Calcium-mediated parathyroid hormone suppression to assess progression of secondary hyperparathyroidism during treatment among incident dialysis patients

CONTEXT

Parathyroid gland function is affected adversely by tissue hyperplasia and gland enlargement in hyperparathyroidism.

OBJECTIVE

We examined the effects of 2 treatment strategies on the progression of secondary hyperparathyroidism using measurements of the nonsuppressible component of calcium-regulated PTH secretion as an index of parathyroid mass.

DESIGN, SUBJECTS, AND INTERVENTION

In this randomized, open-label study, subjects managed with hemodialysis for >3 but <12 months before entering the trial (mean, 7.2 months) who had baseline plasma PTH levels >300 pg/mL received cinacalcet and low-dose vitamin D sterols (Cin-D, n = 153) or larger, varying doses of calcitriol, or other vitamin D analogs (Flex-D, n = 151). Study drug doses were adjusted periodically based on PTH and serum total calcium determinations.

MAIN OUTCOME MEASURES

The exploratory endpoint was calcium-regulated PTH release, assessed using a standardized PTH suppression test before and after 52 weeks of treatment and 4 weeks after withdrawing treatment. PTH and serum total calcium were measured before hemodialysis using high-calcium (3.5 mEq/L or 1.75 mmol/L) dialysate and after 150 and 180 minutes.

RESULTS

Mean (95% confidence interval) nonsuppressible calcium-regulated PTH release at baseline did not differ between Cin-D, 33.4% (25.9%, 40.9%), and Flex-D, 28.1% (23.2%, 32.9%). Corresponding values after 52 weeks of treatment were 34.3% (29.7%, 38.9%) and 42.0% (32.7%, 51.3%), not significant, and did not change measurably in either group when reevaluated 4 weeks after treatments were withdrawn.

CONCLUSION

Disease progression over 12 months was not documented using a PTH suppression test in this population. Calcium-mediated PTH suppression was maintained fully, however, in Cin-D despite reductions in serum total calcium concentration, whereas values did not increase in Flex-D despite substantial increases in serum calcium.

Treatment of Refractory Diffuse Diabetic Macular Edema with Intravitreal Bevacizumab

To analyze the short term visual acuity and anatomic response after a single dose of off-label intravitreal injection of bevacizumab in diffuse diabetic macular edema (DME) not responding to conventionallaser photocoagulation.

Patients arid Methods: Prospective analysis of consecutive case series of 45 eyes of 38 patients with refractory diffuse DME who had one intra-vitreal injection of 1.25 mg of bevacizumab (Avastin) and followed up for 3 months. All patients passed at least six months since their last laser treatment before inclusion in the study. Patients underwent best corrected visual acuity determination, intraocular pressure measurement, stereoscopic biomicroscopy of the macula and measurement of the retinal thickness by optical coherence tomography (OCT) at base line and follow up visits.

Results: At 1 month post-injection, visual acuity improved by 1 line in 7 eyes, unchanged from the preinjection levels in 24 eyes and deteriorated in 14 eyes. At 3 months post injection, visual acuity improved in 18 eyes, it remained unchanged in 13 eyes and deteriorated in 14 eyes. The mean logMAR visual acuities were 0.60 (SD ± 0.34), 0.64 (SD ± 0.31) and 0.61 (SD ± 0.32) at pre-injection, at 1 month post-injection and at 3 months post-injection respectively; but this mean decrease in vision was statistically not significant (P value = 0.099). The foveal thickness on optical coherence tomography had decreased in 27 eyes and it increased in 18 eyes at 1 month post-injection. At 3 months following injection, foveal thickness was reduced in 34 eyes, but was increased in 11 eyes. The mean foveal thicknesses were 444.95 u (SD ± 127.36), 394.95 u (SD ± 138.03) and 378.32 u (SD ± 11 2.01) at pre-injection, 1 month post-injection and 3 months post-injection respectively. This decrease in the foveal thickness was statistically significant (P value <  0.001).

