Role of NAD+ and ADP-ribosylation in the maintenance of the Golgi structure

We have investigated the role of the ADP- ribosylation induced by brefeldin A (BFA) in the mechanisms controlling the architecture of the Golgi complex. BFA causes the rapid disassembly of this organelle into a network of tubules, prevents the association of coatomer and other proteins to Golgi membranes, and stimulates the ADP-ribosylation of two cytosolic proteins of 38 and 50 kD (GAPDH and BARS-50; De Matteis, M.A., M. DiGirolamo, A. Colanzi, M. Pallas, G. Di Tullio, L.J. McDonald, J. Moss, G. Santini, S. Bannykh, D. Corda, and A. Luini. 1994. Proc. Natl. Acad. Sci. USA. 91:1114-1118; Di Girolamo, M., M.G. Silletta, M.A. De Matteis, A. Braca, A. Colanzi, D. Pawlak, M.M. Rasenick, A. Luini, and D. Corda. 1995. Proc. Natl. Acad. Sci. USA. 92:7065-7069). To study the role of ADP-ribosylation, this reaction was inhibited by depletion of NAD+ (the ADP-ribose donor) or by using selective pharmacological blockers in permeabilized cells. In NAD+-depleted cells and in the presence of dialized cytosol, BFA detached coat proteins from Golgi membranes with normal potency but failed to alter the organelle's structure. Readdition of NAD+ triggered Golgi disassembly by BFA. This effect of NAD+ was mimicked by the use of pre-ADP- ribosylated cytosol. The further addition of extracts enriched in native BARS-50 abolished the ability of ADP-ribosylated cytosol to support the effect of BFA. Pharmacological blockers of the BFA-dependent ADP-ribosylation (Weigert, R., A. Colanzi, A. Mironov, R. Buccione, C. Cericola, M.G. Sciulli, G. Santini, S. Flati, A. Fusella, J. Donaldson, M. DiGirolamo, D. Corda, M.A. De Matteis, and A. Luini. 1997. J. Biol. Chem. 272:14200-14207) prevented Golgi disassembly by BFA in permeabilized cells. These inhibitors became inactive in the presence of pre-ADP-ribosylated cytosol, and their activity was rescued by supplementing the cytosol with a native BARS-50-enriched fraction. These results indicate that ADP-ribosylation plays a role in the Golgi disassembling activity of BFA, and suggest that the ADP-ribosylated substrates are components of the machinery controlling the structure of the Golgi apparatus.

Regulation of Golgi structure through heterotrimeric G proteins

We have previously shown that ilimaquinone (IQ), a marine sponge metabolite, causes complete vesiculation of the Golgi stacks. By reconstituting the IQ-mediated vesiculation of the Golgi apparatus in permeabilized cells, we now demonstrate that this process does not require ARF and coatomers, which are necessary for the formation of Golgi-derived COPI vesicles. We find that IQ-mediated Golgi vesiculation is inhibited by G alpha(s)-GDP and G alpha(i3)-GDP. Interestingly, adding betagamma subunits in the absence of IQ is sufficient to vesiculate Golgi stacks. Our findings reveal that IQ-mediated Golgi vesiculation occurs through activation of heterotrimeric G proteins and that it is the free betagamma, and not the activated alpha subunit, that triggers Golgi vesiculation.

