Ambulatory blood pressure monitoring in pheochromocytoma - paraganglioma: A single center experience

CONTEXT/AIMS

Pheochromocytoma and paraganglioma (PPGL) are rare tumors, and data on ambulatory blood pressure monitoring (ABPM) in these patients and the effect of blocking on ABPM parameters is limited. We aimed to describe ABPM parameters in a cohort of PPGL at our center in western India.

METHODS

Retrospective study of patients with PPGL whose ABPM data was available. Demographic details, secretory status, and ABPM data were retrieved. Coefficient of variability (CV) was calculated as standard deviation/mean in percentage.

RESULTS

In the 39 included patients, mean age at presentation was 39.3 ± 14.2 yr; 20 (51.3%) were males, 25 (64.1%) hypertensive, and mean tumor diameter was 5.3 cm. In 18 patients whose baseline ABPM was done without medications, those with nocturnal blood pressure dipping (6/18, 33%) had higher serum metanephrines (median 313.2 vs. 34.7 pg/ml, P = 0.028). Despite normal office blood pressure (BP), 8.9% of systolic BP readings were >140 mmHg, and 1.2% were >160 mmHg. Among 29 patients with both pre and post-block ABPM, mean BP (systolic 121.6 vs. 132.5 mmHg, P = 0.014; diastolic 68.9 vs. 76.4 mmHg, P = 0.005) and percentage of BP readings above 140 mmHg (median 9.4% vs. 24.4%, P = 0.016) were significantly lowered after the preoperative blockade in hypertensive ( n = 19) patients, whereas CV was similar. The post-blockade ABPM characteristics were similar in patients blocked with amlodipine or prazosin.

CONCLUSION

ABPM provides additional information about BP characteristics in PPGL. The preoperative blocking decreases the magnitude of BP excursions but does not affect BP variability.

46,XX aromatase deficiency: A single-center experience with the varied spectrum and recurrent variants, and a systematic review of hormonal parameters

BACKGROUND

Aromatase deficiency is a rare disorder, with only a few cases reported in India. We describe a single-center experience in western India, with a systematic review of genetically proven 46,XX aromatase deficiency patients to evaluate hormonal parameters.

METHODS

Retrospective review of case records, collating phenotypic and genotypic data and molecular modeling. Systematic review of 46,XX aromatase deficiency, analyzing data on gonadotropins, estrogen and androgens.

RESULTS

In the seven patients from our center, presentation was frequent in childhood or adolescence (4/7: delayed puberty or hyperandrogenism), with maternal virilization (4/7), predominance of Prader III/IV (5/7), and initial rearing as females (6/7). Three patients had hypoplastic ovaries. One patient had spontaneous regular menses. We report three novel (p.Arg115Pro, p.Arg192Pro, and c.145+1_145+4delins) and two recurrent variants (p.Val370Met, and c.145+1_145+4delins) in western and northern India, respectively. On systematic review (n=43), gonadotropins were elevated (FSH>LH) across ages (except preterm infants), androgens were elevated in about one-third of cases during childhood and puberty, and estradiol was lower than in controls in mini-puberty and puberty. Spontaneous thelarche and streak ovaries were significantly more frequent in patients with non-truncating and truncating variants, respectively.

CONCLUSION

We report uncommon presentations with possible founder variants, and highlight hormonal parameters across ages. Serum FSH levels were elevated except in preterms, and can be used as a diagnostic marker.

Giant prolactinoma in Asian-Indians: A single-center experience from Western India

PURPOSE

Giant prolactinomas (GP) are rare tumors accounting for 4.3% of prolactinomas, with paucity of literature from India. We aim to describe clinical, biochemical, radiological, and treatment outcomes in a large series of Asian-Indian patients with GP.

METHODS

A single-center retrospective analysis of GPs (n=84), age-based (adults: 66 versus pediatric: 18) and gender-based (males: 64 versus females: 20) comparison was done.

