Acute pancreatitis induces cytokine production in endotoxin-resistant mice

OBJECTIVE

The purpose of this study was to determine whether pathologic progression and cytokine responses in acute pancreatitis (AP) are altered in the absence of endotoxemia.

SUMMARY BACKGROUND DATA

Previous studies have demonstrated that AP is characterized by rapid production and release of inflammatory cytokines, which play a major role in the local pancreatic and systemic complications of this disease. Infection and endotoxemia have been implicated as a major source of morbidity and death in AP and as possible stimuli for the overwhelming cytokine response seen in this disease.

METHODS

AP was induced by a choline-deficient and ethionine-supplemented diet for 4 days in normal C57BL/6J mice (controls, n = 23) and in CD14 knockout mice (CD14KO, n = 23), which cannot produce circulating cytokines in response to endotoxin. Control and endotoxin-resistant mice were killed at time 0, then at 24, 48, 72, and 96 hours after the start of the diet. At each time point serum was collected for amylase, glucose, and cytokine measurements (tumor necrosis factor-alpha [TNFalpha] and interleukin-1beta [IL1beta]), and the pancreas was removed for histologic examination. TNFalpha was measured with a bioassay using WEHI-2F cells and IL1beta with a bioassay using D10.G4.1 cells.

RESULTS

CD14KO mice developed biochemical manifestations of AP with alterations in amylase levels, hypoglycemia, weight loss, and histologic changes of pancreatitis similar to the pattern seen in control mice. TNFalpha and IL1beta production had similar kinetics in both groups, with significant peak TNFalpha serum levels at 72 hours and a progressive rise of IL1beta levels throughout the study period. Histologic changes appeared earlier and were more pronounced in the control versus the CD14KO mice. However, the mortality rate was identical (20% at 96 hours) for both groups.

CONCLUSIONS

These results demonstrate that the progression of AP, the cytokine response associated with the disease, and early death are independent of endotoxin action. These findings, which suggest that an uncharacterized stimulus is responsible for triggering the cytokine cascade in this disease, may have significant implications for the management of patients with AP.

Collaboration between schools of nursing and local education agencies to provide health care services to pre-kindergarten through twelfth grade students: elements of cooperative agreements

Establishing cooperative relationships between schools of nursing and local education agencies for the delivery of health care services to children from pre-school through the twelfth grade is a process all too often characterized by numerous legal, insurance, and administrative roadblocks. While nursing faculty and their students may wish to cooperate with professional educators and their students to enhance the health care of the children, there are obstacles. Both institutions are represented by attorneys, insurance companies and others who must attend to aspects of the process other than direct health care delivery. A model for joint planning and a list of elements of effective agreements are offered as a way of engaging all parties in a constructive and useful process of collaboration.

Catabolism dominates the first-pass intestinal metabolism of dietary essential amino acids in milk protein-fed piglets

To investigate the extent of first-pass intestinal metabolism of dietary amino acids, seven female pigs (28 d old, 8.0 kg) were implanted with arterial, venous, portal and gastric catheters and with an ultrasonic portal blood flow probe. The pigs were fed a milk-based diet once hourly and infused intragastrically with [U-13C]algal protein. On average, 56% of the essential amino acid (EAA) intake appeared in the portal blood. However, the net portal balance of methionine (48% of intake) and threonine (38% of intake) tended (P = 0.08) to be lower than the mean of all EAA. The net portal balance (expressed as a percentage of intake) of alanine (205%), tyrosine (167%) and arginine (137%) exceeded their intake. Net portal outflow of ammonia accounted for 18% of total amino acid nitrogen intake. As a percentage of the enteral tracer input, there was substantial first-pass metabolism of lysine (35%), leucine (32%), phenylalanine (35%) and threonine (61%). However, only 18, 21, 18 and 12% of the total first-pass metabolism of lysine, leucine, phenylalanine and threonine, respectively, were recovered in mucosal protein. We conclude that roughly one third of dietary intake of EAA is consumed in first-pass metabolism by the intestine and that amino acid catabolism by the mucosal cells is quantitatively greater than amino acid incorporation into mucosal protein.

