Insulin-dependent diabetes mellitus (IDDM) is associated with CTLA4 polymorphisms in multiple ethnic groups

Linkage disequilibrium (association) analysis was used to evaluate a candidate region near the CTLA4/CD28 genes using a multi-ethnic collection of families with one or more children affected by IDDM. In the data set unique to this study (Spanish, French, Mexican-American, Chinese and Korean), the transmission/disequilibrium test (TDT) revealed a highly significant deviation for transmission of alleles at the (AT)n microsatellite marker in the 3' untranslated region (P = 0.002) and the A/G polymorphism in the first exon (P = 0.00002) of the CTLA4 gene. The overall evidence for transmission deviation of the CTLA4 A/G alleles is also highly significant (P = 0.00005) in the combined data set (669 multiplex and 357 simplex families) from this study and a previous report on families from USA, Italy, UK, Spain and Sardinia. Significant heterogeneity was observed in these data sets. The British, Sardinian and Chinese data sets did not show any deviation for the A/G polymorphism, while the Caucasian-American data set showed a weak transmission deviation. Strong deviation for transmission was seen in the three Mediterranean-European populations (Italian, Spanish and French) (P = 10(-5)), the Mexican-American population (P = 0.002) and the Korean population (P = 0.03). These results suggest that a true IDDM susceptibility locus (designated IDDM12) is located near CTLA4.

NonO enhances the association of many DNA-binding proteins to their targets

NonO is an unusual nucleic acid binding protein not only in that it binds both DNA and RNA but that it does so via functionally separable domains. Here we document that NonO enhances the binding of some (E47, OTF-1 and OTF-2) but not all (PEA3) conventional sequence-specific transcription factors to their recognition sites in artificial substrates as well as in an immunoglobulin VHpromoter. We also show that NonO induces the binding of the Ku complex to DNA ends. Ku has no known DNA sequence specificity. These enhancement of binding effects are NonO concentration dependent. Using the E box activity of E47 as a model, kinetic studies demonstrate that the association rate of the protein-DNA complex increases in the presence of NonO while the dissociation rate remains the same, thereby increasing the sum total of the interaction. Oligo competition experiments indicate that NonO does not contact the target DNA in order to enhance the binding activity of DNA binding proteins. Rather, methylation interference analysis reveals that the induced E47 binding-activity has the same DNA-binding sequence specificity as the normal binding. This result suggests that one of the effects of NonO is to induce a true protein-DNA interaction. In this way, it might be possible for NonO to play a crucial role in gene regulation.

Hemodynamic effects of chronic tetrandrine and propranolol administration on portal hypertensive rats

The purpose of this study was to investigate the therapeutic effects of tetrandrine and propranolol, alone or in combination, on portal hypertensive rats. Portal hypertension was induced by partial portal vein ligation in Sprague-Dawley rats. Animals were allocated into one of the four groups: vehicle group (0.1 N.HCl, 0.7 ml/day), tetrandrine group (50 mg/kg/ day), propranolol group (30 mg/kg/day), and tetrandrine (50 mg/kg/day) plus propranolol (30 mg/kg/day) group. Drug or vehicle was administered by gavage for consecutive 9 days. After 9 days of treatment, the portal venous pressure and mean arterial pressure in each treatment group were significantly lower than those in the vehicle group. The cardiac index was not changed by tetrandrine alone, but reduced in the two groups receiving propranolol alone or in combination. Total peripheral resistance was significantly decreased in the tetrandrine group and significantly increased in the tetrandrine plus propranolol group as compared with the vehicle group. Our results suggested that tetrandrine or propranolol alone induced portal hypotensive effects, with propranolol achieving better antihyperdynamic effects in terms of cardiac index, and in combination propranolol effects predominated over those of tetrandrine.

Genetic mapping of 20 novel expressed sequence tags from midgestation mouse embryos suggests chromosomal clustering

Current knowledge of genes that regulate pattern formation and differentiation processes during mammalian embryonic development is limited. In an effort to isolate developmentally relevant genes, 20 novel, end-sequenced cDNAs selected from a Day 10.5 postcoitum mouse embryo library were genetically mapped in intersubspecific backcross mice. Eleven of 20 cDNA clones mapped to three mouse autosomes (Chr 5, 11, and 14), a result that was unlikely (P < 0.03) if the distribution of genes expressed in embryos is random within the mouse genome. Several clones were candidates for mouse developmental mutations by virtue of genetic colocalization and concordance of embryonic expression patterns with the distribution of defects in mutant mice: Estm11 was a candidate for the mouse mutation wabbler-lethal (wl), since Estm11 mapped in the vicinity of wl on mouse Chr 14 and was expressed in those regions of embryonic brain that exhibit axonal degeneration in wl. End-sequence analysis, genetic mapping, and in situ hybridization appeared to be an effective combination of methods for identification and characterization of genes with potential regulatory functions during mammalian embryogenesis.

Inositol phosphate responses in portal veins from portal hypertensive rats: receptor- and nonreceptor-mediated responses

BACKGROUND/AIMS

Venous hyporesponsiveness in portal hypertension has been reported previously by us. The present study was undertaken to investigate possible changes of phosphoinositide signal transduction pathway in the portal veins from portal hypertensive rats

METHODS

Portal hypertension was induced by partial portal vein ligation. Fourteen days after surgery, portal veins were removed for measurement of [3H]inositol phosphate responses to both receptor- and nonreceptor-mediated stimuli.

RESULTS

Basal [3H]inositol phosphate formation was similar between the two groups. Both phenylephrine and angiotensin II stimulated [3H]inositol phosphate formation in portal veins, but the responses were attenuated in the portal hypertensive group. In contrast, the [3H]inositol phosphate formation by nonreceptor-mediated stimuli (GTP gamma S, NaF/AlCl3, and phospholipase C) was similar between the two groups.

CONCLUSION

Our results showed that the receptor-mediated [3H]inositol phosphate formation was attenuated, while the non-receptor-mediated formation was unaltered, in the portal vein from portal hypertensive rats.

Evaluating the merits of option-3 methods in relative attachment level measurement in a healthy population

Attachment loss is the principal clinical indicator for periodontal disease progression. However, the attachment measurement can be inaccurate due to outliers. A remedial scheme, the option-3 scheme, has been suggested in the literature. This scheme involves first measuring the relative attachment twice at any given site. A third measurement is required if there is a large disagreement between the first two probings. When the third measurement is taken, there are several possible ways to make the final assessment of the true attachment level. Among them are the average of the 3 measurements, the average of the closest 2, and the median of the 3. This report evaluates the merits of the option-3 scheme by comparing it with other schemes to reduce measurements variance and outliers. Since true attachment levels are unknown, we chose to check accuracy through measurement consistency between visits in healthy subjects using the fact that such subjects should have little real change in attachment levels. 12 healthy subjects participated in the study. They visited the clinic 4 times in 4 months. Two types of the Florida stent probe were used by 2 calibrated examiners. It was found that option-3 schemes were more accurate than a single probing or duplicate probings in estimating the relative attachment level. The 3 final assessment schemes performed almost equally well from a practical standpoint, but the median was the best among them in a statistical sense.

