Cardiovascular effects of methamphetamine

Stimulant abuse has grown in popularity, particularly since the advent of crack cocaine. Another commonly abused drug is methamphetamine (MAP) hydrochloride. Known as crank, crystal, ice, crystal meth, and speed, MAP can be produced easily from ephedrine, and it is widely available. This article describes the pharmacology, cardiovascular effects, and toxicology of MAP, as well as the management principles of MAP abuse.

Betaine:homocysteine methyltransferase--a new assay for the liver enzyme and its absence from human skin fibroblasts and peripheral blood lymphocytes

Chronic elevation of plasma homocysteine is associated with increased atherogenesis and thrombosis, and can be lowered by betaine (N,N,N-trimethylglycine) treatment which is thought to stimulate activity of the enzyme betaine:homocysteine methyltransferase. We have developed a new assay for this enzyme, in which the products of the enzyme-catalysed reaction between betaine and homocysteine are oxidised by performic acid before being separated and quantified by amino acid analysis. This assay confirmed that human liver contains abundant betaine:homocysteine methyltransferase (33.4 nmol/h/mg protein at 37 degrees C, pH 7.4). Chicken and lamb livers also contain the enzyme, with respective activities of 50.4 and 6.2 nmol/h/mg protein. However, phytohaemagglutinin-stimulated human peripheral blood lymphocytes and cultured human skin fibroblasts contained no detectable betaine:homocysteine methyltransferase (less than 1.4 nmol/h/mg protein), even after cells were pre-cultured in media designed to stimulate production of the enzyme. The results emphasize the importance of the liver in mediating the lowering of elevated circulating homocysteine by betaine.

Use of a 25-gauge Whitacre needle to reduce the incidence of postdural puncture headache

We studied 200 orthopaedic inpatients (111 males) aged 15-84 yr who received spinal anaesthesia with one of two types of Whitacre spinal needle: 22-gauge or 25-gauge. The incidence of headache, backache, failure of spinal anaesthesia and patient acceptability was investigated using a questionnaire. The incidence of postdural puncture headache (PDPH) was 4% in the 22-gauge group and 2% in the 25-gauge group. The incidence of backache and headache of other origin was similar in both groups. Spinal anaesthesia was carried out successfully in all patients in both groups. Patient acceptance was high (98%) and there were no serious complications observed. We conclude that spinal anaesthesia is easy to perform with a 25-gauge pencil-point needle and is associated with a low incidence of PDPH.

Free-standing surgery centers; the wave of the future

To summarize, it should be realized that acceptance of surgicenters has happened. Surgery centers expect heightened awareness of their services as patients, in conjunction with their own physicians, make decisions based on cost, service, and convenience of the care provided. As copayments and deductibles increase, consumers have become better educated, taking a more active role in selecting their health care providers. This activity has given rise to joint ventures between physicians and hospitals offering new ambulatory care packages previously based in hospitals alone. The net effect will divide the health care industry into two markets, one that will manage high-intensity surgical procedures and one that will promote outpatient surgical procedures.

Validation of World Health Organization guidelines for cancer pain relief during the last days and hours of life

The efficacy of the World Health Organization's guidelines for cancer pain relief was examined in 401 dying patients. At the time of death, only 3% of the patients experienced severe or very severe pain; whereas 52% had no pain at all, 24% experienced only mild or moderate pain, and 20% were unable to rate their pain intensity. Analgesic drugs were the mainstay of therapy during the last 24 hr of life, being administered by mouth in 47% and parenterally in 44% of the patients. Only 9% of the patients required no systemic analgesics. Nonopioid analgesics alone were effective in 5% and a combination of nonopioids and "weak" opioids were effective in 16% of the patients. In the remaining 70% of the patients "strong" opioids alone or in combination with nonopioid analgesics were necessary to achieve adequate pain reduction. Additional adjuvant drugs to treat special types of pain or other symptoms were prescribed in 90% of the patients. Nonpharmacological measures, such as radiotherapy, nerve blocks or neurosurgery played only a very minor role at this stage of the disease. This study shows that cancer pain can be treated satisfactorily until death.

Comparison of clinical, radionuclide, and radiographic features of osteoarthritis of the hands

Simultaneous clinical, scintigraphic, and macroradiographic assessments were carried out on 32 patients with hand osteoarthritis and the results at entry and one year reported. The presence and growth of osteophyte correlated with symptoms and a positive scan. The scan did not detect the radiographic features of juxta-articular radiolucencies, subchondral sclerosis, or cartilage thinning. Osteophytes, particularly when fast growing, produce pain, a 'hot' scan, and may predict disintegration of joint architecture.

