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Biomedical subjects

T Naicker

Publications and source records attributed to T Naicker.

At least 19 recordsLinked to original sources
PubMed2002

Transforming growth factor beta(1) levels in platelet depleted plasma in African women with pre-eclampsia.

Recently it has been suggested that TGF-beta(1) may play an important role in trophoblast invasion of spiral arteries in pre-eclampsia. This study was designed to investigate TGF-beta(1) levels in pre-eclampsia. Platelet depleted plasma TGF-beta(1) levels were measured by ELISA in 43 normotensive healthy non-pregnant women, 30 normotensive healthy pregnant and 42 pre-eclamptic women: TGF-beta(1) levels were increased significantly in the pre-eclamptics (4.9+/-0.9 ng/ml) compared to the normotensive pregnant (1.9+/-0.54 ng/ml; P<0.001) and normotensive non-pregnant groups (2.1+/-0.41 ng/ml; P<0.0001). There was no significant difference in TGF-beta(1) levels between normotensive pregnant and non-pregnant groups (1.9+/-0.54 vs. 2.1+/-0.41 ng/ml; P=0.2). There was a highly significant correlation between neonatal weight (r=0.63; P<0.0001) and TGF-beta(1) levels. The finding of increased levels of plasma TGF-beta(1) suggests an aetiological role of this peptide in pre-eclampsia.

Adolescent↗
PubMed2001

Immunolocalisation and endothelin-1 values In pre-eclampsia: an immunocytochemical study.

Maternal plasma ET-1 levels and the immunolocalisation of ET1 in the fetal membranes of pre-eclamptic primigravidae at >/=28 weeks, gestation were studied. The levels of maternal plasma ET1 and immunoreactive ET-1 were increased in pre-eclampsia. Immunoreactive ET-1 was localised in the amnion, chorion and decidua of normal pregnant women as well as those with preeclampsia-eclampsia. Intense labelling was observed in moderate pre-eclampsia (BP 140/90 - 170/110 mmHg) with very intense labelling in severe pre-eclampsia (BP >170/110 mmHg), especially in the amniotic epithelium, chorionic villi, maternal blood vessels, cytotrophoblasts and giant cells of the decidua. The increased ET-1 levels demonstrated in fetal membranes of pre-eclamptic women are probably produced in a paracrine and/or autocrine manner, contributing to the hypertension, vasospasm and fetal growth restriction characteristic of the syndrome. A larger study would be required to show significant change in endothelin production in pre-eclampsia.

Journal Article↗
PubMed2000

Tissue kallikrein activity in pregnancy.

To determine tissue kallikrein (TK) activity in black African women with hypertensive disorders of pregnancy; 140 women were recruited and divided into the following groups: group A--35 preeclamptic women, group B--35 mild to moderate hypertensive pregnant women and group C--35 normotensive pregnant women, and group D--35 normotensive non-pregnant healthy women. The activity of tissue kallikrein was determined from a random untimed urine sample using a selective, synthetic chromogenic tripeptide substrate having the sequence H-D-Val-Leu-Arg-pNA (S-2266). Urinary sodium and potassium levels was determined by flame photometry. Tissue kallikrein activity was decreased in women with preeclampsia (1.54 +/- 0.95 vs 3.05 +/- 0.83 ngTK/microg protein; p < 0.0001) and mild to moderate hypertensive group (2.03 +/- 0.76 vs 3.05 +/- 0.83 ngTK/microg protein; p < 0.0001) compared with normotensive pregnant women. There was also a significant difference in tissue kallikrein activity between the pregnancy groups (1.54 +/- 0.95 vs 2.03 +/- 0.76 ngTK/microg protein; p < 0.001). No difference in tissue kallikrein activity was observed between normotensive pregnant and normotensive non-pregnant healthy women (3.05 +/- 0.83 vs 3.14 +/- 0.88 ngTK/microg protein; p = 0.51). There was no difference in the excretion of urinary sodium and potassium in pregnancy groups compared to normotensive pregnant group. Tissue kallikrein activity is decreased in hypertensive disorders of pregnancy.

Adult↗
PubMed2000

How do South African obstetricians manage hypertensive disorders of pregnancy--a survey.

