Clinical pharmacokinetics of pravastatin

The hypolipidaemic agent pravastatin differs from other US Food and Drug Administration (FDA)-approved HMG-CoA reductase inhibitors (e.g. lovastatin and simvastatin) because it has greater hydrophilicity, as a result of the hydroxyl group attached to its decalin ring. The hydrophilic nature of pravastatin accounts for its minimal penetration into the intracellular space of nonhepatic tissues, including an apparent inability to cross the blood-brain barrier. The drug is also well tolerated because it is rapidly absorbed and excreted, and does not accumulate in plasma even with repeated administration. Pravastatin is taken up into the liver by an active transport carrier system, and the hepatic extraction ratio is high (0.66). The drug and its metabolites are cleared through both hepatic and renal routes (53 and 47%, respectively). The dual route of elimination reduces the need for dosage adjustment if the function of either of these organs is impaired. Dosage adjustments are also not required on the basis of age or gender. Furthermore, the drug can be given without regard to food intake, an important consideration for compliance since lipid-lowering therapy is generally required long term. The drug is approximately 50% protein bound, and, therefore, compared with other members of its class the tendency for displacement of highly protein bound drugs such as warfarin is decreased. This minimal potential for drug-drug interactions is important for patients who are taking multiple drugs because of concomitant medical problems. However, as with any HMG-CoA reductase inhibitor, caution should be exercised when pravastatin is given with nicotinic acid (niacin), gemfibrozil or cyclosporin, because of increased risk for myopathy in patients receiving combination therapy.

Zoonotic transmission of giardiasis: a case control study

A case control study of locally acquired giardiasis was carried out in a district in East Anglia. Thirty-three primary cases were matched for age and sex with 112 controls selected from Family Health Service Authority registers. An association was shown between giardiasis and contact with farm animals (odds ratio 4.77; confidence interval 1.31-17.38) and pets (odds ratio 14.55; confidence interval 4.18-50.62).

Prevalence and diversity of constitutional mutations in the p53 gene among 21 Li-Fraumeni families

The entire coding sequence of the p53 gene was analysed for the presence of mutations in 12 families conforming to a restricted definition of Li-Fraumeni syndrome (classic LFS) and nine families with features of LFS conforming to a broader definition. Mutations were detected in seven families. Six were point mutations with one each affecting codons 175, 180, and 220 and three affecting codon 248. The seventh was a deletion/insertion mutation in exon 4. Germline mutations in p53 were a feature of families which included children with rhabdomyosarcoma and/or adrenal cortical carcinoma. Germline p53 mutations were detected in six of the nine families with such tumors. An analysis of these 7 mutations, together with 34 published examples, showed that more than one-half were transitions at CpG dinucleotides, suggesting that the majority of germline p53 mutations may arise as a result of spontaneous events. The most common cancers occurring in the 41 families with germline p53 mutations, in common with classic LFS, were bone and soft tissue sarcoma, breast cancer, brain tumors, leukemia, and adrenocortical carcinoma, although less than one-half of the probands with germline p53 mutations came from classic LFS families. More than one-half of the cancers overall and nearly one-third of the breast cancers were diagnosed before 30 years of age. These observations have important implications for asymptomatic carriers of germline p53 mutations, and there is a need for international collaboration in the development of protocols for the management of such families.

Integrin expression and function in HPV 16-immortalised human keratinocytes in the presence or absence of v-Ha-ras. Comparison with cervical intraepithelial neoplasia