RESULTS

The mean age at presentation was 34.1±13years, and 64 (76.2%) were males. Males were younger at presentation (32.1±12.2 versus 40.1±13.8years, P: 0.01). The majority presented with mass-effect-related manifestations (visual disturbances: 91.6%, headache: 84.5%) and/or hypogonadism (98.7%). At baseline, largest tumor dimension was 5.3±1.0cm, and serum prolactin was 8343 (3865.5-12,306) ng/mL; most (94.6%) had gonadal axis involvement. Dopamine-agonist (DA) as first-line therapy (45/67, 67.2%) achieved normoprolactinemia (maximum cabergoline dose: 2.0±1.2mg/week) in 36/45 (80%) and tumor response (≥50% reduction) in 36/37 (97.3%) patients at the last follow-up (median duration: 33 [14.5-53.5]months). Notably, gonadal axis recovery was poor (6/30, 20%) despite normoprolactinemia post-DA monotherapy. At latest follow-up, secondary hypothyroidism (32.5% versus 82.6%, P: 0.001) and central hypocortisolism (5.6% versus 42.9%, P: 0.007) were less frequent in DA monotherapy (n=43) than in multimodal therapy group (n=23). The proportion of males (94.4% versus 71.2%, P: 0.04) was higher in the pediatric age group, with DA-induced (first-line) normoprolactinemia observed in 66.7% of them.

CONCLUSION

GP has male predominance, DA as first-line therapy normalized prolactin in four-fifths of patients with better preservation of HPT and HPA axes in patients with DA monotherapy.

Exonic WT1 pathogenic variants in 46,XY DSD associated with gonadoblastoma

OBJECTIVE

The literature regarding gonadoblastoma risk in exonic Wilms' tumor suppressor gene (WT1) pathogenic variants is sparse. The aim of this study is to describe the phenotypic and genotypic characteristics of Asian-Indian patients with WT1 pathogenic variants and systematically review the literature on association of exonic WT1 pathogenic variants and gonadoblastoma.

DESIGN

Combined retrospective-prospective analysis.

METHODS

In this study, 46,XY DSD patients with WT1 pathogenic variants detected by clinical exome sequencing from a cohort of 150 index patients and their affected relatives were included. The PubMed database was searched for the literature on gonadoblastoma with exonic WT1 pathogenic variants.

RESULTS

The prevalence of WT1 pathogenic variants among 46,XY DSD index patients was 2.7% (4/150). All the four patients had atypical genitalia and cryptorchidism. None of them had Wilms' tumor till the last follow-up, whereas one patient had late-onset nephropathy. 11p13 deletion was present in one patient with aniridia. The family with p.Arg458Gln pathogenic variant had varied phenotypic spectrum of Frasier syndrome; two siblings had gonadoblastoma, one of them had growing teratoma syndrome (first to report with WT1). On literature review, of >100 exonic point pathogenic variants, only eight variants (p.Arg462Trp, p.Tyr177*, p.Arg434His, p.Met410Arg, p.Gln142*, p.Glu437Lys, p.Arg458*, and p.Arg458Gln) in WT1 were associated with gonadoblastoma in a total of 15 cases (including our two cases).

CONCLUSIONS

WT1 alterations account for 3% of 46,XY DSD patients in our cohort. 46,XY DSD patients harboring exonic WT1 pathogenic variants carry a small but definitive risk of gonadoblastoma; hence, these patients require a gonadoblastoma surveillance with a more stringent surveillance in those harboring a gonadoblastoma-associated variant.

Disseminated gestational choriocarcinoma presenting with hepatic and uveal metastases, hook effect, and choriocarcinoma syndrome

Choriocarcinoma is a human chorionic gonadotrophin (HCG)-secreting tumor that comprises vascular channels. It has a tendency for widespread metastasis, common sites for which include the lung, vagina, brain, liver, bone, intestine, and kidney. We describe a 30-year-old female who presented with hepatitis-like features and bilateral diminution of vision, and subsequently developed hemothorax and hemoperitoneum-all rare and seemingly unrelated manifestations which were finally attributable to metastases from gestational choriocarcinoma. To further complicate the clinical scenario, the serum HCG of the patient was mildly raised (due to a phenomenon called hook effect). Subsequently, the patient developed disseminated intravascular coagulation and succumbed to her illness. In this report, we discuss the imaging findings of choriocarcinoma, its potential sites of metastases, and the hook effect.

Thoracoscopic oesophageal atresia/tracheo-oesophageal fistula (OA/TOF) repair is associated with a higher stricture rate: a single institution’s experience

PURPOSE

Thoracoscopic OA/TOF repair was first described in 1999. Currently, less than 10% of surgeons routinely employ minimally access surgery. Our primary aim was to review our immediate-, early- and long-term outcomes with this technique compared with the open approach.

