Collateral sensitivity to nitrosoureas in multidrug-resistant cells selected with verapamil.

We have examined the effects of the nitrosoureas, streptozotocin (STZ) and 1,3-bis(chloroethyl)-1-nitrosourea (BCNU), on a human multiple myeloma cell line, RPMI 8226, and its drug-resistant variants. Cell lines selected for doxorubicin (DOX) resistance alone displayed a STZ and BCNU cytotoxicity profile similar to that of the parent cell line. In contrast, two of the drug-resistant variants selected with DOX plus verapamil, an agent which inhibits P-glycoprotein-mediated multidrug resistance, displayed a collateral sensitivity to STZ and BCNU. Verapamil was included in the selection protocol because it has been shown to inhibit the P-glycoprotein-mediated multidrug resistance phenotype and is now in clinical trials as a chemosensitizing agent. The collateral sensitivity to these nitrosoureas seen in the DOX plus verapamil-selected cell lines is due to the functional loss of a DNA repair molecule, O6-Methylguanine DNA methyltransferase (MGMT). The functional loss of MGMT is secondary to the loss of MGMT gene expression. The loss of MGMT gene expression is not due to loss or gross rearrangement of the MGMT-coding region. If this selection pressure applied in vitro reflects the in vivo situation, then new chemotherapeutic strategies may be devised to exploit this phenomenon. These cell lines will serve as useful models for delineating mechanisms which govern MGMT expression.     

Exacerbation of lymphocytic choriomeningitis in mice treated with the inducible nitric oxide synthase inhibitor aminoguanidine

To elucidate the possible involvement of the inducible nitric oxide synthase (iNOS) and NO in the development of lymphocytic choriomeningitis (LCM), the consequences of inhibition of iNOS by the inhibitor aminoguanidine was examined in mice following intracerebral infection with LCM virus (LCMV). Aminoguanidine administration to mice infected with LCMV completely blocked increased plasma nitrate/nitrite levels and led to increased proinflammatory cytokine gene expression at early stages of lesion development in the brain, enhanced clinical severity and decreased survival time. The levels of LCMV recovered from the brain of aminoguanidine treated mice did not differ from those in infected control mice. These findings argue against either an anti-viral or pathogenic role of NO in LCM but rather suggest a possible protective action of this mediator.     

cDNA Sequencing of the 5′ Noncoding Region (5′ NCR) to Determine Hepatitis C Genotypes in Patients with Chronic Hepatitis C

Reports suggest that response tointerferon-alpha therapy is influenced by both hepatitisC viral genotype and titer. Our aim was to determine ifdirect, automated, cycle sequencing of the PCR productfrom an HCV RNA detection assay could be used toreliably determine HCV genotype. In addition, theapproach was used to determine the HCV genotypedistribution in our patient population and to learn ifthere was a correlation between HCV genotype and RNAtiter that could be used to predict response totreatment. In all 143 consecutive patients were testedfor both HCV RNA titer and genotype. Automated, cycle sequencing of PCR product was highly effectiveand failed to yield a genotype in only 3 (2%) patients.The distribution of HCV genotypes was: 1a (40%), 1b(39%), 2a (2%), 2b (6%), 3a (4%). There were significant differences in the median HCV RNA titersbetween genotypes 1, 2, and 3. 6 High HCV RNA titers>4.4 × 10⁶ copies/ml were only seenin genotype 1. However, the HCV RNA level should not beused as a surrogate marker of genotype because of a significantoverlap of titers within the genotypes.     

EXTERNAL CEPHALIC VERSION

External cephalic version has been used periodically for centuries to manage breech presentations. As cesarean section rates have escalated in the last two decades, ways to curb this rise have been evaluated. By reducing the number of infants that arrive in labor in a representation, it is possible to impact the overall cesarean section rate. External cephalic version is a safe, effective method when used in appropriate cases of breech presentation. A forward or backward roll can be accomplished in women at term with singleton gestations, adequate amniotic fluid, and reactive nonstress tests. Parity, fetal and placental position, and descent of the presenting part may all influence the success rate of the version.     

