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Biomedical subjects

J D Lewis

Publications and source records attributed to J D Lewis.

At least 19 recordsLinked to original sources

Maternal serum alpha-fetoprotein levels as an index of fetal risk.

In a prospective study on an obstetric population (1,059 cases) an association was found between elevated levels of maternal serum AFP at weeks 16 to 22 and the occurrence of premature labor or the need for emergency cesarean section in the third trimester. There was no association with other late fetal complications including perinatal death, perinatal asphyxia, and intrauterine growth retardation. The sensitivity of the test in respect of premature labor was 14 per cent but the high incidence of false-positive results reduces the practical value of the test.

Cesarean Section

Is measurement of placental function and maternal weight worth while?

A prospective survey of 1029 women delivered during 1976 at St. Bartholomew's Hospital was undertaken to assess the predictive value of a variety of clinical, ultrasonic, and biochemical variables in the detection of high-risk pregnancies. The best antenatal predictors of fetal risk were severe pre-eclampsia, depressed maternal serum levels of human placental lactogen, low maternal weight at 32 weeks' gestation, and heavy smoking by the mother. 62% of the high-fetal risk group had one or more of these features, but so did 33% of the controls.

Body Weight

Danazol therapy in hormone-sensitive mammary carcinoma.

The effect of Danazol, a synthetic gonadotropin inhibitor, on two groups of Sprague-Dawley rats with dimethylbenze (a) anthracine (DMBA) induced mammary carcinoma was studied. Twenty-four (83%) of 29 control animals developed mammary tumors. Forty-four rats in one treatment group received Danazol after tumor reached 0.5 cm in diameter. Twenty-nine (66%) demonstrated tumor regression (p less than 0.005) and in 16 (36%) tumor disappeared (p less than 0.005). In a second treatment group (given Danazol daily after administration of DMBA), only seven of 50 rats (14%) developed palpable mammary carcinoma (p less than 0.0005). Danazol therapy resulted in regression of established mammary carcinoma in rats, and produced a striking inhibition of carcinogenesis in those animals treated from the time DMBA was administered. Danazol is clinically safe; studies using it in the treatment of breast cancer in women who are candidates for hormonal ablative therapy seem warranted.

9,10-Dimethyl-1,2-benzanthracene

Deep venous thrombosis in patients having aorto-iliac reconstruction.

The 125I-labelled fibrinogen test has been used to assess the incidence of deep venous thrombosis in 88 patients who had undergone elective aorto-iliac reconstruction. Deep venous thrombosis was detected in 18 (20.5 per cent). The results suggest that these patients merit prophylaxis.

Adult

Computerized evaluation of electroencephalographic changes accompanying exchange transfusion in Reye's syndrome.

The EEGs of 7 children with Reye's syndrome (fatty liver and encephalopathy) were continuously recorded on magnetic tape for times ranging from 12 to 80 h. During these times the major therapy consisted of exchange blood transfusions. The tapes were automatically processed on a LINC-8 computer using a peak-detection algorithm. The main parameters investigated were the delta and theta indices, the mean EEG frequency, the mean peak-to-peak amplitude, and the frequency versus amplitude characteristics of the delta waves. In 5 patients who responded to therapy, a marked decrease in the delta activity and an increase in mean frequency were noted subsequent to exchange transfusions. In all 5 cases the delta waves exhibited a similar pattern of decreasing amplitude and increasing frequency following therapy. However, in 2 patients with a fatal outcome, no favorable EEG response was observed during treatment, and a simultaneous decline in both delta frequency and delta amplitude was noted as the clinical condition worsened. The results of this study indicate that continuous EEG monitoring in Reye's syndrome may be an important clinical adjunct in evaluating the effectiveness of exchange transfusion therapy and in signaling the need for further treatment.

Adolescent

Antithrombin III deficiency causing postsplenectomy mesenteric venous thrombosis coincident with thrombocytopenia.

The most commonly recognized cause of mesenteric venous thrombosis following splenectomy is hypercoagulation secondary to reactive thrombocytosis. A case is reviewed in which hypercoagulation followed splenectomy for idiopathic thrombocytopenic purpura (ITP) in spite of persistent thrombocytopenia. Episodic mesenteric venous occlusion occurred due to antithrombin III deficiency. This hypercoagulable state may be the cause of primary acute mesenteric venous occlusive disease. Symptoms and signs suggesting thrombosis in the portal circulation demand immediate coagulation studies since even in the thrombocytopenic patient thrombotic proglems can occur. Surgical intervention is the treatment of choice for segmental small bowel ischemia; warfarin therapy is indicated when there is evidence of antithrombin III deficiency.

Adult

Circulating levels of pregnancy-specific beta1-glycoprotein and human placental lactogen in the third trimester of pregnancy: their relationship to parity, birth weight, and placental weight.

