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Featured researches published by D.P. De Klerk.


The Journal of Urology | 1990

The glycosaminoglycans of the gubernaculum during testicular descent in the fetus

Chris F. Heyns; H.J. Human; C.J. Werely; D.P. De Klerk

Tissues were obtained from 387 male pig fetuses ranging from 60 to 120 days of gestation. The relative wet mass and water content of the gubernaculum increased during and decreased after the period of testicular descent. The extracellular glycosaminoglycans (GAG) were assayed to determine whether these polyanionic macromolecules are responsible for the increased water content of the gubernaculum. The total GAG/wet tissue mass in the gubernaculum decreased during and increased after descent, while the total GAG/dry mass decreased during and after descent, indicating an accumulation of water during descent, with a loss of water and an increase in less hydrated tissue components after descent. The major GAG fraction in the gubernaculum was dermatan sulfate, but the percentage hyaluronate in the gubernaculum was two times higher than in striated muscle or umbilical cord, indicating that this GAG fraction may be responsible for the increased water content of the gubernaculum, which probably serves to dilate the inguinal canal and scrotum, thus facilitating descent.


The Journal of Urology | 1985

Nonoperative Management of Renal Stab Wounds

Chris F. Heyns; D.P. De Klerk; M.L.S. de Kock

A prospective clinical study of 54 patients with stab wounds and hematuria was conducted to evaluate the safety of selective nonoperative management compared to mandatory surgical exploration of these patients. In the absence of signs of severe blood loss, associated intra-abdominal injury or major abnormality on the excretory urogram patients were randomized to undergo mandatory surgery (group 1) or nonoperative management (group 2). Patients with signs of severe blood loss, associated intra-abdominal injury or gross abnormality on excretory urography were selected for an operation (group 3). The rate of probably needless operations (defined as minor renal injury without associated intra-abdominal lacerations) was 78 per cent in group 1 and 0 per cent in group 3. Pulmonary complications occurred in 33 per cent of the patients in group 1, 4 per cent in group 2 and 38 per cent in group 3. Despite an operation delayed renal hemorrhage occurred in 1 patient (5 per cent) in group 1 and 2 (15 per cent) in group 3, and resulted in nephrectomy in 2 of these patients. No instance of secondary hemorrhage occurred in group 2 patients. The mean length of hospitalization was 9, 5 and 11 days in groups 1 to 3, respectively. Our results indicate that the selective nonoperative management of patients with renal stab wounds can lead to a decrease in the rate of unnecessary operations, postoperative complications and length of hospitalization compared to a policy of mandatory surgical intervention.


The Journal of Urology | 1984

Glycosaminoglycans of Human Prostatic Cancer

D.P. De Klerk; D.V. Lee; H.J. Human

The glycosaminoglycans of normal, benign hyperplastic and cancerous prostate were studied. In both prostatic hyperplasia and cancer the chondroitin sulfate:dermatan sulfate ratio was increased. In prostatic cancer this increase correlated with both the differentiation and extent of cancer in the prostate. The percentages heparan sulfate and heparan sulfate sulfation were decreased in prostatic cancer. Hyaluronic acid increased with dedifferentiation of the cancer. Histochemically, sulfated glycosaminoglycans were concentrated in the prostatic stroma at the stromal-epithelial interface. The increased chondroitin sulfate:dermatan sulfate ratio may be a nonspecific response or requirement for epithelial growth.


The Journal of Urology | 1983

Stab wounds associated with hematuria--a review of 67 cases.

Chris F. Heyns; D.P. De Klerk; M.L.S. de Kock

The clinical records of 67 patients who underwent surgical exploration for stab wounds associated with hematuria were reviewed in an attempt to evaluate the need for mandatory operation and to define criteria for possible nonoperative of such cases. Minor renal injuries without associated intra-abdominal lacerations were found in 61 per cent of the patients. Delayed renal hemorrhage occurred in 15 per cent of the patients despite early exploration, suture and drainage of the kidney, and antibiotic prophylaxis. Of 7 nephrectomies 5 were performed for secondary hemorrhage. Postoperative pulmonary complications arose in 28 per cent of the patients. A policy of mandatory operation on all patients with stab wounds and hematuria led to apparently needless surgery in 61 per cent of the patients in this series. Retrospective analysis revealed that the rate of probably unnecessary operations could have been reduced to 24 per cent by selecting for operation only those patients with signs of severe hemorrhage, associated intra-abdominal injury or major extravasation of contrast material on excretory urography.