METHODS

A retrospective review of all patients undergoing primary OA/TOF (Type C) repair at our institution from 2009 was conducted. Outcome measures included length of surgery, conversion rate from thoracoscopy, early complications such as anastomotic leak and post-operative complications such as anastomotic strictures needing dilatations. Fisher's exact and Kruskal-Wallis tests were used for statistical analysis.

RESULTS

95 patients in total underwent OA/TOF repair during the study period of which 61 (64%) were completed via an open approach. 34 were attempted thoracoscopically of which 11 (33%) were converted. There was only one clinically significant anastomotic leak in our series that took place in the thoracoscopic group. We identified a significantly higher stricture rate in our thoracoscopic cohort (72%) versus open surgery (43%, P < 0.05). However, the median number of dilations (3) performed was not significantly different between the groups. There was one recurrent fistula in the thoracoscopic converted to open group. Our median follow-up was 60 months across the groups.

CONCLUSION

In our experience, the clinically significant leak rate for both open and thoracoscopic repair as well as recurrent fistula is much lower than has been reported in the literature. We do not routinely perform contrast studies and are, thus, reporting clinically significant leaks only. The use of post-operative neck flexion, ventilation and paralysis is likely to be protective towards a leak. Thoracoscopic OA/TOF repair is associated with a higher stricture rate compared with open surgery; however, these strictures respond to a similar number of dilatations and are no more refractory. Larger, multicentre studies may be useful to investigate these finding further.

Homozygous p.Val89Leu plays an important pathogenic role in 5α-reductase type 2 deficiency patients with homozygous p.Arg246Gln in SRD5A2

OBJECTIVE

To evaluate the pathogenic role of a few benign variants and hypomorphic pathogenic variants in SRD5A2.

DESIGN AND METHODS

We retrospectively analyzed phenotypes and genotypes in 23 Indian patients with genetically proven steroid 5α-reductase 2 (SRD5A2) deficiency. The interactions of the SRD5A2 enzymes resulting due to the most common benign variant (p.Val89Leu), the most common (hypomorphic) pathogenic variant (p.Arg246Gln) and the double variants (p.Val89Leu and p.Arg246Gln) in SRD5A2 were compared with that of the wild type (WT) enzyme by molecular dynamics (MD) simulation.

RESULTS

The majority (n = 19, 82.61%) of patients presented for atypical genitalia and had male gender identity (16/20). Including the two novel ones (p.Leu83Pro, p.Ala28Leufs*103), a total of nine different pathogenic variants were observed. p.Arg246Gln was the most common pathogenic variant (n = 12). Homozygous p.Arg246Gln (n = 9) variant was associated with milder undervirilization (Sinnecker score of ≤3a: 8/9 vs 6/14, P = 0.04) and had concurrent homozygous p.Val89Leu in all patients. Interestingly, asymptomatic fathers of two index patients were homozygous for p.Arg246Gln which questioned the pathogenicity of the variation as a sole factor. Unlike all symptomatic homozygous p.Arg246Gln patients who were also homozygous for p.Val89Leu, asymptomatic homozygous p.Arg246Gln fathers were heterozygous for p.Val89Leu. On MD simulation SRD5A2 p.Val89Leu-Testeosterone (T) and SRD5A2 p.Arg246Gln-T complexes, but not SRD5A2 p.Val89Leu and p.Arg246Gln-T complex, demonstrated close interaction between NADPH and T as that of SRD5A2 WT-T.

CONCLUSIONS

p.Arg246Gln may not be pathogenic as a sole variation even in the homozygous state; additional contribution of homozygous p.Val89Leu variant may be essential for the pathogenicity of p.Arg246Gln in SRD5A2.

Hashimoto's thyroiditis: relative recurrence risk ratio and implications for screening of first-degree relatives

CONTEXT

The relative recurrence risk ratio (λ_R ) for Hashimoto's thyroiditis (HT) has not been widely studied. The age at which thyroid function evaluation should be initiated for relatives of HT patients remains unclear.

OBJECTIVE

To study λ_R and age-related prevalence of HT in first-degree relatives of HT patients.

METHODS

First-degree relatives (n = 861) of 264 HT patients were evaluated for goitre, thyroid function tests, thyroid antibodies (TAb) and urinary iodide concentration (UIC). HT was defined as TAb positivity and hypothyroidism (subclinical/overt). λ_R was calculated as {number of index patients whose relatives (of particular subtype) had HT/number of index patients having relatives of same subtype}÷ population prevalence of HT (5·1%). The age-related prevalence of HT was studied using Kaplan-Meier method.