The hemodynamic effects of AT-112, an analog of ketanserin, in portal hypertensive rats

A serotonin mechanism has been reported to contribute to the hyperdynamic circulation of portal hypertension. Different studies have demonstrated that serotonin antagonists decrease portal pressure in portal hypertensive patients and animals. The present study was undertaken to investigate the effect of AT-112, an analog of ketanserin, on portal hypertension induced by partial portal vein ligation in rats. Since ketanserin is known to possess alpha 1-adrenergic antagonistic activity, the effect of AT-112 was compared to that of prazosin. A single dose (prazosin 4.2 micrograms/kg, AT-112 1 mg/kg) was chosen to produce a similar hypotensive effect (-20 +/- 4% for prazosin and -24 +/- 4% for AT-112). At this dose, prazosin significantly decreased total peripheral resistance whereas AT-112 significantly decreased cardiac index and heart rate. Both agents significantly decreased the portal tributary blood flow and portal pressure. In rats receiving AT-112, a significant correlation was found between the magnitudes of decrease in cardiac index and the decrease in portal tributary blood flow. We also found that the magnitude of reduction in portal pressure was greater following AT-112 administration. This study suggested that AT-112 may have more beneficial hemodynamic effects than prazosin in portal hypertensive rats. Our results provide further support for the serotonergic mechanism in the pathogenesis of hyperdynamic circulation in portal hypertension.

Recombinant Coccidioides immitis complement-fixing antigen: detection of an epitope shared by C. immitis, Histoplasma capsulatum, and Blastomyces dermatitidis

We undertook an investigation to assess the utility of a recombinant Coccidioides immitis complement-fixing (CF) antigen for detecting CF antibody in sera from patients with coccidioidomycosis. Enzyme-linked immunosorbent assays established that recombinant CF antigen and, for comparison, a commercially available coccidioidin were reactive with 19 of 19 sera from patients with active coccidioidomycosis. The recombinant antigen was significantly more sensitive than coccidioidin. The median titer obtained when patients' sera were assayed against recombinant CF antigen was 1:51,200 compared to 1:25,600 with coccidioidin (P < 0.027). The recombinant antigen was also more effective in distinguishing the antibody levels in sera from patients with pulmonary coccidioidomycosis than in sera from those with disseminated disease. Whereas patients with pulmonary disease showed a median antibody titer of 1:25,600, those with multifocal disease showed a median titer of 1:102,400 (P < 0.028). The recombinant CF antigen was found, however, to express an epitope(s) that reacted with sera from 6 of 12 patients with histoplasmosis and 2 of 12 patients with blastomycosis.

Identification of a RING protein that can interact in vivo with the BRCA1 gene product

The hereditary breast and ovarian cancer gene, BRCA1, encodes a large polypeptide that contains the cysteine-rich RING motif, a zinc-binding domain found in a variety of regulatory proteins. Here we describe a novel protein that interacts in vivo with the N-terminal region of BRCA1. This BRCA1-associated RING domain (BARD1) protein contains an N-terminal RING motif, three tandem ankyrin repeats, and a C-terminal sequence with significant homology to the phylogenetically conserved BRCT domains that lie near the C terminus of BRCA1. The BARD1/BRCA1 interaction is disrupted by BRCA1 missense mutations that segregate with breast cancer susceptibility, indicating that BARD1 may be involved in mediating tumour suppression by BRCA1.

Chronic administration of octreotide increases vascular responsiveness in rats with portal hypertension

1. It has been reported that ortreotide partially corrects the hyperdynamic state in patients and animals with portal hypertension. The aim of the present study was to investigate whether chronic administration of octreotide can increase vascular responsiveness in rats with portal hypertension. 2. Portal hypertension was induced by partial portal vein ligation. Octreotide was given for 9 days subcutaneously (100 micrograms/kg every 12 h) starting 1 day before ligation. The aorta and mesenteric artery were then removed to study contraction after pressure recording. 3. Octreotide treatment significantly reduced portal pressure and plasma glucagon concentrations compared with the vehicle-treated group. Both phenylephrine and vasopressin induced concentration-dependent contractile responses in the aorta and mesenteric artery from both groups. The maximum contractile responses to phenylephrine and vasopressin in aorta and mesenteric artery were significantly greater in the octreotide-treated group than in the vehicle-treated group. The EC50 values for phenylephrine and vasopressin were significantly different in the aorta, but not in the mesenteric artery, but not in the mesenteric artery, between the two groups. In contrast, octreotide treatment did not alter the contractile responsiveness of arteries rom sham-operated rats. 4. These results show that, in rats with portal vein stenosis, octreotide increases arterial contractile responsiveness and reduces portal pressure.

Extensive intra-abdominal-retroperitoneal fat necrosis in a patient with renal cell carcinoma

Extensive intra-abdominal-retroperitoneal fat necrosis is rare, especially its occurrence in cases of renal cell carcinoma (RCC). We report a patient who presented with a palpable left lower abdominal mass. The RCC was an incidental radiographic finding. The fat necrosis exhibited properties similar to a liposarcoma at laparotomy and on histologic examination of frozen tissue sections. Debulking surgery with left hemicolectomy, transverse colostomy and a midrectal Hartmann pouch was performed. In subsequent surgery, radical right nephrectomy and closure of the colostomy were performed. There were no discernible factors predisposing this patient to fat necrosis. To our knowledge, such extensive intra-abdominal-retroperitoneal fat necrosis is extremely rare. A literature search failed to find a similar case of intra-abdominal or retroperitoneal fat necrosis in association with RCC.

Vascular hyporesponsiveness in aorta from portal hypertensive rats: possible sites of involvement

Vascular hyporesponsiveness in portal hypertension has been proposed to be due to postreceptor defect. The present study was aimed to investigate possible sites of involvement in such hyporesponsiveness. Portal hypertension was induced by partial portal vein ligation (PVL). Concentration-response curves to KCI and phenylephrine in both groups showed that the Emax values were significantly lower in the PVL group. The EC50 values were not different between the two groups. In Ca++ free condition, phenylephrine induced a phasic contraction, which was significantly smaller in the aorta from PVL rats. Cumulative readdition of CaCl2 (1.0-2.5 mM) induced tension increases, which were all significantly lower in the PVL group. Basal contents of [3H]inositol phosphates in the aorta were similar between the two groups. Phenylephrine induced concentration-dependent increase of [3H]inositol phosphates in the aorta from both groups. The responses at 10(-8), 10(-7), 10(-6) and 10(-5) M were significantly smaller in the PVL group than in the sham-operated group. Both okadaic acid and phorbol 12,13-dibutyrate induced slowly developing contractile responses in the aorta. The responses were similar between the two groups at all time points. Our results suggested that in the aorta from PVL rats, vascular hyporesponsiveness was observed, together with decreased contractile responses due to: voltage- and receptor-dependent calcium influx as well as intracellular calcium release, and decreased receptor-coupled inositol phosphate formation. Contractile responses due to activation of protein kinase C or phosphatase inhibition were not impaired.

