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Biomedical subjects

J K Phillips

Publications and source records attributed to J K Phillips.

At least 37 records · Page 2Linked to original sources
PubMed1996

Alpha-adrenergic, neurokinin and muscarinic receptors in rat mesenteric artery; an mRNA study during postnatal development.

Developmental studies show that the innervation of autonomic targets is accompanied by increases in the density of receptors, maturation of receptor-signalling pathways and changes in receptor subtype. The innervation of the rat mesenteric artery occurs over the first 3 postnatal weeks. In this study, we investigated whether alterations in receptor gene expression may underlie physiological changes recorded during development and maturity in this vessel. Total RNA, from mesenteric arteries of rats at birth and postnatal days 7, 14, 28, 240 and 360, was reverse transcribed and amplified using primers specific for the alpha 1 (A, B, D)- and alpha 2 (A, B, C)-adrenergic, neurokinin (NK1-NK3) and muscarinic (m1-m5) receptors. Results showed that all receptor genes expressed at 28 days, except the alpha 1D-adrenergic receptor, were already expressed at birth. Some receptor subtypes showed no change in their relative expression, always being either strongly (alpha 1A, alpha 2B, NK3) or weakly (alpha 2A, alpha 2C, NK1) expressed. Relative to the expression of these receptors, others showed a developmental increase in expression up to 14 days postnatal (alpha 1B, alpha 1D, m2, m3, m5) but no further change with maturity. These latter changes coincide with the development of sympathetic and sensory nerve plexuses in the mesenteric artery, but do not correlate with the physiological changes seen during development and ageing.

Animals↗
PubMed1996

Physiologically based pharmacokinetic/pharmacodynamic modeling of the toxicologic interaction between carbon tetrachloride and Kepone.

Carbon tetrachloride (CCl4) lethality in Sprague-Dawley rats is greatly amplified by pretreatment of Kepone (decachlorooctahydro-1,3,2-metheno-2H-cyclobuta[cd] pentalen-2-one). The increase in lethality was attributed to the obstruction of liver regenerative processes. These processes are essential for restoring the liver to its full functional capacity following injury by CCl4. Based on the available mechanistic information on Kepone/CCl4 interaction, a physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) model was constructed where the following effects of Kepone on CCl4 toxicity are incorporated: (1) inhibition of mitosis; (2) reduction of repair mechanism of hepatocellular injury; (3) suppression of phagocytosis. The PBPK/PD model provided computer simulation consistent with previously published time-course results of hepatotoxicity (i.e., pyknotic, injured and mitotic cells) of CCl4 with or without Kepone. As a further verification of this model, the computer simulations were also consistent with exhalation kinetic data for rats injected with different intraperitoneal (i.p.) doses of CCl4 in our laboratory. Subsequently, the PBPK/PD model, coupled with Monte Carlo simulation, was used to predict lethalities of rats treated with CCl4 alone and CCl4 in combination with Kepone. The experimental lethality studies performed in our laboratories were as follows: Sprague-Dawley rats were given either control diet or diet containing 10 ppm Kepone for 15 days. On day 16, rats in the Kepone treated group were given i.p. doses of 0, 10, 50, and 100 microliters/kg CCl4 (n = 9) while control rats were exposed to 0, 100, 1000, 3000, and 6000 microliters/kg CCl4 (n = 9). Lethality was observed at the 1000 (1/9), 3000 (4/9), and 6000 (8/9) microliters/kg doses for the control group and at the 50 (4/9) and 100 (8/9) microliters/kg for the treated group. Based on Monte Carlo simulation, which was used to run electronically 1000 lethality experiments for each dosing situation, the LD50 estimates for CCl4 toxicity with and without Kepone pretreatment were 47 and 2890 microliters/kg, respectively. Monte Carlo simulation coupled with the PBPK/PD model produced lethality rates which were not significantly different from the observed mortality, with the exception of CCl4 at very high doses (e.g., 6000 microliters/kg, p = 0.014). Deviation at very high doses of the predicted mortality from the observed may be attributed to extrahepatic systemic toxicities of CCl4, or solvent effects on tissues at high concentrations, which were not presently included in the model. Our modeling and experimental results verified the earlier findings of Mehendale (1990) for the 67-fold amplification of CCl4 lethality in the presence of Kepone. However, much of this amplification of CCl4 lethality with Kepone pretreatment was probably due to pharmacokinetic factors, because when target tissue dose (i.e., model estimated amount of CCl4 metabolites) was used to evaluate lethality, this amplification was reduced to 4-fold.

Animals↗
PubMed1995

A randomized study of MOD versus VAD in the treatment of relapsed and resistant multiple myeloma.

67 patients with relapsed or resistant multiple myeloma were randomized to receive either VAD (vincristine, doxorubicin, dexamethasone) or MOD (mitozantrone, vincristine, dexamethasone). 12/30 (40%) patients receiving VAD and 15/37 (41%) patients receiving MOD achieved plateaux. The median duration of plateaux was significantly longer on VAD (15 months) than on MOD (8 months). No significant difference in overall survival was seen between the two treatment arms. The only toxicity which was severe in more than 5% of treatment cycles on either treatment arm was myelosuppression. No toxicity was significantly more severe on MOD than VAD. However, hair loss was significantly more severe on VAD than MOD. The frequencies of thrombocytopenia, haematuria and cutaneous toxicity were significantly greater on VAD than on MOD. Raised serum direct bilirubin levels were seen significantly more often on MOD than VAD. MOD and VAD have similar efficacy in relapsed/resistant multiple myeloma. MOD is the less toxic of the two regimens.

