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D Diehl

Publications and source records attributed to D Diehl.

12 recordsLinked to original sources
PubMed1999

Regulation of the high-affinity H+/peptide cotransporter in renal LLC-PK1 cells.

Di- and tripeptides and peptide mimetics such as beta-lactam antibiotics are efficiently reabsorbed from the tubular lumen by a high-affinity peptide transporter. We have recently identified and characterized this H+-coupled high-affinity peptide transport system in the porcine proximal tubular cell line LLC-PK1. Here we describe for the first time the regulation of the renal high-affinity peptide cotransporter at the cellular level. Uptake of 5 microM 3H-D-Phe-L-Ala into LLC-PK1 cells was significantly increased by lowering [Ca2+]in and decreased by increasing [Ca2+] in. Moreover, it was shown that the [Ca2+]in effects on peptide transport activity were dependent on Ca2+ entry from the extracellular site (e.g., via a store-regulated capacitative Ca2+ influx). Protein kinase C (PKC) was found to transmit the effects of [Ca2+]in on peptide transport. Although we demonstrate by pHin measurements that the PKC inhibitor staurosporine did decrease the transmembrane H+ gradient and consequently should have reduced the driving force for peptide uptake, the only effect on transport kinetics of 3H-D-Phe-L-Ala observed was a significant decrease in Km from 22.7+/-2.5 microM to 10.2+/-1.9 microM with no change in maximal velocity.

Animals↗
PubMed1998

Subtypes of constipation predominant irritable bowel syndrome based on rectal perception.

BACKGROUND: Patients who complain of constipation can be divided into those who have lost the natural call to stool, but develop abdominal discomfort after several days without a bowel movement (no urge); and those who experience a constant sensation of incomplete evacuation (urge). AIMS: To determine whether the two groups differ in symptoms, colonic transit, and perceptual responses to controlled rectal distension. METHODS: Forty four patients with constipation were evaluated with a bowel symptom questionnaire, colonic transit (radiopaque markers), and rectal balloon distension. Stool (S) and discomfort (D) thresholds to slow ramp (40 ml/min) and rapid phasic distension (870 ml/min) were determined with an electronic distension device. Fifteen healthy controls were also studied. RESULTS: All patients had Rome positive irritable bowel syndrome (IBS); 17 were no urge and 27 urge. Mean D threshold to phasic rectal distensions was 28 (3) mm Hg in no urge, 27 (3) mm Hg in urge (NS), but higher in the control group (46 (2) mm Hg; p < 0.01). Sixty seven per cent of no urge and 69% of urge were hypersensitive for D. Slow ramp distension thresholds were higher in no urge (S: 26 (3); D: 45 (4) mm Hg) compared with urge (S: 16 (2); D: 31 (3) mm Hg; p < 0.01), or with controls (S: 15 (1); D: 30 (3); p < 0.01). CONCLUSIONS: Hyposensitivity to slow rectal distension is found in patients with IBS who complain of constipation and have lost the call to stool even though their sensitivity to phasic distension is increased.

Adult↗
PubMed1998

Endogenous expression of the renal high-affinity H+-peptide cotransporter in LLC-PK1 cells.

The reabsorption of filtered di- and tripeptides as well as certain peptide mimetics from the tubular lumen into renal epithelial cells is mediated by an H+-coupled high-affinity transport process. Here we demonstrate for the first time H+-coupled uptake of dipeptides into the renal proximal tubule cell line LLC-PK1. Transport was assessed 1) by uptake studies using the radiolabeled dipeptide D-[3H]Phe-L-Ala, 2) by cellular accumulation of the fluorescent dipeptide D-Ala-Lys-AMCA, and 3) by measurement of intracellular pH (pHi) changes as a consequence of H+-coupled dipeptide transport. Uptake of D-Phe-L-Ala increased linearly over 11 days postconfluency and showed all the characteristics of the kidney cortex high-affinity peptide transporter, e.g., a pH optimum for transport of D-Phe-L-Ala of 6.0, an apparent Km value for influx of 25.8 +/- 3. 6 microM, and affinities of differently charged dipeptides or the beta-lactam antibiotic cefadroxil to the binding site in the range of 20-80 microM. pHi measurements established the peptide transporter to induce pronounced intracellular acidification in LLC-PK1 cells and confirm its postulated role as a cellular acid loader.

Acids↗
PubMed1998

Efficacy of an oral vaccinia-rabies glycoprotein recombinant vaccine in controlling epidemic raccoon rabies in New Jersey.