The mammalian immediate-early TIS21 protein and the leukemia-associated BTG1 protein interact with a protein-arginine N-methyltransferase

The TIS21 immediate-early gene and leukemia-associated BTG1 gene encode proteins with similar sequences. Two-hybrid analysis identified a protein that interacts with TIS21 and BTG1. Sequence motifs associated with S-adenosyl-L-methionine binding suggested this protein might have methyltransferase activity. A glutathione S-transferase (GST) fusion of the putative methyltransferase modifies arginine residues, in appropriate protein substrates, to form NG-monomethyl and NG,NG-dimethylarginine (asymmetric). We term the protein- arginine N-methyltransferase (EC 2.1.1.23) gene "PRMT1, " for protein-arginine methyltransferase 1. GST-TIS21 and GST-BTG1 fusion proteins qualitatively and quantitatively modulate endogenous PRMT1 activity, using control and hypomethylated RAT1 cell extracts as methyl-accepting substrates. PRMT1 message appears ubiquitous, and is constitutive in mitogen-stimulated cells. Modulation of PRMT1 activity by transiently expressed regulatory subunits may be an additional mode of signal transduction following ligand stimulation.

Surgical treatment of hepatocellular carcinoma originating from the caudate lobe

Hepatocellular carcinoma (HCC) originating from the caudate lobe is rare, and its surgical management is difficult because of its unique anatomic location. We have seen six such cases at our hospital. For patients with fair to excellent liver reserve, we advocated caudate lobectomy combining other types of hepatic resection. For patients with marked liver cirrhosis and poor liver reserve or a small HCC, we advocated simple partial caudate lobectomy (limited hepatic resection). There was no operative mortality or major operative morbidity. We conclude that such approaches are safer, less time-consuming, and less technique-demanding, and they produce a fair survival result compared with the approaches of other procedures. With such approaches, it is our experience that patients with HCC from the caudate lobe have a prognosis comparable to that of patients with HCC in other parts of the liver.

The predominant protein-arginine methyltransferase from Saccharomyces cerevisiae

We have identified the major enzymatic activity responsible for the S-adenosyl-L-methionine-dependent methylation of arginine residues (EC 2.1.1.23) in proteins of the yeast Saccharomyces cerevisiae. The RMT1 (protein-arginine methyltransferase), formerly ODP1, gene product encodes a 348-residue polypeptide of 39.8 kDa that catalyzes both the NG-mono- and NG, NG-asymmetric dimethylation of arginine residues in a variety of endogenous yeast polypeptides. A yeast strain in which the chromosomal RMT1 gene was disrupted is viable, but the level of NG,NG-[3H]dimethylarginine residues detected in intact cells incubated with S-adenosyl-L-[methyl-3H]methionine is reduced to less than 15% of the levels found in the parent strain, while the NG-[3H]monomethylarginine content is reduced to less than 30%. We show that soluble extract from parent cell, but not from mutant rmt1 cells, catalyzes the in vitro methylation of endogenous polypeptides of 55, 41, 38, 34, and 30 kDa. The hypomethylated form of these five polypeptides, as well as that of several others, can be mono- and asymmetrically dimethylated by incubating the mutant rmt1 extract with a purified, bacterially produced, glutathione S-transferase-RMT1 fusion protein and S-adenosyl-L-[methyl-3H]methionine. This glutathione S-transferase-RMT1 fusion protein is also able to methylate a number of mammalian polypeptides including histones, recombinant heterogeneous ribonucleoprotein A1, cytochrome c, and myoglobin, but cannot methylate myelin basic protein. RMT1 appears to be a yeast homolog of a recently characterized mammalian protein-arginine methyltransferase whose activity may be modulated by mitotic stimulation of cells.

Hyperglucagonaemia in cirrhotic patients and its relationship to the severity of cirrhosis and haemodynamic values

Plasma glucagon concentrations were measured in 160 cirrhotic patients (Pugh's grade A in 52 patients, Pugh's grade B in 64 patients and Pugh's grade C in 44 patients). These values were compared with plasma glucagon concentrations in 57 age and sex-matched healthy subjects. Systemic and portal haemodynamic measurements, effective renal plasma flow and creatinine clearance were recorded for each patient. Plasma glucagon levels were significantly increased in cirrhotic patients compared with healthy subjects. In addition, plasma glucagon levels were higher in cirrhotic patients with ascites than in those without ascites and were increased in relation to the severity of cirrhosis as assessed by Pugh's score. Multiple linear regression found that only Child-Pugh's score was estimated to be an independent predictor of hyperglucagonaemia in cirrhotic patients. However, in patients with different degrees of oesophageal varices and in patients without oesophageal varices, plasma glucagon concentrations were no different among the different groups of patients, but were still higher than plasma glucagon concentrations in healthy subjects. In contrast, plasma glucagon levels were negatively correlated with mean arterial pressure and systemic vascular resistance. The results of the present study suggest that impairment of liver function plays, in part, a role in increased plasma glucagon levels observed in patients with cirrhosis. In addition, these data support the hypothesis that hyperglucagonaemia may contribute, at least in part, to the pathogenesis of peripheral arterial vasodilatation in cirrhosis with portal hypertension.

Alimentary tract duplications

A total of 17 patients with alimentary tract duplications underwent surgery at National Taiwan University Hospital from 1978 to 1994. Fifteen patients (88%) had gastrointestinal duplication and two (12%) had esophageal duplication. Common presenting symptoms of gastrointestinal duplication were melena and abdominal pain. The ileum was the most common site of duplication. Multiple duplications were seen in three patients. All duplications were cystic, except for one single appendiceal duplication. Ectopic gastric mucosa was detected in nine of the 16 nongastric duplications. One patient with ileal duplication had ectopic pancreatic tissue. Twelve patients received resection of the duplication with a segment of bowel and primary anastomosis, three patients underwent simple excision and two patients had partial resection of the duplication and stripping of the residual mucosa. Two patients had other associated congenital anomalies: one had ventricular septal defect and the other, imperforate anus and malrotation of intestine. There was no operative mortality or morbidity in this series.

Effect of verapamil on renal haemodynamics in a portal hypertensive rat model

In order to investigate the effects of verapamil on renal haemodynamics in rats with portal hypertension, verapamil was given at either a low (0.2 mg/kg) or high (2 mg/kg) dose to rats after portal vein ligation. An approximate 12% decrease in mean arterial pressure followed administration of low dose verapamil, with a significant decrease in cardiac output and renal blood flow, as well as reduced portal pressure, observed; these signs were all indicative of a rise in renal vascular resistance. In contrast, the marked fall in both mean arterial pressure and cardiac output with high dose verapamil, accompanied by a significant decrease in portal pressure and no change in renal blood flow, suggests a reduction in renal vascular resistance. This study shows that the acute effects of verapamil on renal haemodynamics may vary with the dose used. Also, acute verapamil administration tends to decrease renal blood flow to alter the autoregulation of the kidney; thus, caution should be taken in the clinical use of verapamil in the treatment of cirrhosis with portal hypertension.