Familial breast-ovarian cancer locus on chromosome 17q12-q23

Familial breast cancer has been linked to the D17S74 locus on chromosome 17q. To confirm this finding and to investigate whether ovarian cancer is also linked to this locus, five large families with a hereditary predisposition to cancer of the breast and ovary were investigated. Three families were positive for linkage. For the largest family the lod score was 2.72. These findings suggest that the chromosomal region 17q12-q23, previously shown to contain a gene for early-onset breast cancer, is also associated with a proportion of hereditary ovarian cancers.

A follow-up study of colonic epithelial proliferation as a biomarker ina Native-American family with hereditary nonpolyposis colon cancer

A 7-year follow-up study of colonic mucosa proliferation markers was conducted on members of a Native-American family with hereditary nonpolyposis colon cancer. Reproducibility of a tritiated thymidine autoradiography assay for labeling indexes during this 7-year biologically significant time frame was established. A good correlation between tritiated thymidine and a newer technique, bromodeoxyuridine immunoperoxidase staining, was seen. No confounding effect could be attributed to standard colon preparation. On average, both baseline and follow-up values for epithelial proliferation were within the accepted normal range. The presence of essentially normal labeling indexes among colon cancer patients and their high-risk offspring suggests the possibility of the significant effect of dietary factors in reducing proliferation. Such factors may account for the low risk of colon cancer that characterizes the Native-American population in the American Southwest.

Specificity of low dose fadrozole hydrochloride (CGS 16949A) as an aromatase inhibitor

CGS 16949A (fadrozole hydrochloride), a potent cytochrome P450-mediated steroidogenesis inhibitor, blocks aromatase at low doses, but other biosynthetic steps at higher concentrations. Recent studies demonstrated inhibition of C11-hydroxylase, corticosterone methyloxidase-II, and deoxycorticosterone to corticosterone conversion with this agent at some-what higher concentrations than those required for blockade of aromatase. Based upon phase I studies, we postulated that relatively selective inhibition of aromatase might be possible if sufficiently low doses of CGS 16949A were used. A phase II study in 54 postmenopausal women with metastatic breast cancer examined the effects of low dose CGS 16949A on estrogen, mineralocorticoid, and glucocorticoid secretion. Two dose schedules and two dose levels were chosen based upon our prior dose escalation protocol study. Plasma estrone, estradiol, and estrone sulfate as well as urinary estrone and estradiol fell equally with 1.8-4 mg CGS 16949A given either on a twice daily or three times daily dose schedule. Isotopic kinetic studies demonstrated an 84% decrease in the rate of conversion of androstenedione to estrone to 0.40 +/- 0.07% (patients receiving 1.8-4 mg CGS 16949A daily). With these three regimens, basal levels of aldosterone and cortisol did not change significantly over a 12-week period of observation. Clinical examination, plasma electrolytes, and urinary sodium/potassium ratios suggested no biological evidence of mineralo-corticoid deficiency. ACTH-stimulated cortisol concentrations, however, were blunted at each dose level compared to pretreatment values. Nonetheless, peak responses exceeded 550 nmol/L, or a basal to peak difference of 190 nmol/L or greater, in 97% of instances. This probably reflected inhibition of C11-hydroxylase, since basal and ACTH-stimulated levels of 11-deoxycortisol were increased in response to CGS 16949A. Androstenedione and 17 alpha-hydroxyprogesterone also exhibited an upward trend in response to drug treatment. ACTH-stimulated aldosterone levels were blunted to a greater extent than those of cortisol, probably as a reflection of corticosterone methyloxidase type II blockade. Overall, the results suggest that CGS 16949A, at doses of 1.8-2 mg daily, blocks aromatase effectively and does not produce clinically important inhibition of cortisol or aldosterone biosynthesis. Thus, this agent can probably be used safely without glucocorticoid or mineralocorticoid supplementation.

Identification and regulation of insulin-like growth factor binding proteins produced by hormone-dependent and -independent human breast cancer cell lines

Using molecular hybridization, ligand blotting and immunoprecipitation, our studies were designed to identify the insulin-like growth factor binding proteins (IGFBPs) produced by human breast cancer cells in culture and evaluate their regulation by estradiol (E2) and polyamines (PA). We demonstrate that the hormone-dependent MCF-7 and -independent BT-20 cell lines express the mRNA for IGFBP-2 (1.7 kb) and secrete this BP (31 kDa) in the conditioned medium. In contrast, the hormone-independent MDA-MB-231 cell line does not express the IGFBP-2 gene, while synthesizing and secreting IGFBP-1. E2 administration (10(-9) M) did not significantly influence IGFBPs secretion in MCF-7 cells. Addition of alpha-difluoromethylornithine (DFMO, 4 mM), an inhibitor of PA biosynthesis, consistently lowered IGFBP-2 mRNA in the MCF-7 and BT-20 cell lines and IGFBP-1 mRNA in MDA-MB-231 cells. Surprisingly, however, this compound either did not influence IGFBPs secretion in MCF-7 cells or actually increased their secretion in the BT-20 and MDA-MB-231 cell lines. PA involvement in IGFBPs production by breast cancer cells is complex and may involve differential regulation of transcriptional and post-translational events.

