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Biomedical subjects

M Lind

Publications and source records attributed to M Lind.

At least 91 records · Page 5Linked to original sources
PubMed1992

Novel approaches with ifosfamide in small cell lung cancer.

During the past 5 years, ifosfamide has been used increasingly in combination chemotherapy for small cell lung cancer (SCLC). The high activity and favorable toxicity spectrum (with the uroprotector mesna) will encourage further use. A policy of no dosage reduction is feasible in patients receiving combination chemotherapy with ifosfamide given as a 24-hour intravenous (IV) infusion, which is much more convenient than the more commonly used 4- to 5-day fractionated regimen. This policy has resulted in actual 2-year survivals of 22% to 33% among SCLC patients not intensively staged. The stability of ifosfamide and its high bioavailability have allowed its use in chronic, 7-day ambulatory IV infusions, with decreased toxicity and hospitalization. Recently, oral and subcutaneous administration also have been tried, again allowing outpatient treatment. The first studies with hemopoietic growth factor support, eg, granulocyte colony-stimulating factor, conducted with combination chemotherapy with ifosfamide-containing regimens in SCLC, demonstrated significant reduction in neutropenia, infections, and antibiotic use. It is clear that the dosage of ifosfamide can be intensified in the future. The broad versatility of the drug will allow interesting new studies, including those to be conducted with outpatients.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

Ultrasound evaluation of the common duct in symptomatic and asymptomatic patients.

We studied common duct (CD) diameter using real time ultrasound in 551 patients. The patients were divided into two groups: those referred for evaluation of the biliary tree [biliary-referred group (BRG)], and those referred for a problem unrelated to potential biliary tree pathology [non-biliary-referred group (NBRG)]. Potentially obstructed CDs were excluded from analysis. The CD diameter in the NBRG patients was found to increase after cholecystectomy (p less than 0.0003), but not in patients in this group with intact gallbladders and cholelithiasis. Dilation was observed in the BRG patients with either cholelithiasis (p less than 6 x 10(-7)) or cholecystectomy (p less than 4 x 10(-10)) compared to patients with intact gallbladders without cholelithiasis. To our knowledge, the former phenomenon has not been described in the literature. Our NBRG data suggest that the normal CD diameter should be set at 5 mm and 8 mm, respectively, for patients with intact gallbladders and patients post-cholecystectomy. No correlation was found between duct size and sex, age, or weight.

Adolescent↗
PubMed1991

Diagnostic and genetic studies in 43 patients with classic cystinuria.

We present results for laboratory screening and diagnostic tests--cyanide-nitroprusside test, semi-quantitative thin-layer chromatography, and quantitative amino acid column chromatography--of 43 patients with classic cystinuria. We report the efficaciousness of the cyanide-nitroprusside test and of thin-layer chromatography, as compared with quantitative amino acid chromatography, for detecting heterozygotes for type II or III cystinuria. The quantitative results for aminoaciduria in 57 blood relatives in 23 families were used to categorize the index patients with classic cystinuria. By column chromatography the ranges of excretion rates (mumol/24 h per 1.73 m2 body surface area) of diagnostic amino acids in the index patients were as follows: cystine 556-54044 (normal 20-128), arginine 131-11543 (10-80), lysine 768-21848 (51-514), ornithine 185-5685 (0-80). Also by column chromatography the median values for arginine and ornithine excretion in cystine-lysinuric heterozygotes (among the 57 blood relatives) were significantly higher (P less than 0.01) than in controls but never approached the values for homozygotes. The cyanide-nitroprusside test results were positive in urine samples of 41 of 43 index patients and in 16 (51.6%) of the urine samples of 31 obligate heterozygotes with column chromatographically proven cystine-lysinuria. Thin-layer chromatography detected all of the homozygotes, all the compound heterozygotes, and 54.8% of the carriers. According to the type of aminoaciduria in their relatives, 11 patients with classic cystinuria could be classified as having classic cystinuria type I, 11 as having type II or III, and three as being compound heterozygotes. We discuss the implications of these results for correct diagnoses and for genetic studies in classic cystinuria.