Clinical spectrum of chronic liver disease in north Indian children

Recent advances in serodiagnosis of hepatotropic viruses have revolutionized the approach to diagnosis and understanding of chronic liver disease (CLD). There are few studies on CLD in children from India. The present study was planned to define the clinical spectrum of CLD in children, its histopathology and seroepidemiology. Forty children with clinical features satisfying the criteria for diagnosing chronic liver disease were studied. All underwent routine laboratory investigations, liver function tests and ultrasound scan of the abdomen. Liver biopsy, upper GI endoscopy and other special investigations were done wherever indicated. The most common presenting features were jaundice (70%), fever (67%), and abdominal distention (60%). On examination hepatomegaly and icterus (80% each) and splenomegaly (67%) were the commonest findings. Serum transaminases were raised in 62.5% of children while prothrombin time was prolonged in 75% patients. Oesophageal and/or gastric varices were seen in 13 out of 29 patients subjected to upper GI endoscopy. Hepatitis B surface antigen (HbsAg) was positive in 5 children (12.5%) while 3 (7.5%) tested positive for anti HCV antibody. The commonest histopathological diagnosis was infantile cholangiopathy (20%) followed by cryptogenic cirrhosis and idiopathic chronic active hepatitis (17.5% each). The study suggests that the incidence of chronic hepatitis B and C is rather low in childhood. However larger and longer studies are required to delineate the exact incidence of these conditions in childhood and their progression in adolescence and early adulthood.

Fine-needle aspiration diagnosis of carotid body tumor: report of a case and review of experience with cytologic features in four cases

A 45-yr-old female presented with a left upper cervical swelling of 4 yr duration. The clinical suspicion of carotid body tumor (CBT) was confirmed by imaging findings, fine-needle aspiration (FNA) cytology, and histology of the resected tumor. Review of our experience with four cases including the present one during 10 yr (1984-1994) showed that the age of the patients ranged from 35 to 45 yr with a mean of 40.8 yr. All four cases were females and had left-sided upper cervical swelling. Clinically one case was diagnosed as cervical lymphadenopathy and there was clinical suspicion of CBT in two cases. Findings of digital subtraction angiogram in four cases and ultrasonography including Doppler ultrasound vascular imaging in three cases were consistent with CBT. The cytodiagnosis was CBT in three cases and inadequate (blood only) in one case. The analysis of detailed cytologic features in three cases revealed blood-rich aspirate with poor to moderate cellularity, indistinct cell outline, and acinar formation. Giant bare nuclei, spindle-shaped tumor cells, and cytoplasmic granulations were observed in two cases each. Histopathology of the resected tumors in two cases confirmed the cytodiagnosis of CBT. FNA cytology played a useful role in arriving at a tissue diagnosis of this rare neoplasm.

Fine needle aspiration cytologic appearance of inflammatory pseudotumor of the liver. A case report

BACKGROUND

Inflammatory pseudotumor (IPT) is a rare space-occupying lesion of the liver that can be clinically confused with a malignant process.

CASE REPORT

A 28-year-old male presented with fever and a palpable, firm liver. Ultrasonography and computed tomography revealed a mass in the right lobe of the liver. Fine needle aspiration biopsy (FNAB) under ultrasonographic guidance showed inflammatory cells, fibroblasts and a few hepatocytes. A diagnosis of inflammatory pseudotumour was suggested and confirmed on a true-cut biopsy.

CONCLUSION

The cytologic appearance of IPT is characteristic. FNAB under ultrasonographic is a quick and easy technique for its diagnosis and differentiation from malignant space-occupying lesions.

Contrast echocardiography displays increased subendocardial perfusion after nitroglycerin administration

A mechanism proposed to contribute to the antianginal effect of nitroglycerin is a redistribution of coronary blood flow to the subendocardium. Contrast echocardiography combines ultrasound with echogenic contrast agents to assess regional myocardial perfusion. This study aims to assess the effect of nitroglycerin on myocardial transmural perfusion with contrast echocardiography in humans. Nine patients scheduled for coronary angiography received 300 microg intracoronary nitroglycerin. Contrast echocardiographic studies were performed before and immediately after the administration of intracoronary nitroglycerin. Videodensitometric analysis was performed off-line to measure subendocardial and subepicardial opacification. Subendocardial opacification greater than subepicardial opacification increased from six of 13 patients before nitroglycerin administration to 11 of 13 after nitroglycerin administration (p <0.05). Similarly, these observations increased from nine of 13 patients to 13 of 13 after nitroglycerin administration during diastole (p <0.05). Contrast echocardiography demonstrates increased subendocardial perfusion after the administration of nitroglycerin in these patients.