Keratinocytes express several receptors of the integrin family which regulate both adhesion and differentiation. We have investigated whether HPV immortalisation, which changes the growth and differentiation properties of keratinocytes, is associated with altered integrin expression or function. We compared two HPV 16-immortalised lines of human keratinocytes, up and vp, with the normal keratinocyte strains, u and v, from which they were derived and with upr, obtained by transfection of up with viral Harvey ras. Immunofluorescence, immunoprecipitation and flow cytometry demonstrated that up and vp had lower levels of integrins than u and v, the reduction in up being greater than in vp. Up and vp also had reduced levels of mRNA encoding the beta 1 integrin subunit. Reduced expression of the alpha 5 beta 1 and alpha 2 beta 1 integrins was correlated with reduced adhesion to fibronectin and collagen in up but not in vp and there were no significant differences between the normal and immortalised cells in adhesion to laminin. Reduced integrin expression was correlated with decreased motility, up showing a greater reduction in motility than vp. Introduction of activated ras into up had no effect on integrin levels, cell motility or tumorigenicity in nude mice; the only difference between up and upr was that upr showed increased adhesion to fibronectin. Examination of eight biopsies of cervical intraepithelial neoplasias with evidence of HPV infection revealed reduced or discontinuous integrin expression in the most severe lesions. We conclude that both in vivo and in culture keratinocytes the impaired differentiation that is associated with the presence of HPV is correlated with reduced integrin expression.

Genitourinary tumors in the families of children with renal tumors

The occurrence of genitourinary tumors in the relatives of a population-based series of 218 children diagnosed with renal tumors was investigated. Family data on 92% (176 of 192) of Wilms' tumor (WT) patients and 77% (20 of 26) of other renal tumor patients were obtained. In all, 21 genitourinary tumors in first-degree relatives in 19 families were ascertained, together with 30 such tumors in second-degree relatives. Ten families were diagnosed with multiple genitourinary tumors, although none of these manifested familial WT. It is proposed that a small proportion of families of children with renal tumors has a genetic predisposition to develop genitourinary tumors and that these tumors may represent further manifestations of the pleiotropic effects of the WT1 gene or of other genes involved in WT predisposition.

An outbreak of infection with Salmonella enteritidis phage type 4 associated with the use of raw shell eggs

A community outbreak of Salmonella enteritidis phage type (PT) 4 infection, associated with eating food from a sandwich bar in Colchester, occurred in July 1991. One hundred and forty-four people were reported with food poisoning, of whom 132 met the clinical case definition. Three cohort studies of 92 people showed that illness was associated with the consumption of food containing mayonnaise. S. enteritidis PT4, indistinguishable by plasmid profile analysis, was isolated from stool samples from 83 people, food items including egg shells from the sandwich bar, and birds taken from the egg producing farm which supplied the eggs. This was the largest recorded outbreak of S. enteritidis PT4 infection in recent years associated with eggs produced in the United Kingdom. Existing advice on avoiding the use of raw eggs in uncooked dishes had not been followed. This outbreak highlights the importance of training in the implementation of this advice.

Hypoadrenal crisis caused by disseminated histoplasmosis

We report a case of disseminated histoplasmosis presenting with acute renal impairment due to adrenal insufficiency. The finding of bilateral adrenal gland enlargement on abdominal ultrasound examination led to a diagnostic CT-guided adrenal biopsy. Prolonged therapy with amphotericin and itraconazole resulted in a clinical cure, although the patient still requires adrenal replacement therapy.

Patterns of cancer in the families of children with soft tissue sarcoma

BACKGROUND

Childhood soft tissue sarcomas are known to occur in a number of genetic syndromes. This study assesses the proportion of soft tissue sarcoma diagnosed in childhood associated with genetic predisposition to cancer.

METHODS

Information on the occurrence of neoplastic disease was collected for 151 of 179 families of a population-based series of children with soft tissue sarcoma.

RESULTS

Considering the index child as the proband, 5 of the 151 families manifested the classic Li-Fraumeni cancer family syndrome according to standard criteria and a further 10 families showed features consistent with the syndrome. One proband had double primary syndrome cancers. One other family had a sibling pair of childhood cancers, seven families had cancer which had occurred in childhood in other relatives, and three families had adult-onset sarcomas in more distant relatives. In another 16 families, one parent or the other had developed a possible syndrome cancer, or had developed cancer when younger than 60 years of age. Two families showed striking clusters of stomach cancer. Five case children were thought to have been affected with neurofibromatosis.

CONCLUSIONS

Genetic predisposition to cancer was thought to be present in 7% to 33% of families interviewed.

Patterns of cancer in the families of children with soft tissue sarcoma

BACKGROUND

Childhood soft tissue sarcomas are known to occur in a number of genetic syndromes. This study assesses the proportion of soft tissue sarcoma diagnosed in childhood associated with genetic predisposition to cancer.