OBJECTIVE: To determine the current management of hypertensive disorders of pregnancy in South Africa. METHOD: A postal questionnaire was sent to 600 South African obstetricians. RESULTS: The response rate was 72% (432/600), with 425 questionnaires suitable for analysis. South African obstetricians disagree on the definitions of various hypertensive disorders of pregnancy. Methyldopa was the antihypertensive used most frequently for the treatment of mild to moderate hypertension (diastolic blood pressure between 90 and 109 mmHg), while intravenous dihydralazine was preferred in severe hypertension (diastolic blood pressure > or = 110 mmHg and proteinuria > or = +2). To stop convulsions in eclampsia, 256 respondents (60%) said they would use diazepam, 28 (11%) said they would continue with a diazepam infusion, and the remaining 228 (89%) preferred magnesium sulphate (MgSO4) to prevent further convulsions. The intramuscular route was the preferred method of administration for MgSO4. In cases of eclampsia, 273 respondents (64%) said they would use intravenous dihydralazine to lower high blood pressure (> or = 160/110 mmHg) and proteinuria; 98 respondents (23%) said they would use methyldopa, 38 (9%) nifedipine, and 8 (2%) apresoline. Eight (2%) said they would not use antihypertensives. In patients with severe pre-eclampsia and impending eclampsia, 330 respondents (78%) said they would use MgSO4 as prophylaxis, 46 (11%) diazepam, and 6 (1.4%) phenobarbitone. Forty-three of the respondents did not prescribe prophylactic anticonvulsant therapy. To prevent pre-eclampsia, 247 of the respondents (58%) said they would prescribe low-dose aspirin. CONCLUSION: This study demonstrates that South African obstetricians show great uniformity in terms of the treatment of hypertensive disorders of pregnancy.

Anticonvulsants↗
PubMed2000

Relationship between histopathological changes in post partum renal biopsies and renal function tests of African women with early onset pre-eclampsia.

BACKGROUND: To improve the diagnostic accuracy of concurrent renal disease in hypertension of pregnancy, biopsy evaluation is essential. In addition, establishing underlying renal disease is important for prognosis on future pregnancies. We therefore designed a study to determine the diagnostic yield of postpartum renal biopsy and the nature and frequency of complications associated with this procedure. Also, to determine relationships, if any, between renal function tests and ultrastructural and histopathological findings. METHODS: Fifty renal biopsies were performed in the immediate postpartum period in black African women with early onset pre-eclampsia. Each biopsy specimen was placed in a separate container and coded so that sampling was unknown to the electron microscopist. Each biopsy specimen was divided into three parts, and processed and stained for light, fluorescent and transmission electron microscopy using conventional techniques. RESULTS: Renal tissue biopsies were adequate for diagnostic purposes in all cases. There were no complications in any of the 50 patients studied. Ultrastructural examination confirmed the light microscopy findings. In addition the ultrastructural findings showed intramembranous deposits, foot process fusion and mesangial deposits. In 16 patients with normal renal function tests; the biopsies evaluation from these patients showed ultrastructural changes. In the remaining 34 patients with abnormal renal function tests of varying severity; biopsy evaluation from these patients showed both ultrastructural and histopathological changes. CONCLUSION: Renal biopsy procedure is safe, and ultrastructural and histological findings obtained from postpartum renal biopsies are more informative than the routine renal function tests.

Adolescent↗
PubMed1999

Laboratory surveillance of Shigella dysenteriae type 1 in KwaZulu-Natal.

OBJECTIVE: To collect data on the antimicrobial susceptibility of Shigella dysenteriae type 1 in KwaZulu-Natal, including the testing of newer therapeutic agents, and to evaluate the ability of laboratories to participate in a provincial surveillance programme. DESIGN: Prospective descriptive study. SETTING: Hospital laboratories in KwaZulu-Natal, including peripheral laboratories and the medical microbiology laboratory of the University of Natal. MAIN OUTCOME MEASURES: Antimicrobial susceptibility pattern of surveillance strains and evaluation of the ability of provincial laboratories to isolate Shigella. RESULTS: All 354 strains tested were resistant to ampicillin, chloramphenicol and tetracycline. Co-trimoxazole resistance was found in 92.2% of strains, and 0.8% of strains were resistant to nalidixic acid. All strains were susceptible to ceftriaxone, ciprofloxacin, ofloxacin, pivmecillinam, azithromycin, loracarbef and fosfomycin. Of the 29 laboratories surveyed, 18 (62.1%) were able to isolate and identify S. dysenteriae correctly, and 9 (32%) were able to serotype it further to S. dysenteriae type 1. Twenty-seven (93.1%) had appropriate culture media and 26 (89.7%) had antisera for Shigella identification. CONCLUSIONS: There is little variation among strains of S. dysenteriae type 1 in KwaZulu-Natal with regard to their antimicrobial susceptibility pattern. Nalidixic acid should remain the antimicrobial of choice for treatment of dysentery in our region as resistance to it is low. The majority of KwaZulu-Natal laboratories have the expertise and equipment to perform the isolation and identification of Shigella species.