Cloning, localization, and structure of new members of the butyrophilin gene family in the juxta-telomeric region of the major histocompatibility complex

New members of the butyrophilin (BT) gene family have been identified by cDNA and genomic cloning. Six genes are described: BT2. 1, 2.2, 2.3, and BT3.1, 3.2, and 3.3. BT2, BT3, and BT form three distinct subfamilies sharing about 95% amino acid identity at the intra subfamily level and 50% identity at the interfamily level. All the BT2 and BT3 subfamily members map close to BT in the juxta-telomeric region of the major histocompatibility complex. The BT2 members have the canonical structural organization of BT, i.e., two immunoglobulin domains followed by a transmembrane anchor and a B30.2 intracytoplasmic domain. In the BT3 subfamily, only BT3.3 has the structural organization of BT. The two other genes, BT3.1 and BT3.2, code for putative protein without the B30.2 domain. In the case of BT3.2, this is due to an Alu insertion in the B30.2 coding exon, leading to a new polyadenylation site.

[Thrombophlebitis and cancer: evaluation of the diagnostic value of abdominal ultrasonography in the acute phase of a deep venous thrombosis. Report of 148 consecutive examinations]

If an association between venous thromboembolism and malignancy is now well established, there is no consensus about the investigations which should be performed to detect occult malignancy after deep vein thrombosis episode. We investigated the usefulness of systematic abdomino-pelvic ultrasonography in 148 consecutive patients older than 40 with deep vein thrombosis and or pulmonary embolism. Ultrasonography was abnormal in 8 patients (5.4%) and detected only 6 cancers. In 5 cases, clinical examination and laboratory tests were sufficient to suggest malignancy. Our results suggest that ultrasonography should not be systematically performed in patients with deep vein thrombosis. Decisions to performed additional diagnostic tests can be based on the finding of the initial clinical examination, that includes medical history, physical examination, routine laboratory tests and chest-x-ray.

Phenylalanine utilization by the gut and liver measured with intravenous and intragastric tracers in pigs

To investigate intestinal and hepatic metabolism of phenylalanine, four conscious pigs (7.5 kg), bearing arterial, venous, and hepatic portal catheters, were fasted for 12 h and infused with [phenyl-2H5]phenylalanine via a peripheral vein and [carboxyl-13C]phenylalanine via the stomach. During the first 6 h of the infusion, the pigs remained fasted and received only the intravenous tracer. During the second 6 h, they received an intragastric infusion of milk replacer and both tracers. In the fasted state, the portal-drained viscera extracted 10% (P < 0.025) of the arterial [2H5]phenylalanine flow of the pigs. In the fed state, the splanchnic tissues metabolized 45% of the enteral tracer and intestinal metabolism accounted for 76% of the total splanchnic extraction. The tracer-to-tracee ratio of both tracers in apolipoprotein B-100 (apo B-100) phenylalanine was twofold (P < 0.001) higher than that of hepatic free phenylalanine. The ratios of the two tracers in portal (13C/2H; 1.66) and apo B-100 (1.76) phenylalanine were similar but higher (P < 0.05) than that of arterial phenylalanine (1.29). We conclude that intestinal metabolism dominates the splanchnic extraction of enteral phenylalanine and that in the fed state, the hepatic protein synthetic precursor pool derives from portal phenylalanine.

Cloning, structural analysis, and mapping of the B30 and B7 multigenic families to the major histocompatibility complex (MHC) and other chromosomal regions

We present the cloning, structural analysis, and mapping of new members belonging to two multigenic families, the B30-RING finger family and the B7.1-B7.2 family, as well as two genes derived by exon shuffling from members of these families. Eight new members were found and three of them map to the human major histocompatibilitiy complex (MHC) region. Phylogenic and physical mapping analysis allowed us to decipher the evolutionary story of these two multigenic families and to shed light on the evolution of the MHC region. We also show that a deductive analysis can be used to predict the existence of a given gene.

Enteral glutamate is the preferential source for mucosal glutathione synthesis in fed piglets

To measure the source and rate of mucosal glutathione (GSH) synthesis, fed piglets (28 days old; 7.7 kg) received a 6-h infusion of intragastric [U-13C]glutamate (n = 11) either with (n = 5) or without (n = 6) an intragastric infusion of [1-13C]glycine (0-6 h) and [1,2-13C2(U-13C)]glycine (3-6 h). Eighty-four percent of the labeled mucosal GSH-glutamate and 86% of the luminal GSH-glutamate was 13C5. The tracer-to-tracee ratio of GSH-[U-13C]glutamate was 75% of that of mucosal glutamate. Sixty percent of the labeled mucosal glutamate was 13C1, 13C2, or 13C3, but the tracer-to-tracee ratios of these isotopomers in GSH-glutamate were not significantly different from zero. After 3 h of infusion, the tracer-to-tracee ratio of GSH-[U-13C]glycine was 46%, and after 6 h of infusion GSH-[13C1]glycine was 82% of that of mucosal glycine. This suggested that the half-life of mucosal GSH was 2.7 +/- 0.1 h. We concluded that, in fed piglets, mucosal GSH-glutamate derived largely from the direct metabolism of enteral glutamate rather than from glutamate that was metabolized within the mucosa.