METHODS

Information on the occurrence of neoplastic disease was collected for 151 of 179 families of a population-based series of children with soft tissue sarcoma.

RESULTS

Considering the index child as the proband, 5 of the 151 families manifested the classic Li-Fraumeni cancer family syndrome according to standard criteria and a further 10 families showed features consistent with the syndrome. One proband had double primary syndrome cancers. One other family had a sibling pair of childhood cancers, seven families had cancer which had occurred in childhood in other relatives, and three families had adult-onset sarcomas in more distant relatives. In another 16 families, one parent or the other had developed a possible syndrome cancer, or had developed cancer when younger than 60 years of age. Two families showed striking clusters of stomach cancer. Five case children were thought to have been affected with neurofibromatosis.

CONCLUSIONS

Genetic predisposition to cancer was thought to be present in 7% to 33% of families interviewed.

Reinfection or recrudescence after apparently successful eradication of Helicobacter pylori infection: implications for treatment of patients with duodenal ulcer disease

Helicobacter pyloris is considered to be aetiologically implicated in gastritis and peptic ulceration, since if H. pyloris infection can be eradicated the risk of subsequent ulcer relapse is markedly reduced. The rate of 'reinfection' following treatment ranges from 0% to 45%, but its origin remains controversial (reappearance of uneradicated original infection or a fresh infection). To distinguish temporary suppression of H. pylori from fresh infection we conducted a retrospective analysis of the criteria used to establish eradication of the original infection in 304 patients. We used the [14C]urea breath test, in which an integrated area under the curve (AUC) value of < 40 in 2 h is considered to indicate eradication of H. pylori in patients tested 1 month after treatment. The results suggest that relapsed infection with H. pylori usually represents recrudescence of the original infection rather than a fresh infection; there was a higher relapse rate in patients with a breath test AUC > 20 < 40, compared with those with an AUC < 20. All 'reinfections' occurred within 24 months of the original treatment. 'Reinfection' was uncommon in patients receiving powerful therapeutic regimens (e.g. triple therapy) compared with those receiving monotherapy or relatively ineffective dual therapy combinations. In patients whose urea breath test remains negative 12 months after treatment the subsequent reinfection rate is only 0.44%/year. This supports the strategy of eradicating H. pylori infection from suitable peptic ulcer patients.

Wilms' tumor in the Li-Fraumeni cancer family syndrome

Scrutiny of the family pedigrees of a population-based series of 176 children diagnosed with Wilms' tumor between 1954 and 1990, along with a review of the literature on the Li-Fraumeni cancer family syndrome, indicate that Wilms' tumor may be an uncommon component of the syndrome and that a small proportion of children with Wilms' tumor may be members of Li-Fraumeni syndrome (LFS) families.

Separation of human epidermal stem cells from transit amplifying cells on the basis of differences in integrin function and expression

The epidermis is believed to contain two types of proliferating cells: stem cells and cells with a lower capacity for self-renewal and higher probability of undergoing terminal differentiation (transit amplifying cells). We report that keratinocytes with characteristics of stem cells can be isolated from cultured human epidermis on the basis of high surface expression of beta 1 integrins and rapid adhesion to extracellular matrix (ECM) proteins. Among keratinocytes there was a log linear relationship between the relative level of beta 1 integrins on the cell surface and proliferative capacity; furthermore, the cells with the highest colony-forming efficiency adhered most rapidly to type IV collagen, fibronectin, or keratinocyte ECM. Proliferating keratinocytes that adhered more slowly had characteristics of transit amplifying cells: after one to five rounds of division, all of their daughters underwent terminal differentiation. Since stem cells can be isolated to greater than 90% purity on the basis of their adhesive properties, it will now be possible to investigate the mechanisms that regulate the fate of their progeny.

