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Biomedical subjects

J Spragg

Publications and source records attributed to J Spragg.

At least 19 recordsLinked to original sources
PubMed1991

The effects of cyclosporin A on eicosanoid excretion in patients with rheumatoid arthritis.

Alterations in renal eicosanoid levels have been postulated as a factor in cyclosporin A (CSA) nephrotoxicity. The effects of CSA on renal eicosanoid excretion in rheumatoid arthritis were studied over a 24-week period, during which treatment with nonsteroidal antiinflammatory drugs was discontinued. The initial dosage of CSA was 4 mg/kg/day; at week 24, the mean dosage of CSA was 3.9 mg/kg/day. At week 24, the mean (+/- SD) serum creatinine level (1.04 +/- 0.24 mg/dl) was 32% above the baseline value; renal blood flow had decreased by 21% (P less than 0.03) and the glomerular filtration rate had decreased by 16%. There was a significant increase (P less than 0.03) in the 2,3-dinor thromboxane B2 level at week 2, but there was no significant change in the levels of the other eicosanoids. This study demonstrates that after CSA treatment, there is a selective increase in a thromboxane metabolite that parallels an increase in renal vascular resistance, even in the absence of nonsteroidal antiinflammatory drugs, and with unimpaired formation of other vasodilator eicosanoids.

Adult↗
PubMed1990

Does lithium carbonate affect the ion transport abnormality in cystic fibrosis?

Lithium is known to affect several aspects of cellular regulation which may be related to ion channel function in epithelial cells. To determine whether the ion transport abnormality in cystic fibrosis (CF) is affected by lithium with resultant changes in clinical status, 36 CF patients, 12-37 years old, were enrolled in a 14 week, double-blind, placebo-controlled trial. Eighteen patients were randomly assigned to receive lithium carbonate for 10 weeks. At the end of therapy their average serum lithium concentration was 0.56 +/- 0.06 mmol (SEM) per liter. Their sweat chloride concentration fell from 92.1 +/- 4.8 mmol per liter to 87.4 +/- 4.0 mmol per liter after 10 weeks of therapy (P = 0.07) and rose to 94.4 +/- 3.5 mmol per liter 4 weeks after end of therapy (P less than 0.001 compared to results at end of therapy). Their forced vital capacity (FVC) fell from 72 +/- 5.3% of predicted to 66 +/- 5.1% of predicted after 4 weeks of therapy (P less than 0.01), and their forced expiratory volume in one second (FEV1) fell from 56 +/- 5.5% of predicted to 51 +/- 5.5% of predicted after 4 weeks of therapy (P less than 0.01). In a non-blind assessment, performed 19 weeks after the end of therapy, their FVC and FEV1 had risen and were not significantly different from baseline. Sweat chloride, FVC, and FEV1 remained unchanged in the placebo group throughout the period of study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

The effect of cyclosporine on urinary kallikrein excretion in patients with rheumatoid arthritis.

The effect of cyclosporine (6 to 8 mg/kg/24 hr) on urinary kallikrein excretion is summarized for 9 patients with rheumatoid arthritis using a specific kallikrein radioimmunoassay. Baseline serum creatinine and BUN values were within the normal range for all patients, and baseline kallikrein excretion rates were either normal (n = 5) or more than two S.D. below the mean of the normal group (n = 4). The patients with normal baseline values excreted significantly less urinary kallikrein three and six months after cyclosporine therapy was started, but all of them completed the six-month protocol. Patients in the subgroup with low baseline values also decreased their kallikrein excretion in response to cyclosporine therapy, and two of the four in this group experienced elevations of BUN such that therapy was terminated. In a low-dose (3 mg/kg/24 hr) open extension that followed the initial trial, kallikrein excretion decreased by almost 50% at least one month before any change in serum creatinine was observed. The data suggest that changes in urinary kallikrein excretion rates may be an indicator or predictor of cyclosporine nephrotoxicity. Decreased kallikrein excretion rates could also be a factor in the diminished renal blood flow reported in patients treated with cyclosporine.