Anti-Bacterial Agents↗
PubMed1999

Urinary tissue kallikrein excretion in black African women with severe pre-eclampsia.

BACKGROUND: A study of tissue kallikrein excretion in African women with severe pre-eclampsia. METHODS: Random untimed urine samples were collected from all women (n=198) recruited to this study; 66 women with severe pre-eclampsia, 66 normotensive pregnant women of similar length of gestation and 66 normotensive non-pregnant women. Urine specimens were analyzed for urinary tissue kallikrein using a selective, synthetic chromogenic tripeptide substrate (S2266) having the sequence H-D-Val-Leu-Arg-pNA. RESULTS: Urinary tissue kallikrein levels were decreased in women with severe pre-eclampsia compared with those of gestation matched normotensive pregnant women at 28 weeks of gestation (1.55+/-0.95 vs. 3.02+/-1.35 ng TK/microg protein; p<0.0001) and at near delivery date (1.21+/-0.53 vis. 3.11+/-1.2 ng TK/microg protein; p<0.0001). In the normotensive pregnant group, there was no significance difference in urinary tissue kallikrein excretion close at delivery date compared to 28 weeks of gestation (3.02+/-1.35 vs. 3.11+/-1.21 ngTK/microg protein; p=0.23). No statistical difference in urinary tissue kallikrein excretion was observed between normotensive pregnant and normotensive non pregnant women (3.02+/-1.35 vs. 2.97+/-1.12 ngTK/microg protein; p=0.16). Urinary tissue kallikrein excretion correlated positively with urinary creatinine levels at 28 weeks of gestation (r=0.69; p<0.0001) and close to delivery date (r=0.84; p<0.0001). There was no correlation between neonatal birthweight and urinary tissue kallikrein levels (r=-0.44; p=0.41). CONCLUSION: The decreased levels of urinary tissue kallikrein excretion in pre-eclamptic patients suggests an etiological role for this serine protease in hypertensive disorders of pregnancy.

Adult↗
PubMed1998

Ultrastructure of Calymmatobacterium granulomatis: comparison of culture with tissue biopsy specimens.

The ultrastructural features of cells of Calymmatobacterium granulomatis from monocyte co-cultures and tissue biopsy specimens were compared. In cultures the bacteria were mainly extracellular, i.e., not within membrane-bound vacuoles. The bacterial body was surrounded by a uniformly extensive homogeneous layer with a relatively high electron density. This layer varied considerably in tissue biopsy specimens, having either homogeneously electron-dense or delicate web-like structures with varying density and thickness. In tissue specimens the bacteria were located predominantly within vacuoles of varying sizes in the cytoplasm of the macrophages and, occasionally, extracellularly within the intercellular spaces of the stroma. The bacterial cytoplasm contained ribosomes scattered throughout with electron-dense granules located peripherally. The trilaminar cell-wall structure was typical of a gram-negative organism, comprising an outer membrane, a middle electron-opaque layer and an inner plasma membrane. Surface structures such as fimbriae, flagella and bacteriophages were not identified in specimens from either source.

Biopsy↗
PubMed1997

Changes in urinary tissue kallikrein excretion in black African women with hypertensive disorders of pregnancy.

