Biomedical subjects

D J Kerr

Publications and source records attributed to D J Kerr.

At least 181 records · Page 10Linked to original sources

PubMed1988

Pharmacokinetics of cis-dichloro-trans-dihydroxy-bis-isopropylamine platinum IV (iproplatinum, CHIP) in patients with normal and impaired renal function and following intraperitoneal administration.

CHIP is a quadrivalent platinum (Pt) complex, introduced clinically as a less toxic alternative to cis-platinum. The drug's major route of excretion is via the kidneys, and in this study the pharmacokinetics of unchanged CHIP, filterable Pt and total Pt have been determined following intravenous administration to patients with a range of renal function. Total Pt and filterable Pt in plasma decayed biexponentially and was fitted to a two-compartment model, whereas unchanged CHIP declined monoexponentially and was best fitted to a one-compartment model, according to Akaike's information criteria. There is a correlation between the unchanged CHIP clearance and 51Cr-EDTA clearance. The pharmacokinetics of CHIP was determined following intraperitoneal (i.p.) administration (dose, 150-300 mg m-2 4 h dwell time) and a regional advantage (peritoneal peak concentration/plasma peak concentration) of approximately 30 fold was seen. It is likely that the dose of CHIP will need to be reduced in patients with impaired renal function, and the use of i.p. CHIP in ovarian carcinoma warrants further study.

Female↗

PubMed1988

A randomized trial of oral nabilone and prochlorperazine compared to intravenous metoclopramide and dexamethasone in the treatment of nausea and vomiting induced by chemotherapy regimens containing cisplatin or cisplatin analogues.

Eighty patients receiving their first course of chemotherapy with regimens containing cisplatin or cisplatin analogues entered this open crossover study comparing nabilone 2 mg and prochlorperazine 5 mg given orally every 12 h for four doses against metoclopramide 2 mg/kg loading dose intravenously (i.v.), then 3 mg/kg as an (i.v.) infusion over 8 h and dexamethasone 20 mg (i.v.) over 3-5 min at the time of chemotherapy. There was complete control of nausea and vomiting in 24 patients (32%) given metoclopramide and dexamethasone compared to 14 patients (19%) given nabilone and prochlorperazine. For the 70 patients who completed the crossover assessment of emesis on a linear analogue scale significantly favoured metoclopramide and dexamethasone (P = 0.02). However, there was no overall patient preference for the metoclopramide and dexamethasone combination (nabilone and prochlorperazine 31 vs. metoclopramide and dexamethasone 26; 13 no preference), because a significant proportion of the patients receiving the cisplatin analogue carboplatin preferred nabilone and prochlorperazine (16 vs. 5; 1 no preference; P = 0.013). For patients receiving cisplatin chemotherapy metoclopramide and dexamethasone remains the antiemetic of choice but for regimens containing carboplatin, nabilone and prochlorperazine is better tolerated and preferred by the patients.

Adolescent↗

PubMed1988

A phase 1 and pharmacokinetic study of didox: a ribonucleotide reductase inhibitor.

A phase 1 study of a new ribonucleotide reductase inhibitor, didox, was performed by administration of escalating doses of the drug by slow i.v. injection. Thirty-four patients with unresponsive metastatic carcinoma received the drug. There were 13 escalations of dosage, from a starting dose of 192 mg m-2 to 10 g m-2. Dose limiting toxicity was encountered at 7.5 g m-2 where disturbances of hepatic and renal function were observed, in addition to severe gastrointestinal toxicity. Pharmacokinetic studies showed that a peak level of didox was achieved within 5 minutes of injection. At 1,728 mg m-2 the data best fitted a 2 compartment open model, with a mean serum alpha t1/2 of 5.2 min, with a beta t1/2 of 41.3 min. Less than 10% of the drug was excreted unchanged in the urine and the majority of this excretion was within 6 h. Didox can therefore be safely given by slow i.v. injection at a dose of 6 g m-2.

Adult↗

PubMed1988

Antitumour activity and pharmacokinetics of niosome encapsulated adriamycin in monolayer, spheroid and xenograft.