Arthritis, Rheumatoid↗
PubMed1989

In vivo inhibition of tissue kallikreins by kininogen sequence analogue peptides.

Kininogen sequence analogs containing amino acid residues around the Arg-Ser cleavage site of bovine kininogens were prepared with bulky aliphatic residues in P3 position. KKI-7 (containing a cyclohexylacetyl group) and KKI-8 (containing an adamantaneacetyl group) both inhibited human urinary kallikrein (HUK) with Ki of 4 microM. These inhibitors were 40 times more potent than the corresponding peptide containing the naturally occurring Pro at P3 and were one-seventh as susceptible to hydrolysis by HUK. Rat submaxillary kallikrein (RSK) and porcine pancreatic kallikrein (PPK) were also inhibited by these analogs. Both analogs were poor inhibitors of human plasma kallikrein, while their capacity to inhibit bovine trypsin was 1/3 and 1/17, respectively, that to inhibit HUK. In a rat blood flow study, KKI-7 infusion depressed the response to injected RSK. The response gradually returned toward normal 30 to 60 min after the infusion was terminated. Blood flow increase of dog jejunal artery in response to infused PPK was blunted by the simultaneous local infusion of Trasylol, KKI-7, or KKI-8, whereas these infusions did not alter the response to infused bradykinin. The vehicle infusion did not attenuate the response either to PPK or bradykinin. These analogs appear to have greater specificity and stability than those previously developed and to be appropriate for the in vivo inhibition of glandular kallikreins.

Amino Acid Sequence↗
PubMed1989

Inhibition of human and rat tissue kallikreins by peptide analog antagonists of bradykinin.

Three representative bradykinin receptor antagonists have been examined for their capacity to inhibit purified human and rat urinary kallikreins. In an amidolytic assay, the Ki values for the inhibition of human urinary kallikrein were 0.5, 0.3, and 2.5 microM for B4307 (DArg-Arg-Pro-Hyp-Gly-Thi-Ser-DPhe-Thi-Arg), B4308 (Lys-Lys-Arg-Hyp-Hyp-Gly-Thi-Ser-DPhe-Thi-Arg) and B3852 (Arg-Pro-Hyp-Gly-Phe-Ser-DPhe-Phe-Arg), respectively. B4308 and B3852 inhibited rat urinary kallikrein with Ki's of 1.0 and 5.5 microM, respectively. B4308 (0.4 to 1.6 microM) also inhibited the kininogenase activity of human urinary kallikrein on human low molecular weight kininogen in a dose-dependent fashion. These bradykinin receptor antagonists may inhibit the kallikrein-kinin system both by blocking the binding of kinins to B2 receptors and by inhibiting the cleavage of kinins from kininogens.

Amino Acid Sequence↗
PubMed1988

Angioedema induced by a peptide derived from complement component C2.

Synthetic peptides that correspond to the COOH-terminal portion of C2b enhance vascular permeability in human and guinea pig skin. In human studies, 1 nmol of the most active peptide of 25-amino acid residues produced substantial local edema. A pentapeptide and a heptapeptide corresponding to the COOH-terminal sequence of C2b each induced contraction of estrous rat uterus in the micromole range; a peptide of 25 amino acids from this region induced a like contraction of rat uterus at a concentration 20-fold lower than the smaller peptides. The vascular permeability of guinea pig skin was enhanced by doses of these synthetic peptides in a similar fashion as that observed for the concentration of rat uterus. The induction of localized edema by intradermal injection in both the guinea pig and the human proceeds in the presence of antihistaminic drugs, suggesting that there is a histamine-independent component to the observed increase in vascular permeability. Cleavage of C2 with the enzymic subcomponent of C1, C1s, yields only C2a and C2b, and no small peptides, whereas cleavage of C2 with C1s and plasmin yields a set of small peptides. These plasmin-cleaved peptides are derived from the COOH terminus of C2b, and they induce the contraction of estrous rat uterus.