Biotype and molecular fingerprints of metronidazole-resistant strains of Helicobacter pylori from antral gastric mucosa

Biotypes, ribosomal RNA gene restriction patterns (ribopatterns), whole-cell protein patterns and plasmid profiles of paired Helicobacter pylori isolates from 17 patients were examined. Each pair comprised a pre- and a post-treatment isolate; nine of the 17 post-treatment isolates were obtained after treatment with tripotassium dicitrate bismuthate (De-Nol) and metronidazole. All strains of H. pylori had identical biotypes, but exhibited diversity between pairs in their molecular fingerprints. Each of the 17 strain pairs had unique ribopatterns; the pre- and post-treatment isolates in most pairs (16 of 17) were similar or identical, irrespective of metronidazole susceptibility. DNA subtype variants were detected in three patient sets. Although nine post-treatment isolates had acquired resistance to metronidazole, most (six of nine) resembled the pre-treatment isolates in their ribopattern, protein and plasmid profiles. No significant correlation was observed between metronidazole resistance and plasmid content in these H. pylori isolates. Emergence of post-treatment metronidazole-resistant isolates of H. pylori was associated only rarely with colonisation by a novel strain or acquisition of a plasmid and, in most patients, probably resulted from spontaneous emergence of resistance in the original infecting strain.

Chemotherapy in the management of infantile fibrosarcoma

Infantile fibrosarcoma (IF) has traditionally been treated with surgery, which may have considerable morbidity. Chemotherapy has been suggested in order to reduce the need for extensive surgery. Nine children with histologically confirmed IF who received chemotherapy are described. Six children were treated with chemotherapy initially, two following conservative surgery, and one following recurrence after surgery. All received vincristine (V) and actinomycin D (A), and six received additional drugs including ifosfamide (I), cyclophosphamide (C), adriamycin (Ad), etoposide (E), and cisplatinum (CDDP). Objective responses were achieved in eight: three responded completely (CR), two responded partially (PR), which allowed conservative surgery, one had stable disease, one had an initial PR, but subsequently had tumour recurrence 1 month after cessation of treatment, necessitating further surgery and chemotherapy, and one had an initial PR but died following local and regional metastases. One child had no response to chemotherapy but is alive with stable residual disease. Thus, five of nine children achieved a CR--three with chemotherapy alone. With the inclusion of chemotherapy as part of their treatment, five children, for whom curative surgery may have resulted in amputation, remain alive with limbs intact. Chemotherapy including V and A should be given to infants with fibrosarcoma in whom curative surgery would be mutilating.

Treatment of refractory familial hypercholesterolemia by low-density lipoprotein apheresis using an automated dextran sulfate cellulose adsorption system. The Liposorber Study Group

A subgroup of patients with familial hypercholesterolemia (FH) respond inadequately to standard diet and drug therapy, and are therefore at high risk for the premature development or progression of coronary artery disease. This study evaluated low-density lipoprotein (LDL) cholesterol and lipoprotein (a) removal in a multicenter, controlled trial with a new LDL apheresis procedure (Liposorber LA-15 System). The study comprised patients with FH who had not responded adequately to diet and maximal drug therapy. There were 54 patients with heterozygous FH (45 randomized to treatment and 9 control subjects) and 10 with homozygous FH (all of whom received LDL apheresis). The study included three 6-week treatment phases and a 4-week rebound phase. Treatments were administered at 7- to 14-day intervals. Mean acute reductions in LDL cholesterol were 76% in heterozygous FH patients and 81% in homozygous ones. Time-averaged levels of LDL cholesterol were reduced 41% (243 to 143 mg/dl) in heterozygous FH patients and 53% (447 to 210 mg/dl) in homozygous ones. The substantial acute reduction of lipoprotein (a) (means: 65%, heterozygous FH; 68%, homozygous FH) has not been reported with other therapies. The Liposorber LA-15 System represents an important therapeutic option in FH patients who respond inadequately to diet and drug therapy.