Aged↗
PubMed1995

P-COMM-B induction chemotherapy in intermediate and high grade non-Hodgkin's lymphoma.

57 patients with newly diagnosed intermediate or high grade non-Hodgkin's lymphoma with stage II to IV disease were treated with P-COMM-B (prednisolone, cyclophosphamide, vincristine, mitozantrone, methotrexate and bleomycin). 46% patients achieved a complete remission and 26% achieved a partial remission. Projected disease-free survival in complete remission at 5 years is 56% and projected overall survival at 5 years is 37%. Neutropenia and proximal myopathy were the commonest severe toxicities encountered and two deaths were clearly related to treatment (3.5%). P-COMM-B is effective first-line chemotherapy in intermediate and high grade non-Hodgkin's lymphoma. The efficacy and toxicity of P-COMM-B appear to be comparable to those of the best contemporary regimen, CHOP.

Adolescent↗
PubMed1993

High-volume postobstructive choleresis after transhepatic external biliary drainage resolves with conversion to internal drainage.

We report high-volume postobstructive choleresis in two patients who underwent transhepatic external drainage for malignant biliary obstruction. Excessive loss of bicarbonate-rich biliary fluid (up to 6.5 L/day) caused orthostatic hypotension, prerenal insufficiency, hyponatremia, and a decrease in serum bicarbonate. Therapy with isotonic fluids containing sodium, chloride, lactate, bicarbonate, and potassium was based on measurement of biliary fluid volume and electrolyte concentrations. Biliary fluid loss was terminated by conversion to internal biliary drainage. The reason for this rare complication of external drainage of biliary obstruction is unknown, but such patients must be closely monitored for volume loss. When high-volume choleresis occurs, biliary fluid and electrolyte losses should be precisely measured and replaced, and external biliary drainage converted to internal drainage.

Adenocarcinoma↗
PubMed1993

Heparin-induced skin reaction due to two different preparations of low molecular weight heparin (LMWH)

Heparin-induced skin reaction is a recognized complication of subcutaneously administered, unfractionated heparin, and has recently been described in association with the use of two LMWH preparations, Fragmin and Fraxiparin. We describe the case of a 25-year-old woman in whom characteristic skin lesions were induced on separate occasions by unfractionated heparin, Fragmin and a third preparation of LMWH, Clexane. This case demonstrates that substitution of one preparation of heparin for another does not prevent recurrence of skin reaction in susceptible patients. Alternative anticoagulants should be considered in these cases.

Adult↗
PubMed1993

Renal failure caused by leukaemic infiltration in chronic lymphocytic leukaemia.

A case of B-CLL which was complicated by chronic renal failure due to leukaemic infiltration of the kidney is reported. Treatment with chlorambucil, prednisolone, and renal bed irradiation resulted in a substantial improvement in renal function which persisted until the the patient's death from marrow failure some eight years later. The temporal association between treatments and response suggested that renal bed radiotherapy had contributed to the improvement in renal function. This case is one of only two reported cases in which chronic renal failure due to CLL has been treated with radiotherapy. It is unique in that the renal response was shown histologically. Leukaemic infiltration of the kidney is common in CLL but, characteristically, is not associated with renal impairment. An improvement in renal function has been described in two patients with acute renal failure after chemotherapy.

Chlorambucil↗
PubMed1993

Acquired haemophilia in association with type III von Willebrand's disease: successful treatment with high purity von Willebrand's factor and recombinant factor VIIa.

A patient with autosomal dominant (Type III) von Willebrand's disease (vWd) developed acquired haemophilia post-operatively, possibly due to exposure to amoxycillin. She refused porcine factor VIII (pFVIII) on religious grounds and was managed successfully with recombinant activated factor VII (rFVIIa) together with highly purified von Willebrand factor concentrate (vWf-VHP). In patients with acquired haemophilia rFVIIa appears to be a suitable agent for symptomatic management.

Factor VIIa↗
PubMed1990

VIM-D salvage chemotherapy in Hodgkin's disease.

A total of 15 patients with relapsed or resistant Hodgkin's disease were treated with a combination of etoposide (VP16), ifosfamide, mitozantrone and dexamethasone (VIM-D). The regime was well tolerated, the only major toxicity being myelosuppression. Complete remissions (CRs) were obtained in 4 patients and were maintained for 2, 4, 10 and 14 months. 10 subjects subsequently received an autologous bone marrow transplant with high-dose chemotherapy (ABMT). Previous exposure to VIM-D did not appear to predict for or prejudice the response to subsequent ABMT.

Adult↗
PubMed1983

Hardness of domestic water and blood lead levels.

The effect on the blood lead levels of residents in an area in which a soft plumbo-solvent water was hardened is examined. Water lead levels fell after hardening was introduced whereas there was a small rise in water lead levels in a control area monitored over the same time. The blood lead levels of residents fell after hardening and the fall was slightly greater than would have been predicted on the basis of the change in water lead levels. This suggests that lead is less well absorbed from hard water than from soft water. Following hardening there was a significant fall in mean blood lead level of subjects living in houses which had initially had negligible amounts of lead in the water. This suggests that hard water may interfere with the absorption of lead from sources other than water.

Humans↗