Amino Acid Sequence↗
PubMed1988

The murine T-lymphocyte response to tyrosine-azobenzenearsonate. Characteristics of a low responder haplotype T-cell clone.

An I-Ab-restricted, L3T4+ Ly2- T-cell clone, 5R-4F3, specific for ABAtyr was established in culture from a B10.A(5R) mouse. Since b haplotype mice respond weakly to ABAtyr compared to other haplotypes, this is a candidate clone of low responder phenotype. In support of this contention, 5R-4F3 grew very poorly under conditions that supported the vigorous growth of E beta bE alpha k-restricted T-cell clones from the same mouse. The I-A (low responder) and I-E (high responder) restricted T-cell clones also differed in their responses to apc pre-pulsed with antigen, compared to apc with antigen present continuously during culture. The low and high responder clones responded comparably to IL-2. Attempts to elevate the response of C57BL/6 mice to ABAtyr in vivo by injecting them with human recombinant IL-2 and antigen together were only partially successful: C57BL/6 mice treated in this way showed a 3-5-fold increase in their proliferative responses to ABAtyr, which was at best only one quarter of the level of response shown by high responder A/J mice to the same antigen dose.

Animals↗
PubMed1988

Effect of cyclosporine on urinary kallikrein excretion in patients with rheumatoid arthritis.

The effect of cyclosporine (6 to 8 mg/kg/day) on urinary kallikrein excretion was examined in 10 patients with rheumatoid arthritis by using a radioimmunoassay for kallikrein, a product of renal tubular biosynthesis. All patients had baseline values of serum creatinine and blood urea nitrogen (BUN) within the normal range. The group had a mean baseline kallikrein excretion of 98.30 +/- 29.98 micrograms/24 hours (mean +/- SEM), and 3 and 6 months after therapy was initiated, kallikrein excretion was 44% and 46% of baseline, respectively (p less than 0.01). The five patients who had a normal mean baseline kallikrein excretion rate (106.60 +/- 15.21 micrograms/24 hr) excreted significantly less (p less than 0.05) kallikrein 3 and 6 months after therapy was initiated (56.60 +/- 3.98 micrograms/24 hr and 34.50 +/- 11.02 micrograms/24 hr, respectively), as did one patient with an elevated baseline kallikrein. All six of these individuals completed the protocol. In a subgroup of four patients with low baseline levels (28.25 +/- 5.06 micrograms/24 hr), two individuals experienced elevations of BUN such that cyclosporine was discontinued; in the two who completed the protocol, there was some further decrement in kallikrein excretion. Kallikrein excretion increased in all patients after a 3-month washout period. During a low-dose (3 mg/kg/day) open extension study that followed the initial trial, kallikrein excretion was determined monthly. Seven episodes in which kallikrein excretion decreased in six patients by 44% +/- 18% over a 1-month interval preceded any increase in serum creatinine by 1 to 4 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Arthritis, Rheumatoid↗
PubMed1987

Cyclosporin A treatment of refractory rheumatoid arthritis.

Ten patients with rheumatoid arthritis were entered into a 24-week pilot study of oral cyclosporin A at a starting dosage of 6 mg/kg/day, followed by a 12-week washout period. Significant improvement in clinical parameters was observed at 12 weeks and 24 weeks (P less than 0.02 versus baseline for joint pain and joint swelling indexes and patient and physician assessments; P less than 0.04 versus baseline in the numbers of painful/tender joints and swollen joints). Adverse reactions were varied: renal impairment occurred in all patients and hypertension occurred in 7. All patients demonstrated an increase in defined disease activity at cessation of treatment and through the washout period. Cyclosporin A is clinically effective in the treatment of patients with refractory rheumatoid arthritis, but its value as an intervention therapy is limited by its toxicity.

