The limbic system-associated membrane protein is an Ig superfamily member that mediates selective neuronal growth and axon targeting.

The formation of brain circuits requires molecular recognition between functionally related neurons. We report the cloning of a molecule that participates in these interactions. The limbic system-associated membrane protein (LAMP) is an immunoglobulin (Ig) superfamily member with 3 Ig domains and a glycosyl-phosphatidylinositol anchor. In the developing forebrain, lamp is expressed mostly by neurons comprising limbic-associated cortical and subcortical regions that function in cognition, emotion, memory, and learning. The unique distribution of LAMP reflects its functional specificity. LAMP-transfected cells selectively facilitate neurite outgrowth of primary limbic neurons. Most striking, administration of anti-LAMP in vivo results in abnormal growth of the mossy fiber projection from developing granule neurons in the dentate gyrus of the hippocampal formation, suggesting that LAMP is essential for proper targeting of this pathway. Rather than being a general guidance cue, LAMP likely serves as a recognition molecule for the formation of limbic connections.

Tyr346-->Cys mutation results in factor VIII:C assay discrepancy and a normal bleeding phenotype - is this mild haemophilia A?

Patients with mild haemophilia A may have a discrepancy in the factor VIII (FVIII) level when measured with a one-stage assay (FVIII:C1) compared with a two-stage assay (FVIII:C2). This discrepancy usually results in the one-stage level being higher than the two-stage level. A F8 mutation resulting in a Tyr346-->Cys substitution within the a1 interdomain region has been described which results in the converse assay discrepancy. We report four individuals (three families) who have this mutation. Mean FVIII:C1 level was 25 IU dL(-1) compared with a mean FVIII:C2 level of 63 IU dL(-1). These individuals had presented opportunistically and did not have a clinically significant bleeding disorder. The bleeding phenotype correlated with the two-stage assay result rather than the one-stage result. FVIII replacement therapy does not appear to be required for these individuals.

Evidence supporting a role for cathepsin B in the generation of T cell antigenic epitopes of human growth hormone.

The elucidation of the enzymatic processing mechanism associated with the formation of antigenic peptide fragments that combine with MHC class II molecules is fundamental to our understanding of the immune system. We have investigated a structurally well defined protein, recombinant human growth hormone (rhGH), as an antigen, and present data supporting the hypothesis that the enzyme cathepsin B can produce peptide fragments bearing T cell epitopes associated with lymphocyte proliferative response to hGH in Balb/c (H-2dhaplotype) mice. Minimal T cell epitopes are not generated; rather the cathepsin cleavage sites flank the three antigenic peptide regions, amino acid residues 31-41, 81-100, and 166-181.

Inhibition of intragastric acidity in healthy subjects dosed with ranitidine 75 mg: a comparative study with cimetidine and placebo.

BACKGROUND: Despite the widespread use of over-the-counter H2-receptor antagonists little is known about their duration of action on human gastric acid secretion. There are studies reporting inhibitory effects for up to 9 h post-dose but few data beyond this period. METHODS: Profiles of 20-h intragastric acidity were measured simultaneously in 24 healthy subjects who were dosed (at 12.30 h) with either ranitidine 75 mg, cimetidine 200 mg or placebo in a three-way crossover study, according to a standard protocol. Five-millilitre aliquots of gastric juice were aspirated half-hourly during the day (0-10 h post-dose) and hourly overnight (10-20 h post-dose). pH was measured to three decimal places with a glass electrode. Weighted intragastric acidity (AUC/time) was calculated for both day- and night-times using 2.5-h intervals during the day and 5-h intervals at night. Statistical analysis was by ANOVA. RESULTS: The results are expressed as mean weighted intragastric acidity (mmol/L). (i) Daytime (0-10 h post-dose): when dosed with placebo the weighted intragastric acidity was 31.03, decreasing to 10.37 (P < 0.001 vs. placebo) and 16.23 (P < 0.001 vs. placebo) when treated with ranitidine and cimetidine, respectively. Ranitidine inhibited weighted intragastric acidity to a greater degree than cimetidine (P < 0.001) during this period. (ii) Night-time (10-20 h post-dose): when dosed with placebo the weighted intragastric acidity was 21.36 decreasing to 16.65 (P < 0.001 vs. placebo) when dosed with ranitidine and remaining unchanged at 20.03 (P = 0.886 vs. placebo) when dosed with cimetidine. Ranitidine inhibited weighted intragastric acidity to a greater degree than cimetidine (P = 0.010) during this period. A sub-analysis of the two 5-h intervals showed that compared to placebo, ranitidine inhibited weighted intragastric acidity significantly in the 10-15 h period. However, its effect in the 15-20 h period did not differ from placebo. CONCLUSIONS: In healthy subjects, the inhibitory effect of ranitidine 75 mg on intragastric acidity can be detected 10-15 h after an oral dose. By contrast, the inhibitory effect of cimetidine 200 mg seems to be restricted to the first 10 h.