The aim of this study was firstly to establish whether tissue kallikrein (TK) was involved in the aetiology of hypertensive disorders of pregnancy. Secondly, to assess whether tissue kallikrein:creatinine ratios may differentiate normotensive pregnant women from those with hypertensive disorders of pregnancy and have a predictive value. Random untimed urine samples were collected from all women (n = 264) recruited to this study. Urine specimens were analyzed for urinary tissue kallikrein using a selective, synthetic chromogenic tripeptide substrate (H-D-Val-Leu-Arg-pNA). Urinary creatinine levels were measured using standard methods. There was a significant difference in the excretion of urinary tissue kallikrein between normotensive pregnant women (2.91 ng TK/microgram protein) and women with mild (2.52 ng TK/microgram protein; p < 0.0001) and severe (1.53 ng TK/microgram protein; p < 0.0001) hypertension in pregnancy. No statistical difference was observed with regard to urinary tissue kallikrein excretion between normotensive pregnant and normotensive non-pregnant women (2.87 ng TK/microgram protein; p = 0.16). A positive correlation was observed between the diastolic blood pressure and urinary tissue kallikrein excretion in women with hypertensive disorders of pregnancy. When compared to the normotensive pregnant group, the urinary kallikrein:creatinine ratios were significantly lower in the mild (0.6 versus 0.3; p < 0.0001) and severe (0.6 versus 0.12; p < 0.0001) hypertensive groups. The urinary creatinine excretion was significantly higher in the mild (9.55 +/- 2.6 mmol/l; p < 0.0001) and in severe (15.62 +/- 5.48 mmol/l; p < 0.0001) hypertensives when compared to normotensive pregnant values (5.65 +/- 2.6 mmol/l). The reduced urinary tissue kallikrein excretion in hypertensive disorders of pregnancy may be a significant factor in the development of the hypertension in pregnancy. Measurement of urinary tissue kallikrein: creatinine ratios may represent a simple and practical predictive test to differentiate women with hypertensive disorders of pregnancy from normotensive pregnant women.

Adult↗
PubMed1997

Localisation of tissue kallikrein in the kidney of black African women with early onset pre-eclampsia: a pilot study.

Increased renal production of vasodilator mediators like kinins would counteract the vasospasm of pre-eclampsia. This study examines the cellular localisation of tissue kallikrein (TK), the potent kinin forming enzyme within the nephron of patients with early onset pre-eclampsia. Using the peroxidase-antiperoxidase immunoenzyme complex, TK was immunolocalised in the principal cells of the distal connecting tubule and the cortical collecting duct cells of the distal nephron of control tissue. Moderate reactivity was observed in the epithelial cells lining the Bowmans capsule. In early onset pre-eclampsia, TK was additionally localised in the proximal tubule cells, however, the intensity of reactivity was reduced when compared to that of the distal tubule cells. In patients with hypertension of pregnancy, the occurrence of TK in the proximal tubule suggests either gene induction or emiocytosis of TK.

Adolescent↗
PubMed1997

Tissue kallikrein in transplant kidney.

Literature survey, thus far, has shown a decrease in the excretion of urinary tissue kallikrein (TK) in transplant patients with a further reduction of the enzyme during episodes of acute rejection. The study aims were to compare, at cellular and subcellular levels, the localisation of tissue kallikrein in biopsies of the transplant kidney to autopsy derived normal renal tissue. Renal biopsies from eighteen transplant patients with deteriorating renal function were obtained. Immunolabelling for tissue kallikrein, using a polyclonal goat anti-TK, antibody raised against recombinant TK, was performed following routine enzymatic, immunofluorescence and electron microscopic techniques. In normal kidney tissue, TK was immunolocalised in the distal connecting tubules and collecting ducts. By comparison the renal transplant tissue showed a reduction in the intensity of label, but maintained the sites of localisation. In the sections examined by electron microscopy, although TK was confined mainly at the luminal side of the cell, some label was noted along the basolateral membranes. In the transplant kidneys, there was a reduction in the overall number of gold particles counted, which correlated with the decreased intensity observed on immunocytochemistry. In addition, there was a shift to a basolateral orientation of the immunolabel. Acute rejection is characterised by oedema, tubulitis and vasculitis. Destruction of the tubule cells and leakage of TK into the interstitial tissue space and the resultant effect of the formed kinins on renal capillary vasculature could explain the observed renal parenchymal oedema and transplant rejection.

Adult↗
PubMed1997

Drug management of hypertensive disorders of pregnancy.