The vasorelaxing action of rutaecarpine: direct paradoxical effects on intracellular calcium concentration of vascular smooth muscle and endothelial cells

We have examined both the hypotensive effect and the mechanism of intracellular Ca++ regulation, underlying rutaecarpine (Rut)-induced vasodilatation. An i.v. bolus injection of Rut in anesthetized Sprague-Dawley rats produced a dose-dependent hypotensive effect. In isolated rat aorta rings, Rut (0.1-3 mu M) inhibited the phasic and tonic responses of norepinephrine- and phyenylephrine-induced contractions, respectively, mainly through an endothelium-dependent mechanism. However, the vasorelaxing effect of Rut (3 microM) persisted in denuded aorta, although to a much less extent than in intact tissue. As determined by the fura-2/AM (1-[2-(5-carboxyoxazol-2-yl)-6-aminobenzofuran-5-oxy]-2-(2'- amino-5'-methylphenoxy)-ethane-N,N,N,N-tetraacetic acid pentaacetoxymethyl ester) method, Rut (10 microM), in the presence of extracellular Ca++, suppressed the KCI-induced increment in the intracellular Ca++ concentration ([Ca++]i) of cultured vascular smooth muscle cells (VSMC). Rut (10 microM) also attenuated the norepinephrine-induced peak rise of [Ca++]i in VSMC placed in Ca++-free solution. On the other hand, Rut (1 and 10 microM) increased the level of [Ca++]i of cultured endothelial cells (EC) in the presence of extracellular Ca++. In conclusion, Rut acts on both VSMC and EC directly. In VSMC, it reduces [Ca++]i through the inhibition of Ca++ influx and Ca++ release from intracellular stores. In EC, Rut augments EC [Ca++]i by increasing Ca++ influx, possibly leading to nitric oxide release. The paradoxical regulation of Ca++ in both VSMC and EC acts simultaneously to cause vasorelaxation which could account, at least in part, for the hypotensive action. This is a most significant and a unique feature of this study.

Effects of long-term administration of octreotide in portal vein-stenosed rats

The hemodynamic effects of long-term administration of octreotide in portal hypertension has not been established. In addition, whether long-term octreotide treatment prevents the development of portosystemic shunts has not yet been evaluated. Hence, the current study was undertaken to evaluate the effects of long-term administration of octreotide in rats with portal vein stenosis. Immediately after portal vein stenosis or sham operation, rats were given either a long-term octreotide administration of 100 micrograms/kg or a placebo every 12 hours by subcutaneous injection for 14 consecutive days. Systemic hemodynamics and regional blood flows, degree of mesenteric-systemic shunts, and plasma glucagon concentrations were measured after the final dose of octreotide or placebo. A fifth group of portal vein-stenosed rats received hemodynamic and plasma glucagon measurements after 1-day octreotide treatment given at 14 days after surgery. Long-term octreotide treatment modified the hyperdynamic circulation without affecting the degree of mesenteric-systemic shunts, and 1-day octreotide treatment decreased portal tributary blood flow without affecting the portal pressure, systemic hemodynamics, and degree of mesenteric-systemic shunts. Plasma glucagon levels were decreased in portal vein-stenosed rats receiving either long-term or 1-day octreodtide compared with rats receiving placebo. In contrast, chronic octreotide treatment did not affect any of the hemodynamic values or plasma glucagon levels in sham-operated rats. In conclusion, long-term administration of octreotide modified in part the development of portal hypertension and hyperdynamic circulation in portal vein-stenosed rats without affecting the degree of mesenteric-systemic shunts.

Role of endotoxaemia in hyperdynamic circulation in rats with extrahepatic or intrahepatic portal hypertension

This study investigated the role of endotoxaemia in the development of hyperdynamic circulation observed in rats with extrahepatic (high collateralization) or intrahepatic (low collateralization) portal hypertension. Compared with sham-operated rats, decreased mean arterial pressure and systemic vascular resistance were detected on days 1, 4, and 14 following partial portal vein ligation. By day 1, the cardiac index of portal vein-ligated rats was similar to that of sham-operated rats and progressively increased, thereafter, reaching statistically higher values days 4 and 14. No differences in plasma endotoxin levels were found between portal vein-ligated and sham-operated rats throughout the observation period. Both carbon tetrachloride-induced cirrhotic rats with and without ascites had a higher cardiac index and lower systemic vascular resistance. Plasma endotoxin levels were higher in cirrhotic rats with ascites (8.6 +/- 2.0 pg/mL; P < 0.01) than those of control rats (2.2 +/- 0.3 pg/mL) and cirrhotic rats without ascites (2.4 +/- 0.6 pg/mL). These results suggest that factors other than endotoxaemia play a role in the development of hyperdynamic circulation observed in rats with extrahepatic portal hypertension and cirrhotic rats without ascites, but that endotoxaemia may contribute to the maintenance of hyperdynamic circulation found in cirrhotic rats with ascites. The severity of liver disease may be a more important factor than the presence of portosystemic shunting for the development of endotoxaemia in portal hypertensive states.

Decreased vascular reactivity of portal vein in rats with portal hypertension

BACKGROUND/AIMS

Vascular hyporesponsiveness in portal hypertension is well documented in the arterial tissue. The present study aimed to investigate the possible changes in the portal vein from portal hypertensive rats.

METHODS

Portal hypertension was induced by partial portal vein ligation. Fourteen days after surgery, portal veins were removed for contractile study and measurement of cAMP, cGMP and [Ca2+]i.

RESULTS

In vitro tension preparation showed a decreased maximum response to norepinephrine in portal vein of portal vein ligated rats (38.3 +/- 4.1 vs. 23.4 +/- 1.5 mN/mm2). The pA2 values of WB4101 and yohimbine (alpha1- and alpha2-adrenoceptor antagonist, respectively) were not different between the two groups. Tissue cAMP (14.4 +/- 0.9 vs. 12.2 +/- 0.7 pmol/mg protein), but not cGMP, content was increased and intracellular calcium [Ca2+]i levels (247 +/- 9 vs. 281 +/- 13 nM) were decreased in portal vein ligated rats.

CONCLUSIONS

These results showed that in portal vein from portal vein ligated rats, vascular hyporesponsiveness and an increase in basal cAMP content and a decrease in basal [Ca2+]i were observed.

Effect of octreotide on total effective vascular compliance in patients with posthepatitic cirrhosis

BACKGROUND/AIMS

This study aimed to evaluate the effect of octreotide on total effective vascular compliance, measured during rapid volume expansion, in patients with posthepatitic cirrhosis.