Nucleolar organiser regions in different colonic epithelia

The argyrophilic technique (AgNOR) was applied to paraffin sections of 10 acute self-limited colitis, 15 ulcerative colitis (UC), 5 ulcerative colitis with indefinite dysplastic change, 10 adenomatous polyps, 20 colorectal adenocarcinomas and 10 normal colorectal mucosa. The mean number of nucleolar organiser regions (NORs) per nucleus ranged between 1.62-2.00 (95% CI 1.77-1.93) for normal colon, 2.47-3.80 (95% CI 2.71-3.21) for acute colitis, 1.66-2.75 (95% CI 2.13-2.44) for UC, 3.60-4.00 (95% CI 3.67-3.94) for UC with indefinite dysplasia, 3.00-4.04 (95% CI 3.41-3.81) for adenomatous polyps and 3.59-6.70 (95% CI 4.04-4.72) for colorectal adenocarcinoma. The differences observed were statistically significant. There was a significant difference of AgNOR counts between adenomatous polyp and UC with indefinite dysplasia in comparison to those observed in regenerative epithelium of acute colitis and UC without dysplasia. Hence the technique may be used as an adjunct to routine histology for delineating dysplastic changes in colonic epithelium.

Acute renal failure in falciparum malaria--increasing prevalence in some areas of India--a need for awareness

Twenty-six cases (4.8%) from a total of 540 patients with acute renal failure (ARF) of diverse aetiology had ARF in association with falciparum malaria. Their ages ranged from 15 to 85 years (mean 31.2). Urinary sediment abnormalities and proteinuria (less than 1 g/24 h) were observed in 15 (57.7%) cases. The probable underlying factors leading to ARF were: volume depletion 17 (65.3%), intravascular haemolysis 8 (30.8%), hyperparasitaemia 8 (30.8%), cholestatic jaundice 6 (23%), and hypotension 5 (19.2%). Dialysis therapy was required in 15 patients (57.7%) as they had severe renal failure, and the remaining 11 patients improved with supportive measures. All patients received antimalarial therapy. The clinical course of ARF was consistent with acute tubular necrosis in 20 patients. Six cases were subjected to percutaneous renal biopsy. One patient showed histological features of necrotizing glomerulonephritis along with acute tubulointerstitial nephritis. The biopsies in the other five patients showed features of acute tubular necrosis in three, and acute interstitial oedema with patchy tubular necrosis in two. The mortality rate was 30.8%. Thus falciparum malaria, which has been an important cause of ARF in certain highly endemic zones of India, is showing an increasing prevalence in other parts such as Eastern Uttar Pradesh due to an imbalance between the increasing population and inadequate sanitary facilities, which further worsen during floods.

Diagnosis and outcome of isolated rectal tuberculosis

PURPOSE

Segmental colonic tuberculosis commonly involves the ascending, transverse, or sigmoid colon. Rectal involvement in tuberculosis is uncommon and poorly characterized. This study describes the clinical presentation, endoscopic features, and outcome of isolated rectal tuberculosis.

METHODS

Isolated rectal tuberculosis was defined as focal lesions of the rectum in the absence of radiologically demonstrable lesions in the small and large bowel on barium contrast studies. Diagnosis of rectal tuberculosis was based on characteristic endoscopic appearance of lesions, histopathologic features of tuberculosis in biopsy/ resected material, and response to antitubercular therapy.

RESULTS

Eight patients with rectal tuberculosis were seen during a four-year period at our hospital. Hematochezia was the most common presenting feature (88 percent), followed by constitutional symptoms (75 percent) and constipation (37 percent). Rectal examination revealed a tight stricture within 10 cm of the anal verge in seven patients. Barium enema showed stricture of variable length, with focal areas of deep mucosal ulceration and increase in presacral space. Proctoscopic findings were tight stricture (7), nodularity with ulceration (6), and multiple aphthous ulcers (1). Granulomatous infiltration was detected in seven of eight patients in biopsy material obtained at endoscopy (6) or surgery (1). Cessation of hematochezia, resolution of constitutional symptoms, and weight gain were seen in all patients following treatment with antitubercular drugs.

