Grade group 4 prostate cancer without intraductal carcinoma on biopsy is more likely to be downgraded on prostatectomy than with intraductal carcinoma

In this study, we investigated the association between intraductal carcinoma of the prostate (IDCP) along with several histopathological features on prostate biopsy and downgrading of grade group 4 (GG4) prostate cancer (PCa) in patients with the highest grade tumor of GG4 PCa in at least one core. A total of 29 cases had the highest grade tumor of GG4 PCa and radical prostatectomy performed between 2016 and 2021. IDCP was detected in 11 out of 29 cases on biopsy. The cases without IDCP were more likely to be downgraded on prostatectomy than with IDCP, with statistical significance (88.9% vs 36.4%, p = 0.003). The proportions of the highest-grade tumors by length and cores involved, average numbers of PCa-positive cores, and mean patient's age did not differ between cases that were downgraded and not downgraded at prostatectomy. Our results suggest that the absence of IDCP on biopsy could be a predictor of downgrading at prostatectomy for patients with the highest grade tumor of GG4 PCa.

Evaluation of Renal Biopsy for Transplant: The Significance of Whole Slide Imaging (WSI) in Telepathology

Introduction/Objective

Percutaneous Renal biopsy remains a gold standard technique to provide diagnostic and prognostic information post kidney transplantation. Recently Whole slide imaging (WSI) telepathology systems have been widely used for clinical, education and research purposes. Our aim was to examine reliability and accuracy of WSI telepathology service in the pathology diagnosis of biopsy specimens from transplanted kidney.

Methods

At our institution we have two renal pathologists. They utilize WSI telepathology service with Aperio scanner for rapid initial assessment of the transplant renal biopsy specimens. We retrospectively reviewed reports of all transplant renal biopsies which were examined remotely utilizing WSI telepathology service and compared the results for initial versus final diagnoses.

Results

In period from Jan 2019 to April 2020 total 160 renal transplant biopsies were evaluated remotely utilizing the WSI scanner. The diagnosis was divided in 4 subcategories as reperfusion injury, rejection (Antibody mediated or T cell mediated), mixed inflammation-favor infection and Polyoma virus infection. There were 48 cases of reperfusion injury; 5 cases of polyoma virus infection, 37 cases of rejection and 28 cases with mixed inflammation and 42 cases with no significant histopathologic findings. There was no discrepancy between the preliminary and final diagnosis for all 160 cases. The ancillary studies including special stains and electron microscopy added to the final diagnosis or confirmed the preliminary diagnosis.

Conclusion

WSI telepathology is a reliable and simple method to rapidly review transplant kidney biopsies. The ability to transmit images from hospitals to pathologists with WSI scanner has the potential for not only an accurate assessment of the rejection but also for additional histopathological findings. Digital pathology enhances the clinical usefulness of immediate assessments of transplant biopsy samples and also provides a platform to share the scanned images with clinicians which also can be utilized for education of trainees.

Progression of Chronic Kidney Disease After Acute Kidney Injury: Role of Self-Perpetuating Versus Hemodynamic-Induced Fibrosis

The relative contribution of self-perpetuating versus hemodynamic-induced fibrosis to the progression of chronic kidney disease (CKD) after acute kidney injury (AKI) is unclear. In the present study, male Sprague-Dawley rats underwent right uninephrectomy and were instrumented with a blood pressure radiotelemeter. Two weeks later, separate groups of rats were subjected to 40 minutes renal ischemia-reperfusion or sham surgery and followed up for 4 or 16 weeks to determine the extent to which glomerulosclerosis and tubulointerstitial fibrosis as a result of the AKI-CKD transition (ie, at 4 weeks post AKI) change over time during the progression of CKD (ie, at 16 weeks post AKI). On average, tubulointerstitial fibrosis was ≈3-fold lower (P<0.05), whereas glomerulosclerosis was ≈6-fold higher (P<0.05) at 16 versus 4 weeks post AKI. At 16 weeks post AKI, marked tubulointerstitial fibrosis was only observed in rats exhibiting marked glomerulosclerosis, proteinuria, and kidney hypertrophy consistent with a hemodynamic pathogenesis of renal injury. Moreover, quantitative analysis between blood pressure and renal injury revealed a clear and modest blood pressure threshold (average 16-week systolic blood pressure of ≈127 mm Hg) for the development of glomerulosclerosis. In summary, modest levels of blood pressure may be playing a substantial role in the progression of renal disease after AKI in settings of preexisting CKD associated with 50% loss of renal mass. In contrast, these data do not support a major role of self-perpetuating tubulointerstitial fibrosis in the progression CKD after AKI in such settings.

A unique case of a serous borderline tumor of the paratestis

Serous borderline tumors of the paratestis are histologically identical to their ovarian counterparts and hypothesized to arise from Mullerian metaplasia of the tunica vaginalis. They are exceedingly rare with many cases probably going clinically unnoticed. We present a case of serous borderline tumor of the paratestis, with, to the best of our knowledge, the first published sonographic and magnetic resonance (MR) images of this entity. It was successfully treated with partial orchiectomy with no disease recurrence after one-and-a-half years.

Glomerulosclerosis in the diet-induced obesity model correlates with sensitivity to nitric oxide inhibition but not glomerular hyperfiltration or hypertrophy

The diet-induced obesity (DIO) model is frequently used to examine the pathogenesis of obesity-related pathologies; however, only minimal glomerulosclerosis (GS) has been reported after 3 mo. We investigated if GS develops over longer periods of DIO and examined the potential role of hemodynamic mechanisms in its pathogenesis. Eight-week-old male obesity-prone (OP) and obesity-resistant (OR) rats (Charles River) were administered a moderately high-fat diet for 5 mo. Radiotelemetrically measured blood pressure, proteinuria, and GS were assessed. OP (n=10) rats developed modest hypertension (142±3 vs. 128±2 mmHg, P<0.05) and substantial levels of proteinuria (63±12 vs. 12±1 mg/day, P<0.05) and GS (7.7±1.4% vs. 0.4±0.2%) compared with OR rats (n=8). Potential hemodynamic mechanisms of renal injury were assessed in additional groups of OP and OR rats fed a moderately high-fat diet for 3 mo. Kidney weight (4.3±0.2 vs. 4.3±0.1 g), glomerular filtration rate (3.3±0.3 vs. 3.1±0.1 ml/min), and glomerular volume (1.9±0.1 vs. 2.0±0.1 μm3×10(-6)) were similar between OP (n=6) and OR (n=9) rats. Renal blood flow autoregulation was preserved in both OP (n=7) and OR (n=7) rats. In contrast, Nω-nitro-L-arginine methyl ester (L-NAME) administration in conscious, chronically instrumented OP (n=11) rats resulted in 15% and 39% increases in blood pressure and renal vascular resistance, respectively, and a 16% decrease in renal blood flow. Minimal effects of L-NAME were seen in OR (n=9) rats. In summary, DIO-associated GS is preceded by an increased hemodynamic sensitivity to L-NAME but not renal hypertrophy or hyperfiltration.