Hereditary nonpolyposis colorectal cancer (Lynch syndromes I & II). Genetics, pathology, natural history, and cancer control, Part I

Hereditary nonpolyposis colorectal cancer (HNPCC) is common, accounting for about 4-6% of the total colorectal cancer burden. It is heterogeneous and appears to be delineated into two clinical subsets, Lynch syndromes I and II. Lynch syndrome I is characterized by an autosomal dominantly inherited proclivity to early onset colonic cancer with proximal predominance and an excess of multiple primary colonic cancer. Lynch syndrome II has all of these features plus extracolonic cancer sites, the most common of which is endometrial carcinoma. The lack of premonitory physical signs or biomarkers of HNPCC makes diagnosis difficult. A careful family history, tempered by an understanding of the clinical and pathologic features of HNPCC, is the key to its assessment. This paper reviews HNPCC's natural history, its integral extracolonic cancer associations, its differential diagnosis, surveillance, and management strategies. Attention is focused upon the need for biomarker research in the interest of improving control of HNPCC.

Hereditary ovarian cancer. Pedigree studies, Part II

Hereditary ovarian carcinoma is heterogenous. There are at least three genetic variants, namely, hereditary site-specific ovarian carcinoma, hereditary breast/ovarian carcinoma syndrome, and Lynch syndrome II. Early age of onset characterizes these disorders. A crucial hallmark of these disorders is the integral association of extraovarian cancers, such as carcinoma of the endometrium and colon in Lynch syndrome II. We have described 24 pedigrees of ovarian cancer-prone families in order to depict the several differing heterogenous variants. Interest in hereditary ovarian cancer has increased remarkably, due in part to the fact that its surveillance has been wholly unsatisfactory, as have therapeutic measures. Prevention through prophylactic oophorectomy offers hope. However, there is a risk for extraovarian peritoneal serous papillary carcinoma, consonant with primary cancer of the ovary. This must be discussed with these at-risk patients. Until a biomarker of acceptable sensitivity and specificity is identified, the family history must remain the key to hereditary ovarian cancer diagnosis.

Polyamine involvement in the secretion and action of TGF-alpha in hormone sensitive human breast cancer cells in culture

These experiments were designed to test polyamine (PA) involvement in the secretion and action of transforming growth factor alpha (TGF-alpha) in hormone responsive MCF-7 breast cancer cells in liquid culture. At the same time, we evaluated the influence of culture conditions (with serum vs. serum depleted) and subclonality of MCF-7 cells on PA involvement in estrogen (E2) and TGF-alpha stimulated cell proliferation. Despite inducing a profound suppression of cellular PA levels and inhibiting basal and E2-stimulated growth, administration of the PA synthesis inhibitor alpha-difluoromethylornithine (DFMO) did not influence either basal or E2-induced TGF-alpha secretion. In the same experiments, on the other hand, addition of DFMO completely blocked the growth stimulatory effect of exogenous TGF-alpha. However, when the culture conditions were changed to serum-free medium, TGF-alpha and E2-induced cell proliferation was affected modestly or not at all by DFMO administration, despite similar suppression of cellular ornithine decarboxylase (ODC) activity and PA levels. In addition, different clones of MCF-7 cells differed in their sensitivity to the antiproliferative effect of DFMO as well as in basal levels of ODC activity and PA. We conclude that PAs are not involved in basal or E2-stimulated TGF-alpha secretion in MCF-7 breast cancer cells. On the other hand, PAs do seem to be important mediators of TGF-alpha and E2-induced breast cancer cell proliferation, though the degree of such involvement appears to be influenced by serum factors and clonal variability of MCF-7 cells.

The effect of E. coli STa enterotoxin on the absorption of weakly dissociable anti-malarial drugs from rat intestine in vivo

1. The effect of E. coli heat stable (STa) enterotoxin on the absorption of radiolabelled anti-malarial weak bases and their appearance in peripheral blood was assessed in vivo by a recirculation procedure in rat intestinal loops. 2. Enterotoxin increased the jejunal disappearance of quinine (P less than 0.05), trimethoprim (P less than 0.05), proguanil (P less than 0.05) and chloroquine (P less than 0.001) and left pyrimethamine disappearance unaltered. Peripheral blood levels of trimethoprim (P less than 0.02) and proguanil (P less than 0.05) were higher after STa exposure. 3. In the ileum, enterotoxin increased the luminal disappearance (P less than 0.05) and peripheral blood appearance (P less than 0.001) of chloroquine. The luminal disappearance rate of trimethoprim was reduced (P less than 0.05) and that of pyrimethamine unchanged. 4. The increased jejunal absorption of the anti-malarial drugs occurred despite STa causing a reduction in the amount of net fluid absorption. It seems likely that the enhanced absorption with STa exposure is related to the effect of STa on the microclimate pH. An elevation in the microclimate pH would increase the amount of undissociated weak base available for non-ionic diffusion. 5. The favourable elevation of microclimate pH by STa seemed to be outweighted by the reduced fluid absorption in the ileum. Only chloroquine still showed enhanced absorption in the ileum and this may have been because unlike the other antimalarial drugs, chloroquine has two dissociable groups likely to be affected by the mucosal surface pH changes.