CONCLUSION

Our data suggest that tubercular involvement of rectum, although uncommon, is an important cause of rectal strictures in India. Response to antitubercular chemotherapy is uniformly good, and surgery is seldom required in these patients.

Endoscopic techniques in the diagnosis of upper gastrointestinal tract malignancies. A comparison

OBJECTIVE

To perform a comparative evaluation of various endoscopic techniques in the diagnosis of upper gastrointestinal tract malignancies.

STUDY DESIGN

Thirty cases of suspected malignancy involving the upper gastrointestinal tract were studied. In all 30 cases, four endoscopic cytology techniques (brushing before biopsy, brushing after biopsy, fine needle aspiration cytology [FNAC] and suction cytology) were evaluated and correlated with histology by forceps biopsy. All the cytologic techniques were used and forceps biopsy carried out in a single sitting, but the forceps biopsy was repeated in 4 of 30 cases.

RESULTS

The respective positive yields of brushing before biopsy, brushing after biopsy, FNAC, suction cytology and forceps biopsy were 80.0%, 86.6%, 83.3%, 76.6% and 90.0%. When two cytologic techniques were combined, 100% accuracy was obtained by brushing after biopsy and FNAC and brushing before biopsy and suction cytology.

CONCLUSION

Brushing cytology is a sensitive diagnostic test, and the combined use of biopsy and brushing offers the highest probability of identifying malignancy.

Membrane fusion in organelle biogenesis

Intracellular membrane fusion is a fascinating reaction that is crucial for cellular function. Several components of the membrane fusion machinery have been identified, although a precise understanding of the fusion mechanism is lacking. More recent studies are revealing novel proteins that regulate membrane fusion during organelle assembly.

Loss of contrast intensity during systole in the left ventricular cavity with the use of the contrast agent Albunex. An analysis of its correlation with pressure and velocity

RATIONALE AND OBJECTIVES

Several investigators have observed a decrease in video intensity in the left ventricular cavity during systole when using contrast echocardiography. It has been suggested that this phenomenon is related to microbubble instability. The authors propose that this phenomenon is, in part, related to the effects of pressure and velocity on the acoustic reflectance of ultrasound contrast agents.

METHODS

Using an in vitro flow tube model and varying concentrations of Albunex contrast agent, the effects of pressure and velocity on microbubble video intensity were investigated. Velocity and pressure were varied independently and the imaging tube was scanned using three transducer frequencies at different concentrations of Albunex. Contrast video intensity was analyzed using high and low velocities (at constant pressure) and high and low pressures (at constant velocity). In addition, the fluid from the system was collected and imaged in a nonflowing reservoir tank to investigate the video intensity of the microbubbles when exposed to variable velocity and pressure.

RESULTS

The video-intensity measurements were inversely and irreversibly related to ambient pressure changes (independent of velocity) in a tube model. However, video intensity varied inversely but reversibly with velocity (independent of pressure). This observation could not be explained simply by the "laminar flow" theory, by a change in transducer angulation, nor by a change in ultrasound imaging frame rate. This phenomenon was limited to Albunex microbubbles and was not observed with a contrast medium (corn starch) devoid of the acoustic properties of Albunex.

Efficacy of low-dose alpha interferon therapy in HBV-related chronic liver disease in Asian Indians: a randomized controlled trial

BACKGROUND/AIMS

Interferon therapy has been shown to be effective in Western patients with chronic hepatitis due to hepatitis B viral infection, but not in Asian Chinese. Its efficacy in Asian Indian subjects with chronic HBV infection is not known.

METHODS

Forty-one patients with HBV-related chronic liver disease received randomly either: (a) recombinant alpha 2b interferon (n = 20) 3 MIU, subcutaneously, three times a week for 4 months, or (b) no treatment (n = 21). Patients were followed up for 12 months after completion of therapy.