Critical blood pressure threshold dependence of hypertensive injury and repair in a malignant nephrosclerosis model

Most patients with essential hypertension do not exhibit substantial renal damage. Renal autoregulation by preventing glomerular transmission of systemic pressures has been postulated to mediate this resistance. Conversely, malignant nephrosclerosis (MN) has been postulated to develop when severe hypertension exceeds a critical ceiling. If the concept is valid, even modest blood pressure (BP) reductions to below this threshold regardless of antihypertensive class (1) should prevent MN and (2) lead to the healing of the already developed MN lesions. Both predicates were tested using BP radiotelemetry in the stroke-prone spontaneously hypertensive rats receiving 1% NaCl as drinking fluid for 4 weeks. Severe hypertension (final 2 weeks average systolic BP, >200 mm Hg) and MN (histological damage score 36±5; n=27) developed in the untreated stroke-prone spontaneously hypertensive rats but were prevented by all antihypertensive classes (enalapril [n=15], amlodipine [n=13], or a hydralazine/hydrochlorothiazide combination [n=15]) if the final 2-week systolic BP remained <190 mm Hg. More impressively, modest systolic BP reductions to 160 to 180 mm Hg (hydralazine/hydrochlorothiazide regimen) initiated at ≈4 weeks in additional untreated rats after MN had already developed (injury score 35±4 in the right kidney removed before therapy) led to a striking resolution of the vascular and glomerular MN injury over 2 to 3 weeks (post-therapy left kidney injury score 9±2, P<0.0001; n=27). Proteinuria also declined rapidly from 122±9.5 mg/24 hours before therapy to 20.5±3.6 mg 1 week later. These data clearly demonstrate the barotrauma-mediated pathogenesis of MN and the striking capacity for spontaneous and rapid repair of hypertensive kidney damage if new injury is prevented.

Effect of the phosphodiesterase-5 inhibitor zaprinast on ischemia-reperfusion injury in rats

PURPOSE

The cardiac and renal protective effects of phosphodiesterase-5 (PDE-5) inhibitors against ischemia-reperfusion injury have recently been demonstrated in animal studies. We evaluated the effect of pretreatment with the PDE-5 inhibitor zaprinast on warm renal ischemia in a rat model.

METHODS

Female Sprague-Dawley rats underwent concomitant right nephrectomy and left renal hilar occlusion for 30 minutes. Twelve animals were equally divided into three groups: Group 1 received no pharmacologic pretreatment, group 2 was pretreated with zaprinast 10 mg/kg, and group 3 was pretreated with zaprinast 20 mg/kg. Zaprinast was dissolved in 25% dimethyl sulfoxide and given as a single intraperitoneal injection 30 minutes before surgery. Serum blood urea nitrogen (BUN) and creatinine levels, histopathology, and TUNEL staining for apoptosis were assessed 24 hours postoperatively.

RESULTS

The mean creatinine level for groups 1, 2, and 3 was 0.73 mg/dL, 0.55 mg/dL, and 0.38 mg/dL, respectively. These values were not statistically different (P=0.099). The mean BUN levels of 35.8 mg/dL for group 1, 27.3 mg/dL for group 2, and 23.3 mg/dL for group 3 were also statistically similar (P=0.278). There were no objective differences in histopathologic evaluation or TUNEL staining between the groups.

CONCLUSION

This study did not demonstrate a beneficial effect of zaprinast pretreatment on renal parameters after warm ischemic injury.

Genomic heterogeneity of translocation renal cell carcinoma

PURPOSE

Translocation renal cell carcinoma (tRCC) is a rare subtype of kidney cancer involving the TFEB/TFE3 genes. We aimed to investigate the genomic and epigenetic features of this entity.

EXPERIMENTAL DESIGN

Cytogenomic analysis was conducted with 250K single-nucleotide polymorphism microarrays on 16 tumor specimens and four cell lines. LINE-1 methylation, a surrogate marker of DNA methylation, was conducted on 27 cases using pyrosequencing.

RESULTS

tRCC showed cytogenomic heterogeneity, with 31.2% and 18.7% of cases presenting similarities with clear-cell and papillary RCC profiles, respectively. The most common alteration was a 17q gain in seven tumors (44%), followed by a 9p loss in six cases (37%). Less frequent were losses of 3p and 17p in five cases (31%) each. Patients with 17q gain were older (P=0.0006), displayed more genetic alterations (P<0.003), and had a worse outcome (P=0.002) than patients without it. Analysis comparing gene-expression profiling of a subset of tumors bearing 17q gain and those without suggest large-scale dosage effects and TP53 haploinsufficiency without any somatic TP53 mutation identified. Cell line-based cytogenetic studies revealed that 17q gain can be related to isochromosome 17 and/or to multiple translocations occurring around 17q breakpoints. Finally, LINE-1 methylation was lower in tRCC tumors from adults compared with tumors from young patients (71.1% vs. 76.7%; P=0.02).

CONCLUSIONS

Our results reveal genomic heterogeneity of tRCC with similarities to other renal tumor subtypes and raise important questions about the role of TFEB/TFE3 translocations and other chromosomal imbalances in tRCC biology.

Abstract 493: Impact of Renal Vasoconstriction on the Relationship Between Blood Pressure and Renal Injury in Angiotensin II-induced Hypertensive Rats