Computed tomography of sternoclavicular joint lesions in spondylarthropathies

To evaluate the computed tomography (CT) findings of inflammatory lesions of the sternoclavicular joints (SCJ) in spondylarthropathies.

DESIGN AND PATIENTS

CT scans of the SCJs were obtained in 23 patients (group 1) with inflammatory SCJ lesions in spondylarthropathies. These scans were reviewed by four readers and compared with the CT scans of 23 matched controls (group 2). Each reader had to complete a 27-item grid.

RESULTS AND CONCLUSION

In the 23 patients of group 1, the mean number of observed signs was 5.3 +/- 4.2 higher (P < 0.01) than in the group of 23 matched controls (2.4 +/- 1.6). Four signs were more frequently observed (P < 0.05) in group 1: surrounded subchondral clavicular erosions and cysts, surrounded subchondral sternal cysts and sternal bone sclerosis. A cyst and/or an erosion was associated with hyperostosis and/or bone sclerosis in 9 of 23 patients in group 1. This association was not observed in group 2; the difference was significant (P < 0.001). A cyst and/or an erosive lesion was observed 18 times in group 1 versus 11 times in group 2; the difference was significant (P < 0.05). Conversely, signs of degenerative lesions (osteophytes, subchondral sclerosis, unevenness of joint surface) were no more frequently observed in controls than in group 1. This study emphasizes the diagnostic value of CT, in particular in the identification of inflammatory lesions, even when pre-existing degenerative disease is present.

B30.2-like domain proteins: a growing family

The B30.2 domain is a conserved domain of around 170 amino acids. It is found associated with different protein domains: immunoglobulin domain in the case of butyrophilin and Ring Finger domain in the case of Ret Finger Protein. B30.2 should therefore be considered a migratory domain. We here report new members of these families as well as new protein families having the B30.2 domain, and we tentatively propose a general function for this domain.

Amine precursor uptake and decarboxylation: significance for processing of the rat gastrin precursor

1. Conversion of prohormone precursors to smaller active products occurs in secretory granules, which also have the capacity to concentrate biogenic amines. We have examined how processing of the gastrin precursor, progastrin, in rat antral mucosa is influenced by modulation of the biogenic amine content of secretory granules. 2. Newly synthesized progastrin-derived peptides in rat antral mucosa were labelled in vitro with 35SO4(2-) using a pulse-chase protocol and detected after immunoprecipitation by HPLC with on-line liquid scintillation counting. Secretory granule morphology was examined by electron microscopy. The effects of experimentally manipulating secretory granule pH and amine content were examined. 3. The dopamine precursor L-beta-3,4-dihydroxyphenylalanine (L-DOPA) inhibited cleavage of 35S-labelled thirty-four amino acid amidated gastrin, i.e. [35S]G34, and of [35S]G34 with COOH-terminal glycine, i.e. [35S]G34-Gly, at a pair of lysine residues, but did not influence cleavage of progastrin at pairs of arginine residues. The effect of L-DOPA was reversed by reserpine, which inhibits the amine-proton exchangers VMAT1 and VMAT2, and by carbidopa, which inhibits aromatic L-amino acid decarboxylase. 4. Treatments that raise intragranular pH, e.g. the weak base chloroquine, the ionophore monensin and the vacuolar proton pump inhibitor bafilomycin A1, had similar effects to L-DOPA. 5. Electron microscopical studies showed that the electron-dense aggregrates in gastrin cell secretory granules were lost after inhibition of the vacuolar proton pump. Treatment with L-DOPA produced reserpine-sensitive dissipation of the electron-dense aggregates, compatible with the idea that increased amine delivery raised intragranular pH. 6. The data suggest that the processes of amine precursor uptake, decarboxylation and sequestration in secretory granules are associated with selective modulation of progastrin cleavage, possibly by raising intragranular pH and thereby inhibiting pH-sensitive prohormone convertases.

Inhibition of peripheral blood mononuclear cell proliferation by cardiac glycosides

INTRODUCTION

Prior studies have shown that ouabain, a cardiac glycoside that inhibits the sodium, potassium adenosine triphosphatase (Na+,K+ ATPase) enzyme, downregulates phytohemagglutinin (PHA)-induced peripheral blood mononuclear cell (PBMNC) proliferation.