METHODS

Twenty-nine patients with posthepatitic cirrhosis were randomly assigned to receive a 100-micrograms/h infusion of octreotide after a 100-micrograms bolus (n = 15), or a placebo (n = 14). Hemodynamic measurements were recorded before and 30 min after drug administration. Thereafter, rapid volume expansion was performed in each patient and hemodynamic measurements were repeated immediately after volume expansion.

RESULTS

Before volume expansion, placebo administration did not affect any of the hemodynamic values, while the hepatic blood flow was significantly decreased following octreotide administration. After volume expansion, the hemodynamic changes were similar between patients receiving octreotide and the placebo. However, the increase in right atrial pressure from the beginning to the end of volume expansion was higher and the total effective vascular compliance was lower in patients receiving octreotide (+3.5 +/- 0.3 mmHg, p = 0.05 and 1.69 +/- 0.16 ml.mmHg-1.kg-1, p < 0.05) compared to patients receiving placebo (+2.5 +/- 0.3 mmHg, 2.60 +/- 0.34 ml.mmHg-1.kg-1).

CONCLUSIONS

The present study suggests that octreotide decreased total effective vascular compliance in patients with posthepatitic cirrhosis. It is possible that, in patients with posthepatitic cirrhosis, venoconstriction was induced following octreotide administration.

Plasma endothelin levels in patients with cirrhosis and their relationships to the severity of cirrhosis and renal function

BACKGROUND/AIMS

Increased plasma endothelin levels have been reported in patients with cirrhosis. However, the relationship between plasma endothelin concentrations and hyperdynamic circulation or renal functions has not been documented.

METHODS

We measured the plasma endothelin-1 and endothelin-3 concentrations using radioimmunoassay in 96 patients with cirrhosis (Pugh's A in 26, Pugh's B in 45 and Pugh's C in 25) and compared these values to 56 age- and sex-matched healthy subjects. Systemic and portal hemodynamic measurements, effective renal plasma flow, creatinine clearance, plasma aldosterone concentration and plasma renin activity were recorded for each patient.

RESULTS

Plasma endothelin-1 and endothelin-3 levels were significantly increased in patients with cirrhosis compared to healthy subjects. Additionally, plasma endothelin-1 and endothelin-3 values were higher in patients with cirrhosis and ascites than in those without ascites. Moreover, plasma endothelin-1 levels increased in relation to the severity of cirrhosis. On the other hand, modest negative correlations were found between endothelin-1 and creatinine clearance or effective renal plasma flow.

CONCLUSIONS

Plasma endothelin-1 and endothelin-3 levels are increased in patients with cirrhosis compared to healthy subjects. The increase in plasma endothelin-1 levels is related at least in part to the severity of cirrhosis. Increased endothelin-1 levels may possibly contribute to renal dysfunction in patients with cirrhosis.

Fructus aurantii reduced portal pressure in portal hypertensive rats

The purpose of this study was to investigate the effects of Fructus Aurantii (the unripe fruits of Citrus aurantium L.) on portal hypertensive rats. Portal hypertension was induced by partial portal vein ligation (PVL) in Sprague-Dawley rats. Sham-operated (Sham) rats served as controls. Hemodynamic and in vitro contractile studies were performed at 14 days after surgery. Both the aqueous extract of Fructus Aurantii and synephrine, one of its purified principles with pressor activity, were infused into the conscious PVL and Sham rats via a syringe pump. Fructus Aurantii (1.25, 2.5, & 5.0 mg/kg/min) dose-dependently reduced portal pressure in PVL and Sham rats, with the percentage change in portal pressure more pronounced in PVL rats. Mean arterial pressure was dose-dependently elevated by Fructus Aurantii. Synephrine (0.095, 0.19, & 0.38 mg/kg/min) also dose-dependently reduced portal pressure and elevated mean arterial pressure in PVL and Sham rats. Fructus Aurantii (2.8-280 micrograms/ml) induced dose-dependent contractile responses mainly in aorta and mesenteric artery, but little response in portal vein. The results showed that Fructus Aurantii infusion reduced portal pressure, possibly by way of arterial vasoconstriction.

Ig gamma 2b transgenes promote B cell development but alternate developmental pathways appear to function in different transgenic lines

Analysis of B cell development in three strains of gamma 2b transgenic mice shows that the gamma 2b H chain can replace the microH chain in promoting B cell differentiation. The 348C line produces 90% gamma 2b-only B cells and 10% B cells; which co-express gamma 2b and endogenous sIgM and sIgD. These IgG2b+ B cells develop into mature, recirculating CD23+ B cells. The 343-1 and gamma 2b-T15 transgenic mice produce sIgMhigh:sIgDlow:CD23- B cells that generally co-express the gamma 2b transgene-encoded H chain. Such B cells are either developmentally arrested immature B cells or arise from B-1 (CD5) progenitors. The gamma 2b-T15 mice can produce gamma 2b-only CD23+ B cells following inactivation of the endogenous mu locus, whereas 343-1 mice fail to develop B cells. Thus, gamma 2b H chains: 1) can act alone to promote the development of mature B cells, 2) synergize with microH chains for allelic exclusion, and 3) vary in their influence on B cell development in different transgenic mouse strains.

Ig gamma 2b transgenes promote B cell development but alternate developmental pathways appear to function in different transgenic lines

Analysis of B cell development in three strains of gamma 2b transgenic mice shows that the gamma 2b H chain can replace the microH chain in promoting B cell differentiation. The 348C line produces 90% gamma 2b-only B cells and 10% B cells; which co-express gamma 2b and endogenous sIgM and sIgD. These IgG2b+ B cells develop into mature, recirculating CD23+ B cells. The 343-1 and gamma 2b-T15 transgenic mice produce sIgMhigh:sIgDlow:CD23- B cells that generally co-express the gamma 2b transgene-encoded H chain. Such B cells are either developmentally arrested immature B cells or arise from B-1 (CD5) progenitors. The gamma 2b-T15 mice can produce gamma 2b-only CD23+ B cells following inactivation of the endogenous mu locus, whereas 343-1 mice fail to develop B cells. Thus, gamma 2b H chains: 1) can act alone to promote the development of mature B cells, 2) synergize with microH chains for allelic exclusion, and 3) vary in their influence on B cell development in different transgenic mouse strains.

Haemodynamic effects of a combination of propranolol and clonidine in patients with post-hepatitic cirrhosis

The haemodynamic effects of a combination of propranolol and clonidine were evaluated in 20 patients with post-hepatitic cirrhosis. Haemodynamic measurements were taken before and 30 min after an intravenous injection of 0.1 mg/kg of propranolol. Thereafter, each patient was given an oral dose of 150 micrograms of clonidine and re-measured 60 min later. In this series, eight patients were defined as 'non-responders' (a decrease in hepatic venous pressure gradient of < 10%) after propranolol treatment. Of both the responders and non-responders, propranolol caused expected decreases in the cardiac index and heart rate while mean arterial pressure remained unchanged. Of the propranolol responders, a significant decrease in hepatic venous pressure gradient was observed. After the addition of clonidine, in both the responders and non-responders there was a further decrease in hepatic venous pressure gradient with a concurrent drop in mean arterial pressure, but cardiac index and heart rate remained unaltered. In conclusion, the combination of propranolol and clonidine in post-hepatitic cirrhotic patients enhanced the reduction of portal pressure achieved by propranolol alone. The beneficial effects of the combination of the two in the reduction of portal pressure appeared to be similar in both the propranolol responders and non-responders. However, the drop in mean arterial pressure following the addition of clonidine may be hazardous to cirrhotic patients.