Ang II is thought to play a prominent role in the development of hypertension-induced renal disease via BP dependent and independent pathways; however the quantitative relationships between BP and renal injury have not been rigorously examined in Ang II-induced hypertension. The major goals of the present study were to assess: 1) the relationship between BP and renal injury in rats with hypertension induced by Ang II vs. renal mass reduction (RMR) and 2) the pressure-flow relationships in conscious Ang II-infused rats. One group of male Sprague-Dawley rats (Charles River) were implanted with a BP radiotransmitter and 10 days later administered Ang II (n=12; 500 ng/kg/min via osmotic minipump) or subjected to 3/4 RMR via right uninephrectomy + infarction of ∼ 1/2 of the left kidney (RKI, n=5). BP was measured continuously and kidneys were perfused fixed at 6 weeks for the assessment of renal injury. In a separate experiment, MAP and RBF (Transonic) were measured in conscious chronically instrumented rats. After recovery from surgery (∼7 days), baseline MAP and RBF were assessed (∼4 hours @ 200 Hz) on 2 consecutive days. Subsequently, rats were administered Ang II (n=6; 500 ng/kg/min) or saline (n=7; sham) via osmotic minipump and MAP and RBF were again assessed every 2-3 days for 10 days. Despite a higher average systolic BP over 6 weeks in Ang II (174±3 mmHg) vs. RKI (165±6 mmHg) rats, glomerulosclerosis (GS) was higher (p<0.05) in RKI (15±7% out of 100 glomeruli) vs. Ang II (6±1% out of 100 glomeruli) rats. Moreover, the slope of the relationship between BP and %GS (Δ%GS/ΔmmHg) was greater in RKI vs. Ang II rats. Both MAP (98±2 vs. 99±3 mmHg) and RBF (8.1±1vs. 8.2±1 ml/min) were similar at baseline in Ang II and sham rats, respectively. MAP was elevated by day 3 (123±6 mmHg) and further increased to 157±5 mmHg by day 10 in Ang II rats. Conversely, RBF was decreased at day 3 (6.6±0.6 ml/min) and the vasoconstriction persisted over the experimental protocol as RBF further decreased to 5.6±0.7 ml/min at day 10 in Ang II rats. In conclusion, Ang II-induced hypertension is associated with a diminished susceptibility to renal injury as compared to rats with RMR likely due, in part, to the AngII-induced vasoconstriction, which reduces BP transmission to the renal microvasculature.

Solid organ transplantation for non-TTR hereditary amyloidosis: report from the 1st International Workshop on the Hereditary Renal Amyloidoses

Fibrinogen A α-chain (AFib) and apolipoprotein AI (AApoAI) amyloidosis due to variants in the AFib and ApoAI genes are the most common types of hereditary amyloidosis in Europe and the United States. Liver is the exclusive source of the aberrant amyloidogenic protein in AFib and responsible for supplying approximately half of the circulating variant ApoAI. Nephrotic syndrome and renal impairment due to renal amyloidosis are common disease manifestations; however, recent research provides evidence to support a more diverse and systemic disease phenotype, which in turn has implications in the management of the hereditary amyloidoses with solid organ transplantation and, in particular, liver transplantation.

Large BP-dependent and -independent differences in susceptibility to nephropathy after nitric oxide inhibition in Sprague-Dawley rats from two major suppliers

The N(ω)-nitro-l-arginine methyl ester (l-NAME) model is widely employed to investigate the role of nitric oxide (NO) in renal injury. The present studies show that Sprague-Dawley rats from Harlan (H) and Charles River (CR) exhibit strikingly large differences in susceptibility to l-NAME nephropathy. After 4 wk of l-NAME (∼50 mg·kg(-1)·day(-1) in drinking water), H rats (n = 13) exhibited the expected hypertension [average radiotelemetric systolic blood pressure (BP), 180 ± 3 mmHg], proteinuria (136 ± 17 mg/24 h), and glomerular injury (GI) (12 ± 2%). By contrast, CR rats developed less hypertension (142 ± 4), but surprisingly no proteinuria or GI, indicating a lack of glomerular hypertension. Additional studies showed that conscious H, but not CR, rats exhibit dose-dependent renal vasoconstriction after l-NAME. To further investigate these susceptibility differences, l-NAME was given 2 wk after 3/4 normotensive nephrectomy (NX) and comparably impaired renal autoregulation in CR-NX and H-NX rats. CR-NX rats, nevertheless, still failed to develop proteinuria and GI despite moderate hypertension (144 ± 2 mmHg, n = 29). By contrast, despite an 80-90% l-NAME dose reduction and lesser BP increases (169 ± 4 mmHg), H-NX rats (n = 20) developed greater GI (26 ± 3%) compared with intact H rats. Linear regression analysis showed significant (P < 0.01) differences in the slope of the relationship between BP and GI between H-NX (slope 0.56 ± 0.14; r = 0.69; P < 0.008) and CR-NX (slope 0.09 ± 0.06; r = 0.29; P = 0.12) rats. These data indicate that blunted BP responses to l-NAME in the CR rats are associated with BP-independent resistance to nephropathy, possibly mediated by a resistance to the renal (efferent arteriolar) vasoconstrictive effects of NO inhibition.

Dynamic blood pressure load and nephropathy in the ZSF1 (fa/facp) model of type 2 diabetes

Diabetes and increased blood pressure (BP) are believed to interact synergistically in the pathogenesis and progression of diabetic nephropathy. The present studies were performed to examine if there were differences in BP load and/or protective renal autoregulatory capacity between the obese diabetic Zucker fatty /spontaneously hypertensive heart failure F1 hybrid (ZSF1) ( fa/ facp) rats and their lean controls. By ∼26 wk of age, ZSF1 ( n = 13) but not their lean controls ( n = 16) had developed substantial proteinuria (180 ± 19 vs. 16 ± 1.4 mg/24 h) and glomerulosclerosis (19 ± 2.4 vs. 0.6 ± 0.2%; P < 0.001). However, average ambient systolic BP by radiotelemetry (12–26 wk of age) was modestly lower in ZSF1 than in lean controls (130 ± 1.4 vs. 137 ± 1.7 mmHg, P < 0.002), although the 24-h BP power spectra showed a mild increase at frequencies <0.1 Hz in the ZSF1. Autoregulatory capacity under anesthesia in response to step changes in perfusion pressure between 100 and 140 mmHg was similarly well preserved in both ZSF1 and lean controls at 16–18 wk of age [autoregulatory indexes (AI) <0.1]. Similarly, differences were not observed for dynamic autoregulation in conscious rats [transfer functions between BP (input) and renal blood flow (output) using chronic Transonic flow probes]. Collectively, these data indicate that the pathogenesis of nephropathy in the ZSF1 model of type 2 diabetic nephropathy is largely independent of differences in systemic BP and/or its potential renal transmission. However, these data do not exclude the possibility that the diabetic milieu may alter the glomerular capillaries in the ZSF1, such that there is an enhanced local susceptibility to injury with even normal glomerular pressures.

Fat poor renal angiomyolipoma: patient, computerized tomography and histological findings

PURPOSE

We reviewed our experience with fat poor cases of angiomyolipoma.

MATERIALS AND METHODS

The records of patients with angiomyolipoma, as determined by pathological study, from 1998 to 2004 were reviewed by recording patient demographics and outcomes. Fat poor cases were defined as the failure of imaging to demonstrate fat in a lesion. Computerized tomography and histological characteristics were assessed.