Nocturnal intragastric acidity after over-the-counter doses of famotidine, ranitidine or placebo.

AIM: To compare the inhibitory effects of over-the-counter doses of famotidine or ranitidine on nocturnal intragastric acidity in a placebo-controlled study. METHODS: Twelve-hour intragastric acidity was measured simultaneously in 24 healthy subjects who ate a standard meal at 18.30 h and were dosed (at 19.30 h) with either famotidine 10 mg, ranitidine 75 mg or placebo in a balanced three-period crossover design. Five-millilitre aliquots of gastric juice were aspirated half-hourly 0-3 h post-dose, and then hourly until the end of the study. pH was measured with a glass electrode. Integrated pH (area under the curve (AUC) of the pH-time curve) was calculated for the intervals 0-12 h and 9-12 h post-dose. Statistical analysis was by ANOVA. RESULTS: In the 0-12 h post-dose period, when the 24 subjects were dosed with placebo, mean AUC was 2.12, increasing by 75% to 3.70 with famotidine (P < 0.001) and by 81% to 3.83 with ranitidine (P < 0.001). In the 9-12 h post-dose period, when the subjects were dosed with placebo, mean AUC was 2.13, increasing by 91% to 4.07 with famotidine (P < 0.001) and by 79% to 3.82 with ranitidine (P < 0.001). There was no significant difference between the pH-raising effects of famotidine and ranitidine in both periods. CONCLUSIONS: Famotidine and ranitidine in over-the-counter doses have a similar, sustained, effect on post-prandial nocturnal intragastric acidity in healthy subjects lasting up to 12 h after oral dosing.

Early and late effects of low-dose famotidine, ranitidine or placebo on pentagastrin-stimulated gastric acid secretion in man.

BACKGROUND: There are no published comparative studies on the effect of low-dose H2-antagonists on pentagastrin-stimulated gastric acid secretion. METHODS: Twenty-four healthy subjects were dosed with either famotidine 10 mg, ranitidine 75 mg or placebo in a balanced three-period cross-over design. The subjects were studied in groups of 12, simultaneously, under identical controlled environmental conditions. Gastric juice was aspirated in 15-min aliquots during sub-maximal (0.6 microgram.h/kg) intravenous pentagastrin stimulation in the third and fourth hours (early period) and the eighth and ninth hours (late period) after oral dosing. The hydrogen ion (H+) content of gastric juice was measured ex vivo, by titrating to pH7 known volumes of gastric aspirate against 0.1 M sodium hydroxide, using a versatile microprocessor-controlled auto-titration unit. Gastric acid output during the period of interest was calculated by adding the hydrogen ion content of 15-min aliquots collected during that period. The geometric mean of the cumulative pentagastrin-stimulated gastric acid output during the early and late periods was determined for the subjects dosed with either famotidine, ranitidine or placebo. Comparisons were performed by ANOVA. RESULTS: During the early period (2-4 h post-dose), When the subjects were given placebo, mean gastric acid output was 46.6 mmol, decreasing by 76% to 11.3 mmol (P < 0.001) when treated with famotidine and by 76% to 11.1 mmol (P < 0.001) when treated with ranitidine. During the late period (7-9 h post-dose), when the subjects were dosed with placebo, mean gastric acid output was 41.2 mmol, decreasing by 38% to 25.7 mmol (P < 0.001) when treated with famotidine and by 27% to 30.0 mmol (P = 0.007) when treated with ranitidine. The difference between the inhibitory effects of famotidine and ranitidine on gastric acid output were non-significant during either period. CONCLUSIONS: Low-dose famotidine and ranitidine, intended for over-the-counter use, inhibit stimulated gastric acid secretion profoundly in the third and fourth hours after an oral dose. Modest effects are still detectable up to 9 h after dosing.

Comparison of two 3-day Helicobacter pylori eradication regimens with a standard 1-week regimen.