RESULTS

In the interferon-treated group, complete response (loss of HBV-DNA and HBeAg) was significantly higher than spontaneous clearance in the control group (50% vs. 4.8% p < 0.05). Seroconversion to anti-HBe was seen in 35% of the treated and 4.8% of the control group (p < 0.05) at 4 months; it was noticeably higher in patients with chronic hepatitis than in those with cirrhosis. In the responders, alanine aminotransferase levels nearly normalized. One year after interferon therapy, HBeAg and HBV-DNA clearance was observed in 65% of patients, with HBsAg clearance in 15%. Reactivation was not seen in any patient. Side-effects were transient and minimal.

CONCLUSION

Low-dose recombinant alpha interferon therapy is quite effective and safe in Asian Indians with chronic liver disease due to hepatitis B infection.

Acute renal failure in eastern India

The present study included 426 patients with acute renal failure age range 7 months to 85 years, during 8-year period (1984-1992). Medical, surgical and obstetric causes were responsible for ARF in 68.3, 17.8, and 14% of cases respectively. The main aetiological factors encountered were volume depletion secondary to gastrointestinal fluid loss (35.2%), acute glomerulonephritis (10.3%), nephrotoxin (8.6%), falciparum malaria (4.2%), obstructive uropathy (13%), post-abortal (10.5%), and miscellaneous factors (1.4%) of patients. The overall mortality was 19.2%. Thus our observation revealed that diarrhoeal diseases (35.2%), obstructive uropathy (13.3%), and septic abortion (10.5%) were the main causes for ARF in medical, surgical, and obstetric groups respectively. In contrast to our studies, acute renal failure associated with diarrhoeal diseases, septicaemia, falciparum malaria and septic abortion are rare in European countries.

Granulomatous hepatitis: a retrospective study

51 cases of granulomatous hepatitis were seen among 1234 liver biopsies over a 10 year period. Tuberculosis was the commonest cause seen in 55 percent of cases. Other causes included leprosy, sarcoidosis, histoplasmosis, brucellosis, amoebic liver abscess, lymphoma and malignant granuloma. 12 percent of cases remained undiagnosed. Clinically these patients presented with pyrexia and hepatosplenomegaly. Jaundice was uncommon. Many showed elevated alkaline phosphatase levels, anaemia and raised ESR Granulomatous hepatitis of unknown aetiology with FUO was seen in 6 percent cases only.

Intestinal metaplasia--its association with gastric cancer

Endoscopic gastric biopsies from 230 patients and post gastrectomy specimens of 18 patients were evaluated for the presence of intestinal metaplasia (IM) and its association with the gastric lesions. There were a total of 78 malignant and 170 benign lesions. IM was present in 53% of patients with gastric carcinoma (GC) and in 10.6% with benign lesions of the stomach. The IM in association with GC was of type 1 (Small Intestinal) in 58.8%; type II (mixed gastric and small intestinal) in 11.8% and type III (Colonic) in 29.4%. In patients with benign lesions the IM was predominantly of type I (94.5%) except in 1 patient who had type III metaplasia. Our findings indicate that type III IM was significantly more frequent in patient with GC than with benign lesions (29.4% Vs 5.5%; p < .005). Therefore we conclude that patients with type III IM should be kept on surveillance for GC.

The formation of Golgi stacks from vesiculated Golgi membranes requires two distinct fusion events

We have reconstituted the fusion and assembly of vesiculated Golgi membranes (VGMs) into functionally active stacks of cisternae. A kinetic analysis of this assembly process revealed that highly dispersed VGMs of 60-90 nm diameter first fuse to form larger vesicles of 200-300 nm diameter that are clustered together. These vesicles then fuse to form tubular elements and short cisternae, which finally assemble into stacks of cisternae. We now provide evidence that the sequential stack formation from VGMs reflects two distinct fusion processes: the first event is N-ethyl-maleimide (NEM)-sensitive factor (NSF) dependent, and the second fusion event requires an NSF-like NEM-sensitive ATPase called p97. Interestingly, while the earliest steps in stack formation share some similarities with events catalyzing fusion of transport vesicles to its target membrane, neither GTP gamma S nor Rab-GDI, inhibitors of vesicular protein traffic, inhibit stack formation.