Niosomes are multilamellar vesicles formed from nonionic surfactants of the alkyl or dialkyl polyglycerol ether class and cholesterol. Adriamycin has been trapped within vesicles prepared from a monoalkyl triglycerol ether and its activity compared with adriamycin solution in human lung tumour cells grown in monolayer and spheroid culture and in tumour xenografted nude mice. The activity of the encapsulated adriamycin in vitro is maintained with similar clonogenic survival curves following treatment of monolayers and identical growth delays following spheroid exposure. The pharmacokinetics of adriamycin are altered in vivo in human lung tumour-bearing nude mice, when it is administered in niosomal form. There is prolonged release of drug from the plasma compartment with significantly lower peak levels; lower peak cardiac adriamycin concentrations with a shorter tissue half-life and decreased cardiac AUC and a greater degree of hepatic metabolism to inactive 7-deoxyaglycones. The tumour peak drug level and AUC was similar irrespective of the mode of administration of adriamycin. The growth delay (i.e. the time taken for the tumour volume to double) was significantly longer for adriamycin (15 days) and niosomal adriamycin (11 days) than for control (5.8 days). It is possible that the therapeutic ratio of adriamycin could be enhanced by administration in niosomal form.

Animals↗

PubMed1988

Results of treatment of non seminomatous germ cell tumours; 122 consecutive cases in the West of Scotland, 1981-1985.

Between January 1981 and December 1985, 122 patients with non-seminomatous germ cell tumours (NSGT) were seen at a regional referral centre. Of these, a total of 98 patients received chemotherapy for metastatic disease. Treatment was given within collaborative EORTC Urology group studies, all of which involved cis-platin-containing schedules. Ninety patients had tumours of testicular origin, and their 2 year actuarial survival rate is 91%; 8 had tumours of extragonadal origin and their 2 year actuarial survival is 25%. Patients with testicular tumours were subdivided by volume of metastatic disease using the recommendations of the Testicular Cancer Subgroup of the MRC Urological Cancer Working Party and survival was significantly worse in the group with very large volume metastatic disease (VLVM, 57%) compared with the groups with large volume metastases (LVM, 100%) and small volume metastases (SVM, 98%). There were 31 patients with Stage I disease at presentation; of these 6 were treated by prophylactic abdominal radiotherapy and 25 were managed by a policy of surveillance only. Seven of these Stage I patients (23%) relapsed with metastatic disease (median 8 months); all have been successfully treated with chemotherapy. These data confirm that the majority of patients now presenting with metastatic NSGCT are curable with chemotherapy, but that a small proportion with very large volume metastases or extragonadal tumours require alternative chemotherapy schedules.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1988

Pharmacokinetics and pharmacodynamics of locoregional 5 fluorouracil (5FU) in advanced colorectal liver metastases.

By measuring peripheral drug levels in plasma, the effect of combining albumin microspheres with angiotensin II on systemic exposure to 5FU when administered by bolus injection into the hepatic artery in patients with advanced colorectal liver metastases has been assessed. The results suggest that despite hepatic arterial administration of 5FU, there was no reduction in systemic exposure when compared with that associated with intravenous injection of the same dose. Neither albumin microspheres nor angiotensin II appeared to improve the regional advantage. There have been a number of reports relating the plasma levels of cytotoxic agents with pharmacodynamic parameters. We have shown significant direct correlations between 5FU clearance and 1 week post treatment platelet and white cell counts, and an inverse relationship between the area under the 5FU plasma concentration-time curve (AUC) and 1 week post treatment platelet count and white cell count respectively.

Albumins↗

PubMed1988

Cytotoxic drug penetration studies in multicellular tumour spheroids.

1. The three-dimensional structure of human lung tumour spheroids conferred a degree of resistance to the anthracyclines adriamycin, 4'-deoxydoxorubicin, daunomycin and daunomycin-low density lipoprotein complex in comparison with cells grown as a monolayer, as assessed by delayed growth and clonogenic cell survival. 2. 4'-Deoxydoxorubicin induced a longer growth delay and greater clonogenic cell kill than adriamycin in spheroids, although it was no more cytotoxic in monolayer. 3. Fluorescent microscopy demonstrated that the more lipophilic analogues partitioned into the spheroid more rapidly and to a greater degree than adriamycin. 4. The spheroid model demonstrated that penetration is an important aspect of resistance to anthracycline drugs, and this approach may represent a better in vitro system for testing lipophilic analogues of cytotoxic drugs.