Amino Acids↗
PubMed1990

Comparative pharmacokinetics of escalating doses of doxorubicin in patients with metastatic breast cancer.

Recombinant human granulocyte colony-stimulating factor (G-CSF) has been shown to reduce neutropenia following cytotoxic therapy, thereby enabling dose escalation to improve the response rate. It is important to know whether drug kinetics change as doses are increased. Doxorubicin was selected because of its broad spectrum of activity and its known efficacy in metastatic breast cancer. Doses of 75, 100, 125 and 150 mg/m2 were given to 11 patients with metastatic breast cancer by infusion over 30 min. Serum concentrations of parent drug and metabolites were determined during the first 48 h following the infusion by high-performance liquid chromatography (HPLC). The serum concentration vs time curve decayed as a triple exponential function in four patients and as a double exponential function in seven. A four-compartment model, one central and three peripheral, would predict concentrations to within 1 SE of the observed values. Doxorubicinol was the principal metabolite, and doxorubicinone and 7-deoxydoxorubicinone were clearly identified. There was a linear increase in the AUC infinity with dose. In addition, a small and transient increase in circulating levels of doxorubicinol and other important metabolites was observed 6 h following the administration of doxorubicin, which suggests the existence of an enterohepatic, or other, re-circulation mechanism. We conclude that in the dose range selected the kinetics of doxorubicin are linear and that the increase in toxicities seen with the higher doses of doxorubicin, following the second and third fortnightly administration, may be due to intracellular drug accumulation in tissues.

Adult↗
PubMed1990

Carboplatin in small cell lung cancer.

The high activity of carboplatin as a single agent in small cell lung cancer was first identified in 30 previously untreated patients who had a 60% response, which included a 10% complete remission (CR). In this and subsequent studies, carboplatin showed high activity without the nephrotoxicity and neurotoxicity associated with cisplatin. Gastrointestinal side effects and alopecia were also generally mild; the major toxicity was myelosuppression. Two important studies of carboplatin 300 mg/m2 and etoposide (300 to 400 mg/m2) in divided doses have reported objective responses of 85% (21% CR) and 65% (21% CR) in previously untreated patients. However, the median survival in the first study was only 9.5 months in both limited- and extensive-stage patients. In this study, 19% of patients had substantial dose reductions because of myelosuppression. The second study reported a better median survival of 15.3 months for limited-stage patients and 8.3 months for extensive-stage patients. These patients received a maximum of six courses of chemotherapy as opposed to four in the first study, and cranial irradiation in addition to mediastinal irradiation. There also appeared to be fewer dose reductions, ie, 11% for carboplatin. Another study using the combination of carboplatin and etoposide in extensive-stage patients only reported a 56% response rate, including 16% CR and a median survival of 8.1 months. The major toxicity in these three studies was myelosuppression, particularly leukopenia, but only three neutropenia-associated deaths occurred in a total of 180 patients. A recent study has reported the use of similar doses of carboplatin and etoposide in combination with ifosfamide 5 g/m2 (with mesna) and midcourse vincristine. Thoracic radiotherapy was given after six courses of chemotherapy in responding patients, but no cranial irradiation was used. In 42 patients, 30 of whom had limited-stage disease, the response rate was 78%, including a 57% CR rate. The median survival was 14 months, and the 2-year actual survival rate is 33%. These and other studies of carboplatin combinations (which are only preliminary) have described high response rates and possibly improved survival compared with less intensive therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Antineoplastic Agents↗
PubMed1989

High-dose, double alkylating agent chemotherapy with DTIC, melphalan, or ifosfamide and marrow rescue for metastatic malignant melanoma.