Directional cloning of an oligonucleotide fragment into a single restriction site

Oligonucleotide fragments can be directionally subcloned into vectors at a single restriction site. By using T4 DNA polymerase exonuclease activity to treat vector DNA, single-stranded ends can be generated. The oligonucleotide sequences are designed to have sequence complementary to these single-stranded ends. Through the homologous annealing of oligonucleotides to the treated vector ends, the successfully subcloned molecules forms a circular recombinant DNA that is ready for transformation. There is no sequence restriction at the ends of the DNA fragment. All restriction site ends are accessible to this method. This approach for oligonucleotide fragment insertion and together with our previously described general method of exonuclease induced DNA subcloning provide convenient methods for the construction of recombinant DNA.

Decreased vascular contractile and inositol phosphate responses in portal hypertensive rats

The purpose of this study was to investigate the vascular contractile and inositol phosphate responses in portal hypertensive rats. Portal hypertension was induced by partial portal vein ligation (PVL) in Sprague-Dawley rats. Sham-operated rats served as controls. Pressures, vasoconstrictor responses, and inositol phosphate responses were determined at 14 days after surgery. The portal venous pressure was significantly higher, while systemic arterial pressure and heart rate were lower, in PVL rats. Dose-dependent contractile responses were observed for both norepinephrine (1 x 10(-8) - 3 x 10(-6) M) and vasopressin (3 x 10(-10) - 3 x 10(-8) M) in the tail artery of both groups. The contractile response to norepinephrine was significantly decreased in PVL rats compared with controls at all doses. The contractile response to vasopressin was significantly decreased in PVL rats at higher doses. After myo-[3H]inositol incorporation in tail artery, the levels of 3H-labelled phosphatidylinositols (cpm/mg) were similar between the two groups. Norepinephrine (10(-7) - 10(-5) M) and vasopressin (10(-10) - 10(-8) M) dose dependently stimulated the 3H-labelled inositol phosphate production in the tail artery of both PVL and sham-operated rats. However, the response was significantly lower in PVL rats. The results suggested that the attenuation of vascular contractile responses in portal hypertension was reflected in the phosphoinositide messenger system.

Change in vascular cAMP and cGMP contents in portal hypertensive rats

The purpose of this study was to investigate the possible changes of cyclic nucleotide contents in portal hypertensive rats. Portal hypertension was induced by partial portal vein ligation (PVL) in Sprague-Dawley rats. Sham-operated rats served as controls. Hemodynamic and cyclic nucleotide measurements were performed at 14 days after surgery. The portal venous pressure was significantly higher, while systemic arterial pressure and heart rate were lower in PVL rats than those in controls. Basal cAMP (PVL, 10.91 +/- 0.98, vs. sham, 8.08 +/- 0.81 pmol/mg protein) and cGMP (PVL, 0.91 +/- 0.12, vs. sham, 0.59 +/- 0.05 pmol/mg protein) contents in the tail artery were significantly higher in PVL rats. Isobutyryl methylxanthine (10(-5) M), a nonspecific phosphodiesterase inhibitor, exerted similarly stimulating effects on the tissue cGMP (PVL, 158 +/- 10, vs. sham, 178 +/- 20%) and cGMP (295 +/- 28 vs. 316 +/- 71%) levels in both PVL and control rats; so did forskolin (10(-6) M) on the cAMP (184 +/- 20 vs. 197 +/- 66%) content in both groups. Our results showed that the arterial cAMP and cGMP contents were higher in PVL rats, which may contribute to the reduction of peripheral resistance in portal hypertension.

Changes in intra- and extracranial tissue blood flow upon stimulation of a reticular area dorsal to the facial nucleus in cats

1. A small area in the dorsal part of the lateral tegmental field specifically responsible for the increase of blood flow in the common carotid artery (CCA) without accompanying change in the resting blood pressure was first identified in our laboratory. Since the area is located just dorsal to the facial nucleus, we named it the dorsal facial area (DFA; Kuo et al. 1987). 2. The purpose of this study was to clarify whether an increase of blood flow in intra- and/or extracranial tissues was responsible for the increase in CCA blood flow upon DFA stimulation, and to determine the role of cholinergic transmission in this response. 3. In 20 cats under chloralose and urethane anaesthesia, microsphere reference flow technique was used to measure the regional blood flow of intra- and extracranial tissues. 4. Electrical stimulation of the DFA appeared to increase the regional blood flow of both cerebral hemispheres (intracranial tissues) and to increase predominantly the regional blood flow of extracranial tissues on the side ipsilateral to stimulation. Increases in the regional blood flow of intracranial tissues were enhanced after i.v. administration of atropine but reduced with physostigmine. In contrast, increases in the regional blood flow of extracranial tissues were reduced after i.v. atropine but enhanced after physostigmine. 5. These findings suggest that DFA stimulation may promote the release of ACh in intra- and extracranial vessels. The muscarinic action may restrict the DFA-induced increase in blood flow of intracranial tissues, but enhance that of extracranial tissues.

Protein carboxyl methylation in Saccharomyces cerevisiae: evidence for STE14-dependent and STE14-independent pathways

We incubated yeast cells (Saccharomyces cerevisiae) with the methyl donor S-adenosyl-L-[methyl-3H]methionine and then fractionated their cellular components by gel electrophoresis in sodium dodecyl sulfate. By analyzing gel slices for [3H]methyl esters by a vapor-phase diffusion assay, we detect major methyl-esterified species that migrate at apparent polypeptide sizes of 24 and 22 kDa and minor species of 49, 38, 35, 33, 31, and 26 kDa. Incubation of extracts from labeled cells with ribonuclease A or proteinase K revealed that the 24- and 22-kDa species represent methyl-esterified RNAs, whereas the other species are methyl-esterified polypeptides. The 38-, 33-, 31-, and 26-kDa polypeptides were not methyl-esterified in an isogenic yeast strain lacking the STE14 gene encoding a C-terminal isoprenylcysteine methyltransferase, suggesting that they are substrates for the STE14 methyltransferase. On the other hand, the amount of the methylated 49-kDa polypeptide is reduced in the ste14 mutant, indicating that at least two methylated polypeptides are present--one a substrate of the STE14 methyltransferase and one a substrate of a STE14-independent methyltransferase. The 35-kDa polypeptide also appears to be methylated by a STE14-independent methyltransferase. When cells were incubated in the presence of the protein synthesis inhibitor cycloheximide, little or no methylation of the STE14-dependent species was detected while the methylation of the STE14-independent substrates was unaffected. Pulse-chase studies revealed significant turnover of all of the methylated species in a 4-h period, with the exception of the 38-kDa polypeptide.(ABSTRACT TRUNCATED AT 250 WORDS)

Outlier reduction by an option-3 measurement scheme

Detecting changes in longitudinal data is important in medical research. However, the existence of measurement outliers can cause an unexpected increase in the false alarm rate in claiming changes. To reduce the outliers, a new method has been developed. In this scheme, two measures are initially taken and, if they are closer than a specified threshold, the average of the two is considered to be the estimate of the true mean; otherwise a third measurement is taken, and the mean of the closest pair is considered to be the estimate. It is shown that this method has considerable sample size advantage over naive repeated measurements. Moreover, this scheme is robust for outlier error distribution. Evidence on outlier removal in dental attachment probing is used as an example.