OBJECTIVE

This study examined and compared the effects of both ouabain and digoxin, a cardiac glycoside used therapeutically in humans, on PBMNC proliferation.

METHODS

Peripheral blood mononuclear cells were isolated from healthy human subjects, incubated for 72 hours with and without PHA (2%) in the presence and absence of ouabain (10(-12) M to 10(-4) M) or digoxin (10(-9) M to 10(-6) M), and pulsed with 3H thymidine.

RESULTS

For PHA-stimulated PBMNCs in the ouabain-treated group (n = 10 subjects), the mean (+/-STD) % uptake (% 3H thymidine uptake in absence of ouabain) was 80.5 +/- 6.0 at 10(-12) M ouabain, 73.1 +/- 8.4 at 10(-10) M, 47.89 +/- 13.1 at 10(-8) M, 6.9 +/- 3.2 at 10(-6) M, and 3.4 +/- 1.6 at 10(-4) M. For PHA-stimulated cells in the digoxin-treated group (n = 9 subjects), the mean (+/-STD) % uptake (% 3H thymidine uptake in absence of digoxin) was 89.8 +/- 9.8 at 10(-9) M digoxin, 92.6 +/- 8.2 at 10(-8) M, 54.3 +/- 19.8 at 10(-7) M, and 1.0 +/- 2.4 at 10(-6) M. Repeated measures ANOVA demonstrated a significant effect of concentration of both glycosides on PBMNC proliferation (P < .01). The inhibitory effect was reversible, but was largely abbrogated if ouabain was added after 48 hours of incubation with PHA. Further, the inhibitory effect extended to PBMNCs stimulated with recall antigen (tetanus) and to fractionated PBMNCs (CD4+, CD8+ and CD19+) stimulated with mitogens. Additionally, dose-response inhibitory effects of glycosides on PBMNC Na+,K+ ATPase enzyme activity and interleukin-2 (IL-2) secretion by PHA-stimulated PBMNC were also noted. Neither glycoside had an effect on spontaneous PBMNC proliferation (no PHA) or trypan blue exclusion.

CONCLUSIONS

These studies demonstrate that both cardiac glycosides inhibited PHA-induced PBMNC proliferation, possibly via Na+,K+ ATPase inhibition, but not via cell toxicity. The concentration range over which inhibition was observed was similar for both glycosides. The results raise the possibility that therapeutic or toxic doses of digoxin could have an effect on cell-mediated immunity in vivo.

Structural and functional analysis of the chick chondroitin sulfate proteoglycan (aggrecan) promoter and enhancer region

Aggrecan is a large chondroitin sulfate proteoglycan, the expression of which is both tissue-specific and developmentally regulated. Here we report the cloning and sequencing of the 1.8-kilobase genomic 5' flanking sequence of the chick aggrecan gene and provide a functional and structural characterization of its promoter and enhancer region. Sequence analysis reveals potential Sp1, AP2, and NF-I related sites, as well as several putative transcription factor binding sites, including the cartilage-associated silencers CIIS1 and CIIS2. A number of these transcription factor binding motifs are embedded in a sequence flanked by prominent inverted repeats. Although lacking a classic TATA box, there are two instances in the 1.8-kb genomic fragment of TATA-like TCTAA sequences, as have been defined previously in other promoter regions. Primer extension and S1 protection analyses reveal three major transcription start sites, also located between the inverted repeats. Transient transfections of chick sternal chondrocytes and fibroblasts with reporter plasmids bearing progressively reduced portions of the aggrecan promoter region allowed mapping of chondrocyte-specific transcription enhancer and silencer elements that are consistent with the sequence analysis. These findings suggest the importance of this regulatory region in the tissue-specific expression of the chick aggrecan gene.

The mode of action of several opioids on cardiac muscle

The objective of the experiments was to investigate the cellular basis of the inotropic effect on myocardium of several opioids which have been implicated in producing cardiotoxic effects in human poisoning. Opioids exerted negative inotropic effects, with half-maximal concentrations between 10 microM (dextropropoxyphene) and 118 microM (pethidine); all agents reduced the magnitude of the intracellular Ca2+ transient and the L-type Ca2+ current, ICa, over a similar concentration range to that which reduced twitch tension. The depression of ICa correlated positively with the value of the opioid oil-water partition coefficient. Effects were not antagonized by the opioid receptor antagonist naloxone. Action potential upstroke rate was also reduced but at significantly higher concentrations. Resting potential and action potential duration were not consistently affected; none of the opioids tested altered intracellular pH. These data suggest that opioids exert a negative inotropic effect by their action on ICa; blockade of the Na+ current is not great enough to exert a significant action. The lack of effect of naloxone implies the actions are independent of the opioid receptor. The correlation of effects with the oil water partition coefficient implies a non-specific effect dependent on the hydrophobicity of the agent.