RESULTS

Histologically confirmed angiomyolipoma was found in 15 patients. Multiple lesions were found in 3 of 15 cases (20%). Of these 15 patients who underwent surgery 11 (73%) had unsuspected angiomyolipoma due to absent fat on computerized tomography and they underwent intervention for presumed renal cell carcinoma. Mean age +/- SD in this group was 54 +/- 15 years and 8 of 11 patients (73%) were female, of whom 4 (50%) had uterine fibroids. These lesions were found incidentally in 7 of 11 cases (64%). Operative complications developed in 2 of 11 patients (18%). Average maximal diameter on pathological evaluation was 3.2 +/- 1.3 cm (range 1.5 to 6). Nonenhanced computerized tomography was available in 7 of 11 cases, of which 3 of 7 (42%) showed hyperdense lesions and 4 of 7 (57%) showed isodense lesions. The percent of fat identified per high power field was less than 25% in 12 of 13 fat poor angiomyolipoma lesions (92%) compared to 2 of 4 classic lesions (50%) known to be angiomyolipoma before surgery (p = 0.04).

CONCLUSIONS

We suggest that a general definition of fat poor angiomyolipoma should be the failure of imaging to reveal fat within a lesion, thus, making it unsuspected at surgery. A pathological definition should be less than 25% fat per high power field, which to our knowledge is a formerly undefined quantity. Not all cases are hyperdense on nonenhanced computerized tomography. These lesions cannot be reliably identified by imaging and they should be managed like all enhancing renal masses.

Spontaneously reduced blood pressure load in the rat streptozotocin-induced diabetes model: potential pathogenetic relevance

The rat streptozotocin (STZ)-induced diabetes model is widely used to investigate the pathogenesis of diabetic nephropathy. However, overt nephropathy is inexplicably slow to develop in this model compared with renal mass reduction (RMR) models. To examine whether blood pressure (BP) differences correlated with the time course of glomerulosclerosis (GS), BP was measured continuously throughout the course by radiotelemetry in control (n = 17), partially insulin-treated STZ-diabetes (average blood glucose 364 +/- 15 mg/dl; n = 15), and two normotensive RMR models (systolic BP <140 mmHg)--uninephrectomy (UNX; n = 16) and 3/4 RMR by surgical excision [right nephrectomy + excision of both poles of left kidney (RK-NX); n = 12] in Sprague-Dawley rats. Proteinuria and GS were assessed at approximately 16-20 wk (all groups) and at 36-40 wk (all groups except RK-NX). At 16 wk, significantly greater proteinuria and GS had developed in the RK-NX group compared with the other three groups (not different from each other). By 36-40 wk, substantial proteinuria and GS had also developed in the UNX group, but both the control and the STZ-diabetic rats exhibited comparable modest proteinuria and minimal GS. Systolic BP (mmHg) was significantly reduced in the STZ-diabetic rats (116 +/- 1.1) compared with both control (124 +/- 1.0) and RMR (128 +/- 1.2 and 130 +/- 3.0) groups (P < 0.01). Similarly, "BP load" as estimated by BP power spectral analysis was also lower in the STZ-diabetic rats. Given the known protective effects of BP reductions on the progression of diabetic nephropathy, it is likely that this spontaneous reduction in ambient BP contributes to the slow development of GS in the STZ-diabetes model compared with the normotensive RMR models.

Heart transplantation in a patient with chloroquine-induced cardiomyopathy

We present the first report of a patient who underwent heart transplantation (HT) after endomyocardial biopsy (EMB) and revealed chloroquine-induced cardiomyopathy (CIC). This patient, who was treated with chloroquine for 6 years, developed a restrictive cardiomyopathy that progressed to congestive heart failure (CHF) resistant to medical management.

Renal Tumors in Young Adults

PURPOSE

The clinical and pathological features of solid or complex cystic renal masses in young adults have not been defined. We present our experience with patients 17 to 45 years old with such renal masses to define the incidence of malignant vs benign lesions, familial tendencies and clinical outcomes.

MATERIALS AND METHODS

The medical records of all patients 17 to 45 years old who presented with a solid or suspicious complex cystic renal mass at 2 tertiary care hospitals between 1988 and 2002 were retrospectively reviewed. Pertinent clinical information was compiled, including age, gender, mode of presentation, renal function, year and type of surgery, pathological analysis and survival data.

RESULTS

There were 114 evaluable patients who underwent a total of 119 nephrectomies. Mean patient age was 37.1 years and males comprised 56.1% of the population. Twelve patients had familial renal cell carcinoma (RCC), the von Hippel-Lindau syndrome. Mode of presentation for patients with sporadic disease was symptomatic (55.9%), incidental (35.3%) or unknown (8.8%). Radical nephrectomy, partial nephrectomy and nephroureterectomy were performed in 80 kidneys (67.2%), 37 (31.1%) and 2 (1.7%), respectively. Malignant lesions comprised 79.8% of all masses and 95.8% of these were renal cell carcinoma. Of the RCCs 75.8% were grade 1 or 2 and 89% were organ confined. Young women were much more likely than men to have a benign lesion (36.0% vs 9.5%, p <0.01) and the diversity of histologies was impressive (of the 24 total benign masses 9 were different tumor types). With an average followup of 38.3 months overall survival is 90.2%. Among patients with RCC 84.9% are alive and cancer-free, 11.6% are dead from disease and 3.5% are alive with recurrent disease.

CONCLUSIONS

We report the largest known series of solid or suspicious complex renal masses in young adults. As expected, familial tumors are more common in this population. While RCC is the most common tumor, a wide variety of potential pathological outcomes are possible, particularly in women, who were much more likely to have a benign lesion. RCC in this patient population appears to have a favorable prognosis, despite symptomatic presentation in the majority of cases.

Comparison of laparoscopy-assisted partial nephrectomy using digital compression versus purely laparoscopic nephrectomy using vascular pedicle clamp in a porcine model

BACKGROUND AND PURPOSE

Laparoscopic partial nephrectomy raises a number of technical issues, particularly in the control of bleeding. We compared digital compression during hand assistance with a vascular clamp.

MATERIALS AND METHODS

Laparoscopic transperitoneal bilateral lower-pole partial nephrectomy was performed on six pigs, with a vascular clamp being used on one side and digital pressure through an Omniport or Lapdisk on the other. The pigs were then euthanized and the kidneys harvested for histologic examination.

RESULTS

Good hemostasis was obtained regardless of the technique. However, the estimated blood loss was significantly greater with digital compression (96.7 versus 9.6 mL). There were no significant micropathological differences in the kidneys. The surgeons rated suture tying and placement much easier with the purely laparoscopic technique.

CONCLUSIONS

Both techniques are feasible. In experienced hands, the purely laparoscopic technique takes no longer than the hand-assisted technique and is associated with less blood loss, easier suturing, and better cosmesis. However, long-term follow-up is needed before clinical use can be contemplated.