Comparative effects of simvastatin and lovastatin in patients with hypercholesterolemia. The Simvastatin and Lovastatin Multicenter Study Participants

The efficacy, safety profile, and tolerability of the HMG-CoA reductase inhibitors simvastatin and lovastatin were compared in a multicenter, randomized, double-blind study in patients with moderate hypercholesterolemia. Commonly prescribed doses of these two drugs were used by 544 men and women, who followed an American Heart Association phase I diet during a 6-week baseline period and for the 24 weeks of active treatment. Simvastatin 10 mg and lovastatin 20 mg produced statistically significant reductions in total and low-density lipoprotein cholesterol (LDL-C). Patients receiving simvastatin 10 mg once daily and lovastatin 20 mg once daily experienced similar reductions in LDL-C and total cholesterol; however, simvastatin 20 mg was statistically superior to lovastatin 40 mg in decreasing these lipid fractions. For all treatment groups, increases in high-density lipoprotein cholesterol were inversely related to baseline levels. Moderate decreases in triglycerides occurred with all doses. Lipoprotein(a) levels, measured in a subset of patients, were similar before and after treatment. Both drugs were well tolerated.

A clinical overview of dyslipidemias: treatment strategies

The strong epidemiologic relationship between specific lipoprotein levels (such as elevated low-density lipoprotein cholesterol or decreased high-density lipoprotein cholesterol) and the future development of coronary heart disease has been well documented. Within the past several years, landmark clinical trials have clearly demonstrated that the incidence of coronary heart disease events is reduced when lipoprotein abnormalities are corrected via pharmacologic therapy. These findings have prompted clinicians to become more vigilant with regard to recognition of dyslipidemias and institution of treatment. This review focuses on the more common primary and secondary dyslipidemias and the currently available lipid-lowering therapies for each disorder. Results of recent coronary angiographic trials are discussed, and implications for the medical management of established coronary heart disease are assessed.

Experience with 'triple' anti-Helicobacter pylori eradication therapy: side effects and the importance of testing the pre-treatment bacterial isolate for metronidazole resistance

At the 1990 World Congresses of Gastroenterology, the Working Party on Helicobacter pylori (H. pylori) recommended that, in suitable patients, the bacterium should be eradicated using a therapeutic regimen comprising a bismuth salt, tetracycline and metronidazole for two weeks. We have treated 40 patients infected with H. pylori with 'triple' therapy consisting of 120 mg tripotassium dicitrato bismuthate q.d.s., 500 mg tetracycline q.d.s. and 400 mg metronidazole t.d.s. for two weeks. The success rate, in terms of bacterial eradication, was 19/21 (90.5%) in patients with metronidazole-sensitive organisms, compared with only 6/19 (31.6%) in patients whose H. pylori were resistant to metronidazole (P less than 0.01). Side effects, particularly diarrhoea and vomiting/nausea, were common: 23/40 patients reported such symptoms during the 14-day course of therapy. Fifteen of these 23 patients completed the entire 14-day course, although suffering from significant side effects, while the remaining eight patients had to discontinue the treatment because side effects became intolerable. If a form of triple therapy is going to be widely used to eradicate H. pylori infection, the regimen will have to be simpler, shorter, produce fewer side effects and be more effective in patients with metronidazole-resistant bacteria.

Hepatic adaptations to iron deficiency and exercise training

Brooks et al. [Am. J. Physiol. 253 (Endocrinol. Metab. 16): E461-E466, 1987] demonstrated an elevated gluconeogenic rate in resting iron-deficient rats. Because physical exercise also imposes demand on this hepatic function, we hypothesized that exercise training superimposed on iron deficiency would augment the hepatic capacity for amino acid transamination/deamination and pyruvate carboxylation. Sprague-Dawley rats (n = 32) were obtained at weaning (21 days of age) and randomly assigned to iron-sufficient (dietary iron = 60 mg iron/kg diet) or iron-deficient (3 mg iron/kg) dietary groups. Dietary groups were subdivided into sedentary and trained subgroups. Treadmill training was 4 wk in duration, 6 days/wk, 1 h/day, 0% grade. Treadmill speed was initially 26.8 m/min and was decreased to 14.3 m/min over the 4-wk training period. The mild exercise-training regimen did not affect any measured variable in iron-sufficient rats. In contrast, in iron-deficient animals, training increased endurance capacity threefold and reduced blood lactate and the lactate-to-alanine ratio during submaximal exercise by 34 and 27%, respectively. The mitochondrial oxidative capacity of gastrocnemius muscle was increased 46% by training. However, the oxidative capacity of liver was not affected by either iron deficiency or training. Maximal rates of pyruvate carboxylation and glutamine metabolism by isolated liver mitochondria were also evaluated. Iron deficiency and training interacted to increase pyruvate carboxylation by intact mitochondria. Glutamine metabolism was increased roughly threefold by iron deficiency alone, and training amplified this effect to a ninefold increase over iron-sufficient animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Does a previous course of tripotassium dicitrato bismuthate affect the subsequent chances of successful Helicobacter pylori eradication?