Right thoracotomy approach to mitral valve surgical procedures

The right thoracotomy approach to mitral valve surgical procedures allows surgeons to achieve excellent, rapid exposures of mitral annuli; facilitates the excision of diseased mitral valves; avoids injury to previously placed coronary artery bypass grafts; and aids surgeons with the insertion of valve prostheses. This approach is especially appropriate for patients with anatomic deviations (e.g., deep chest cavities, counterclockwise rotations of the heart) and hostile mediastina (i.e., previously opened mediastina with severe adhesions around the heart and posterior side of the sternum). This article discusses mitral valve disease, compares the right thoracotomy approach to median sternotomy, describes perioperative nursing care of patients undergoing mitral valve surgical procedures, and presents a case study.

Isolation and identification of a novel Ala-Pro-Gly-Trp-amide-related peptide inhibiting the motility of the mature oviduct in the cuttlefish, Sepia officinalis

A novel myotropic neuropeptide was isolated from 110 optic lobes (OL) of mature females of the cuttlefish Sepia officinalis L. by mean of high performance liquid chromatography (HPLC). The peptide inhibits the motility of the oviduct by decreasing the tonus, the frequency and the amplitude of the contractions. The primary structure of the peptide was determined as Gly-Trp-NH2. This new dipeptide is closely related to the Ala-Pro-Gly-Trp-NH2 family first identified in gastropod molluscs. On the perfused oviduct, GWa appeared to be 3000 times more potent than APGW-amide. The processing of synthetic APGWa into GWa by diaminopeptidyl activity has been clearly observed in OL extract. Nevertheless, the analysis in MALDI-MS of HPLC OL fractions did not reveal any APGWa related peptides of the known: APGWa, KPGWa, RPGWa and TPGWa. GWa could be processed from a not yet identified APGWa related peptide.

Oral myiasis: a case study

This case reports an unusual finding of fly larvae infesting the maxillary hard and soft tissues (myiasis) following a chronic suppurating infection of dental origin in an Afro-Caribbean male. It also highlights the future therapeutic uses of such organisms in general medical, and possibly even dental, surgery.

Effects of the low-osmolality contrast medium ioversol (Optiray) on renal function in a geriatric population

PURPOSE

To assess the incidence of nephrotoxicity following i.v. injection of the iodinated low-osmolality contrast medium ioversol 300 (Optiray) in a geriatric population compared with a control group aged under 60 years, neither group presenting any associated risk factors.

MATERIAL AND METHODS

CT with i.v. bolus injection of ioversol 300 mg I/ml was performed at a mean dose of 1.36+/-0.06 ml/kg (range 1-2 ml/kg b.w.) in 47 patients aged over 69 years. Serum creatinine level was measured and creatinine clearance was calculated at 24, 48 and 72 h after the examination, and compared to a reference serum creatinine value taken before CT. The findings were compared with a control group of 44 patients aged under 60 years.

RESULTS

No significant increase in serum creatinine (+0.6 mmol/l) or in creatinine clearance (+0.7 ml/min) was found during the course of 3 days after the injection. Only one patient (aged 82) presented an increase of 25% in serum creatinine (109 mmol/l).

CONCLUSION

The trial did not demonstrate any significant difference between the 2 groups, although the elderly patients had a subclinical renal impairment revealed by the decrease of the initial creatinine clearance. The use of low-osmolality ioversol makes it possible to perform examination with an iodinated contrast agent without increasing the incidence of nephrotoxicity in elderly subjects.

Improving laboratory results turnaround time

BACKGROUND

Physicians need prompt results of laboratory tests before early morning rounds or on a stat basis to support time-critical decisions that can impact patient care or length of stay. At The Methodist Hospital, we formed a multidisciplinary performance improvement team that was successful in reducing the length of time between collection of specimen and availability of laboratory test results (turnaround time). Our goals were to have Stat results available in less than 60 minutes, and results for morning blood tests available by 8 AM for acute care units and 7 AM for critical care units.