Arthritis, Rheumatoid↗
PubMed1987

In vivo assay of specific kallikrein inhibitors.

Kininogen sequence analogs containing amino acid residues around the Arg-Ser cleavage site of bovine kininogens were prepared with bulky aliphatic residues in the P3 position as specific inhibitors of tissue kallikrein. KKI-7 (containing a cyclohexylacetyl group) and KKI-8 (containing an adamantaneacetyl group) both inhibited human urinary kallikrein with KI = 4 microM. These inhibitors are 40 times more potent than the corresponding peptide containing the naturally occurring prolyl residue at P3 and one-seventh as susceptible to hydrolysis. KKI-7 and KKI-8 are poor inhibitors of human plasma kallikrein (KI = 244 and 358 microM, respectively) while their capacity to inhibit trypsin is 1/3 and 1/17, respectively, that of their inhibitory capacity for human urinary kallikrein. When KKI-7 was tested in a rat blood flow model, the infused peptide (50 micrograms/kg/min) depressed the response to injected rat submandibular kallikrein (200-500 ng) to 52% of the control response when it was injected less than 10 minutes after infusion was started and to 16% of the control response when it was injected between 10 and 30 minutes after infusion of the inhibitor, the response gradually returned toward normal. Similar results were obtained with porcine pancreatic kallikrein. Infusion of the inhibitor did not affect the response to bradykinin and infusion of the vehicle itself did not alter the response to either injected kallikrein or bradykinin. These analogs have greater specificity and stability than those previously developed and are appropriate for the in vivo inhibition of glandular kallikreins.

Animals↗
PubMed1986

Interaction of human low molecular weight kininogen with human mast cell tryptase.

The capacity of purified tryptase, the major neutral tryptic protease of human lung mast cells, to serve as a kininogenase was examined with purified human low molecular weight kininogen (LMWK) as the substrate. Incubating of 25 mug of tryptase with LMWK for 2 to 30 minutes, with or without heparin, yielded no net time-dependent kinin release as determined on the estrous rat uterus. The 0.4 mug of kinin seen represented less than 10% of that released from excess LMWK by 5 mug of human urinary kallikrein in 5 min. Incubation at pH 5.5 with or without heparin did not significantly alter this result. LMWK did not appear by SDS-PAGE to be cleaved by tryptase either in the presence or absence of heparin. In contrast to its action on HMWK, tryptase did not extensively cleave LMWK, or destroy its reactivity with kallikrein.

Heparin↗
PubMed1985

Isosorbide dinitrate and glyceryl trinitrate: demonstration of cross tolerance in the capacitance vessels.

Cross tolerance to the arterial effects of sublingual glyceryl trinitrate (GTN) has been demonstrated in subjects taking oral isosorbide dinitrate (ISDN). To determine if cross tolerance also develops in the venous system, the effects of 0.6 mg of GTN on venous capacitance were assessed before (stage A) and during (stage B) therapy with ISDN. Venous capacitance was assessed using the radionuclide blood pool method, with relative changes in regional blood volume measured in the forearm in 6 patients and the splanchnic circulation in 4 patients. Heart rate, blood pressure and blood volume were measured before and at 1-minute intervals for 10 minutes after GTN; there was less than 2% variability in regional blood volume during 6 control measurements. During stage A, 5 minutes after GTN, systolic blood pressure (mean +/- standard deviation) decreased by 14% (from 125 +/- 15 to 107 +/- 19 mm Hg, p less than 0.01) and heart rate increased by 17% (from 68 +/- 14 to 80 +/- 17 beats/min, p less than 0.001), while regional blood volume increased to 101 +/- 2% at 1 minute (difference not significant [NS]), 111 +/- 2% at 5 minutes (p less than 0.001) and 107 +/- 3% at 10 minutes (p less than 0.01) relative to baseline measurements.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Kallikrein excretion in renal transplant recipients and in uninephrectomized donors.