Conclusions: Intravitreal bevacizumab is effective in patients with diffuse DME which is refractory to treatment with conventional macular laser photocoagulation. Key words: bevacizumab, intravitreal, diffuse diabetic macular edema

Meta-analysis of randomized controlled trials on the safety and effectiveness of day-case laparoscopic cholecystectomy

BACKGROUND

Although day-case laparoscopic cholecystectomy can save bed costs, its safety has to be established. The aim of this meta-analysis is to assess the advantages and disadvantages of day-case surgery compared with overnight stay in patients undergoing elective laparoscopic cholecystectomy.

METHODS

Randomized clinical trials addressing the above issue were identified from The Cochrane Library trials register, Medline, Embase, Science Citation Index Expanded and reference lists. Data were extracted from these trials by two independent reviewers. For each outcome the relative risk, weighted mean difference or standardized mean difference was calculated with 95 per cent confidence intervals based on available case analysis.

RESULTS

Five trials with 215 patients randomized to the day-case group and 214 to the overnight-stay group were included in the review. Four of the five trials were of low risk of bias. The trials recruited 49.1 per cent of patients presenting for cholecystectomy. There was no significant difference between day case and overnight stay with respect to morbidity, prolongation of hospital stay, readmission rates, pain, quality of life, patient satisfaction, and return to normal activity and work. In the day-case group 80.5 per cent of patients were discharged on the day of surgery.

CONCLUSION

Day-case laparoscopic cholecystectomy is a safe and effective treatment for symptomatic gallstones.

Day-case versus overnight stay in laparoscopic cholecystectomy

BACKGROUND

Although day-case elective laparoscopic cholecystectomy can save bed costs, its safety remains to be established.

OBJECTIVES

To assess the safety and benefits of day-case surgery compared to overnight stay in patients undergoing elective laparoscopic cholecystectomy.

SEARCH STRATEGY

We searched The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded until February 2007 for identifying randomised trials using search strategies.

SELECTION CRITERIA

Only randomised clinical trials, irrespective of language, blinding, or publication status, comparing day-case and overnight stay in elective laparoscopic cholecystectomy were considered for the review.

DATA COLLECTION AND ANALYSIS

We collected the data on the characteristics of the trial, methodological quality of the trials, morbidity, prolonged hospitalisation, re-admissions, pain and quality of life from each trial. We analysed the data with both the fixed-effect and the random-effects models using RevMan Analysis. For each outcome we calculated the relative risk, weighted mean difference, or standardised mean difference with 95% confidence intervals (CI) based on available case-analysis.

MAIN RESULTS

Five trials with 429 patients randomised to the day-case group (215) and overnight stay group (214) were included in the review. Four of the five trials were of low risk of bias regarding randomisation and follow up, but all lacked blinding. The trials recruited 49% of patients undergoing cholecystectomy. The selection criteria varied, but most included only patients without other diseases. The patients were living in easy reach of the hospital and with a responsible adult to take care of them. On the day of surgery, 81% of day-case patients were discharged. The drop-out rate after randomisation varied from 6.5% to 12.7%. There was no significant difference between day-case and overnight stay group as regards to morbidity, prolongation of hospital stay, re-admission rates, pain, quality of life, patient satisfaction and return to normal activity and work.

AUTHORS' CONCLUSIONS

Day-case elective laparoscopic cholecystectomy seems to be a safe and effective intervention in selected patients (with no or minimal systemic disease and within easy reach of the hospital) with symptomatic gallstones. Because of the decreased hospital stay, it is likely to save costs.

Prospective randomized trial of end-to-end versus side-to-side biliary reconstruction after orthotopic liver transplantation

BACKGROUND

Biliary reconstruction is the Achilles heel of liver transplantation. Side-to-side anastomosis of donor and recipient bile duct has been claimed to be superior to end-to-end anastomosis in uncontrolled studies.