METHODS

Before making changes, we first devised a system of measurement. The most efficient way to obtain data was to query the mainframe laboratory information system for times of specimen collection, times for reception in the laboratory, and times for results verification. We also decided that patient-specific information on specimens that did not meet the goals-exceptions-would be crucial for effective follow-up and corrective action. During several measurement and assessment cycles, we identified opportunities to improve our process.

RESULTS

The percentage of early morning specimens meeting the specified turnaround time improved from 60% in August 1995, to greater than 90% in May 1996. The average turnaround time for early morning specimens takes only 95 minutes rather than 186 minutes. The average turnaround time for a stat specimen declined from 69 minutes to 45 minutes during this process. The volume of stat specimens has also declined significantly.

CONCLUSION

Laboratory test results turnaround time is impacted by a variety of health-care providers, and a multidisciplinary team can work together to improve prompt availability of test results to support time-critical decisions.

Myeloma stem cells in autografting in multiple myeloma

Autologous transplantation has been used increasingly over the last 10 years for the treatment of multiple myeloma. As is the case in other cancers treated by high-dose therapy and stem cell rescue, the contribution of occult tumor cells in the graft to relapse posttransplant remains to be resolved. In this report, we review the biology and differentiation of plasma cells in the context of their significance as an origin of relapse in multiple myeloma.

Automated continuous positive airway pressure titration for obstructive sleep apnea syndrome

This study tested the effectiveness of the AutoSet self-titrating nasal continuous positive airway pressure (nCPAP) system in treating obstructive sleep apnea (OSA), and choosing a suitable pressure for subsequent conventional fixed-pressure nCPAP therapy. Twenty-one adult men with untreated OSA were studied with full polysomnography on each of four nights: diagnostic, manual and AutoSet nCPAP titration (in random order), and conventional fixed-pressure nCPAP at the pressure recommended by the AutoSet titration. Titration was satisfactorily performed in 20 of 21 subjects. Severe mask leak prevented automated titration in one subject and caused transient unnecessary increases in pressure in three subjects. In the 20 subjects, respiratory disturbance index (RDI) was 60.3 +/- 5.7 events/h (mean +/- SEM) on the diagnostic night. RDI was lower with manual titration (10.1 +/- 3.0, p < 0.001), and lower still with Autoset (2.8 +/- 0.9, p < 0.01) and fixed pressure (2.5 +/- 0.7, p = ns versus AutoSet) nCPAP. There were similar changes in the arousal index, which was 52.7 +/- 4.6 events/h on the diagnostic night, 14.2 +/- 2.4 with manual titration and 8.9 +/- 0.9 with AutoSet titration, and 9.5 +/- 1.0 on the night of conventional fixed-pressure CPAP (p < 0.001 versus diagnostic). We conclude that the AutoSet system is suitable for automated nCPAP pressure titration.

Cysteine string proteins are associated with chromaffin granules

In this work, we have examined the subcellular distribution of cysteine string proteins (Csps) in bovine adrenal medullary chromaffin cells. Csps did not leak from digitonin-permeabilized chromaffin cells, suggesting that there is no cytosolic pool of the protein in these cells. Subcellular fractionation studies confirmed that there was essentially no Csp immunoreactivity in the cytosolic fraction. However, immunoreactivity was detected in the membrane fractions of these cells. Csp immunoreactivity codistributed with dopamine beta-hydroxylase, a granule marker protein, in sucrose gradient-separated granule fractions. Immunofluorescence studies showed that all chromaffin cells in culture were stained with a punctate appearance consistent with a granular localization. These results were confirmed by immunogold labeling, which demonstrated specific labeling of chromaffin granule membranes. In addition to its presence on synaptic vesicles, cysteine string protein is therefore a bona fide chromaffin granule membrane protein.

Expressed sequence tags identify human isologs of the ARF-dependent phospholipase D

By searching into Expressed Sequence Tags databases (dbEST) using Blast X algorithm software and a plant phospholipase D as template, we have identified a cDNA from human brain (Z45777) which encodes for a protein similar to the amino acid region 743-929 of the human phospholipase D1 (PLD1), and a cDNA from human liver (R93485) which encodes for a protein similar to region 815-932 of PLD1. Sequence comparison between cloned phospholipases showed the presence of 3 conserved amino acid sequences: AFVGGIDLAYGRWD (box A), IIGSANINDRS (box B), and YIYIENQFFI (box C). Phylogenic analysis indicated that the cDNA from brain and liver encoded for human isologs of PLD1.