We have performed a retrospective study of 103 patients with either peptic ulcer or non-ulcer dyspepsia, infected with metronidazole-sensitive strains of Helicobacter pylori (H. pylori), who were treated with a combination of tripotassium dicitrato bismuthate and metronidazole for a period of at least two weeks. Dual therapy with tripotassium dicitrato bismuthate plus metronidazole showed similarly high eradication rates (greater than or equal to 80%) of H. pylori from patients irrespective of age, gender or clinical diagnosis. Most importantly, dual therapy achieved a similar eradication rate of H. pylori infection in 41 patients who had previously been treated with tripotassium dicitrato bismuthate alone or in combination with an antibiotic other than metronidazole. It therefore appears that H. pylori does not become resistant to treatment with tripotassium dicitrato bismuthate.

Detection of EBV DNA in post-nasal space biopsy tissue from asymptomatic EBV-seropositive individuals

The association between EBV and nasopharyngeal carcinoma (NPC) has been well documented although the precise role of the virus in the genesis of the tumour is not understood. We undertook this study to examine the prevalence of EBV infection in nasopharyngeal tissue obtained from 33 healthy individuals not considered to be at risk of developing NPC. Using polymerase chain amplification (PCR) and in situ hybridization we have identified EBV DNA in 70% (23/33) of the tissues examined. Our data demonstrate that EBV is present at the site of tumour development in the low-risk population and by inference that the virus is also present before the onset of disease in the high-risk group. This survey supports the concept of NPC pathogenesis as a multifactorial process.

Hyperlipidemia after heart transplantation: report of a 6-year experience, with treatment recommendations

Mean plasma lipid values in 100 patients who survived greater than 3 months after heart transplantation increased significantly at 3 months over pretransplantation values: total cholesterol from 168 +/- 7 to 234 +/- 7 mg/dl, low density lipoprotein (LDL) cholesterol from 111 +/- 6 to 148 +/- 6 mg/dl, high density lipoprotein (HDL) cholesterol from 34 +/- 1 to 47 +/- 1 mg/dl and triglycerides from 107 +/- 6 to 195 +/- 10 mg/dl. There were no significant increases after this time. The LDL cholesterol values reamined greater than or equal to 130 mg/dl in 64% of patients and triglyceride values remained greater than or equal to 200 mg/dl in 41% of patients 6 months after postoperative dietary instructions. Beginning in 1985, select patients whose total cholesterol values remained greater than 300 mg/dl despite 6 months of dietary intervention were treated with lovastatin given alone in a high dose (40 to 80 mg/day) or in combination with another hypolipidemic agent. Four of the five patients so treated developed rhabdomyolysis; two of the four had acute renal failure. Beginning in 1988, a second protocol--lovastatin at 20 mg/day as monotherapy--was used in patients who despite dietary intervention had total cholesterol greater than 240 mg/dl (mean follow-up 13 months). In the 15 patients so treated, mean total cholesterol decreased from 299 +/- 10 mg/dl before treatment with lovastatin to 235 +/- 9 mg/dl during treatment (21% reduction, p less than 0.001) and mean LDL cholesterol was reduced from a baseline value of 190 +/- 10 to 132 +/- 12 mg/dl during treatment (31% reduction, p less than 0.001). In this study, lovastatin at a dose of less than or equal to 20 mg/day as monotherapy was a well tolerated, effective treatment for hyperlipidemia after heart transplantation. It did not result in rhabdomyolysis and required no alteration in immunosuppressive therapy. However, the dose should not exceed 20 mg/day and combination therapy with either gemfibrozil or nicotinic acid should be avoided, even if the target LDL cholesterol value is not reached.