Renoprotection by ACE inhibition or aldosterone blockade is blood pressure-dependent

Renin-angiotensin-aldosterone system blockade has been shown to protect against renal damage in salt-supplemented, stroke-prone spontaneously hypertensive rats (SHRsp). Based on intermittent tail-cuff blood pressure (BP) measurements, it has been claimed that such protection is BP-independent and mediated by a blockade of the direct tissue-damaging effects of angiotensin and/or aldosterone. BP radiotelemetry was performed for 8 weeks in approximately 10-week-old male SHRsp who received a standard diet and either tap water (n=10) or 1% NaCl to drink. Saline-drinking SHRsp were either left untreated (n=12), received enalapril (50 mg/L) in drinking fluid (n=9), or had subcutaneous implantation of time-release 200-mg pellets of aldactone (n=10). The average systolic BP (mean+/-SEM) during the final 3 weeks was significantly higher (P<0.05) in untreated saline-drinking (215+/-6 mm Hg) SHRsp but not aldactone-treated (198+/-4 mm Hg) or enalapril-treated treated SHRsp (173+/-1 mm Hg), as compared with tap water-drinking SHRsp (197+/-3 mm Hg). Histological renal damage scores at 8 weeks paralleled the BP in all groups, with an excellent correlation (r=0.8, P<0.001, n=41). Moreover, a renal damage score of >5 was only observed in SHRsp whose average systolic BP during the final 3 weeks exceeded 200 mm Hg, indicating a threshold relation with BP. These data show that protection by renin-angiotensin-aldosterone system blockade in this model is BP-dependent and mediated by preventing the severe increases in BP seen in untreated salt-supplemented SHRsp and further underscore the limitations of interpretations based on conventional tail-cuff BP measurements.

Low protein diet mediated renoprotection in remnant kidneys: Renal autoregulatory versus hypertrophic mechanisms

BACKGROUND

The mechanism of low protein diet conferred renoprotection in the ablation model remains controversial. Blockade of glomerular hypertrophy, reduced preglomerular vasodilation, and preserved autoregulation have all been postulated. The potential differential impact of calcium channel blockers on these mechanisms and glomerulosclerosis was examined.

METHODS

Rats with 5/6 renal ablation received either a 25% standard protein diet, an 8% low protein diet and a low protein diet with either verapamil or amlodipine. Renal autoregulatory and morphometric studies were performed at 3 weeks before the development of significant injury, and the assessment of glomerulosclerosis after 7 weeks of continuous blood pressure radiotelemetry in additional rats.

RESULTS

The preserved renal autoregulation in low protein rats was abolished by both calcium channel blockers, with the impairment being either comparable to (low protein + verapamil) or greater than the standard protein rats (low protein + amlodipine). Neither calcium channel blocker blocked the inhibitory effects of low protein diet on renal blood flow, kidney weight, and glomerular volume. Results (mean +/- SE) for glomerular volume (microm-3x 10(-6)): low protein (N = 11), 1.6 +/- 0.1; low protein + verapamil (N = 10), 1.7 +/- 0.1; low protein + amlodipine (N = 12), 1.7 +/- 0.2; versus standard protein (N = 10), 2.2 +/- 0.1; P < 0.05. Only amlodipine, but not verapamil, reduced average systolic blood pressure (143 +/- 2 mm Hg versus low protein rats, 168 +/- 5 mm Hg, and standard rats, 170 +/- 6 mm Hg; P < 0.01). Nevertheless, the glomeruloprotection seen in low protein (N = 15) as compared to standard protein (N = 14) rats (9%+/- 3% versus 28%+/- 6% glomerulosclerosis; P < 0.01) was abolished in both low protein + verapamil (N = 14, 32%+/- 7%) and low protein + amlodipine rats (N = 16, 27%+/- 7%).

CONCLUSIONS

Preservation of renal autoregulation and not inhibition of hypertrophy is the critical component in low protein diet-conferred glomeruloprotection.

Increased genetic susceptibility to renal damage in the stroke-prone spontaneously hypertensive rat

BACKGROUND

The spontaneously hypertensive rat (SHR) develops much less renal damage than the stroke-prone strain of SHR (SHRsp) after salt-supplementation, and it has been proposed that these strains differ in their genetic susceptibility to renal damage. However, radiotelemetric BP measurements have shown that salt-supplementation results in more severe and accelerated hypertension in the SHRsp. Therefore, it is unclear whether the differences in renal damage are due to differences in BP exposure or true differences in intrinsic (genetic) renal susceptibility to hypertensive damage.

METHODS

Kidney cross transplantation was performed between the SHR and SHRsp strains in uninephrectomized recipients to allow an investigation of the susceptibility to renal damage in SHR and SHRsp kidneys maintained in the same host and exposed to the same BP profile and metabolic environment. Following transplantation, BP was radiotelemetrically monitored before and after an 8% NaCl diet given to accelerate hypertension and renal damage. Then the kidneys were removed and renal damage was assessed histologically.

RESULTS

In the SHR recipients, the SHRsp donor kidneys exhibited more hypertensive damage than the contralateral native SHR kidneys, but histologic evidence of mild cellular immunologic rejection also was observed that could have facilitated the increased renal damage. However, even in SHRsp recipients, the native SHRsp kidneys exhibited twice the damage seen in the contralateral transplanted SHR kidneys.

CONCLUSION

These data unequivocally demonstrate that the SHRsp kidneys are intrinsically more susceptible than the SHR kidneys to renal damage when exposed to exactly the same BP and metabolic environment.

Comparative effects of selective T- and L-type calcium channel blockers in the remnant kidney model

We have previously reported that the dihydropyridine L-type calcium channel blockers (CCBs) have an adverse impact on glomerulosclerosis (GS) in the remnant kidney model despite significant blood pressure (BP) reduction, because of the concurrent deleterious effects on renal autoregulation. The effects of the CCB mibefradil, which is approximately 10-fold more selective for T- than L-type channels, were compared with the L-type selective amlodipine. One week after 5/6 ablation, rats were left untreated or received mibefradil or amlodipine. Systolic BP was monitored by continuous radiotelemetry. At 7 weeks, proteinuria and percent GS were quantitated. Average BP was significantly and comparably reduced after mibefradil (141+/-3 mm Hg) and amlodipine (143+/-5 mm Hg) compared with untreated rats (188+/-5 mm Hg). Despite the reduction in BP, proteinuria and percent GS in the mibefradil- or amlodipine-treated groups were not significantly different from those in the untreated rats. Excellent correlations were observed between BP and GS in each group (r=0.74 to 0.85, P<0.02). However, the slope of the relationship between GS and BP (increase in percent GS/mm Hg increase in average BP) was made significantly steeper by both mibefradil (2.7+0.6) and amlodipine (1.9+0.6) as compared with untreated rats (0.7+/-0.2; P<0.01). Thus, at any given BP elevation, greater GS was seen in mibefradil- and amlodipine-treated rats as compared with untreated rats. Additional studies performed at 3 weeks after renal ablation showed that the ability to autoregulate renal blood flow, already impaired in untreated rats, was essentially abolished by both mibefradil and amlodipine, thus providing an explanation for the shift in the slope of the relationship between BP and GS. These data indicate that CCBs with selectivity for either the T- or L-type calcium channel fail to protect against GS despite significant BP reductions because of the similar adverse effects on renal autoregulation and BP transmission.