Thirty-seven patients with widely metastatic malignant melanoma were treated with one of three chemotherapy regimens, incorporating high-dose dacarbazine (DTIC). The chemotherapy was followed by autologous bone marrow rescue which was harvested under local anesthesia in 25 of the patients. The three regimens comprised a 24-hour infusion of DTIC (Regimen A for patients less than 45 years of age, 4.3 to 10.5 g/m2; B, if greater than 45 years of age 2.7 to 4.0 g/m2; and later C, if greater than 45 years of age 7.0 to 8.0 g/m2). The second alkylating agent was given at +8 and +16 hours from the start of DTIC. The total doses of the melphalan ranged from 60 to 130 mg/m2 for Regimen A and 30 to 40 mg/m2 for Regimen B. Ifosfamide 5.0 to 8.0 g/m2 was given instead of melphalan in Regimen C. The response rates for the regimens were 81% (25% CR) for A, 27% (11% CR) for B, and 20% (with no complete responders) for Regimen C. There was no statistically significant difference between the three regimens for survival with a median value of 6 months. One of the 16 patients treated with the very high dose Regimen A died of septicemia and three of ten patients in Regimen C died within the first 2 weeks of treatment. There was statistically significant greater myelosuppression, stomatitis, and diarrhea in the very high dosage DTIC and melphalan (Regimen A) compared with the other two regimens. No significant difference in response rate or toxicity was observed for the different dosages escalated within each of the three regimens. Although hematologic and gastrointestinal toxicity were very severe, no unusual side effects were noted except for one episode of severe acute renal failure in the high-dose DTIC and melphalan, Regimen A. Responses occurred mainly in nonvisceral, nodal, and cutaneous sites and occasionally in pulmonary metastases. The Karnofsky performance improved 4 to 6 months after treatment notably with the high-dose DTIC and melphalan therapy. No survival benefit for the combination chemotherapy despite the high dosages was detected and such an approach currently cannot be recommended.

Adult↗
PubMed1989

Carboplatin, ifosfamide and etoposide with mid-course vincristine and thoracic radiotherapy for 'limited' stage small cell carcinoma of the bronchus.

Forty-two patients with small cell lung cancer were treated with a combination of carboplatin, ifosfamide and etoposide. Vincristine was given on day 14 of each course, the courses being repeated every 28 days for a maximum of six. Thoracic radiotherapy was given 4 weeks after the last course of chemotherapy but no prophylactic cranial radiotherapy was administered. Thirty patients had clinically limited state disease, the remaining patients having contralateral neck lymphadenopathy and/or pleural effusions. Elevated enzyme levels (alkaline phosphatase, LDH, ALT, GGT) were noted in 69% of patients. Twenty-four patients (57%) achieved a complete response (CR) when assessed one month after the end of treatment. A further 21% of patients had a partial response (PR). Median duration of CR was 14 months and of PR 8 months. Cerebral metastases were the sole site of relapse in 13% of the CR patients. Myelosuppression was severe with a median nadir of neutropenia of 0.2 x 10(9) cells 1-1. However, 74% of the patient group received all six courses of chemotherapy and only 16 courses (7%) were delayed because of toxicity. There were three deaths associated with treatment-related neutropenia. The median survival of the total group was 14 months, with an actuarial 2 year survival of 37% and a minimum follow-up of 18 months. [A recent analysis, March 1989, demonstrated a 33%, 2 year actual survival.]

Adult↗
PubMed1989

A simple outpatient treatment with oral ifosfamide and oral etoposide for patients with small cell lung cancer (SCLC).