RESULTS

A total of 861 relatives (205 parents, 336 siblings and 320 offspring) participated in the study. About 38·3% were TAb positive. The prevalence of HT was 16·7% (22·9% in parents, 19·6% in siblings and 9·6% in offspring). TAb positivity (48·3% vs 33·1%) and HT (23·5% vs 13·6%) were significantly more common in the goitrous group (n = 267) vs nongoitrous group. The median UIC for the study population was 182·5 μg/l. Computed λ_R was 9·1 for any one relative being affected, 5·9 for parents, 6·3 for siblings and 3·1 for offspring. The prevalence of HT increased with age and exceeded the adult population prevalence of 5·1% at 20 years in females and 27 years in males.

CONCLUSIONS

Relatives of HT patients have a ninefold increased risk for developing HT as compared to the general population. The risk of developing HT exceeds that of the general population at 20 years in females and 27 years in males.

Ultrasonographic Features of Ulnar Nerve Affected by Hansen's Disease

Leprosy continues to be a major public health problem in some areas of our country. It predominantly afflicts peripheral nerves and skin and may lead to deformities. Social stigma as a result of deformities further plagues the situation. Prompt and early diagnosis coupled with adequate treatment, concurrent rehabilitative strategies if deformities do occur, and health education help to control the problem. Definitive diagnosis of leprosy has traditionally been based on assessment of slit skin smears (SSS) after AFB-staining and characteristic histopathology after biopsyof the lesion. However, recently, thickening of the peripheral nerves has been demonstrated by ultrasonography and this can be used as a sensitive tool to assess and measure enlargement of peripheral nerves, which are hallmarks for leprosy especially in clinical settings. In this report, the ultrasonographic findings of ulnar nerve enlargement due to leprosy in a fourteen-year-old male patient are described.

Juvenile Granulosa Cell Tumour of the Ovary with Unilocular Pure Cystic Presentation: A Case Report and Review of Literature

Background

Granulosa cell tumours of the ovary are rare, hormonally active, oestrogen-secreting tumours of the ovary existing in two forms: the adult form and the even rarer juvenile form. These tumours present as predominantly solid lesions while the cystic, unilocular presentation is uncommon.

Case Report

We present an 18-year-old unmarried girl who presented with complaints of chronic pain, abdominal distension and presence of facial hair. Radiological examination revealed a large, purely cystic, unilocular lesion without any solid components, debris or septations. Histopathological diagnosis was of a juvenile granulosa cell tumour.

Conclusions

Radiological criteria suggestive of malignant ovarian masses include thick, irregular walls and septae; papillary projections and solid, echogenic foci. Nonetheless, we propose that a malignant ovarian lesion should be included in the differential diagnosis of a unilocular, purely cystic ovarian lesion.

A Series of Congenital High Airway Obstruction Syndrome - Classic Imaging Findings

Congenital high airway obstruction syndrome (CHAOS) is a very rare entity with very poor prognosis in which upper airway is intrinsically obstructed, the most common reason being laryngeal atresia. In summary prenatal early diagnosis of patients with CHAOS is necessary so that perinatal management can be undertaken successfully or elective termination of pregnancy can be undertaken. The fetoscopic approach may be a life saving modality in a subset of CHAOS patients. Involving a multidisciplinary team comprising of paediatricians, radiologists, obstetricians and anaesthesiologists increases the efficiency of management.

Ocular cysticercosis with intermittent blindness

We report this peculiar case of ocular cysticercosis with intermittent blindness which is never reported to our knowledge. This case highlights use of Ultrasound for examination of the posterior segment of eye globe. In limited facilities Ultrasound is the main modality to reach the diagnosis. We also wish to enforce the point that in endemic regions and in young population primary cysticercosis and its complications must be kept in differentials of cystic mass or calcified mass, as in this case, we have seen both the stages of cysticercosis progression.

An Association of Chronic Hyperaldosteronism with Medullary Nephrocalcinosis

Background

An association between chronic hyperaldosteronism and medullary nephrocalcinosis has rarely been made, with only a handful of cases described in literature.

Case Report

We describe five cases of hyperaldosteronism with a long- standing history in whom associated medullary nephrocalcinosis was established.