Differential salt-sensitivity in the pathogenesis of renal damage in SHR and stroke prone SHR

The spontaneously hypertensive rat (SHR) and the stroke prone SHR (SHRsp) display contrasting susceptibilities to the development of the severe hypertensive lesions of malignant nephrosclerosis, both with aging and after the provision of a high salt intake on the background of a Japanese style "stroke prone" rodent diet. The SHR is relatively resistant, whereas the SHRsp is markedly susceptible. The responsible mechanisms remain controversial. Blood pressure (BP) radiotelemetry was used to investigate the interrelationship between salt intake, systolic BP, and renal damage in 8- to 12-week-old male SHR and SHRsp given a standard North American style diet for 6 weeks, a standard diet plus 1% NaCl as drinking water for 6 weeks, or an 8% NaCl diet plus tap water for 4 weeks. After 4 weeks, BP was significantly greater in the SHRsp compared to the SHR and was significantly more sensitive to supplemental salt in the SHRsp than in SHR. Average systolic pressures during week 5 (after 4 weeks on standard diet plus tap water, standard diet plus 1% NaCl, and 8% NaCl diet plus tap water) were 188.0 +/- 3.0 mm Hg, 207.3 +/- 5.6 mm Hg, and 226 +/- 9.4 mm Hg in SHRsp compared with 171.4 +/- 3.8 mm Hg, 180.6 +/- 3.8 mm Hg, and 190.3 +/- 5.0 mm Hg in SHR. In the absence of supplemental NaCl, both strains exhibited minimal evidence of hypertensive renal damage until about 16 weeks of age. A high salt intake resulted in the development of lesions of malignant nephrosclerosis (fibrinoid necrosis and thrombosis of small vessels and glomeruli) in the SHRsp but not in the SHR; semiquantitative histologic renal damage scores in SHRsp versus SHR being 10.4 +/- 2.0 versus 0.7 +/- 0.2 after 6 weeks of standard diet plus 1% NaCl, and 32.1 +/- 2.5 versus 0.7 +/- 0.4 after 4 weeks of 8% NaCl diet plus tap water; P < .001 for both comparisons. The development of more severe hypertension in salt-supplemented SHRsp could only partly account for the severity of renal damage in SHRsp, the increase in which was disproportionate to the increase in absolute BP. However, the rate of increase of BP was greater in the SHRsp and this might have contributed to the greater renal damage observed in the SHRsp. These data indicate that the contrasting genetic susceptibility to renal damage between SHR and SHRsp is mediated, at least in part, by a differential BP salt sensitivity.

Genetic isolation of a chromosome 1 region affecting susceptibility to hypertension-induced renal damage in the spontaneously hypertensive rat

Linkage studies in the fawn-hooded hypertensive rat have suggested that genes influencing susceptibility to hypertension-associated renal failure may exist on rat chromosome 1q. To investigate this possibility in a widely used model of hypertension, the spontaneously hypertensive rat (SHR), we compared susceptibility to hypertension-induced renal damage between an SHR progenitor strain and an SHR congenic strain that is genetically identical except for a defined region of chromosome 1q. Backcross breeding with selection for the markers D1Mit3 and Igf2 on chromosome 1 was used to create the congenic strain (designated SHR.BN-D1Mit3/Igf2) that carries a 22 cM segment of chromosome 1 transferred from the normotensive Brown Norway rat onto the SHR background. Systolic blood pressure (by radiotelemetry) and urine protein excretion were measured in the SHR progenitor and congenic strains before and after the induction of accelerated hypertension by administration of DOCA-salt. At the same level of DOCA-salt hypertension, the SHR.BN-D1Mit3/Igf2 congenic strain showed significantly greater proteinuria and histologically assessed renal vascular and glomerular injury than the SHR progenitor strain. These findings demonstrate that a gene or genes that influence susceptibility to hypertension-induced renal damage have been trapped in the differential chromosome segment of the SHR.BN-D1Mit3/Igf2 congenic strain. This congenic strain represents an important new model for the fine mapping of gene(s) on chromosome 1 that affect susceptibility to hypertension-induced renal injury in the rat.

Calcium is required in reassembly of bovine papillomavirus in vitro

Papillomaviruses are small DNA viruses which infect and induce benign warts and sometimes malignant tumours in the epithelium of the skin or mucosa. The viruses do not replicate in conventional tissue culture systems and little is known about the requirements for virus assembly. We investigated the effect of ethylene glycol-bis(aminoethyl ether)-tetraacetic acid (EGTA) and dithiothreitol (DTT) treatment on the stability of bovine papillomavirus type 1 (BPV-1) particles in vitro. Removal of calcium ions by 11 mM EGTA at pH 8.0 together with reduction of disulfide bonds by 15 mM DTT destabilized BPV particles. Electron microscopy examination of treated particles showed that the BPV particles had been disrupted to capsomeres. Addition of exogenous calcium ions to the disruption buffer prevented virus destabilization. Adding calcium to the disrupted BPV particles resulted in the reassembly of disrupted particles. The reassembled particles were morphologically similar to intact BPV virions. We further quantified the efficiency of reassembly by focus formation assay. We recorded 500-fold less infectivity for reassembled BPV and 4-fold less haemagglutination activity compared to untreated BPV, pointing towards a decrease in the amount of reassembled particles recovered.

Genetic susceptibility to hypertension-induced renal damage in the rat. Evidence based on kidney-specific genome transfer

To test the hypothesis that genetic factors can determine susceptibility to hypertension-induced renal damage, we derived an experimental animal model in which two genetically different yet histocompatible kidneys are chronically and simultaneously exposed to the same blood pressure profile and metabolic environment within the same host. Kidneys from normotensive Brown Norway rats were transplanted into unilaterally nephrectomized spontaneously hypertensive rats (SHR-RT1.N strain) that harbor the major histocompatibility complex of the Brown Norway strain. 25 d after the induction of severe hypertension with deoxycorticosterone acetate and salt, proteinuria, impaired glomerular filtration rate, and extensive vascular and glomerular injury were observed in the Brown Norway donor kidneys, but not in the SHR-RT1.N kidneys. Control experiments demonstrated that the strain differences in kidney damage could not be attributed to effects of transplantation-induced renal injury, immunologic rejection phenomena, or preexisting strain differences in blood pressure. These studies (a) demonstrate that the kidney of the normotensive Brown Norway rat is inherently much more susceptible to hypertension-induced damage than is the kidney of the spontaneously hypertensive rat, and (b) establish the feasibility of using organ-specific genome transplants to map genes expressed in the kidney that determine susceptibility to hypertension-induced renal injury in the rat.