BACKGROUND: The duration of Helicobacter pylori eradication regimens has decreased to 1 week with cure rates of over 90%. This can be attributed to the use of triple drug regimens including potent inhibitors of gastric acid secretion and clarithromycin. There is no theoretical reason why shorter regimens should not be possible. AIM: To compare two 3-day, low-dose, twice daily regimens with 1 week of omeprazole 20 mg b.d., clarithromycin 250 mg b.d., and metronidazole 400 mg b.d. (OCM) METHODS: Outpatients referred for gastroscopy were screened by biopsy urease test. H. pylori-positive patients were randomized to receive either lansoprazole 30 mg b.d., tri-potassium dicitrato bismuthate one tablet b.d., clarithromycin 250 mg b.d., and amoxycillin 1 g b.d. for 3 days (LTdbCA), or ranitidine bismuth citrate 400 mg b.d., clarithromycin 250 mg b.d. and amoxycillin 1 g b.d. for 3 days (RbcCA) or omeprazole 20 mg b.d., clarithromycin 250 mg b.d. and metronidazole 400 mg b.d. for 1 week (OCM). They were not pre-treated with a gastric acid inhibitor. After 8 weeks, H. pylori status was assessed by 13C urea breath test. RESULTS: 974 out of 1114 patients referred for gastroscopy were screened by biopsy urease test. 140 patients were not screened either because they were anticoagulated or for technical reasons. 334 patients were H. pylori-positive: 154 were excluded mostly because of allergy to penicillin and personal reasons but 180 were randomized to treatment All regimens were well tolerated. For LTdbCA (n=60), RbcCA (n=59), and OCM (n=61) the H. pylori cure rates (95% CI) were 23% (12-34), 14% (5-23) and 87% (79-95), respectively, using intention-to-treat analysis and 25% (14-36), 15% (6-24) and 88% (80-96), respectively, if analysed per protocol. OCM was significantly superior to LTdbCA and RbcCA (P < 0.001) but there was no significant difference between regimens LTdbCA and RbcCA. CONCLUSIONS: OCM is an extremely effective H. pylori eradication regimen. The 3-day regimens tested both have poor cure rates. Pre-treatment with a proton pump inhibitor, higher doses or more frequent dosing may be necessary to increase the cure rate of short duration regimens. However, this could make them less acceptable than the H. pylori eradication regimens currently available.

Low-dose famotidine and effervescent cimetidine in healthy subjects: a placebo-controlled overnight pH study.

BACKGROUND: Amongst the low-dose H2-receptor antagonists available for the self-medication of dyspepsia, both famotidine 10 mg and cimetidine 200 mg have been shown to raise intragastric pH, but there is a delay after ingestion before significant effects can be demonstrated. A new effervescent preparation of cimetidine 200 mg releases an acid buffer which has a more rapid effect on intragastric pH. AIM: To investigate the relative abilities of low-dose famotidine and effervescent cimetidine to raise intragastric pH after a single postprandial evening dose. METHODS: Twenty-four healthy subjects (12 men, 12 women, median age 32 years) completed a three-period crossover trial of famotidine 10 mg, effervescent cimetidine 200 mg and placebo. After a standard meal was given at 18.30 h to subjects fasted for 5.5 h, drug or placebo was given at 19.30 h. Intragastric pH was recorded with combined glass electrodes from 18.00 to 07.30 h by digital recorders. RESULTS: Over the 12 h post-dose period the mean area under the pH/time curve (AUC) after famotidine 10 mg was 3.73, after cimetidine 200 mg effervescent 2.79, and after placebo 2.07. Over the same period the median pH and percentage of time that recordings were above pH 3 were 3.45 and 52.5 after famotidine 10 mg, 2.40 and 33.8 after cimetidine 200 mg effervescent, and 1.68 and 15.9 after placebo. Both active treatments were significantly different from placebo by each measure (P < 0.001), and famotidine 10 mg was significantly more effective than cimetidine 200 mg effervescent by each measure over the 0-12 h period (P < 0.001). Comparisons of mean AUCs for each 15 min period after dosing showed that decrease in acidity was significantly greater after cimetidine 200 mg effervescent than after famotidine 10 mg for the first 60 min. In the later post-dose period only famotidine 10 mg raised pH for all time points to 12 h, whilst the effect of effervescent cimetidine 200 mg was detectable to = 8 h. CONCLUSIONS: Inhibition of gastric acidity over the 12 h post-dose period was significantly greater and endured longer after famotidine 10 mg than after effervescent cimetidine 200 mg, but for the 60 min period immediately after dosing the effect on intragastric pH was significant following effervescent cimetidine 200 mg but not famotidine 10 mg. This suggests effervescent formulations of H2-receptor antagonists with an acid buffer have a more rapid effect on intragastric pH than film-coated tablets.

Helicobacter pylori-associated antibodies in patients with duodenal ulcer, gastric and oesophageal adenocarcinoma.