Drugs used in the acute and long-term management of hypertension in pregnancy and the preeclampsia-eclampsia syndrome have been reviewed and their therapeutic effects and maternal and fetal adverse effects have been considered. The review also focuses on recent developments in the areas of prevention and management of pre-eclampsia-eclampsia syndrome. Although a number of new drugs have emerged, as potentially useful in the management of hypertension in pregnancy and pre-eclampsia-eclampsia syndrome, some remain at the cornerstone of therapy; for example, methyldopa for long-term treatment of chronic hypertension, hydralazine or nifedipine for rapid reduction of severely elevated blood pressure, and magnesium sulphate for eclampsia. Some of these agents, especially the calcium antagonists, show promise in that their use is associated with fewer side effects. Safety for the fetus, however, has not been adequately evaluated yet. Neither aspirin nor calcium supplements appear to improve the outcome in pregnancy. Currently, the dilemma whether to treat hypertension in pregnancy and pre-eclampsia-eclampsia syndrome with old, established, cost-effective drugs or the promising newer drugs provides an interesting academic challenge.

Adrenergic Antagonists↗
PubMed1997

Growth and cultural characteristics of Calymmatobacterium granulomatis--the aetiological agent of granuloma inguinale (Donovanosis).

Granuloma inguinale is a chronic destructive granulomatous disease of the genitalia. The clinical diagnosis is often unreliable and the definitive diagnosis is based on the visualisation of 'Donovan bodies' in tissue smears or biopsy specimens. The organism implicated in its aetiology, Calymmatobacterium granulomatis, was reported to have been cultured > 30 years ago, but little is known about the organism because of its fastidious nature and the difficulty in culturing it. Twenty-two biopsy specimens from female patients with clinical and laboratory-confirmed granuloma inguinale were treated with amikacin 10 mg/L and inoculated in a monocyte co-culture system with peripheral blood mononuclear cells (PBMC) from a single donor and autologous sera. The method was subsequently modified by pretreatment of specimens with vancomycin 5 mg/L and metronidazole 10 mg/L in addition to amikacin 10 mg/L for the purpose of decontamination, pooled blood donor PBMC and by the use of heat-inactivated fetal calf serum instead of autologous serum for culture. This modified method was used to culture additional biopsy specimens and genital ulcer scrapings from female and male patients, respectively. All monocyte co-cultures were examined by a rapid Giemsa (RapiDiff) stain and by an indirect immunofluorescence test with immune sera. Representative cultures were examined by transmission electron microscopy. C. granulomatis was successfully isolated in pure culture by the monocyte co-culture system from four biopsy specimens and 14 genital ulcer scrapings. The cultured organisms were visible both intra- and extra-cellularly and were extremely pleomorphic, with characteristic single and biopolar condensation. The numbers of the organisms increased after each passage. All positive cultures showed bright fluorescence when tested with immune sera. Transmission electron microscopy of the cultured bacteria demonstrated a typical gram-negative cell wall consisting of an outer membrane, middle electron opaque layer and an inner plasma membrane. The capsule was thick and electron dense. Numerous electron dense granules were present within the cytoplasm.

Azure Stains↗
PubMed1997

Correlation between histological changes and loss of anionic charge of the glomerular basement membrane in early-onset pre-eclampsia.

This study morphometrically evaluates the glomerular anionic charge and examines the renal pathology in African women with early-onset pre-eclampsia. Polyethyleneimine-labelled anionic sites were decreased within the glomerular basement membrane in the early-onset pre-eclampsia group as compared with the control group (p < or = 0.02). A strong correlation (r = -0.76) was obtained between the number of anionic sites and the severity of proteinuria. Renal biopsy specimens revealed the coexistence of decreased glomerular charge with pathology of glomerular basement membrane, endothelial cells, foot processes, and mesangial cell proliferation. The loss of glomerular charge induces structural alterations of the glomerular filtration barrier and may be the mechanism responsible for proteinuria in early-onset pre-eclampsia.

Anions↗
PubMed1996

Hexane cardiotoxicity--an experimental study.