Carboxyl terminus of bovine papillomavirus type-1 L1 protein is not required for capsid formation

The papillomavirus major capsid protein L1 can assemble into capsids in vitro. To identify areas within the bovine papillomavirus type-1 L1 (BPV L1) protein that are important for virus assembly, we constructed a set of 24 baculovirus recombinants expressing BPV L1 deletion mutants that span the entire L1 open reading frame. Virus-like particle (VLP) formation of the L1 mutants was examined by electron microscopy. Wild-type (wt) BPV L1 expressed in recombinant baculovirus formed VLPs, while capsomeres and aggregates were seen for most of the mutants screened. However, the C-terminal truncation mutant, lacking the last 24 amino acids (delta C2), was observed to form VLPs (threefold more efficiently than wt BPV L1). This suggests that this C-terminal region of L1 protein is not critical for capsid formation. As capsids assembled from BPV L1 are able to agglutinate mouse red blood cells (RBC) by binding to a membrane protein, we tested the ability of the mutants to hemagglutinate mouse RBCs. Most aberrant capsids or aggregates derived from deletion mutants were unable to agglutinate the RBCs with the exception of deletion mutants delta 11 (aa 231-271), delta 14 (aa 291-331), delta 21 (aa 431-471), and the carboxyl-terminus truncation mutant delta C2.

Early phase in the infection of cultured cells with papillomavirus virions

The fate of full bovine papillomavirus (BPV) virions and virus-like particles after binding to C127 or CV-1 cells was studied by electron microscopy and indirect immunofluorescence. After incubation at 4 degrees for 1 hr, BPV virions were found to be bound to the plasma membrane, and most viruses were absorbed by the cells after 30 min incubation at 37 degrees. Ninety minutes after the virions had been bound to the plasma membrane, the uptake of the virions was completed and most of the antigen was found to be localized in the nucleus. The viruses were transported in phagosomes and the uptake and transportation could be inhibited by cytochalasin B and taxol, suggesting the possible involvement of microfilaments and microtubules in the virus particle uptake and transportation. The capsid proteins could be detected for about 14 hr, until degradation and deposit of the viral antigen in the Golgi complexes. Although binding to the plasma membrane and uptake of virions into large cytoplasmic vesicles could be monitored by electron microscopy, no complete virions were observed in the nucleus of infected cells despite a very strong nuclear fluorescent staining for both L1 and L2 proteins. This may indicate that disintegration of the virions occurs in the cytoplasm and the L1/L2 proteins migrate to the nucleus via their nuclear localization signals.

Renal cell carcinoma developing in the pediatric recipient of an adult cadaveric donor kidney

Renal cell carcinoma is an uncommon renal tumor in children, comprising between 1.8% and 6.3% of all malignant renal tumors of childhood (whereas renal cell carcinoma is the commonest renal tumor in adults). We describe a 15-year-old girl with chronic renal failure secondary to renal dysplasia and branchio-oto-renal syndrome, who received a cadaveric renal transplant at 8 years of age from a 25-year-old male donor. She developed severe chronic rejection 4 years after the transplant. A transplant nephrectomy was performed because of persistent gross hematuria. Histopathology of this graft showed chronic severe rejection and papillary necrosis. A fortuitous finding was a 1.5-cm renal cell carcinoma at one of the poles. We suggest that tumors which occur more commonly in adults and less commonly in children must be considered in children receiving adult organ transplants.

Radiotelemetric BP monitoring, antihypertensives and glomeruloprotection in remnant kidney model

The mechanisms by which antihypertensives exert a glomeruloprotective effect in the remnant kidney model remain controversial. Based on periodic tail-cuff BP measurements, the variable glomeruloprotective efficacy of antihypertensive agents has been ascribed to mechanisms other than or in addition to their ability to lower BP. To more precisely define the relationship between BP control and glomeruloprotection, systolic BP was continuously monitored radiotelemetrically at 10-minute intervals for approximately 65 days in rats after approximately 5/6 renal ablation. Rats with remnant kidneys received either no therapy or one of three antihypertensive regimens in their drinking water after the first week: enalapril, a triple therapy regimen (reserpine, hydralazine, hydrochlorothiazide); or a high dose triple therapy regimen. Although all antihypertensive regimens significantly lowered BP, considerable interanimal variability was observed. Additionally, marked lability of BP was present in both untreated and treated rats. Glomerular injury in individual animals (N = 34) was very strongly correlated with their overall averaged systolic BP during the final eight weeks (r = 0.91) and with the frequency of systolic BP readings > 150 mm Hg (r = 0.89). These data do not provide evidence of a therapeutic advantage for any of the regimens independent of their antihypertensive effects but indicate that the glomeruloprotective efficacy of these antihypertensive regimens is directly proportional to their antihypertensive efficiency.

Method of renal mass reduction is a critical modulator of subsequent hypertension and glomerular injury

The hypertension, proteinuria, and glomerulosclerosis that develop in the remnant kidney model (uninephrectomy plus infarction of approximately 2/3 of the other kidney) have been generally considered to represent the adverse consequences of a severe reduction in nephron number. To differentiate the blood pressure (BP) responses to infarction from those of reduced renal mass per se, BP was continuously monitored radiotelemetrically in rats whose total renal mass was reduced by 2/3 (infarction) and by 5/6 (infarction or surgical excision of both poles) and in sham-operated controls. Hypertension only developed in the two infarcted groups. Overall averages of systolic BP monitored every 10 min over 6 wk were 144 +/- 8 and 156 +/- 5 mm Hg in the 2/3 and 5/6 infarction groups (N = 10 each), respectively, as compared with 120 +/- 2 mm Hg (N = 12) in the approximately 5/6 surgical excision group (P < 0.01) and 117 +/- 5 mm Hg (N = 8) in controls. Changes in kidney weights, glomerular volumes, RBF, GFR, and renal autoregulatory ability after renal mass reduction by the two methods were qualitatively similar in additional animals from each group monitored for 2, 4, or 6 wk without radiotelemetry. Significant proteinuria and glomerulosclerosis only developed in the two infarction (hypertensive) groups. At 6 wk, 18 +/- 4 and 19 +/- 3% of the glomeruli exhibited injury in the 2/3 (N = 22) and the 5/6 infarction groups (N = 21), respectively, in contrast to 3 +/- 1% glomerular injury in the 5/6 surgical excision group (N = 24) (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence and consistency of ALT elevation in plasmapheresis donors: implications for the assessment of blood product infectivity

Alanine aminotransferase (ALT) levels were determined in 8,420 plasmapheresis donations obtained from 431 donors over a period of 18 months. Using sex-differentiated normal ranges 2.5% of donations but 23% of donors exhibited elevated ALT levels on at least 1 occasion. Amongst the donors with elevated ALT this was only seen on 1 occasion in one third, while a quarter had elevations in consecutive donations. No donors with consecutive elevations above 100 IU/l were detected. The results are discussed in terms of the guidelines currently recommended for assessing post-transfusion hepatitis infectivity of blood products, such as factor VIII. It is concluded that the current allowance for infection acquired from sources other than blood products under consideration may be over-generous, leading to a potential underestimate of the true rate of infection.