Effect of temperature in focal ischemia of rat brain studied by 31P and 1H spectroscopic imaging

³¹P, ¹H and lactate spectroscopic imaging was used to evaluate the effects of hypothermia on focal cerebral ischemia produced by middle cerebral artery occlusion. The effects on high energy phosphate metabolism, pH, lactate and NAA were investigated in 24 spontaneously hypertensive rats subjected to either permanent or transient ischemia. Under either normothermic (37.5°C) or hypothermic (32°C) conditions, with permanent 6-h occlusion, there was little difference between groups in either the NMR measurements or the volume of infarction. In animals that underwent 3 h of ischemia followed by 12 h of reperfusion, the ischemic changes in lactate, pH, NAA, and high-energy phosphate returned toward control values, and there was a protective effect of hypothermia (infarct volume of 211 ± 26 and 40 ± 14 mm³ in normothermic and hypothermic groups, respectively). Thus, hypothermia did not ameliorate the changes in lactate, pH, NAA, or high energy phosphate levels occurring during ischemia, however, during reperfusion there was an improvement in both the recovery of these metabolites and pathological outcome in hypothermic compared with normothermic animals.     

Focus groups: their role in developing calcium-related education materials

Because attitudes concerning a topic can diminish the effectiveness of educational materials, previously identified attitudes concerning calcium intake were explored through focus group interviews during the developmental stages of calcium education materials. Although four focus groups of six to seven participants were planned, each of the four groups consisted of two to six women. All focus groups followed the same format, lasting for 60–90 min; questions progressed from the general to more specific. The focus groups revealed several attitudinal barriers toward dietary behavioural change, including lack of prior interest in the topic and lack of time. Attitudes about dairy calcium included the belief that dairy foods were high in fat and should be avoided, and the belief that dairy foods would cause stomach upsets. Also, neither younger nor older women felt that osteoporosis was a problem their age group needed to address. Readability scales were not necessarily predictive of preference. This study shows that focus group interviews make a valuable contribution to planning and evaluating nutrition education materials.     

Bilateral aberrant internal carotid arteries.

This case report represents the first well-documented case of aberrant internal carotid arteries in both middle ears. CT and DSA can establish the diagnosis before surgical intervention. Aberrant internal carotid artery represents a rare finding in the differential diagnosis of middle ear masses. Most patients manifest either vertigo, tinnitus, or a variable hearing loss. Clinical findings include a red or blue mass behind the eardrum that may or may not be pulsatile. The otolaryngologist should be aware that this potential landmine may be obscured by serous otitis media. Once suspected, the mass should be evaluated by radiographic studies before surgical intervention.     

Long-term outcome of completion gastrectomy for nonmalignant disease

Between 1989 and 1995 we performed completion gastrectomy for non-malignant disease in 21 patients (11 men and 10 women, mean age 48.4 years). These patients had undergone a total of 48 prior gastric operations. Indications for completion gastrectomy in this group were anastomotic ulceration with stricture in eight patients, alkaline reflux gastritis and/or esophagitis in eight, postsurgical gastroparesis in two, gastroesophageal necrosis in two, and gastrocutaneous fistula in one. Major preoperative symptoms included nausea and vomiting in 16 cases, abdominal pain in 15, dysphagia in 14, heartburn in seven, and weight loss in five. Following completion gastrectomy, five patients (24%) had serious complications and there was one postoperative death (5%). Five patients were lost to follow-up. For the remaining 15 patients, mean follow-up has been 30 months with a range of 1 to 70 months. These patients were all interviewed and eight (53%) report significant improvement, two (13%) report moderate improvement, and four (27%) report no improvement; one patient (7%) has had worsening of symptoms since undergoing completion gastrectomy. The average body weight index was essentially unchanged after completion gastrectomy. We conclude that completion gastrectomy with Roux-en-Y esophagojejunostomy results in a favorable outcome in the majority of selected patients with diseases of the foregut who are unresponsive to less radical treatment. Presented at the Thirty-Seventh Annual Meeting of The Society for Surgery of the Alimentary Tract, San Francisco, Calif., May 19–22, 1996.