OBJECTIVE: To associate Helicobacter pylori-associated antibodies with clinical disease in groups of patients with duodenal ulcer, gastric adenocarcinoma, oesophageal adenocarcinoma and normal mucosa. DESIGN: Prospective observational sero-epidemiology study. Identification of consecutive in-patients with duodenal ulcer, gastric adenocarcinoma, oesophageal adenocarcinoma and normal mucosa. Analyses of sera for antibodies to whole H. pylori, Cag A and Vac A antigens using ELISA and Western blot. Statistical analyses. SETTING: Walsgrave Hospital, Coventry, a district general hospital that serves a population of 350,000. PARTICIPANTS: Consecutive in-patients with an endoscopic diagnosis of duodenal ulcer (n = 31), gastric adenocarcinoma (n = 31), oesophageal adenocarcinoma (n = 40) and normal mucosa (n = 46). MAIN OUTCOME MEASURES: A profile of antibodies was constructed for each patient group and between-group comparisons were made. A logistic regression model determined the H. pylori-associated antibody that could best predict a patient's diagnosis. A discriminatory power for each antibody was calculated. RESULTS: Whole H. pylori, Cag A and Vac A antibodies are found more commonly in duodenal ulcer patients when compared to oesophageal adenocarcinoma (P < 0.003) and normal mucosa patients (P < 0.015). Similarly, gastric adenocarcinoma patients have antibodies to whole H. pylori, Cag A and Vac A more frequently than oesophageal adenocarcinoma (P< 0.002) and normal mucosa patients (P < 0.006). Vac A antibodies discriminate between duodenal ulcer/gastric adenocarcinoma and oesophageal adenocarcinoma/normal mucosa patients (odds ratio 5.56, log likelihood -90.06, P < 0.001) more effectively than Cag A antibodies (odds ratio 4.17, log likelihood -91.88, P < 0.001). CONCLUSIONS: Similar profiles of H. pylori-associated antibodies are seen in patients with duodenal ulcer and gastric adenocarcinoma, confirming that virulent H. pylori are involved in the pathogenesis of both diseases. Antibodies to Vac A could be used to identify patients at increased risk of developing H. pylori-associated disease.

Lead poisoning from Asian traditional remedies in the West Midlands--report of a series of five cases.

1. Traditional remedies are an unusual, but recognised cause of lead poisoning. Only two cases have previously been reported in this country. 2. We report a series of five cases of lead poisoning due to traditional remedies in the West Midlands. All developed typical clinical features. 3. Blood lead and zinc protoporphyrin (ZPP) concentrations were elevated 2-10 times the upper limit of normal. The remedies contained up to 60% lead by weight. One also contained traces of mercury, another arsenic, and a third aluminium and tin. 4. Confirmation of the medicines as the cause of the poisoning was made in one patient by measurement of lead isotopic ratios. 5. The present morbidity from traditional remedies may be far greater than is realised, and will continue until such time as the supply of harmful preparations can be effectively limited. There needs to be increased awareness of their dangers amongst doctors and the communities at risk. This will best be achieved by appropriately targeted education.

Purpura fulminans: recognition, diagnosis and management.

Purpura fulminans (PF) is a haematological emergency in which there is skin necrosis and disseminated intravascular coagulation. This may progress rapidly to multi-organ failure caused by thrombotic occlusion of small and medium-sized blood vessels. PF may complicate severe sepsis or may occur as an autoimmune response to otherwise benign childhood infections. PF may also be the presenting symptom of severe heritable deficiency of the natural anticoagulants protein C or protein S. Early recognition and treatment of PF is essential to reduce mortality and to prevent major long-term health sequelae. However, management strategies require accurate identification of the underlying cause. This review focuses on the clinical features, differential diagnosis and laboratory features of the range of PF disorders and includes expert consensus opinion about immediate and on-going management.

Epicardial lymphocytes: an autopsy study.

Lymphocytes appear as a diffuse infiltrate within the epicardium in the second trimester of intrauterine life, and can be found there throughout adult life. Aggregates are found in some individuals, and are strongly associated with the presence of old myocardial infarction.

Transcription termination factor rho activity is altered in Escherichia coli with suA gene mutations.

Rho factor has been purified from a strain of E. coli containing the Su78 mutation in the suA gene and assayed in another strain with an amber mutation in the suA gene. The rho from the Su78 mutant strain is present in normal amounts but has altered termination function; it does not terminate transcription at some sites that are recognized effectively by the rho factor from the isogenic wild-type strain. Rho in cells with an amber mutation in the suA gene has been assayed by its RNA-dependent ATPase activity. Extracts of cells of this strain have only 9% as much of this rho activity as extracts of cells of the isogenic wild-type strain. These results suggest that rho is the product of the suA gene. Since mutations in the suA gene are known to decrease polar effects of mutations in other genes, it is also suggested that rho factor is at least partially responsible for polar effects.