An adenomatous polyp case-control study to assess occupational risk factors following a workplace colorectal cancer cluster

To assess potential etiologic factors among a population of Texas polypropylene workers previously found to have an excess of colorectal cancer (concentrated among mechanical and process workers), the authors conducted an adenomatous polyp case-control study. Cases (n = 24) were workers found to have adenomatous polyps during a company-sponsored colorectal cancer screening program, while controls (n = 72) were workers found to be free of polyps. Exposure assessment utilized a thorough industrial hygiene and toxicologic review of operations in conjunction with work activity interviews of cases and controls to develop chemical-specific exposure scores weighted by time, exposure level, and frequency of exposure. Stratified analyses and logistic regression found that cases tended to have higher exposure to pre-extrusion polymer plus additives (odds ratio (OR) = 2.6, 90% confidence interval (CI) 1.1-6.3) and higher exposure to certain finishing additives (OR = 4.8, 90% CI 1.5-15.3). Analyses by job category or area of the plant did not indicate additional risk factors. The exposures identified in this study are discussed in light of the available toxicologic data on these and related compounds. The need for confirmatory experimental and epidemiologic studies is noted.

Failure to detect homocysteine in the acid-hydrolysed plasmas of recent myocardial infarct patients

We have sought the very high levels of homocysteine-containing compounds in the plasma hydrolysates of myocardial infarct patients reported by Olszewski and Szostak (Atherosclerosis, 69 (1988) 109-113). We studied 6 adult males with recent myocardial infarcts and 6 healthy adult males. We found that after hydrolysis of their plasmas for 5 h in 4 mol/l HCl at 110 degrees C, the amino acid chromatographs contained several small peaks in addition to the expected substantial peaks of the protein-constituent amino acids. However, the small peaks which eluted at the same times as homocysteine, homocystine and the mixed disulphide of homocysteine and cysteine, were in each case shown not to represent these compounds. Furthermore no homocysteine thiolactone was found in the chromatographs. We found no significant differences in the size of the small peaks between the patients and the controls. Prolonged hydrolysis resulted in decreased size of all but one of the small peaks suggesting that they were hydrolytic intermediates in the breakdown of plasma proteins. Electrophoresis at pH 10.39 of the unhydrolysed plasmas showed that the proteins were not significantly more homocysteinylated in patients than in controls. Thus we have been unable to substantiate some key observations made by Olszewski and Szostak.

Quantitative microfocal radiographic assessment of disease and progression in osteoarthritis of the hand

Macroradiographic examination of the wrists and hands of 32 patients with osteoarthritis (OA) over an 18 month period showed that, compared with healthy control subjects, 44% of the patients had significant joint space narrowing at entry, which increased to 65%. Subchondral cortical thickness was greater in all patients at entry and increased with time. Osteophytes and juxtaarticular radiolucencies were present in all patients at study entry; by the end, osteophytes had increased in number and area, and juxtaarticular radiolucencies in area only. We conclude that in OA of the hand, bony changes have progressed significantly before joint space narrowing.

Selectivity of polyamine involvement in hormone action on normal and neoplastic target tissues of the rat

The present experiments were designed to evaluate the polyamine involvement in hormonal actions on proliferation and receptor content of neoplastic tissue (hormone-responsive breast cancer) as well as on growth of normal endocrine target tissue (uterus) in the same animals. Administration of estradiol and perphenazine (to stimulate endogenous prolactin release) stimulated N-nitrosomethyl-urea (NMU)-induced rat mammary tumor growth following ovariectomy-induced tumor regression. Such hormonal activation of breast cancer growth was completely abolished by treatment with alpha-difluoromethyl-ornithine (DFMO), a specific irreversible inhibitor of ornithine decarboxylase, which lowered tumor content of polyamines. The growth inhibitory effect of DFMO was partially reversible by exogenous putrescine administration. In contrast, the rise in cytosolic content of progesterone receptors induced by hormonal treatment was not affected by suppression of tumor polyamine levels by DFMO. Similarly, DFMO administration failed to influence the hormone-induced increase in uterine weight in the same animals. Thus, our data suggest selectivity of polyamine involvement in hormone actions, which, in our experimental system, seems to be restricted to the endocrine control of neoplastic cell proliferation.