Conclusions

We infer that a chronic hyperaldosteronic status, whether primary or secondary, is a causal factor in the etiopathogenesis of medullary nephrocalcinosis. This article illustrates and summarizes various postulated theories that support our proposed association between hyperaldosteronism and nephrocalcinosis. We conclude that chronic hyperaldosteronism should be included as one of the causes of nephrocalcinosis and that our case series emphasizes the need of a well-organized retrospective study to prove it further.

Renal Cysts and Nephrocalcinosis in a Patient Deficient in 11 beta-Hydroxylase Enzyme

BACKGROUND

Chronic hypokalemia is known to induce renal structural and functional abnormality. The former includes induction of renal cyst formation and interstitial fibrosis while the latter entails urine-concentrating defect. However, these hypokalemia-mediated changes occur in a handful of conditions including primary aldosteronism, distal renal tubular acidosis, Liddle's disease, apparent mineralocorticoid excess syndrome and Bartter's type 3 syndrome. Such a finding has never been described in an 11 beta-hydroxylase deficient individual.

CASE REPORT

We describe a case of a 15-year-old male, deficient in 11 beta-hydroxylase enzyme, presenting with hypertensive haemorrhage in basal ganglia and chronic hypokalemia-mediated nephrocalcinosis and renal cysts. To add to the uniqueness, our patient was discovered to harbour bilateral testicular adrenal rests as well.

CONCLUSIONS

An early diagnosis could help prevent these sequelae and preserve long-term renal function and safeguard against ill-effects of hypertension. Besides, aetiology of nephrocalcinosis should be sought for and corrected.

Radiological illustration of spontaneous ovarian hyperstimulation syndrome

BACKGROUND

The role of radiology is of utmost importance not only in diagnosing s-OHSS but also in ruling out other cystic ovarian diseases and to determine the underlying etiology and course of the disease. We presented a radiological algorithm for diagnosing the various causes of s-OHSS.

CASE REPORT

A 26-year-old female, gravida one was referred to radiology department with history of lower abdominal pain, nausea and vomiting since 2 days which was gradual in onset and progression. The patient had no significant medical and surgical history.

CONCLUSIONS

This article illustrates and emphasizes that diagnosis of s-OHSS and its etiology can be completely evaluated radiologically. Biochemical markers will confirm the radiological diagnosis.

Prevalence of nonalcoholic fatty liver disease in patients with type 2 diabetes mellitus

OBJECTIVES

Nonalcoholic fatty liver disease (NAFLD) is commonly associated with type 2 diabetes mellitus (DM) though its prevalence is not well studied. We conducted a prospective study of prevalence and risk factors of NAFLD in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

204 type 2 DM patients attending an out-patient diabetic clinic underwent abdominal sonography. Ninty of 127 patients with fatty infiltration on ultrasound consented for liver biopsy, clinical and biochemical workup.

RESULTS

Eighty seven percent had NAFLD on histology with 62.6% steatohepatitis and 37.3% fibrosis. Age, duration of diabetes mellitus, degree of glycemic control, body mass index, waist circumference, family history of diabetes mellitus, did not predict the presence or severity of NAFLD or fibrosis. Serum alanine aminostranferase (ALT) and alkaline phosphatase levels, though within normal limits, were significantly higher in patients with steatohepatitis. Prevalence of NASH increased with increase in the components of the metabolic syndrome. Serum AST/ALT ratio were also significantly higher (p-0.049) in patients with severe fibrosis. All patients with severe fibrosis had metabolic syndrome.

CONCLUSIONS

Prevalence of NAFLD and NASH in our cohort of type 2 DM patients is high and increases with multiple components of metabolic syndrome. NASH and advanced fibrosis can occur in diabetic patients without any symptoms, signs or routine laboratory test abnormalities.

Sonography in Budd-Chiari syndrome

OBJECTIVE

The objective of this presentation is to provide an overview of sonographic manifestations of Budd-Chiari syndrome (BCS).

METHODS

Patients were scanned with ultrasound systems using mainly a 2- to 5-MHz curvilinear transducer and in some patients a 5- to 12-MHz linear transducer. The patients were asked to fast from the previous night or for at least 6 hours. Color and spectral Doppler sonography was performed in all patients.