Antibiotics, Antineoplastic↗

PubMed1987

Phase I and pharmacokinetic study of flavone acetic acid.

Flavone acetic acid is the second in a series of compounds based on the flavonoid aglycone ring structure to be clinically evaluated in malignant disease. Preclinical studies have indicated that a minimum plasma level of 150 micrograms/ml is required before therapeutic efficacy (in a wide range of experimental tumors) is seen in mice; both in vitro and in vivo studies also suggest that the duration of drug exposure is crucial in determining activity. Thus a Phase I trial has been performed in a total of 54 patients using 3 schedules, i.e., a 1-, 3-, and 6-h infusion. In each case, treatment was given once weekly for a minimum of 3 weeks. The maximum tolerated doses were 6.4, 6.4, and 10.0 g/m2, respectively. Dose limiting toxicity was denoted by an intense feeling of warmth and flushing with a 1-h infusion, hypotension with a 3-h infusion, and hypotension and diarrhea with a 6-h infusion. No objective responses were seen in this Phase I trial. The recommended doses for Phase II trials of flavone acetic acid in Europe are 4.8 g/m2 over 1 h or 8.6 g/m2 over 6 h. At these doses the peak plasma concentrations obtained are 650 and 388 micrograms/ml, respectively. Total drug exposure (assessed by an area under the curve greater than 100 micrograms/ml) was approximately 50% greater for the 6-h schedule. This Phase I trial indicates that peak plasma concentrations associated with experimental activity are achievable in humans, although optimal drug exposure times have not yet been defined.

Adult↗

PubMed1987

Comparative cardiotoxicity and antitumour activity of doxorubicin (adriamycin) and 4'-deoxydoxorubicin and the relationship to in vivo disposition and metabolism in the target tissues.

4'-Deoxydoxorubicin (4'-DOX) is an analogue of the anticancer drug Adriamycin (ADR) believed to lack its cardiotoxicity. Bioreduction to a semi-quinone free radical has been implicated in the etiology of ADR induced cardiotoxicity. We have studied (in a rat model) acute cardiotoxicity (after 16 mg/kg i.v. of both drugs), antitumour activity (after 5 mg/kg i.v.) and the relationship to disposition and metabolism in the target tissues (after 5 mg/kg i.v.). 7-Deoxyaglycones, which are considered inactive lipophilic metabolites derived from ADR semi-quinone, were utilised as markers of in vivo tissue free radical generation. Both drugs produced toxicity of equal severity to hearts after 24 hr, associated with high cardiac levels of 7-deoxyaglycones in the case of ADR (AUC0-48 hr, micrograms/g X hr: ADR, 47; ADR 7-deoxyaglycone (ADR-DONE), 24; and adriamycinol 7-deoxyaglycone (AOL-DONE), 35) compared to low cardiac levels of 7-deoxyaglycones but a times five higher peak cardiac concentration of parent drug in the case of 4'-DOX (AUC0-48 hr, micrograms/g X hr: 4'-DOX, 68; 4'-DOX-DONE, 3.8; and 4'-DOL-DONE, 0.8). 4'-DOX displayed superior antitumour activity to ADR against the MC 40A sarcoma growing sub-cutaneously, achieving higher concentrations of parent drug in tumour (AUC0-48 hr, micrograms/g X hr: 4'-DOX, 150; ADR, 60). There was an absence of 7-deoxyaglycones of both drugs in the tumour. These data suggest that drug bioreduction is involved principally only in ADR induced cardiotoxicity and that the level of unchanged parent drug achieved in the tumour is the most important pharmacokinetic determinant of antitumour activity for both ADR and 4'-DOX.

Animals↗

PubMed1987

Aspects of cytotoxic drug penetration, with particular reference to anthracyclines.

Experimental data, particularly derived from tumour spheroids, indicate that drug penetration barriers may be an important determinant of cytotoxic drug efficacy, even in spheroids of only a few hundred microns in diameter. Clinically, tumour masses of this size would equate with those micrometastases which are the target of adjuvant chemotherapy in a wide range of tumour types. It is apparent, therefore, that even at this relatively early stage of the metastatic process, which ultimately proves to be fatal in many patients, measures aimed at improving drug penetration may prove to be crucial in improving the therapeutic efficacy of cytotoxic agents.