A field trial to evaluate the efficacy of an oral vaccinia-rabies glycoprotein recombinant virus vaccine in controlling epidemic raccoon (Procyon lotor) rabies was conducted by distributing 180,816 doses (10(8.2)TCID50/ml) of vaccine in wax ampules within fish-meal polymer baits at a rate of 64 doses/km2/treatment throughout a 552 km2 area, forming an 18 km wide band across the northern Cape May Peninsula of New Jersey (USA). Vaccination treatments were conducted in the spring and fall between May 1992 and October 1994 from a helicopter along ecotones and from motor vehicles along roads. Vaccine-laden baits were removed by animals from tracking stations within 3 wk and 61% of the identifiable tracks were those of raccoons. Tetracycline incorporated in the baits as a biomarker was detected in 155 (73%) of the vaccination area raccoons following the fall 1993 and spring 1994 vaccinations. Eleven (61%) of the raccoons sampled in the same time period seroconverted (> or = 0.5 IU) in response to rabies virus glycoprotein. A raccoon diagnosed with rabies from the northern border of the vaccination area on 30 April 1993 provided the first evidence that the barrier was being challenged by the rabies epidemic. The prevalence of rabies in raccoons from the vaccination area for the first year (10%, n = 96) and second year (8%, n = 61) of challenge was reduced more than six-fold by vaccination compared to unvaccinated raccoons from northern adjacent surveillance areas during the corresponding first (65%, n = 189) and second years (53%, n = 43). Vaccination also effectively reduced by three-fold the rate at which the epidemic moved through the raccoon population (15 km/yr). The breach of the vaccination area resulted in a resumption of the high rate (43 km/yr) of epidemic movement and a significant nine-fold increase in rabies prevalence (77%, n = 47). The maximum linear movement (12.9 km) among five ear-tagged rabid raccoons in the study area was significantly greater than that of 19 normal radio-collared raccoons (2.58 km) in the area. These large movements of rabid raccoons, together with relocation of nuisance raccoons, spillover of raccoon rabies in skunks (Mephitis mephitis) and other species, insufficient funding and a decision to discontinue the program in 1994 (which could have resulted in insufficient population immunity among raccoons in the vaccination area) may have contributed to the eventual breach of the barrier.

Administration, Oral↗
PubMed1996

Symptom duration in patients with irritable bowel syndrome.

OBJECTIVES: The etiology and natural history of irritable bowel syndrome (IBS) is poorly understood. We compared rectal sensory thresholds and compliance, SCL-90 scores, and follow-up questionnaires among normal controls, patients with longstanding ( > 5 y) disease (L-IBS), and patients with recent onset ( > 2 y) disease (R-IBS). The onset of symptoms in R-IBS was related to specific events such as infection (n = 10), surgery (n = 5), and stress (n = 4), but no specific event could be identified in six patients. METHODS: A diagnosis of IBS was made using Manning criteria ( > or = 3) and clinical grounds. Psychological data were obtained by psychometrics (SCL-90) scores. Rectal wall compliance and thresholds for the sensation of stool and discomfort were evaluated using the electronic barostat. RESULTS: The mean thresholds for phasic and ramp distention were similar for R-IBS and L-IBS groups for the perception of stool and discomfort. When compared with normals, the mean stool thresholds for phasic distention were significantly lower for L-IBS and R-IBS groups. SCL-90 scores were significantly increased in L-IBS in the mean phobia score (45 R-IBS vs 61 L-IBS), anxiety score (49 R-IBS vs 63 L-IBS), paranoia score (44 R-IBS vs 60 L-IBS), and hostility score (47 R-IBS vs 61 L-IBS) (all p < 0.05). On follow-up questionnaire, 60% of R-IBS versus 46% of L-IBS patients indicated that their symptoms had improved (p < 0.05). R-IBS patients also experienced fewer episodes of abdominal pain per week at follow-up than L-IBS patients (3.9 +/- 1.0 vs 8.5 +/- 1.7, respectively) (p < 0.05). CONCLUSIONS: Our findings suggest that IBS patients with short symptom duration and fewer psychological symptoms have a better prognosis than patients with a long history of IBS and associated psychological distress, although long term prospective studies are needed.

Adolescent↗
PubMed1994

Molecular cytogenetic analysis of RB-1 deletions in chronic B-cell leukemias.

Deletions or translocations of 13q, most commonly involving band 13q14, belong to the most frequent structural chromosome abnormalities in B-cell chronic lymphocytic leukemia (B-CLL). In a combined metaphase and interphase cytogenetic study using conventional G-banding analysis and fluorescence in situ hybridization (ISH) we previously analysed the retinoblastoma susceptibility gene (RB-1) and its chromosomal locus 13q14 in 35 patients with chronic B-cell leukemias. We report here on the interphase cytogenetic analysis of 109 cases with chronic B-cell leukemias [B-CLL = 90; B-prolymphocytic leukemia (B-PLL) = 6, hairy cell leukemia (HCL) = 13]; a subset of 49 patients (B-CLL = 45; B-PLL = 4) was studied by conventional G-banding analysis. By G-banding, 5/45 (11%) patients with B-CLL had deletions or translocations affecting band 13q14; in contrast, ISH to interphase cells showed RB-1 deletion in 19/90 (21%) patients with B-CLL. No 13q14 abnormalities or RB-1 deletion were detected in patients with B-PLL and HCL. Our data confirm the high frequency of RB-1 deletions in B-CLL and further emphasize the possible pathogenetic role of this genomic region.

