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Featured researches published by Jan D. Esser.


Cancer | 1991

The value of estrogen and progesterone receptor determinations in advanced breast cancer. Estrogen receptor level but not progesterone receptor level correlates with response to tamoxifen

W. R. Bezwoda; Jan D. Esser; Roger Dansey; Ivan Kessel; M. Lange

Four hundred fifteen patients with metastatic breast cancer with known hormone receptor status received primary treatment with tamoxifen. Measured values for the estrogen receptor (ER, i.e., with estrogen binding) followed a continuous distribution (range, 3 to 1000 fmol/mg of protein). These values correlated positively with age. The response to treatment with tamoxifen correlated with the ER level, with response rates of approximately 80% when the ER level was greater than 30.1 fmol/mg of protein. Two hundred eighteen (218 of 415, 52%) patients had progesterone receptor (PR) values greater than 10 fmol/mg. The PR positivity correlated with the ER level. Patients with PR levels greater than 10 fmol/mg of protein (124 of 226, 55%) had a significantly higher response rate than those with values less than 10 fmol/mg of protein (45 of 189, 24%). However, in a multivariate analysis including both receptor levels, age, site, and number of metastases, only the ER level was significant in predicting the response to treatment with tamoxifen. A quantitative estimation of the ER level thus is the best predictor of response to hormonal treatment with tamoxifen for advanced breast cancer.


American Journal of Cardiology | 1999

Association of left ventricular systolic performance and cavity size with angiotensin-converting enzyme genotype in idiopathic dilated cardiomyopathy ☆

Geoffrey P. Candy; Daniel Skudicky; Urs Kurt Mueller; Angela J. Woodiwiss; Karen Sliwa; Frank Luker; Jan D. Esser; P. Sareli; Gavin R. Norton

The insertion-deletion (ID) polymorphism of the angiotensin-converting enzyme (ACE) gene is a marker linked to differences in plasma and cardiac ACE activity as well as to an increased mortality in patients with idiopathic heart failure. We examined the possibility that ACE gene ID variants are associated with differences in left ventricular (LV) systolic performance or internal LV dimensions in a high-risk cohort of patients with idiopathic dilated cardiomyopathy (IDC). The ACE genotype was determined in 171 patients selected with IDC in New York Heart Association functional class II to III heart failure and with a LV ejection fraction of < or = 40%. Left ventricular performance and dimensions were assessed using echocardiography (n = 161) and radionuclide ventriculography (n = 169). The frequency of ACE gene ID alleles was not different in the study versus non-age-matched (n = 171; odds ratio 0.94) and age-matched (n = 106, odds ratio 0.88) control groups. Ejection fraction was found to be worse in patients with the DD genotype (echocardiography, DD = 23.5 +/- 0.70, ID + II = 26.8 +/- 0.8, p = 0.009; ventriculography, DD = 21.7 +/- 0.9, ID + II = 25.3 +/- 0.8, p = 0.003). LV end-systolic and end-diastolic diameters were increased in patients with the DD genotype. Multifactor regression analysis showed the ACE genotype to be an independent predictor of both ejection fraction (echocardiography, p <0.02; ventriculography, p <0.03) and end-diastolic diameter (p <0.02). In conclusion, the results of this study indicate that the DD genotype of the ACE gene is independently associated with both a reduced LV systolic performance and an increased LV cavity size in patients with IDC.


Oncology | 1987

Aromatisation of Androstenedione by Human Breast Cancer Tissue: Correlation with Hormone Receptor Activity and Possible Biologic Significance

W. R. Bezwoda; N. Mansoor; R. Dansey; Jan D. Esser

The conversion of 1 beta [3H] androstenedione to estrone in the presence of NADPH by breast cancer homogenates was assessed in tumors from 35 subjects together with estrogen and progesterone receptor concentration. Breast cancers from post menopausal women had significantly higher aromatase activity than those from premenopausal women. Although in many instances the local production of estrogens was sufficient to the capable of exerting a biologic effect, there was, however, no correlation with tumor estrogen or progesterone receptor content. Further studies of the biological significance of tumor aromatisation will depend on direct observation of tumor aromatase and response to suitable doses of aromatase inhibitors.


Clinical Nuclear Medicine | 1987

Radioisotopic flow scanning for portal blood flow and portal hypertension.