RESULTS

Commonly seen findings in BCS include inferior vena cava (IVC) webs and thrombi, IVC narrowing, hepatic venous thrombosis, enlarged caudate lobes, ascites, intrahepatic or extrahepatic collaterals, monophasic to absent flow in the hepatic veins, and high flow velocities in areas of stenosis in the IVC or hepatic veins. Inferior vena cava stents used in the treatment of BCS could also be seen.

CONCLUSIONS

Budd-Chiari syndrome is an uncommon disorder; outcome is poor in many cases; and the condition is often misdiagnosed or underdiagnosed. Sonography is a noninvasive and effective modality for diagnosis of BCS.

Sonographic diagnosis of placental teratoma

Placental teratomas are very rare, and the features that distinguish them on sonography and allow their differentiation from other placental tumors have not been fully described. Prenatal recognition of this tumor is prognostically useful because, unlike other neoplasms, placental teratoma is benign and almost never associated with congenital deformities in the fetus. We describe the case of a 27-year-old pregnant woman in whom prenatal color Doppler sonographic examination performed during early-stage labor revealed a heterogeneous mass at the placental margin. This lesion, which measured 10 x 8 x 5 cm, had an echogenic focus consistent with calcification and hyperechoic foci consistent with fat. Placental teratoma and fetus acardius amorphus were considered in the differential diagnosis, but the segmental organization and umbilical cord-like structures that characterize the latter diagnosis were absent. The sonographic diagnosis, placental teratoma, was confirmed postnatally by histopathologic examination. The neonate, a healthy boy, was delivered vaginally at term. Although the presence of tissues of varied echogenicity, such as calcification, fat, and fluid, and the absence of both polarity and an umbilical cord-like structure support the sonographic diagnosis of placental teratoma, fetus acardius amorphus should be considered in the differential diagnosis. Histopathologic examination may be needed to establish a definitive diagnosis in such cases.

Antenatal detection of idiopathic arterial calcification with hydrops fetalis

Idiopathic arterial calcification of infancy, or occlusive infantile arterial calcification, is a rare cause of arterial calcification. This condition is inherited as an autosomal recessive pattern, which is almost always fatal. In most of the 100 cases described in the literature, the diagnosis was made at autopsy; a few cases have been reported in which an antemortem diagnosis was made on the basis of radiographic or sonographic demonstration of arterial calcification. The clinical characteristics are extremely variable, and respiratory distress with cardiac failure is the most common finding. Hypertension that is refractory to treatment is present in most cases. Most infants die before the age of 6 months, and very few have survived for more than 1 year. Mortality in this condition is caused by myocardial ischemia due to coronary artery involvement or refractory cardiac failure. The purpose of this report is to describe the prenatal diagnosis of idiopathic arterial calcification. Fewer than 10 cases of antenatal detection of this condition have been reported in the literature. This case is 1 of 2 cases with the earliest diagnosis of this condition so far (Table 1).

Pro-survival function of Akt/protein kinase B in prostate cancer cells. Relationship with TRAIL resistance

Tumor necrosis factor superfamily member TRAIL/Apo-2L has recently been shown to induce apoptosis in transformed and cancer cells. Some prostate cancer cells express constitutively active Akt/protein kinase B due to a complete loss of lipid phosphatase PTEN gene, a negative regulator of phosphatidylinositol 3-kinase pathway. Constitutively active Akt promotes cellular survival and resistance to chemotherapy and radiation. We have recently noticed that some human prostate cancer cells are resistant to TRAIL. We therefore examined the intracellular mechanisms of cellular resistance to TRAIL. The cell lines expressing the highest level of constitutively active Akt were more resistant to undergo apoptosis by TRAIL than those expressing the lowest level. Down-regulation of constitutively active Akt by phosphatidylinositol 3-kinase inhibitors, wortmannin and LY294002, reversed cellular resistance to TRAIL. Treatment of resistant cells with cycloheximide (a protein synthesis inhibitor) rendered cells sensitive to TRAIL. Transfecting dominant negative Akt decreased Akt activity and increased TRAIL-induced apoptosis in cells with high Akt activity. Conversely, transfecting constitutively active Akt into cells with low Akt activity increased Akt activity and attenuated TRAIL-induced apoptosis. Inhibition of TRAIL sensitivity occurs at the level of BID cleavage, as caspase-8 activity was not affected. Enforced expression of anti-apoptotic protein Bcl-2 or Bcl-X(L) inhibited TRAIL-induced mitochondrial dysfunction and apoptosis. We therefore identify Akt as a constitutively active kinase that promotes survival of prostate cancer cells and demonstrate that modulation of Akt activity, by pharmacological or genetic approaches, alters the cellular responsiveness to TRAIL. Thus, TRAIL in combination with agents that down-regulate Akt activity can be used to treat prostate cancer.