Adult↗
PubMed1993

A vaccinia-vectored rabies vaccine field trial: ante- and post-mortem biomarkers.

During the field safety evaluation of a vaccinia-rabies glycoprotein recombinant virus vaccine for wildlife, two biomarkers were used to identify potential contact with vaccine-laden baits. Tetracycline, a commonly used and reliable calciphilic tissue marker, was included in a fish-meal polymer bait matrix and was evaluated from post-mortem bone samples. Additionally, an ante-mortem marker was needed to identify, for prospective study, raccoons which had contacted baits and thus, potentially, vaccine. Sulfadimethoxine (SDM) was included in an attractant slurry surrounding the bait, as a novel short-term seromarker. Preliminary laboratory studies in raccoons demonstrated SDM residues for up to one week following ingestion of a single 250 mg dose. During the first six days after bait distribution, 49 individual raccoons were live-trapped in the vaccination area. SDM was detectable in 38 of 49 (77.5%) serum samples. Similarly, 47 of 56 (83.9%) bone samples from raccoons collected in the vaccination area throughout the twelve-month study were tetracycline-positive. Conversely, none of the serum samples (n = 12) from the first six days of the trial nor any of the bone samples (n = 34) from raccoons in the surveillance area were biomarker-positive.

Administration, Oral↗
PubMed1993

VIP modulates intracellular calcium oscillations in human lymphoblasts.

Vasoactive intestinal polypeptide (VIP) has been shown to stimulate adenylate cyclase in a human lymphoblast cell line (MOLT 4). In the present study, we monitored fluorescence in cell suspensions and in single fura-2 loaded MOLT 4 lymphoblasts to determine if VIP modulates intracellular calcium concentrations ([Ca2+]i), and if this modulation is mediated by adenylate cyclase. The distribution of [Ca2+]i in resting and stimulated cells was non-homogeneous, with gradients of high [Ca2+]i present in the subplasmalemmal space. In a subset of cells (10-30% of all cells studied), [Ca2+]i showed La(3+)-sensitive, temporal changes in the form of [Ca2+]i oscillations with a baseline [Ca2+]i value of 115 +/- 10 nM, an oscillation amplitude of 150 +/- 18 nM and a mean period of 9.2 +/- 2 s. The remaining non-oscillating cells showed a constant [Ca2+]i level of 75 +/- 5 nM (n = 65 cells from 4 experiments). In the subset of cells with spontaneous [Ca2+]i oscillations, VIP dose-dependently (10(-12) to 10(-8) M) increased the amplitude of oscillations but did not stimulate their frequency. The stimulatory effect of VIP was correlated with baseline [Ca2+]i in these cells, was attenuated in the presence of La3+ (25 microM), but was unaffected by cell depolarization (126 mM KCl). Dibutyryl cyclic AMP (10(-4) to 10(-3) M) and forskolin (10(-4) M) had no effect on [Ca2+]i oscillations, or on [Ca2+]i in cells without oscillations. In cell suspensions, baseline [Ca2+]i was found to be 55.1 +/- 11.2 nM (mean +/- S.E.M., n = 11); VIP, cyclic AMP analogues or forskolin had no significant effect on [Ca2+]i. These findings suggest that: a) VIP modulates the amplitude of [Ca2+]i oscillations generated by a cytosolic [Ca2+] oscillator in a subset of cells at a concentration of 10(-12) M, a thousand-fold below the KD for the VIP receptor; b) baseline [Ca2+] values may be related to both the ability of cells to generate spontaneous [Ca2+] oscillations and of oscillating cells to respond to VIP; c) due to the small number of responding cells, VIP-induced [Ca2+]i changes are not detectable when studied in cell suspensions.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1993

Recombinant rabies vaccines: efficacy assessment in free-ranging animals.

With the advancement of recombinant DNA techniques, a number of potent biologicals are available for the oral vaccination of free-ranging animals. Once oral immunogenicity and vaccine safety have been demonstrated, efficacy then becomes of paramount importance. Classical assessment of efficacy is conducted under carefully controlled laboratory conditions, whereas efficacy of oral wildlife rabies vaccination programs, to date, have been assessed by the lack (or occurrence) of field cases of rabies in a vaccinated area. This communication describes an intermediate vaccine efficacy strategy in which self-vaccinated, free-ranging animals from a study site were captured seven months after vaccine-laden bait distribution for laboratory rabies challenge. This technique is specifically reviewed in the context of available recombinant products for the consideration of extension towards dog rabies control.

Animals↗