Circulating levels of pregnancy-specific beta1-glycoprotein (SP1) and human placental lactogen (HPL) were measured in 153 normal subjects during the third trimester of pregnancy. The levels of SP1 and HPL showed a skewed distribution and rose progressively to reach a plateau by the 36th week. The normal range was calculated by ranking the data and division into centiles as well as by logarithmic transformation of the values. A low but significant correlation was observed between SP1 and HPL levels, SP1 and birth weight. There was also a correlation between HPL levels and placental weight.

Birth Weight

Pregnancy in cirrhotic and noncirrhotic portal hypertension.

The course of pregnancy in 1 patient with chronic active hepatitis (CAH) and cirrhosis, and another with extrahepatic portal vein obstruction (EHPVO) is described. The management of pregnancy in these diseases associated with portal hypertension is discussed and risks of pregnancy are compared. The patient with CAH presented with anovulatory cycles, and ovulation occurred following immunosuppressive therapy. Both women experienced massive upper gastrointestinal bleeding from esophageal varices. Bleeding was difficult to control and required variceal ligation in 1. Both patients manifested features suggesting cerebral edema indicating the need for caution with fluid and electrolyte therapy. Recovery of the woman with CAH after termination of pregnancy was slow. Review of literature demonstrated that variceal bleeding occurred in 43% of women with EHPVO compared to 23% of those with CAH and cirrhosis. Additional complications including hepatocellular failure (24%) occurred in patients with CAH but not in EHPVO. The management of pregnancy in portal hypertension and advice for contraception or sterilization are discussed.

Adult

Dose dependence of immunopotentiation and tumor regression induced by levamisole.

Breast cancer was induced in female Sprague-Dawley rats by 7,12-dimethylbenz(a)anthracene. Once tumors had become established, they were treated with varying doses of the immunopotentiating drug, levamisole. Tumor growth was measured in the various dosage groups, and at 6 months after tumor induction the animals were sacrificed. Their immunological competence at this time was measured by the mitogen responses of splenic lymphocytes. Untreated animals with breast cancer were found to be immunosuppressed compared to normal animals. The drug levamisole resulted in immunopotentiation, but at high doses it was immunosuppressive. Tumor regression was observed at doses that resulted in immunopotentiation, but not at high doses. There was a significant correlation between immune competence and tumor regression. It is concluded that levamisole can cause regression of breast cancer in the rat but that this effect is critically dependent on the dose of the drug; these observations confirm previous studies carried out on human cells in vitro. It is recommended that high doses of the drug be avoided in human clinical trials and that the patients who receive this drug should have their immune responses carefully monitored.

9,10-Dimethyl-1,2-benzanthracene

Fibrinolytic activator in the endothelium of the veins of the lower limb.

The local fibrinolytic acitivity of the femoral, popliteal and soleal veins has been studied using a histochemical technique. The results suggest that the fibrinolytic activity in the soleal veins may be low when compared with that in the femoral and popliteal veins. This may be an aetiological factor responsible for the high incidence of thrombi occurring in the soleal veins.

Aged

Which breast to biopsy: an expanding dilemma.

To provide insight into the significance of findings reported from screening asymptomatic women for breast cancer, we reviewed 19,928 mammographic studies with the accompanying physical examination and correlated these findings with 554 breast biopsies. Of 83 breast biopsies with suspicious findings on both physical examination and mammography, 72 demonstrated breast cancer (87%). Of 155 biopsies for suspicious changes on mammography alone, 50 (32%) demonstrated breast cancer. The accuracy of suspicious mammography was independent of findings limited to physical examination, 34 (17%) had breast cancer; 31 were in 152 biopsies of patients with mammography interpreted as normal (20%) and three were in biopsies of 52 patients (6%) in whom a visualized mass was interpreted as benign. One hundred and twelve breast biopsies were performed for changes interpreted as normal or benign. Six malignancies were discovered (5%). No cancer was found in 31 biopsies for nonpalpable benign mammographic abnormalities. Our results emphasize the importance of discriminating between nonvisualization of a mass and mammographic recognition of either a benign or malignant tumor. The reliability of interpretation is considerably greater for a visualized lesion than a nonvisualized one.

Biopsy

Response of HeLa cells to irradiation with pi- mesons.

HeLa cell suspensions were irradiated at various depths of Perspex in a beam of 70 MeV pi- mesons. The dose-rate in the Bragg peak varied between 40 rad hour-1 and 150 rad hour-1. The cells were assayed in vitro for loss of reproductive integrity. The results for irradiation in the peak indicated an RBE of about 2-1 when compared to the response obtained using 60Co gamma-rays at comparable dose-rates. At dose-rates of 100-150 rad hour-1, the RBE peak-to-plateau was about 1-4, while at lower dose-rates, the RBE peak-to-plateau was about 1.

Cell Survival