Identifying proteins from two-dimensional gels by molecular mass searching of peptide fragments in protein sequence databases.

A rapid method for the identification of known proteins separated by two-dimensional gel electrophoresis is described in which molecular masses of peptide fragments are used to search a protein sequence database. The peptides are generated by in situ reduction, alkylation, and tryptic digestion of proteins electroblotted from two-dimensional gels. Masses are determined at the subpicomole level by matrix-assisted laser desorption/ionization mass spectrometry of the unfractionated digest. A computer program has been developed that searches the protein sequence database for multiple peptides of individual proteins that match the measured masses. To ensure that the most recent database updates are included, a theoretical digest of the entire database is generated each time the program is executed. This method facilitates simultaneous processing of a large number of two-dimensional gel spots. The method was applied to a two-dimensional gel of a crude Escherichia coli extract that was electroblotted onto poly(vinylidene difluoride) membrane. Ten randomly chosen spots were analyzed. With as few as three peptide masses, each protein was uniquely identified from over 91,000 protein sequences. All identifications were verified by concurrent N-terminal sequencing of identical spots from a second blot. One of the spots contained an N-terminally blocked protein that required enzymatic cleavage, peptide separation, and Edman degradation for confirmation of its identity.

Insulin-like growth factor expression in human cancer cell lines.

The insulin-like growth factors (IGFs), IGF-I and IGF-II, are potent mitogens for human lung and other epithelial cancer cell lines. Previous studies in defined medium lacking added IGF or insulin suggest that an IGF-related ligand can act as an autocrine growth factor for many cancer cell lines through action via the type I IGF receptor (IGF-R). Analysis of RNA isolated from human lung and breast cancer cell lines by reverse transcription of mRNA and polymerase chain reaction reveal that IGF-I and IGF-II mRNAs were co-expressed with IGF-R in the majority of cell lines. IGF-I mRNA was detected in 11/12 small cell lung cancer cell lines (SCLC), 13/14 nonsmall cell lung cancer (NSCLC) cell lines, and 1/2 breast cancer cell lines. IGF-II mRNA was detected in 8/10 SCLC, 11/12 NSCLC cell lines, and 2/2 breast lines. All cell lines expressed IGF-R. For analysis of IGF peptide secretion, cell lines were adapted to growth in serum/hormone-free culture medium (R0), and to avoid interference by IGF-binding proteins, secreted IGF peptides were isolated under acidic conditions and analyzed by Western blotting. Based upon measurement of the sensitivity of the anti-IGF antibodies for detection of recombinant human IGFs, IGF peptides accumulated in conditioned medium at greater than picomolar concentrations should have been readily detected. In three cell lines (two lung and one breast) secreted IGF immunoreactivity was detected as three molecular mass species of 23, 14, and 6 kDa. Isolation and NH2-terminal sequencing of each of these species definitively identified them as differentially processed forms of the IGF-II prohormone. Despite the high frequency of IGF-I gene expression detected by reverse transcription-polymerase chain reaction analysis, only one lung cancer cell line, NCI-N417d, was found that unequivocally secreted IGF-I peptide. This direct sequence determination unambiguously identifies IGF-II as the predominant IGF involved in the autocrine growth stimulation of human lung and breast epithelial tumor cell lines and supports a growing body of literature that implicates IGF-II/IGF-R autocrine loops as a common growth mechanism in epithelial carcinogenesis.

An endothelial ligand for L-selectin is a novel mucin-like molecule.

The adhesive interaction between circulating lymphocytes and the high endothelial venules (HEV) of lymph nodes (LN) is mediated by lymphocyte L-selectin, a member of the selectin family of cell adhesion proteins. Previous work has identified a sulfated 50 kd glycoprotein (Sgp50) as an HEV ligand for L-selectin. We now report the purification of this glycoprotein and the utilization of the derived N-terminal amino acid sequence to clone a cDNA. The predicted sequence reveals a novel, mucin-like molecule containing two serine/threonine-rich domains. The mRNA encoding this glycoprotein is preferentially expressed in LN. Antibodies against predicted peptides immunoprecipitate Sgp50 and stain the apical surface of LN HEV. These results thus define a tissue-specific mucin-like endothelial glycoprotein that appears to function as a scaffold that presents carbohydrates to the L-selectin lectin domain.