Constitutively active Akt is an important regulator of TRAIL sensitivity in prostate cancer

TRAIL/Apo-2L is a member of the tumor necrosis factor superfamily and has recently been shown to induce apoptosis in cancer cells, but not in normal cells. In nude mice injected with human tumors, TRAIL reduces the size of these tumors without side effects. Akt promotes cell survival and block apoptosis. Some prostate cancer cells express high levels of Akt due to lack of active lipid phosphatase PTEN, a negative regulator of PI-3 kinase pathway, which may be responsible for drug resistance. The objective of this paper is to investigate the intracellular molecules that regulate TRAIL resistance. We have examined caspase-8 activity, BID cleavage, Akt activity, mitochondrial membrane potential (DeltaPsi(m)) and apoptosis in prostate cancer (LNCap, PC-3, PC-3M and DU145) cells treated with or without TRAIL. PC-3, PC-3M and DU145 cells are sensitive to TRAIL, whereas LNCap cells are resistant. LNCap cells express the highest level of constitutively active Akt, which is directly correlated with TRAIL resistance. TRAIL activates caspase-8 in all the cell lines. Downregulation of constitutively active Akt by PI-3 kinase inhibitors (wortmannin and LY-294002), dominant negative Akt or PTEN, renders LNCap cells sensitive to TRAIL. Inhibition of TRAIL sensitivity occurs at the level of BID cleavage. Inhibition of protein synthesis by cycloheximide also causes LNCap cells sensitive to TRAIL. Overexpression of Bcl-2 or Bcl-X(L) inhibits TRAIL-induced DeltaPsi(m) and apoptosis. Overexpression of constitutively active Akt in PC-3M cells (express very low levels of constitutively active Akt) restores TRAIL resistance. These data suggest that elevated Akt activity protects LNCap cells from TRAIL-induced apoptosis, and the PI-3 kinase/Akt pathway may inhibit apoptotic signals by inhibiting processing of BID. Thus, constitutively active Akt is an important regulator of TRAIL sensitivity in prostate cancer.

Progressive renal disease: does the quality of the proteinuria matter or only the quantity?

Proteinuria is now accepted to be not just a sign of renal disease but also a contributory factor to the development of progressive tubulointerstitial fibrosis. Excellent correlations between the degree of proteinuria and rate of decline of glomerular filtration rate have been demonstrated. What has been investigated less is whether the type of protein found in the urine is important. Using transformed and primary human proximal tubular epithelial cells, we have investigated the binding of albumin and retinol binding protein to plasma membrane preparations and studied the response of the intact cells to increasing concentrations of these same proteins. We have preliminary evidence for differences in the pattern of binding of these two proteins to the plasma membrane receptors and also for differential release of pro-inflammatory cytokines from intact cells. These in vitro results, along with those of other groups, and some recent clinical findings suggest that the quality of proteinuria may play a role in the early development of interstitial fibrosis. Furthermore, the use of such in vitro model systems based on human proximal epithelial cell culture can provide a means of evaluating the potential significance of different markers of tubular damage.

Reference ranges for plasma cystatin C and creatinine measurements in premature infants, neonates, and older children

AIM

To establish a reference range in the paediatric population for the new glomerular filtration rate (GFR) marker, cystatin C, and to compare it with that of creatinine.

METHODS

Cystatin C and creatinine were measured by particle enhanced nephelometric immunoassay (PENIA) and fixed interval Jaff¿e methods, respectively, in 291 children aged 1 day to 17 years, including 30 premature infants with gestational ages ranging from 24 to 36 weeks.

RESULTS

In the premature infants, concentrations of both cystatin C and creatinine were significantly raised compared with term infants, with cystatin C concentrations being between 1.10 and 2.06 mg/litre and creatinine between 32 and 135 micromol/litre. In premature infants, there was no significant relation between gestational age and cystatin C or creatinine concentration. Creatinine concentrations fell to a nadir at 4 months of age, rising gradually to adult values by about 15-17 years of age, in contrast to cystatin C, which fell to a mean concentration of 0.80 mg/litre by the 1st year of life, and remained constant throughout adulthood up to the age of 50 years. Neither analyte showed any influence of sex.

