accurate and predictable reconstruction. Scars are placed in inconspicuous or concealed areas. Simultaneous bony reconstruction can be done. Details of the procedure and an evaluation of postoperative results are presented.

Adipose Tissue↗
PubMed1979

The types of hearing loss and ear pathology noted in screening craniofacial patients.

Seventy patients who underwent craniofacial reconstruction were screened by otological and audiological examinations. Thirty-seven patients had visible ear pathology, thirty-six had conductive hearing impairments. No sensorineural losses were detected. The high incidence of otological pathology in craniofacial patients emphasizes the importance of multi-disciplinary care. Otological rehabilitation should be integrated into the treatment plan to provide maximum function throughout the period of craniofacial reconstruction. Suggestions are made to facilitate communication in the immediate post operative period.

Adolescent↗
PubMed1978

Urea and dilatation of the cervix.

The minimal elasticity of the uterine cervix has been related to its high collagen content. By interfering with cohesive forces that hold the collagen fiber bundle together, it is possible to diminish the physical strength of collagen. Urea has been used in collagen chemistry to dissociate collagen by interfering with hydrophobic linkages and hydrogen bonds. This results in a change of mechanical properties such as a decrease in tensile strength and an increase in elasticity. Basic studies of rat tail tendon demonstrated the additive effects of pH, concentration of urea, and temperature on the mechanical characteristics of collagen fibers. In vitro testing was performed using an injection of 30 per cent urea at pH 4. Serial measurements with a spring gauge instrument showed a reduction in cervical resistance. A cervical injection technique has been developed and toxicity of urea studied.

Animals↗