Animals↗

PubMed1987

Occurrence of circulating 7-deoxyaglycone metabolites of 4'-deoxydoxorubicin in man.

In five cancer patients we have determined the pharmacokinetics of 4'-deoxydoxorubicin (4'-DOX), its alcoholic metabolite 4'-deoxydoxorubicinol and the occurrence of circulating 7-deoxyaglycone metabolites. The 7-deoxyaglycone of the alcohol metabolite, the major aglycone of Adriamycin (ADR) present in man, was not detected in any serum sample. The 7-deoxyaglycone of the parent drug, which appears in concentrations in excess of 30 ng/ml after ADR administration, was detected in only 2/5 patients in trace amounts. These preliminary data indicate a difference in biotransformation between ADR and 4'-DOX despite their close structural similarities.

Biotransformation↗

PubMed1987

The effect of the non-ionic surfactant Brij 30 on the cytotoxicity of adriamycin in monolayer, spheroid and clonogenic culture systems.

The effects of a non-ionic polyoxyethylated lauryl ether surfactant (Brij 30) on monolayer uptake and spheroid penetration of adriamycin have been studied. Co-incubation of adriamycin with Brij 30 increases intracellular adriamycin levels by 2-3-fold. Although, in the concentrations used, Brij 30 alone is not cytotoxic, adriamycin and Brij 30 mixtures are significantly more cytotoxic (monolayer ID90 = 0.6 microgram/ml; disaggregated spheroid ID50 = 1.9 micrograms/ml) and induce significantly longer spheroid growth delay than adriamycin alone (monolayer ID90 = 2.1 micrograms/ml; disaggregated spheroid ID50 = 3.3 micrograms/ml). Adriamycin is equally cytotoxic to mouse normal granulocytes and chronic myeloid leukaemic (M1 cell line) cells in agar clonogenic cultures. The addition of Brij 30 appears to enhance preferentially the activity of adriamycin against these tumour cells relative to the normal granulocytes.

Animals↗

PubMed1987

Circadian variation of thyrotrophin, determined by ultrasensitive immunoradiometric assay, and the effect of low dose nocturnal dopamine infusion.

The effect of low dose dopamine infusion on the circadian rhythm of thyrotrophin (TSH), prolactin and cortisol in a group of six healthy male volunteers is reported. Subjects were infused in random order with either saline (154 mmol/l NaCl solution; control) or dopamine (0.1 and 1 microgram min-1 kg-1) between 21.00 and 01.00 hours, in random order. The serum TSH profile was characterized by a maximal peak occurring at 23.00 hours and higher nocturnal than diurnal values. Superimposed on this are short term oscillations in serum TSH levels, typical of an ultradian rhythm. The maximal peak in TSH, occurring at 23.00 hours, was abolished by dopamine infused at a rate of 1 microgram min-1 kg-1, and was unaffected by the lower rate of dopamine infusion (0.1 microgram min-1 kg-1). The serum prolactin profile was characterized by a peak occurring soon after the onset of sleep (23.30-00.30 hours), which fell during the morning, and began to rise in late evening. Low dose dopamine (0.1 microgram min-1 kg-1) had a slight but insignificant effect with decreased prolactin levels at the end of the infusion whereas the higher dopamine dose was associated with significantly lower prolactin levels during and throughout the infusion. There was a rebound to levels significantly higher than control on cessation of the infusion. Cortisol levels were unaffected by dopamine.

Adult↗

PubMed1987

Microparticulate drug delivery systems as an adjunct to cancer treatment.

In an attempt to improve the therapeutic ratio of cytotoxic drugs, which have steep dose-response curves, microparticulate drug delivery systems (MDDS) have been designed for regional administration. Introduction of antineoplastic drug containing microspheres, of appropriate size, into the arterial system of an organ harboring primary or metastatic tumor, will cause tumor infarction by an embolic effect and provide a slow release source of drug trapped within the tumor microvasculature. This review describes recent innovations in synthesis of MDDS and their potential clinical application.

Antineoplastic Agents↗

PubMed1987

In vitro chemosensitivity testing using the multicellular tumor spheroid model.