Hesdorffer Cs; W. R. Bezwoda; Mervyn D. Danilewitz; Jan D. Esser; Milton Tobias

The use of a simple, noninvasive, isotope scanning technique for the determination of relative portal blood flow and detection of portal hypertension is described. Using this technique the presence of portal hypertension was demonstrated in seven of nine patients known to have elevated portal venous pressure. By contrast, esophageal varices were demonstrated in only five of these patients, illustrating the potential value of the method. Furthermore, this technique has been adapted to the study of portal blood flow in patients with myeloproliferative disorders with splenomegaly but without disturbances in hepatic architecture. Results demonstrate that the high relative splenic flow resulting from the presence of splenomegaly may in turn be associated with elevated relative portal blood flow and portal hypertension. The theoretic reasons for the development of flow-related portal hypertension and its relationship to splenic blood flow are discussed.


Clinical Nuclear Medicine | 1985

Technetium-99m glucoheptonate as a scanning agent in hepatocellular carcinoma

Jan D. Esser; Michael C. Kew; Milton Tobias; Ruth Winterton; Ina Savitch; Joseph Levin

Technetium-99m glucoheptonate (Tc-99m GH) is concentrated in pulmonary and cerebral tumors. The purpose of this study was to assess the uptake of this radionuclide by hepatocellular carcinoma. Its concentration by the primary tumor was compared with that in the non-neoplastic hepatic tissue in 31 patients who showed obvious defects on a colloid scan, and its uptake by pulmonary metastases was examined in six patients with x-ray evidence of this complication. In two patients, the uptake by the tumor was greater than, in six it was equal to, and in ten it was less than that in the non-neoplastic hepatic tissue. In the remaining 13 patients, there was no concentration at all in the tumor. In none of the six patients with multiple pulmonary metastases could uptake of Tc-99m GH by the metastases be demonstrated. It is concluded that Tc-99m GH is of limited value in the diagnosis of primary or metastatic hepatocellular carcinoma.


Clinical Nuclear Medicine | 1986

Demonstration of Post-traumatic Bile Leak Using Technetium-99m DISIDA

Ina Savitch; Jan D. Esser; Springolo E; Michael C. Kew

A 25-year-old miner was admitted with an acute abdomen and marked pallor following a crush injury to the abdomen. CT showed an irregular, patchy appearance of the posterosuperior portion of the liver with a coefficient of density appreciably less than the rest of the liver, consistent with the presence of a hepatic hematoma. The patient was treated conservatively. During the two weeks that followed, fluid accumulated in the peritoneal cavity. At laparotomy, a large volume of bile- and blood-stained fluid was found in the peritoneal cavity. Tc-99m DISIDA imaging was done after laparotomy.


Clinical Nuclear Medicine | 1985

The clinical value of scintigraphic brain scanning. Experience at the Hillbrow Hospital, Johannesburg, South Africa.

Winterton R; Milton Tobias; Joseph Levin; Jan D. Esser; Ina Savitch; Springolo E; Vellet D

Patients were referred to the Department of Nuclear Medicine for brain scintigraphy to be screened for possible intracranial pathology. These referrals were made in order to reduce the heavy load on the transmission computerized tomography (TCT) facilities. Great clinical importance, therefore, has been attached to scintigraphic findings; this emphasizes the need for an accurate assessment of the predictive value of this procedure.


Hepatology | 1989

The role of membranous obstruction of the inferior vena cava in the etiology of hepatocellular carcinoma in southern African Blacks

Michael C. Kew; Ann McKnight; John Hodkinson; Stanley Bukofzer; Jan D. Esser


The Journal of Nuclear Medicine | 1983

Uptake of Tc-99m di-isopropyliminodiacetic acid by hepatocellular carcinoma: concise communication

Ina Savitch; Michael C. Kew; Alan Paterson; Jan D. Esser; Joseph Levin


The Journal of Nuclear Medicine | 1996

Hepatobiliary Kinetics of Technetium-99m-IDA Analogs: Quantification by Linear Systems Theory

Shawn Araikum; Trevor Mdaka; Jan D. Esser; Michele Zuckerman

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Michael C. Kew

University of the Witwatersrand

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Joseph Levin

University of the Witwatersrand

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Milton Tobias

University of the Witwatersrand

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W. R. Bezwoda

University of the Witwatersrand

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Angela J. Woodiwiss

University of the Witwatersrand

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Ann McKnight

University of the Witwatersrand

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Daniel Skudicky

Chris Hani Baragwanath Hospital

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Elsa Springolo

University of the Witwatersrand

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Frank Luker

University of the Witwatersrand

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