For the first time in a clinical study oral Ifosfamide was used: 65 elderly or unfit patients with small cell lung cancer (SCLC) were treated as outpatients with fractionated oral Ifosfamide and Etoposide. Forty patients (62%) had extensive stage (ED) disease. The median age of the patients was 66 years. In the 60 patients evaluable for response the objective response rate was 90% with a complete response (CR) rate of 32% and a partial response (PR) rate of 58%. The overall median survival of all 65 patients was 11 months (13 months for LD, 9.5 months for ED). In those patients with LD achieving a CR or a PR radiotherapy was given to the mediastinum. No prophylactic cranial irradiation was given. There was a rapid improvement in the responding patients' performance status and symptoms generally with the first treatment cycle. Overall haematological toxicity was mild, with intravenous antibiotics only being required in 4% of the courses and with only one treatment-related death from septicaemia. A higher than expected rate of CNS toxicity was seen (30%). This was generally mild and always fully reversible and consisted mainly of forgetfulness, occasionally hallucinations, nightmares and somnolence. In only one case did encephalopathy necessitate early termination of treatment. This raises the question of whether Ifosfamide metabolism differs quantitatively or qualitatively when given by the oral route as opposed to the usual intravenous route. We conclude that this simple outpatient based treatment gives a high response rate with rapid improvement in symptoms.

Administration, Oral↗
PubMed1989

Computer analysis of manometric recordings. A study of overnight rectal activity in normal children.

To read and analyze manometric tracings from selected biological systems, a computer program was produced using low cost personal computer hardware. The program contains facilities for automatic scoring of contractions, intercontractile intervals (modality) and frequency analysis. This report concerns analysis of two overnight rectal motility recordings in 11 normal teenagers. After A/D conversion of data the developed software offers a set of options i.e. automatized scoring of contraction, detection of intervals between contractions and analytical tools such as histographic presentation of data, and presentation in the time domain. The A/D conversion time and computer analysis time for an 8 hour recording was 15 and 13 minutes, respectively. The analysis of frequency distribution overnight showed for the material as a whole 63% of no activity, 33% of 0-2 contractions x min-1 and 4% of more than 2 contractions x min-1. Modality analysis showed a peak between 15 and 25 seconds. Approximately 30% of the tracings showed accumulated intervals, which were multiples of the peak. No significant correlation was found between the first and second night of observation regarding the number of contractions and maximum frequency overnight. Significant correlation was found for the number of periods with high frequency activity between the two nights (p less than 0.05). Long-term pressure activity can be analyzed using the presented computer-aided method, providing a rapid and objective measurement of classical parameters and access to more in-depth analysis. This actual study of normal overnight rectal activity showed a large inter- and intra-individual variation.

Adolescent↗
PubMed1989

Induction of theophylline metabolism by pentobarbital.

Theophylline concentrations in plasma and urine were determined during maintenance treatment in nine healthy volunteers during one dosage interval before and after 10 days of simultaneous treatment with pentobarbital (100 mg each night). During the pentobarbital period, total plasma clearance of theophylline increased by 40% (range -4-79%), whereas renal clearance remained unchanged. It is concluded that therapeutic doses of pentobarbital induce the metabolism of theophylline with marked interindividual variation.

Adult↗
PubMed1988

Intraindividual variability in the relative systemic availability of cyclosporin after oral dosing.

We have measured total and unbound plasma concentrations of cyclosporin A in seven healthy men after single oral doses (12 mg per kg body weight) on two occasions at least two weeks apart. There was an up to two-fold intraindividual and a more than three-fold interindividual variation in the AUCs of both total and unbound drug. The intraindividual variability in the AUC of cyclosporin is similar to that of many other drugs and needs to be taken into account in the planning of pharmacokinetic studies.

Administration, Oral↗
PubMed1988

Increased nonrenal clearance and increased diuretic efficiency of furosemide in cystic fibrosis.

The pharmacokinetics of furosemide and its diuretic effect were studied in six patients with cystic fibrosis (CF) and in six age-matched healthy volunteers. Furosemide was given intravenously at a dose of approximately 0.5 mg/kg. Renal excretion of furosemide was decreased in CF because nonrenal clearance was more than twice as high as in controls (p = 0.03). Nonrenal clearance correlated with the volume of distribution (r2 = 0.52, p = 0.01), which makes a difference in the distribution and binding determinants for clearance. Another reason for increased nonrenal clearance could be induction of drug metabolism in CF, but the excretion of furosemide conjugate did not differ significantly between the groups. Although 26% less furosemide was excreted in CF than in controls (p = 0.03), the diuretic response (calculated as excretion of water and electrolytes) did not differ. Thus the diuretic efficiency was higher in CF for Na+ (p = 0.02), Cl- (p = 0.01), K+ (p = 0.07), and volume (p = 0.005). This difference is probably secondary to the different rates of delivery of furosemide into urine.