Using growth delay and clonogenic cell survival as end points, we have shown that the 3-dimensional structure of human lung tumour spheroids confers a degree of resistance to the anthracyclines doxorubicin and 4'-deoxydoxorubicin, relative to cells grown as monolayer. 4'-deoxydoxorubicin induces a longer growth delay and greater clonogenic cell kill than doxorubicin in spheroids, although it is no more cytotoxic in monolayer. Using fluorescent microscopy we have demonstrated, qualitatively, that lipophilic anthracycline analogues partition into the spheroid more rapidly and to a greater degree than doxorubicin. It is apparent that penetration is an important aspect of anthracycline drug resistance in spheroids, and the spheroid model may represent a better in vitro system for testing lipophilic analogues of cytotoxic drugs.

Antibiotics, Antineoplastic↗

PubMed1987

Single photon emission computed tomographic studies (SPECT) of hepatic arterial perfusion scintigraphy (HAPS) in patients with colorectal liver metastases: improved tumour targetting by microspheres with angiotensin II.

As intra-arterial chemotherapy for liver metastases of colorectal origin becomes accepted, methods of further improving drug delivery to the tumour have been devised. Degradable microspheres have been shown to reduce regional blood flow by transient arteriolar capillary block, thereby improving uptake of a co-administered drug, when injected into the hepatic artery. In our study of five patients, we combined hepatic arterial perfusion scintigraphy (HAPS) and SPECT to assess the localization of approximately 1 X 10(5) labelled microspheres of human serum albumin (99Tcm MSA) in tumour. In addition, in three patients, we assessed the effect of an intra-arterial infusion of the vasoactive agent angiotension II during HAPS. Results were interpreted by comparing transaxial slices with corresponding slices of a tin colloid liver-spleen scan. Two of five patients showed good localization of 99Tcm MSA in tumour without an angiotensin II infusion. Of the three patients receiving angiotensin II, all showed good tumour targetting with the vasoconstrictor compared with only one of these three before its use. Thus, hepatic arterial infusion of angiotensin II greatly improves microsphere localization in tumour in some patients with colorectal liver metastases. This technique may be useful in the assessment of tumour targetting before and during locoregional therapy.

Angiotensin II↗

PubMed1987

Arteriovenous shunting of microspheres in patients with colorectal liver metastases: errors in assessment due to free pertechnetate, and the effect of angiotensin II.

In patients receiving locoregional therapy for liver metastases degradable microspheres are being increasingly used in an attempt to improve cytotoxic delivery to the tumour. However, counterproductive arteriovenous shunting through the liver following intrahepatic arterial injection can occur, leading to deposition in the lung. Measurement of the degree of shunting is important in the monitoring of this kind of therapy. In this study we describe the use of technetium-labelled microspheres of serum albumin (99Tcm MSA) to measure baseline shunting during hepatic arterial perfusion scintigraphy in five patients with liver metastases of colorectal origin, and assess the significance of the values obtained for relative lung uptake (RLU) which we define as: RLU = Activity in lung field/Activity in liver + lung fields X 100%. We found that shunting was less than 5% in all cases, zero shunting occurring in 14 of the 16 patients studied. The sources of error in this technique have been assessed, the most important being the presence of free pertechnetate in the injectate. The use of Boots 10 ml vials and glass syringes respectively to dispense and administer this radiopharmaceutical reduces this error to a small predictable level. In our small group of patients, we found no evidence to suggest that use of the vasoactive agent angiotensin II significantly increases baseline shunting in patients with colorectal liver tumour.

Angiotensin II↗

PubMed1987

Generalised peripheral nerve dysfunction in acromegaly: a study by conventional and novel neurophysiological techniques.

Twenty four patients with clinical, radiological and biochemical evidence of acromegaly were investigated by a number of independent neurophysiological tests. Two-thirds of the patients showed evidence of generalised peripheral nerve dysfunction. A significant correlation was found between total exchangeable body sodium, an indicator of disease activity, and the severity of the neuropathy. The generalised peripheral nerve abnormality was found to occur independently of the associated carbohydrate intolerance human growth hormone levels and other endocrinological dysfunction in this disorder.

Acromegaly↗