The rate of tissue kallikrein (EC 3.4.21.35) excretion into the urine has been examined with an active site-specific radioimmunoassay for kallikrein in renal transplant recipients, in post-uninephrectomy kidney donors, and in a normal control population. Normal individuals on uncontrolled diets excreted 96.88 +/- 7.00 (SEM) micrograms of active kallikrein/24 hr and 113.68 +/- 8.39 micrograms of total kallikrein/24 hr, as determined after trypsin treatment of urine samples. Uninephrectomized donors secreted significantly less (P less than 0.05) active (44.99 +/- 6.39 micrograms/24 hr) and total (73.59 +/- 11.95 micrograms/24 hr) kallikrein than either the entire normal population or an age-matched subpopulation. Recipients with good renal function who had received kidneys 2 to 13 years prior to kallikrein assay excreted less (P less than 0.05) active (13.21 +/- 2.50 micrograms/24 hr) and total (18.69 +/- 3.65 micrograms/24 hr) kallikrein than either normal or uninephrectomized populations. Similar values for active (11.05 +/- 1.56 micrograms/24 hr) and total (17.60 +/- 1.96 micrograms/24 hr) kallikrein were seen in patients who had received kidneys within 6 months of assay. Thus, kallikrein excretion in kidney recipients remains significantly lower than in uninephrectomized donors. As compared to normal individuals, the reduced kallikrein excretion in post-uninephrectomized kidney donors and in renal allograft recipients suggests that renal kallikrein excretion may reflect functional distal tubular mass.

Adolescent↗
PubMed1984

Detection of hybridomas secreting monoclonal antibodies to human gamma interferon using a rapid screening technique and specificity of certain monoclonal antibodies to gamma interferon.

An immunoprecipitation technique, which uses radiolabeled human gamma interferon (HuIFN-gamma) and a sheep anti-mouse F(ab')2 serum, is described for the rapid detection of mouse monoclonal antibodies to IFN-gamma in hybridoma culture supernatants. This technique which can be performed in 4 h detects both neutralizing and nonneutralizing antibodies to IFN-gamma. Certain monoclonal antibodies prepared against natural (glycosylated) IFN-gamma which neutralized the antiviral activity of natural IFN-gamma bound strongly to rDNA (unglycosylated) IFN-gamma derived from E. coli, but failed to neutralize its antiviral activity.

Animals↗
PubMed1983

Purification of single-chain human low-molecular-weight kininogen and demonstration of its cleavage by human urinary kallikrein.

Human low-molecular-weight kininogen (LMWK) was purified to apparent physical and functional homogeneity by a six-step procedure consisting of ion-exchange chromatography, reverse ammonium sulfate gradient solubilization, hydrophobic chromatography on phenyl-Sepharose, gel filtration, and removal of contaminating proteins by their affinity for Affi-Gel blue and zinc. The recovery averaged 15.6% (n = 4). Purified LMWK presented as a single stained band on alkaline polyacrylamide gel electrophoresis which corresponded to the region of function in eluates from a duplicate gel. The apparent homogeneity was also observed in sodium dodecyl sulfate (SDS)-gel electrophoresis, where the protein presented as a single band of Mr = 65,000 without reduction and 68,000 with reduction. A mole of substrate released 0.8 mol of kinin in 5 min when cleaved by human urinary kallikrein (HUK), and 0.9 mol after 30 min. Cleavage of the single-chain LMWK released kinin from within a disulfide loop as indicated by the SDS-gel electrophoresis of reduced and unreduced kinin-free LMWK. The heavy chain exhibited an Mr = 62,000, which is similar to the Mr of the amino-terminal chain of human HMWK and is consistent with their antigenic relatedness. In contrast to the Mr = 64,000 procoagulant chain of human HMWK, the small (less than 10,000) carboxy-terminal chain of LMWK has no procoagulant activity and may serve only to protect the kinin moiety in the intact substrate.

Chemical Phenomena↗