Adolescent↗
PubMed1987

The debrisoquin hydroxylation phenotype does not predict the metabolism of phenytoin.

Phenytoin plasma elimination kinetics and accrual of phenytoin metabolites in urine were studied in seven rapid and five slow hydroxylators of debrisoquin. There was no interphenotypic difference in phenytoin clearance, plasma half-life, volume of distribution, maximum rate of metabolism (Vmax), or Michaelis-Menton constant (Km). The total recovery of metabolites as percentage of given dose and the metabolite profiles in urine were similar for the two debrisoquin hydroxylator phenotypes. Similarly, no differences were observed between the groups with respect to stereoselective production of either dihydrodiol or para-phenolic metabolites of phenytoin. The debrisoquin hydroxylation phenotype was also investigated in 74 epileptic patients treated with phenytoin. Vmax and Km were graphically estimated from plasma concentrations at varying phenytoin dosage regimens in 36 of the patients. There was no correlation between the debrisoquin hydroxylation index and Vmax or Km. We conclude that the debrisoquin hydroxylation phenotype has no predictive value in guiding phenytoin dosage.

Adult↗
PubMed1987

Synthetic peptide homologous to beta protein from Alzheimer disease forms amyloid-like fibrils in vitro.

Progressive amyloid deposition in senile plaques and cortical blood vessels may play a central role in the pathogenesis of Alzheimer disease. We have used x-ray diffraction and electron microscopy to study the molecular organization and morphology of macromolecular assemblies formed by three synthetic peptides homologous to beta protein of brain amyloid: beta-(1-28), residues 1-28 of the beta protein; [Ala16]beta-(1-28), beta-(1-28) with alanine substituted for lysine at position 16; and beta-(18-28), residues 18-28 of the beta protein. beta-(1-28) readily formed fibrils in vitro that were similar in ultrastructure to the in vivo amyloid and aggregated into large bundles resembling those of senile plaque cores. X-ray patterns from partially dried, oriented pellets showed a cross-beta-conformation. A series of small-angle, equatorial maxima were consistent with a tubular fibril having a mean diameter of 86 A and a wall composed of pairs of cross-beta-pleated sheets. The data may also be consistent with pairs of cross-beta-sheets that are centered 71-A apart. [Ala16]beta-(1-28) formed beta-pleated sheet assemblies that were dissimilar to in vivo fibrils. The width of the 10-A spacing indicated stacks of about six sheets. Thus, substitution of the uncharged alanine for the positively charged lysine in the beta-strand region enhances the packing of the sheets and dramatically alters the type of macromolecular aggregate formed. beta-(18-28) formed assemblies that had even a greater number of stacked sheets, approximately equal to 24 per diffracting domain as indicated by the sharp intersheet reflection. Our findings on these homologous synthetic assemblies help to define the specific sequence that is required to form Alzheimer-type amyloid fibrils, thus providing an in vitro model of age-related cerebral amyloidogenesis.

Alzheimer Disease↗
PubMed1983

On the question of dose-dependent chloroquine elimination of a single oral dose.

Subjects (n = 45) were randomly given single oral doses of 2 (n = 11), 3 (n = 9), 5 (n = 8), 10 (n = 10), or 15 mg/kg (n = 7) chloroquine base. Chloroquine was analyzed by HPLC in serum samples taken at 3 to 168 hr after dosing. AUCs, calculated for the time period of 0 to 168 hr were proportional to the doses. Mean AUC value increased 6.7 times when the dose was increased 7.5 times (from 2 to 15 mg/kg). These data do not support the existence of significant capacity-limited chloroquine elimination within the dose range studied.

Adolescent↗