METHODS

A total of 100 consecutive patients undergoing orthotopic liver transplantation were randomized after commencement of the transplant procedure to end-to-end or side-to-side anastomosis. No T tube drainage was employed. Endoscopic retrograde cholangiography was performed 2 weeks after transplantation and findings were reported by an experienced endoscopist as normal, leak or stricture. Median follow-up was 53 (range 35-63) months.

RESULTS

Patient age, sex, the graft preservation time and indication for transplantation were similar in both groups. Sixty patients received end-to-end and 40 side-to-side anastomosis. Ten patients randomized to side-to-side anastomosis had an end-to-end procedure. The total number of biliary complications was similar in both groups (end-to-end 32 per cent versus side-to-side 30 per cent) as were the number of leaks (17 versus 18 per cent) and biliary strictures (15 versus 12 per cent). There was no difference in the number of biliary complications that required interventional treatment (22 per cent in both groups).

CONCLUSION

Side-to-side and end-to-end biliary anastomosis at liver transplantation are equally effective.

Prospective study of hepatobiliary scintigraphy and endoscopic cholangiography for the detection of early biliary complications after orthotopic liver transplantation

BACKGROUND

Biliary complications are a significant cause of morbidity and death after orthotopic liver transplantation (OLT). This study was a prospective evaluation of endoscopic retrograde cholangiography (ERC) and hepatobiliary scintigraphy (HBS), using 99mTc Mebrofenin, to detect early biliary complications following OLT.

METHODS

One hundred consecutive patients who had OLT with a biliary duct-to-duct anastomosis were studied. Of these, 67 had both ERC and HBS performed within 30 days of OLT. Sensitivity, specificity and diagnostic accuracy of HBS in identifying biliary leak or stricture was calculated.

RESULTS

Of the 67 cholangiographies performed 45 were normal. In 22 patients there was radiological evidence of a leak (n = 14) or stricture (n = 8) which required further intervention in nine and four patients respectively. The sensitivity and specificity of scintigraphy for the detection of biliary leak after transplantation was 50 and 79 per cent and for biliary stricture 62 and 64 per cent respectively. No patient with normal scintigraphy required biliary intervention. Only six of 14 patients with biliary leaks and two of 20 with strictures suggested by scintigraphy required intervention. If both ERC and HBS reported leak or stricture, the intervention rate was considerably higher at five of seven leaks and two of five strictures.

CONCLUSION

This study suggests that scintigraphy is a useful screening test for biliary complications after OLT, ERC is only necessary if HBS is abnormal.

Prospective study of hepatobiliary scintigraphy and endoscopic cholangiography for the detection of early biliary complications after orthotopic liver transplantation

BACKGROUND

Biliary complications are a significant cause of morbidity and death after orthotopic liver transplantation (OLT). This study was a prospective evaluation of endoscopic retrograde cholangiography (ERC) and hepatobiliary scintigraphy (HBS), using 99mTc Mebrofenin, to detect early biliary complications following OLT.

METHODS

One hundred consecutive patients who had OLT with a biliary duct-to-duct anastomosis were studied. Of these, 67 had both ERC and HBS performed within 30 days of OLT. Sensitivity, specificity and diagnostic accuracy of HBS in identifying biliary leak or stricture was calculated.

RESULTS

Of the 67 cholangiographies performed 45 were normal. In 22 patients there was radiological evidence of a leak (n = 14) or stricture (n = 8) which required further intervention in nine and four patients respectively. The sensitivity and specificity of scintigraphy for the detection of biliary leak after transplantation was 50 and 79 per cent and for biliary stricture 62 and 64 per cent respectively. No patient with normal scintigraphy required biliary intervention. Only six of 14 patients with biliary leaks and two of 20 with strictures suggested by scintigraphy required intervention. If both ERC and HBS reported leak or stricture, the intervention rate was considerably higher at five of seven leaks and two of five strictures.

CONCLUSION

This study suggests that scintigraphy is a useful screening test for biliary complications after OLT, ERC is only necessary if HBS is abnormal.