The Journal of Urology | 1986

Hyperplasia and Hypertrophy of the Gubernaculum During Testicular Descent in the Fetus

Chris F. Heyns; H.J. Human; D.P. De Klerk

The role of the gubernaculum during testicular descent was investigated in 115 male pig fetuses ranging from 68 to 109 days of gestation. Descent of the testis through the inguinal canal occurred between 77 and 94 days. There was a marked increase in the total and relative wet mass as well as the wet/dry mass ratio of the gubernaculum, denoting an increase in the water content of this structure during descent of the testis. Similar changes were not seen in other fetal tissues. Asymmetrical descent of the testes occurred in seven of the 40 fetuses between 81 and 92 days of gestation. Descended testes had gubernacula with a greater relative wet mass than the gubernacula of undescended testes. These findings indicate that the increase in mass of the gubernaculum plays an important part in testicular descent. An increase in both the DNA content (hyperplasia) and the RNA/DNA ratio (hypertrophy) was noted in the gubernaculum during descent of the testis. Hyperplasia in the gubernaculum occurred at a rapid rate initially and ceased after the completion of descent. Hyperplasia was also seen in the testis and epididymis, but occurred at a slower rate initially, with a rapid acceleration after the completion of descent. Cellular hypertrophy was not noted in the testis and epididymis, but did occur in umbilical cord tissue. If gonadotropins acting via androgen secretion by the testis provide the stimulus for these changes, the observed difference in response between the gubernaculum and testis could be due to a difference in end-organ sensitivity. However, it is also possible that some unidentified non-androgenic gubernaculotropin, possibly secreted by the fetal testis, provides the stimulus for gubernacular growth.


The Journal of Urology | 1985

The Glycosaminoglycans of Human Bladder Cancers of Varying Grade and Stage

D.P. De Klerk

Abstract The glycosaminoglycans of four normal human bladders and fourteen bladder cancers were characterized and quantitated (after proteolytic extraction) by specific enzyme digestion, cellulose acetate electrophoresis and densitometry. Hyaluronic acid, heparan sulfate, dermatan sulfate and chondroitin sulfate were identified in both normal and cancerous bladders. Hyaluronic acid and dermatan sulfate were the major glycosaminoglycans of the normal epithelium/submucosa while heparan sulfate and dermatan sulfate were predominant in normal bladder muscle. Bladder cancer glycosaminoglycan content was influenced by the stage and grade of the neoplasm. Hyaluronic acid and dermatan sulfate tended to decrease and chondroitin sulfate to increase in infiltrating cancers, whereas a decrease in the percentage of heparan sulfate correlated closely with higher grade tumors. The bladder cancer glycosaminoglycan profile may be indicative of the tumor’s invasive potential.


The Journal of Urology | 1988

Agenesis of the bladder and urethra: A case report

C L Krull; Chris F. Heyns; D.P. De Klerk

Agenesis of the bladder is an extremely rare congenital anomaly. We describe a girl with complete agenesis of the bladder and urethra, who is alive 2 years after bilateral cutaneous ureterostomy.


The Journal of Urology | 1987

Nephroblastoma in an Ovotestis of a True Hermaphrodite: A Case Report

Chris F. Heyns; D.J.T. Van Niekerk; D.J. Rossouw; E.C. Burger; D.P. De Klerk

We describe a patient who presented with a painful mass in the left inguinoscrotal region, gynecomastia, perineal hypospadias with chordee and a bifid scrotum with a small gonad in the right hemiscrotum. At operation the left mass was found to be an ovotestis with hemorrhage in a corpus luteum cyst. A rudimentary uterus and fallopian tube were situated next to the ovotestis. The right gonad also was an ovotestis with a tiny focus of small cell malignancy that was suggestive of nephroblastoma.


World Journal of Urology | 1986

Urinary glycosaminoglycan excretion in metastatic prostate cancer

D.P. De Klerk; C.J. Werely

SummaryUrinary glycosaminoglycan (GAG) excretion is increased in many disseminated cancers. We have postulated that patients with metastatic prostatic cancer may have an increased urinary GAG excretion and that this parameter may have potential as a tumor marker during the management of these patients. Urinary GAGs were precipitated with cetylpiridinium chloride, separated by cellulose acetate electrophoresis and stained with alcian blue. Heparan sulphate and chondroitin sulphate were identified in all, and hyaluronic acid in most patients by cellulose acetate electrophoresis and specific enzyme digestion. A fourth alcianophilic, non-GAG band could be identified in the urinary extract and is thought to be a urinary glycoprotein. In patients with localised prostatic cancer, total urinary GAG excretion was elevated in 2 of 18 patients, while in patients with metastatic prostatic cancer not in remission after hormonal therapy, 21 of 31 patients had elevated total urinary GAG levels. Separating and quantifying the urinary heparan sulphate and chondroitin sulphate content increased the sensitivity to 22 of 31 patients. Urinary glycosaminoglycan excretion may have value as a tumor marker in the follow-up of patients with prostatic cancer.


The Journal of Urology | 1985

The Gubernaculum during Testicular Descent in the Pig Fetus

Chris F. Heyns; D.P. De Klerk

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H.J. Human

Stellenbosch University

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C.J. Werely

Stellenbosch University

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C L Krull

Stellenbosch University

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D.J. Rossouw

Stellenbosch University

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D.V. Lee

Stellenbosch University

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E.C. Burger

Stellenbosch University

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