Spectrum of gastrointestinal malignancy over a period of 10 years at a tertiary referal center of India

We studied the frequency of different gastro intestinal malignancies (GIM) diagnosed in a given year, among patients attending gastroenterology department, and changing pattern of their occurrence over a period of 10 years (1984-1993). The records of all patients with histologically confirmed GIM were screened. Out of 83380 outdoor patients registered in the department over 10 years, there were a total of 1751 (2.1%) patients with GIM. The relative distribution of malignancy according to site was esophagus 36.0%, stomach 19.9%, liver secondaries 13.9%, colon 9.8%, periampullary 5.6%, gall pladder 4.5%, duodenum 3.0%, malignant ascites 2.6%, HCC 2.3% and pancreas 1.1%. Mean age for cancer of esophagus was 53.5 +/- 11.4 year, stomach 51.8 +/- 12.9, colon 49.1 +/- 16.7, duodenum 45.3 +/- 11.4, malignant ascites 51.8 +/- 13.1, pancreas 46.9 +/- 15.3 and HCC 52.5 +/- 12 years with an overall mean age of all GIM being 49.7 +/- 13.4 years. All malignancies were common in males except for cancer of gall bladder. The annual distribution of GIM did not confirm to a rising or declining trend with reference to the frequency of occurrence or age and sex distribution over the last decade.

Clinical, angiographic and histopathological predictors of restenosis after directional coronary atherectomy

Out of 127 directional coronary atherectomy (DCA) procedures done in our laboratory, there were 81 patients who had completed a minimum of six months of follow-up. To study the factors predisposing restenosis after successful DCA, we analysed the clinical and angiographic profile of the patients and the histopathological findings of the excised tissue in 44 patients whose complete follow-up data was available with us. The indication of DCA was an extremely eccentric significant stenosis located in the proximal or midsegment of a large vessel (> or = 3 mm size) in 97 percent of the cases. Angiographic restenosis, defined as more than 50 percent luminal diameter stenosis was absent in 24 (54.5%, Group A) and present in 20 (45.5%, Group B) patients. On univariate analysis, the factors which predisposed to restenosis were: (i) left anterior descending location, (ii) longer lesion length (9.6 +/- 3.1 mm vs 5.2 +/- 1.6, p < 0.01) and (iii) greater post-procedure residual luminal diameter stenosis (13.1 +/- 10.8% vs 4.3 +/- 6%, p < 0.01). No significant difference was found between the two groups for other variables like unstable angina, the location and the morphological characteristics of the lesion and the ratio of the vessel diameter to the size of the Atherocath. Histopathological examination of the retrieved tissue revealed the presence of media with or without external elastic lamina in 8 (33%) patients in Group A--without restenosis compared to only 1 (5%) patients in Group B--with restenosis (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Reconstitution of vesiculated Golgi membranes into stacks of cisternae: requirement of NSF in stack formation

We have developed an in vitro system to study the biochemical events in the fusion of ilimaquinone (IQ) induced vesiculated Golgi membranes (VGMs) into stacks of cisternae. The Golgi complex in intact normal rat kidney cells (NRK) is vesiculated by treatment with IQ. The cells are washed to remove the drug and then permeabilized by a rapid freeze-thaw procedure. VGMs of 60 nm average diameter assemble into stacks of Golgi cisternae by a process that is temperature dependent, requires ATP and a high speed supernatant from cell extract (cytosol), as revealed by immunofluorescence and electron microscopy. The newly assembled stacks are functionally active in vesicular protein transport and contain processing enzymes that carry out Golgi specific modifications of glycoproteins. The fusion of VGMs requires NSF, a protein known to promote fusion of transport vesicles with the target membrane in the exocytic and endocytic pathways. Immunoelectron microscopy using Golgi specific anti-mannosidase II antibody reveals that VGMs undergo sequential changes in their morphology, whereby they first fuse to form larger vesicles of 200-300-nm average diameter which subsequently extend into tubular elements and finally assemble into stacks of cisternae.