Duct-to-duct biliary reconstruction following liver transplantation for primary sclerosing cholangitis

The biliary complications in patients undergoing biliary reconstruction by duct-to-duct (D-D) anastomosis or with a Roux-en-Y loop (RL) at the time of liver transplantation for primary sclerosing cholangitis (PSC, 16 D-D, 10RL) or primary biliary cirrhosis (PBC, 31 D-D, 1 RL) were reviewed and compared. Patients were followed up for a mean period of 32 months. Extrahepatic biliary strictures occurred in 18.7%, 10% and 9.7% of DD-PSC, RL-PSC and DD-PBC patients, respectively, leaks in 6.2%, 20% and 6.4% DD-PSC, RL-PSC and DD-PBC patients, respectively (P = NS). Four intrahepatic biliary abnormalities developed in the PSC group. Duct-to-duct anastomosis did not significantly increase the risk of stricture formation or bile leaks in PSC patients compared to PBC patients. We conclude that duct-to-duct biliary reconstruction following liver transplantation for PSC is satisfactory unless the distal common bile duct is strictured.

Insulin and counterregulatory hormones influence acute-phase protein production in human hepatocytes

After trauma or sepsis, the liver undergoes a reprioritization of export protein synthesis with elevated production of some acute-phase reactants and reduced production of others. We have examined the effects of combinations of insulin and the counterregulatory hormones (dexamethasone, glucagon, and epinephrine), in the presence or absence of interleukin (IL)-6, on the production by isolated hepatocytes of the positive acute-phase proteins C-reactive protein, alpha 1-antichymotrypsin, alpha 1-acid glycoprotein, and haptoglobin, and the negative acute-phase proteins prealbumin and transferrin. The effect of IL-6 on the production of the above proteins was influenced significantly by insulin and all of the counterregulatory hormones. Significant three-way interactions as well as higher order interactions between the stress hormones and insulin were seen in the case of C-reactive protein. The results indicate that both positive and negative acute-phase proteins respond differently to insulin and the counterregulatory hormones and that the potential exists for the regulation of synthesis of individual acute-phase reactants by interaction between the cytokine network and the classical endocrine hormones.

Transforming growth factor-beta 1 and mannose 6-phosphate/insulin-like growth factor-II receptor expression during intrahepatic bile duct hyperplasia and biliary fibrosis in the rat

These studies investigate the role of transforming growth factor-beta 1, a potent inhibitor of epithelial cell proliferation and stimulator of extracellular matrix biosynthesis, during intrahepatic bile duct hyperplasia and biliary fibrosis. These pathogenic responses were induced in rats by common bile duct ligation. Bile duct cell replication, measured by the bromodeoxyuridine labeling index, was significantly increased 24 hr after common bile duct ligation. This response diminished to baseline by 1 wk. Liver collagen content, determined by quantification of hydroxyproline, was increased significantly after 1 wk of common bile duct ligation, and by 4 wk was increased by a factor of 4. Immunohistochemistry revealed low levels of TGF-beta 1 in normal intrahepatic bile duct epithelium. In contrast, the bile duct epithelium in bile duct-ligated rats stained strongly positive for transforming growth factor-beta 1 at 1 and 4 wk after ligation. These results suggest that transforming growth factor-beta 1 may play a role in both the termination of the bile duct epithelial cell proliferative response and the induction of fibrogenesis after common bile duct ligation. In addition, the mannose 6-phosphate/insulin-like growth factor II receptor was up-regulated in hyperplastic bile duct epithelium 1 and 4 wk after ligation. Because the mannose 6-phosphate/insulin-like growth factor-II receptor has been shown to facilitate the proteolytic activation of transforming growth factor-beta 1, these results suggest that the bile duct epithelium may also be involved in the activation of transforming growth factor-beta 1.