Continuous telemetric blood pressure monitoring and glomerular injury in the rat remnant kidney model

The pathogenesis of glomerular injury in the remnant kidney (RK) model remains controversial. Increased glomerular transmission of systemic hypertension has been postulated to be an important pathogenic mechanism, but the precise relationship between systemic pressures and glomerular injury has not been defined because of the limitations of the tail-cuff method. Systolic blood pressure (BP) was continuously recorded radiotelemetrically at 10-min intervals for 6 wk in rats after approximately 5/6 renal ablation (n = 16) or sham ablation (n = 7). Overall mean systolic BP in RK rats was significantly higher than sham (138 +/- 3.3 vs. 117 +/- 1.3 mmHg, P < 0.01). Additionally, marked lability of systolic BP was observed in RK rats as compared with sham rats. Glomerular injury was essentially confined to RK rats, but the percentage of injured glomeruli ranged between 1 and 55%. Glomerular injury in individual animals was strongly correlated (r = 0.88) with the mean systolic BP during the last approximately 4 wk and with the frequency of systolic BP readings of > 140 mmHg. These data strongly suggest that transmission of systemic hypertension to the renal microvasculature plays a predominant role in the pathogenesis of glomerular injury in the RK model and also support the potential usefulness of the radiotelemetric technique to investigate hypertensive target organ injury.

Lipopolysaccharide alters suckling rat liver glycogenolysis

Gram-negative sepsis/septic shock in the newborn continues to be a major medical problem, causing high mortality. Hyperglycemia followed by hypoglycemia is a common symptom in endotoxic shock. However, the mechanism of newborn glucoregulatory response to endotoxin has not been well understood. Paradoxically, monocyte-phagocytes can contribute to shock by overwhelming secretion of cytokines and also host defense by detoxifying endotoxin. Since monocyte-phagocyte function is immature in the newborn, this study was performed to evaluate Kupffer cell's role in liver glycogenolysis during endotoxic shock. Endotoxin (LPS) induced hyperglycemia in 10-day-old rats, and increased net glucose output in the isolated perfused liver. 1) Cytarabine decreased Kupffer cell function (decreased hepatic colloid carbon uptake) and blunted LPS-increased liver net glucose output in the Cytarabine + LPS-treated group (104 +/- 4 vs. 146 +/- 3 micrograms/min/g wet liver in the LPS-treated group: P < .001). 2) Indomethacin (IND) suppressed LPS-induced liver net glucose output in the LPS + IND-treated group (133 +/- 5 vs. 146 +/- 3 micrograms/min/g wet liver, P < .05). Thus, prostaglandins were suggested to contribute to glycogenolysis in the 10-day-old rat liver. 3) Phorbol 12-myristate 13-acetate (PMA) increased liver net glucose output (166 +/- 4 micrograms/min/g wet liver), and H-7, a protein kinase C inhibitor, blunted PMA-induced liver glucose output (140 +/- 2 micrograms/min/g wet liver, P < .05). H-7 enhanced LPS-induced liver net glucose output (196 +/- 9 micrograms/min/g wet liver, P < .01). Therefore, protein kinase C may not be the dominant cell signaling system for LPS stimulation in suckling rat Kupffer cells.

Prostaglandins do not mediate impaired autoregulation or increased renin secretion in remnant rat kidneys

The rat remnant kidney model, produced by approximately five-sixths reduction in functional renal mass, is characterized by renal vasodilation, impaired autoregulation, and increased activity of the renin-angiotensin system. The present studies were designed to investigate the role of vasodilatory prostaglandins (PGs) in the altered hemodynamics in the remnant kidney. Four weeks post-ablation, renal blood flow (RBF), was significantly higher in rats fed a standard protein (SP) diet (n = 16) compared with low-protein-fed (LP) rats (n = 7) (6.2 +/- 0.6 vs. 3.7 +/- 0.5 ml/min; P < 0.01), autoregulation was impaired in SP rats [autoregulation index (AI) 1.0 +/- 0.1 (SP) vs. 0.2 +/- 0.1 (LP); P < 0.05], and renin secretory rates were significantly increased in SP rats both during the basal state [24 +/- 7 (SP) vs. 2 +/- 1 (LP) ng.ml-1 x h-1 x min-1; P < 0.05] and after reduction in renal perfusion pressure [110 +/- 29 (SP) vs. 16 +/- 7 (LP); P < 0.05]. Indomethacin administration (5 mg/kg bolus + 5 mg.kg-1 x h-1 infusion) in additional SP rats (n = 11) decreased RBF from 7.4 +/- 1.1 to 5.9 +/- 1.0 ml/min (P < 0.05) without improvement in autoregulation (AI = 1.1 +/- 0.3). Renin basal secretory rate and response to decreased renal perfusion pressure were not altered by indomethacin. These data suggest that PGs contribute to the renal vasodilation in the rat remnant kidney model, but they do not mediate the impaired renal autoregulation or the increased renin release.

The spectrum of monoclonal immunoglobulin deposition disease associated with immunocytic dyscrasias

Immunocytic dyscrasias may be manifested by MIDD often presenting with renal manifestations. The diagnosis is established when deposits are shown by immunopathologic methods to contain a single light-chain isotype in patients who have a monoclonal Ig in the serum or urine, altered kappa:lambda ratio in bone marrow, and/or abnormal biosynthesis of Igs in bone marrow cell cultures. The morphologic expressions of deposits are varied: fibrillar in AL, granular and punctate in LCDD, granular or crystalline in LHCDD, and crystalline in type I cryoglobulinemia.

Nonamyloidotic monoclonal immunoglobulin deposits lack amyloid P component

Deposits in tissues from 13 patients with amyloid, 8 with monoclonal light chain or light and heavy chain deposition disease, and 2 with both amyloid and nonamyloidotic light chain deposits of the same isotype were examined in parallel for the presence of amyloid P component by immunofluorescence and/or immunoperoxidase methods. Amyloid P component was detected in the amyloid but not the nonamyloid deposits, even in the 2 individuals in whom both types of deposits were present, indicating a specific relationship between the amyloid P component and the amyloid fibrils.