Rapid assay of the monoamine content in small volumes of rat plasma

A method for the simultaneous measurement of serotonin catecholamines, and their metabolites in rat plasma by ultrafiltration and microbore liquid chromatography with electrochemical detection (LC-ED) in small volumes is established. Prior to the LC assay, sixteen plasma ultrafiltrates are readily prepared within 30 min in the present study. The present method, applying a dual-electrode detection technique, provides an additional reliable assignment or measurement of peaks by identifying the peaks on the basis of their redox ratios. In addition, the important early-eluting peaks and interfering peaks are eliminated in the cathodic chromatogram resulting in a reliable measurement of norepinephrine, epinephrine, and 3,4-dihydroxyphenylacetic acid. Isocratic separation of serotonin, catecholamines, and their metabolites by a microbore column is achieved within 15 min. Hence, theoretically, over 90 analyses can be performed in a working day. The limit of detection (signal-to-noise ratio = 3) of this method is ca. 0.2-0.5 pg per injection for all analytes. The required volume of the plasma samples can be less than 100 microliters. Hence, the remainder of the plasma sample can be analysed for other substances. This rapid, simple, and sensitive method can thus be used as a research tool in the simultaneous measurement of rat plasma serotonin, catecholamines, and their metabolites.

Study on the vascular reactivity and alpha 1-adrenoceptors of portal hypertensive rats

1. Vascular hyporesponsiveness in portal hypertension has been demonstrated to various vasoconstrictors including noradrenaline (NA). The present study aimed to determine whether the attenuated vascular responsiveness to NA is due to a change in the affinity or the number of alpha 1-adrenoceptors. 2. Partial portal vein ligation (PVL) was performed in Sprague-Dawley rats to produce portal hypertension. Vascular responsiveness to NA was assayed in portal vein, mesenteric artery or tail artery. The affinity and number of alpha 1-adrenoceptors were determined by specific binding of [125I]-HEAT (2-beta-4-hydroxy-3-iodophenyethyl-aminomethyltetralone). 3. In the presence of yohimbine (10(-7) M, an alpha 2-adrenoceptor antagonist), propranolol (10(-6) M, a beta-adrenoceptor antagonist), and two catecholamine uptake inhibitors, desipramine (10(-7) M) and normetanephrine (10(-6) M), the maximum responses to NA were decreased in all three blood vessels of PVL rats: 45% decrease in portal vein, 25% in mesenteric artery and 18% in tail artery. 4. The EC50 values of NA and the pA2 values of prazosin, an alpha 1-adrenoceptor antagonist, in all three blood vessels were not significantly different between sham-operated and PVL rats. 5. The KD and Bmax values for specific binding of [125I]-HEAT or the Ki values for NA in the crude membrane preparations of either mesenteric artery or tail artery were also not significantly different between the two groups. 6. It is concluded that the vascular hyporesponsiveness to NA in the mesenteric artery or tail artery of PVL rats is not due to changes in the affinity or number of alpha 1-adrenoceptors.

Testing concomitancy between two physiological pulse series

Statistical methods for detecting synchronization of onsets of two physiological events, such as concomitant releases of prolactin (PRL) and luteinizing hormone (LH), are studied in this paper. Usually, the two events are measured regularly and simultaneously and the onset times are then determined by the changes in the values of the measurements. Owing to difficulties in determining the exact onset times, a leeway is allowed for counting the onset synchronizations in most physiological studies. Using such a relaxed definition of synchronization and needing to allow for a recovery time between two episodes make the traditional hypergeometric test of concomitance inappropriate. Based on a truncated geometric inter-arrival distribution, Clifton et al. have used simulation to construct a table of critical values for performing tests of significance of the observed number of coincidences in a series of 73 measurements. In this paper, the conditions under which their method can be used are examined from a statistical point of view. Methods for testing cases not covered by Clifton et al. are also described.

Effects of reserpine administration in two models of portal hypertension in rats

The effects of reserpine were investigated in two models of portal hypertension in rats. Twenty-four hours after 1 mg/kg of reserpine was administered intraperitoneally to normal and portal vein stenosed rats, the cardiac index, mean arterial pressure, heart rate, and portal pressure were significantly decreased compared with normal and portal vein stenosed rats receiving placebo. In addition, the portal tributary blood flow was significantly decreased in portal vein stenosed rats receiving reserpine, but was unchanged in normal rats. In cirrhotic rats receiving a single dose of reserpine, 0.1 mg/kg intraperitoneally for 24 h, there were significant decreases in cardiac index, mean arterial pressure and heart rate compared with cirrhotic rats receiving placebo, while the portal pressure and portal tributary blood flow followed a decreasing trend after reserpine administration. The degree of hemodynamic change was similar in the groups of rats receiving reserpine, even though cirrhotic rats received lower doses than either normal or portal vein stenosed rats. This study suggests enhanced sympathetic nervous activity observed in cirrhotic rats.

The strategy and advantage in use of an electronic probe for attachment measurement

Attachment level has been used as the "gold standard" for assessment of the progression of periodontal disease. However, the measurement of attachment level by periodontal probing can be subject to a large number of error sources. Recently, we have designed experiments by using an electronic probe to identify the magnitude of error components due to the instrument, gingival tissue condition, position or probing angle, and time interval between replicate probings. Even with a very careful clinical setting, a few percent of uncontrollable large errors or outliers could not be avoided. A previously used 'option-3' probing scheme to reduce the unexpected large error is justified from the mathematical viewpoint.

Change detection on longitudinal data in periodontal research

Longitudinal data of attachment level (AL) or the alveolar bone level are often used to assess the progression of periodontal disease. This paper tries to identify the most efficient method to detect the changes of AL in a general periodontal research environment; that is, a sequential decision based on multiple sites. Several existing methods suggested in the periodontal research literature such as the tolerance, running median, cusum, and regression methods as well as change-point detection methods in the statistical literature are examined. It is found that the regression method is most convenient among the several methods that are equally effective in change detection. Formulae, tables and their usage are discussed in detail.