Exogenous neuropeptide Y blocks myoelectric activity in the upper gastrointestinal tract of starved dogs. Brain neuropeptide Y converts a fasting pattern of myoelectric activity to a fed pattern

The effect of intracerebroventricular (ICV) neuropeptide Y (NPY) on the migrating motor complex (MMC) was examined in five starved dogs. Myoelectric activity was recorded using gastric, duodenal, and jejunal electrodes. Intragastric pressure was monitored via a gastric fistula, and ICV injections were given through a cerebroventricular guide. Recordings were made with no ICV injection and before and after 250-microliters bolus injections of vehicle as control (0.1% dog serum albumin in saline) or 500 pmol/kg NPY. The mean interval between MMCs was 98 +/- 10 min without ICV injection and 96 +/- 7 min after control solution. After ICV injection of NPY no further MMCs were recorded in any dog, even though the study was continued for a minimum of 3.5 h. Instead, the myoelectric pattern became indistinguishable from that in fed dogs. We conclude that central NPY plays a role in modulation of upper gastrointestinal myoelectric activity. This may reflect a central regulatory role for NPY in the coordination of feeding.

Technique of intraluminal biliary ultrasonography during laparoscopic cholecystectomy

Intraluminal ultrasonography of the common duct was performed in nine patients undergoing laparoscopic cholecystectomy, using a system comprising a 20-MHz crystal in a 95-cm, blunt-tipped 6F sheath, mechanically rotated at 1,800 rpm. The probe was introduced through an incision in the cystic duct and passed into the duodenum. When the catheter was withdrawn, excellent visualization of the common and cystic ducts and lower end of the common hepatic duct was achieved. In seven patients, the biliary tree was normal. A small calculus was discovered in the common duct in one patient. This stone was not seen on a subsequent cholangiogram and was subsequently retrieved. An additional patient had mucus or sludge noted in the duct, which cast no acoustic shadow and thus was distinguished from calculi. The technique was fast, efficient, and easy to perform in this small group of patients and holds promise for screening the common duct pathology during laparoscopic cholecystectomy.

The effect of octreotide on hepatic regeneration in rats

The effect of the long-acting somatostatin analog octreotide on liver regeneration was studied in rats in vitro and in vivo. The effect of continuous subcutaneous octreotide infusion on regenerative liver weight and relative DNA synthesis was examined in rats that had undergone 70% hepatectomy. Administration of octreotide resulted in a 33% reduction of regenerating liver weight at 72 hours and a 67% reduction of regenerative hepatocellular hyperplasia at 24 hours. This effect was reversed within 12 hours after withdrawal of the drug. The mechanism for the inhibitory effect of octreotide appears to be indirect, because experiments in hepatocyte cultures did not demonstrate a direct inhibitory effect on serum-free or epidermal growth factor-induced regenerative hepatocyte proliferation. Because insulin levels were suppressed by octreotide in the in vivo experiments, suppression of hepatotrophs may be the mechanism by which octreotide inhibits liver regeneration.

Secretin receptors in a new preparation of plasma membranes from intrahepatic biliary epithelium

Secretin is thought to cause choleresis by acting on a receptor expressed by bile duct epithelial cells. In this study, the receptor was characterized using a new preparation of intrahepatic bile duct plasma membranes. Hyperplastic biliary trees were obtained from 3-week bile duct-ligated rats. The biliary trees were homogenized, filtered, and subjected to an aqueous two-phase partition technique to yield highly purified plasma membranes (confirmed by a 14-fold enrichment in gamma-glutamyl transpeptidase activity and a 10-fold enrichment in 125I-secretin binding). 125I-secretin bound saturably with high affinity and in a dose-dependent fashion (Kd = 1.3 +/- 0.1 nM, Bmax = 273 +/- 23 fmole/mg) to purified plasma membranes. The binding characteristics of secretin were most consistent with a single site receptor model. Competitive binding studies indicated that the secretin-related peptides glucagon, peptide histidine isoleucine, gastric inhibitory peptide, and growth hormone releasing factor did not inhibit binding. Vasoactive intestinal peptide (1 microM) reduced maximal binding by 19 +/- 1%. The GTP analogs guanylylimidodiphosphate and guanosine 5'-O-[3-thiotriphosphate] (1 microM) inhibited binding by 16 +/- 2 and 13 +/- 1%, respectively. In conclusion, secretin binds to a specific, high-affinity receptor in intrahepatic bile duct epithelium that is coupled to a G-protein-linked signal transduction system.