Ventricular arrhythmia has been postulated as a possible cause of death in young black children who abuse volatile substances, primarily benzine and certain glues that contain n-hexane. A series of protocols were designed to determine the effect of n-hexane on myocardial function and morphology in male laboratory rats. In the first protocol, experiments were designed to study the effect of n-hexane in initiating ventricular fibrillation and in modifying myocardial magnesium and potassium levels. The results showed that the thresholds for ventricular fibrillation and myocardial magnesium and potassium levels were reduced compared to control values. In the second protocol, n-hexane-treated rats were supplemented with intragastric administration of magnesium and potassium salts. The outcome of the experiments indicated that although the myocardial magnesium and potassium levels were corrected, the threshold for ventricular fibrillation remained low compared to control values. In the third protocol, experiments were designed to examine myocardial morphology by electron microscopy. Cellular changes were observed in the myocardium as a result of administering n-hexane. These cellular changes were considered to be responsible for the decreased threshold for ventricular fibrillation. The present study indicates that n-hexane, a constituent of benzine and certain glues, is cardiotoxic.

Animals↗
PubMed1996

The effect of a low dose versus a conventional dose of hydrochlorothiazide on ventricular fibrillation threshold and electrolyte levels in laboratory rats.

We studied the effect of hydrochlorothiazide on metabolic and electrolyte parameters. In the first protocol, six groups of rats were studied to determine whether changes in ventricular fibrillation threshold, and serum and myocardial potassium occur after treatment with different doses of hydrochlorothiazide; three groups (N = 15) served as controls and the other three groups (N = 15) were given different doses of hydrochlorothiazide for a 3 month period. Two rats from each group were sacrificed daily. One rat heart was perfused using the Langendorff perfusion apparatus and the other used for myocardial potassium analysis. Blood was also collected for serum potassium analysis. There was no change in the threshold for ventricular fibrillation in groups treated with 0.04 mg and 0.09 mg hydrochlorothiazide compared to control values. There was a nonsignificant decrease in serum and myocardial potassium levels in rats treated with 0.04 mg and 0.09 mg hydrochlorothiazide compared to control. Seven of the 15 rats treated with 0.18 mg hydrochlorothiazide showed significantly lower ventricular fibrillation threshold levels and decreased serum potassium (P < 0.02) compared to control animals. In addition, a significant decrease in myocardial potassium was noted (P < 0.05). In the second protocol, 8 of the 15 rats treated with 0.18 mg hydrochlorothiazide showed reduced ventricular fibrillation threshold and serum potassium levels (P < 0.05). A significant decrease in myocardial potassium was also observed (P < 0.05). These variables were corrected by the intragastric administration of potassium salts. The present study indicates that 0.04 mg and 0.09 mg hydrochlorothiazide have no effect on ventricular fibrillation threshold level or on serum or myocardial potassium levels. There was a significant decrease in ventricular fibrillation threshold and serum and myocardial potassium levels in 7 of the 15 animals studied in protocol one and 8 of the 15 animals studied in protocol two, treated with 0.18 mg hydrochlorothiazide and these variables were corrected by the intragastric administration of potassium salts.

Animals↗
PubMed1995

Morphological aspects of microarterial anastomoses: a comparison of nylon with polydioxanone.

The morphological appearance of longitudinally sectioned rat femoral arteries was determined in intact arteries and from 3 to 435 days after vessel division and anastomosis with either 9/0 gauge nylon or polydioxanone (PDS) in 26 animals. The purpose of the study was to establish the mechanisms and compare the quality of healing after microarterial anastomosis and to determine whether PDS was degraded before sufficient anastomotic healing had taken place. The results revealed that there was no difference in the process of healing or quality of anastomosis with either suture material. From 3 to 21 days post anastomosis, there was a progressive separation of the ends of vessels within the developing scar. Anastomotic patency was established and maintained at first by an adventitial overgrowth of fibroblasts and undifferentiated adventitial cells and later by the growth of a smooth myocyte scar that stretched between the cut ends of the vessel and over the intima in the form of elongated circumferential plaques. The vessel was morphologically healed by the 21st day. The sutures served little or no purpose in maintaining anastomotic integrity after the 5th day, being situated in the scar forming between the separating vessel ends. PDS was present within the vessel wall up to 120 days post anastomosis and was certainly intact at the time of morphological healing, suggesting that this material is safe as a microvascular suture.

Anastomosis, Surgical↗