Responsiveness to synthetic parathyroid hormone in the portal vein of portal hypertensive rats

In addition to its hypotensive action, the parathyroid hormone also decreases portal pressure in portal hypertensive rats. The purpose of this study was to characterize the vascular effects of the parathyroid hormone on the portal vein of portal vein-stenosed rats. When intravenously infused at the rate of 1.62 x 10(-11) mol/kg per min, the parathyroid hormone lowered portal pressure (15.1 +/- 0.7 vs. 14.0 +/- 0.8 mmHg) without affecting systemic blood pressure. With the portal vein isolated, the parathyroid hormone shifted the dose-response curves of KCl and acetylcholine to the right. However, the vasodilator effect of the parathyroid hormone was significantly less in portal hypertensive rats (EC50 of KCl increased 129.2% and acetylcholine 199.3%), compared to sham-operated rats (EC50 of KCl increased 158.7% and acetylcholine 270.2%). Similar results were found for the vasodilator action of verapamil (10(-9)-10(-6) M). On the other hand, the vasodilator effect of forskolin was similar for both groups. These results suggest that decreased responsiveness to the parathyroid hormone may be associated with calcium utilization by vascular smooth muscles.

Measuring clinical attachment: reproducibility of relative measurements with an electronic probe

During the past few years, improvements in detecting longitudinal changes in clinical attachment or alveolar bone density have been introduced. For example, constant-force electronic probes and computer-assisted subtraction analysis of longitudinal radiographs have been reported to be more sensitive and reproducible in detecting changes in clinical attachment or alveolar bone density, respectively. Use of these new technologies requires that sources of measurement error be identified and their contribution quantified. This study investigated the reproducibility of a constant-force electronic probe in a careful clinical setting. Measurements were performed from individually fabricated acrylic stents. Three groups of subjects were selected for the study: 10 adults without oral disease, 10 adults with gingivitis, and 10 adults with moderate periodontitis. Four probing designs were employed to investigate the reproducibility of the probe. In design A, the probe tip was left in the sulcus between successive probings. In design B, the probe tip was removed from the gingival margin between probings but the next probing followed immediately. In design C, successive whole-mouth probings were interrupted by a 5-minute interval and a mouth rinse. In design D there was a 4-week interval between each successive probing. Three measurements were taken at each site for each design. The main purpose of this study was to identify variance components in the attachment level variation. The maximum probing error standard deviation ranged from 0.2 to 0.3 mm depending on the periodontal health of the subject. This level of variation is considerably smaller than that found in most previous studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Reproducibility of an electronic probe in relative attachment level measurements

4 probing designs have been employed to investigate the reproducibility of the Florida Probe. 3 groups (each composed of 10 subjects) were selected for the study: healthy adults, gingivitis subjects, and periodontitis subjects. The 4 probing designs were as follows: (a) the probe tip was left in the sulcus between successive probings; (b) the probe tip was removed from the gingival margin between probings but the next probing followed immediately; (c) successive whole-mouth probings were interrupted by a 5-min interval and a mouthrinse; (d) there was a 4-week interval between each probing. 3 measurements were taken for each design. The main purpose of this study was to identify variance components in the attachment level variation. The maximum probing error standard deviation was found to be around 0.3 mm, which is considerably smaller than that found in most previous studies. The errors associated with the periodontal condition and probing effect were also estimated. The variance components obtained here can be used for determining the sample size in controlled clinical studies.

Effects of endothelin in portal hypertensive rats

1. Effects of endothelin-1 on systemic arterial blood pressure, heart rate and portal venous pressure were compared in normal Sprague-Dawley rats and rats with portal hypertension induced by CCl4 and partial portal vein ligation. 2. Endothelin-1 produced biphasic effects on systemic blood pressure and portal venous pressure in all three groups of rats. However, the magnitude of the changes in blood pressure was less in portal hypertensive rats. 3. The ability of endothelin-1 to increase the portal venous pressure was also significantly diminished in portal hypertensive rats. On the other hand, the initial decrease in portal pressure was augmented in rats with partial portal vein ligation, and disappeared at higher dosage in CCl4-treated rats. 4. In accordance with the pressure recording in vivo, the dose-response vasoconstrictive activity of endothelin-1 was significantly attenuated in the intrahepatic vasculature. 5. The plasma immunoreactive endothelin concentration was significantly higher (5.55 +/- 0.81 fmol/ml) in Sprague-Dawley rats than in CCl4-treated rats (2.83 +/- 0.56 fmol/ml) and rats with partial portal vein ligation (2.68 +/- 0.53 fmol/ml). 6. It was concluded that a lower plasma level of endothelin and a reduced vascular responsiveness may contribute, at least in part, to the hyperdynamics of portal hypertension.

Predictive power of various models for longitudinal attachment level change

Several statistical models that have been suggested in the periodontal literature for describing longitudinal attachment level changes, such as the gradual loss, single-burst, multiple-burst, and random walk models as well as other models introduced in this paper are compared by their power to predict future attachment loss. The data used in this analysis is from 1061 sites of 8 subjects, with moderate to severe periodontal disease, monitored monthly for about a year. This study found that none of the suggested models could significantly outperform the naïve mean predictor, which predicts the future attachment level from the past mean. It was also found that no single model, such as the burst, gradual, or random walk, together with measurement error can fully explain the variation in the data. These results indicate that in the course of one year, the attachment level change may not follow the same model. Consequently, a model that fits well to past data cannot be accurately extended to the future.

Lung deposits of lipiodol in normal and cirrhotic rats

The distribution of Lipiodol in the liver and lungs following arterial or portal injection was studied in normal (n = 55) and cirrhotic rats (n = 20). Using magnified xeroradiography and radioisotope labeled tracers, it was found that Lipiodol was deposited mainly in the liver and lung after either arterial or portal administration. In control rats after arterial injection, deposits in the lung peaked after 2 hours and gradually declined over 48 hours; whereas after portal injection, the deposit steadily increased for 48 hours. Twenty-five percent of cirrhotic rats demonstrated a Lipiodol-induced military pattern in the lung. An increased number of portosystemic shunts in cirrhotic rats was also noted. These results suggest that cirrhosis of the liver may be a potential risk factor for developing pulmonary complications after Lipiodol administration.

Evaluation of statistical methods for monitoring periodontal disease

Three methods for detecting the progression of periodontal disease based on the change in attachment level on teeth are compared from a statistical point of view. Regardless of gradual or burst disease progression theories, the regression method is found to be the most efficient way to detect changes. The exact false alarm rate is computed when the decision is based on the maximum regression coefficient at all sites during several visits.

cAMP and vascular action of endothelin

Endothelin, a potent vasoconstricting peptide, induced maximal contraction of the rat tail artery within 3 min of administration. Endothelin also caused a dose-dependent decrease in tissue levels of cAMP. Concentrations of cAMP decreased about 60% 1 min after endothelin (10(-8) M) administration, but returned to basal levels in 5 min. By contrast, tissue levels of cGMP were not changed by endothelin. Modulation of cAMP production may provide one mechanism for the vascular action of endothelin.