Intracerebroventricular neuropeptide Y stimulates bile secretion via a vagal mechanism

The effect of intracerebroventricular injection of neuropeptide Y on biliary secretion was studied in conscious dogs, prepared with gastric and duodenal fistulas and cerebroventricular guides. Bile secretion was increased in a dose-dependent fashion by intracerebroventricular neuropeptide Y. The peak increase was seen after 500 pM/kg of neuropeptide Y which resulted in a 30 x 2% increase in bile flow over the period 30-150 minutes after injection. (

CONTROL

23 x 2 (1 x 2) ml/2 hours; neuropeptide Y 500 pM/kg: 30 x 5 (1 x 1) ml/2 hours). Biliary lipid composition was not altered significantly but bicarbonate output was increased at all doses tested. Intravenous infusion of neuropeptide Y (1000 pM) for 1 hour had no significant effect. Intracerebroventricular neuropeptide Y (1000 pM/250-300 mg body weight) also increased bile flow in urethane-anaesthetised rats. This effect was abolished by cervical vagotomy. The demonstration of a central stimulation of alkaline bile flow suggests that bile secretion may be subject to central modulation.

The effects of liver denervation on the regulation of hepatic biliary secretion

Effects of liver denervation on bile formation were studied in eight dogs prepared with chronic biliary fistulas. The animals were studied in the basal state, after feeding, and during infusion of glucagon 50 ng/kg/min, secretin 2 U/kg/hr, or somatostatin 200 ng/kg/min. After this first set of experiments the animals underwent a total hepatic denervation that consisted of section of the hepatic ligaments and a careful dissection of the portal vein, hepatic artery, and common duct with stripping of all the surrounding connective tissue and topical application of phenol. The above experiments were then repeated. Denervation did not modify bile flow, or bile salts, cholesterol, or phospholipid concentration or output. Biliary response to glucagon and secretin was similar before and after denervation. Somatostatin had an anticholerectic effect in both intact and denervated animals, but significantly reduced bile salt output only in the intact dogs. Feeding had a choleretic effect pre- and postdenervation, and the infusion of somatostatin following feeding decreased bile flow to the same degree before and after denervation. In the intact animals the output of all three biliary lipids was reduced by somatostatin after feeding but they were unaffected by somatostatin after denervation. Moreover, cholesterol and phospholipid outputs were stable after feeding in intact animals, but significantly decreased after denervation. 14C-erythritol clearance studies indicated no change in the canalicular component of bile flow with denervation, except again during somatostatin suppression of feeding. These data indicate that basal bile flow is normal after denervation but that innervation may play an important role in the modulation of responses to somatostatin and more complex stimuli such as feeding.

Localization and characterization of secretin binding sites expressed by rat bile duct epithelium

The goal of the present studies was to identify and characterize the site of secretin action in the liver. Sections of normal and bile duct-ligated rat livers were used for in vitro 125I-secretin receptor autoradiography. Saturable binding was observed in both normal and bile duct-ligated livers but was much greater in the bile duct-ligated preparations. Binding was limited to biliary epithelium and the increased secretin binding observed in the ligated livers correlated with the increase in ductular tissue. Saturable binding was inhibited in a dose-dependent fashion by increasing concentrations of nonradioactive secretin. Analysis of saturation binding showed that 125I-secretin binding was best fit by a one-site receptor model with a Kd of 5.3 +/- 1.1 nmol/L. Glucagon, vasoactive intestinal polypeptide, gastric inhibitory polypeptide, growth hormone-releasing hormone, and cholecystokinin did not inhibit saturable 125I-secretin binding at concentrations of 1 pmol/L to 1 mumol/L. The authors conclude that high-affinity, specific secretin binding sites are present in rat intrahepatic biliary epithelium. When bile ducts are stimulated to proliferate by bile duct ligation, secretin binding is also increased.