CONCLUSION

The measurement of cystatin C, rather than creatinine, is more practical for monitoring GFR changes in the paediatric population.

The use of optical sensors to understand cellular interactions with renal cells

Optical biosensor technology has revolutionized the assessment of receptor binding, enabling the characterization of low affinity interactions in real time. We report the application of the LAsys Optical Biosensor to the investigation of the affinity and specificity of the putative proximal tubular scavenging receptor for protein reabsorption and the specificity of AGE-modified protein interactions with primary human mesangial cells. Using the LLCPK cell line, the carboxy-methyl dextran cuvette surface and five different proteins (ranging in size and charge), we have shown that there is evidence to support the existence of a single scavenging receptor for all the proteins tested. The proteins competed with each other differing only in their relative binding affinity for the common receptor. We have also shown that human mesangial cells can bind to AGE-modified human serum albumin (AGE-HSA) immobilized onto the carboxylate surfaced planar cuvette and that binding can be inhibited using increasing concentrations of soluble AGE-HSA. However, increasing concentrations of soluble Non-AGE modified HSA can also inhibit binding to a similar extent which implies that there is relatively little AGE-receptor (RAGE) expression on cultured primary human mesangial cells. These results demonstrate the exciting potential of this technology as a tool to explore cellular interactions with renal cells.

Measurement of the kinetics of protein uptake by proximal tubular cells using an optical biosensor

BACKGROUND

The affinity and specificity of protein reabsorption by proximal tubular cells have been investigated using techniques for monitoring endocytosis, demonstrating a high capacity but low affinity process. It is not known whether uptake is through binding to a single binding site/receptor with differing affinities, or if there are several classes of binding sites receptors, each specific for differing proteins or groups, such as, high or low molecular weight proteins.

METHODS

We have developed a novel technique for analyzing the kinetics of protein binding to tubular cells using a optical biosensor system. We have studied the binding of cultured LLCPK cells to albumin and RBP immobilized onto the sensor. By adding increasing concentrations of competing proteins [varying in molecular weight from 66,000 to 11,800 D and pI from 4.6 to 9.2 as represented by albumin, alpha1-microglobulin (alpha1M), retinol binding protein (RBP), cystatin C and beta2-microglobulin (beta2m)], specific and inhibitable cell binding was demonstrated.

RESULTS

Equilibrium constants, KA, could be calculated from the reciprocal of the protein concentration causing 50% inhibition in binding rate. These were: albumin = 8.0 x 10(4) M(-1), alpha1M = 2.0 x 10(5) M(-1), RBP = 2.7 x 10(4) M(-1), cystatin C = 2.0 x 10(4) M(-1), beta2m = 4.2 x 10(3) M(-1). There were no significant differences between the measured KA's whether RBP or albumin were immobilized on the surface.

CONCLUSIONS

All the proteins gave similar shaped inhibition profiles, suggesting that there is one binding site/receptor for all proteins studied, regardless of molecular weight or charge, but there are differing affinities for each protein.

Development and validation of an automated latex-enhanced immunoassay for prealbumin

The measurement of circulating prealbumin has been shown to be clinically useful in the assessment of nutritional status, both as an initial screen and in the monitoring of nutritional recovery. We describe a fully automated, noncompetitive, homogeneous, light-scattering immunoassay that has been developed for this analyte on a Dimension (Dade) analyzer. A sheep anti-prealbumin IgG fraction was covalently coupled to 40-nm chloromethyl styrene particles and, after the addition of sample, polyethylene glycol-assisted immunoagglutination was monitored by turbidimetry. The prealbumin working assay range was 8-550 mg/L at a sample volume of 2 microL and a reaction time of 6.5 min. When data were analyzed using ANOVA, total and within-run assay imprecision values (CVs) were 1-5%, and calibration and reagent stabilities were in excess of 40 days. Mean analytical recoveries were 102% +/- 4% (SD), and there was no lack of parallelism. Hemolysis, lipemia, and bilirubin did not interfere. Both plasma anticoagulated with heparin or EDTA and serum from plain or serum-separation tubes were acceptable as sample matrices. Comparison with the Beckman Array method gave a Passing and Bablok regression of: Dimension analyzer = 1.01Beckman + 7.1 (n = 103), using a common calibrator. We conclude that the prealbumin method is appropriate for clinical use according to the analytical criteria used in this study.