Circadian rhythm of gastric pH in patients with healed ulcer under placebo and constant-rate ranitidine infusions.
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Biomedical subjects
Publications and source records attributed to J Moore.
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Host cell factors act together with regulatory genes of the human immunodeficiency virus (HIV) to control virus production. Human-Chinese hamster ovary hybrid cell clones were used to probe for human chromosomes involved in regulating HIV gene expression. DNA transfection experiments showed that 4 of 18 clones had high levels of HIV gene expression measured by both extracellular virus production and transactivation of the HIV long terminal repeat in the presence of the trans-activator (tat) gene. Karyotype analyses revealed a 94% concordance (17/18) between human chromosome 12 and HIV gene expression. Other chromosomes had an 11 to 72% concordance with virus production.
Eighteen Burkitt's lymphoma (BL) cell lines were analyzed for rearrangement and expression of the delta gene. None had rearrangement of the delta gene locus within the 9.0-kb BamHI restriction fragment. Cell lines that expressed the delta gene contained both mu alleles, with at least one productively rearranged. Thirteen of 18 cell lines had detectable transcripts hybridizing with the delta probe. In 10 of the 13 cell lines with delta transcripts, cytoplasmic delta chains were detected, but only two of these expressed delta chains strongly on the surface. All 13 lines made cytoplasmic mu chains, and all except one made cytoplasmic light chains. Surface IgM was detected in all except two of the 13 cell lines. Although BL has generally been considered not to express IgD, except in occasional cases, previous studies have been confined to examination of the cell surface. Many of the cell lines that we examined express delta mRNA transcripts as well as produce cytoplasmic delta chains but no detectable surface IgD. This suggests that delta chains are detectable in the cytoplasm prior to being apparent on the surface. Our findings argue against an origin of BL from germinal center cells since IgD is almost totally lacking in normal B cells present in germinal centers.
The early diagnosis of infection with human immunodeficiency virus (HIV) in infants born to infected mothers is essential for early treatment, but current tests cannot detect HIV infection in newborns because of the presence of maternal antibodies. We used the polymerase chain reaction, a new technique that amplifies proviral sequences of HIV within DNA, to detect HIV infection in peripheral-blood mononuclear cells obtained from infants of seropositive women during the neonatal (age less than 28 days) and postneonatal periods. In blood obtained during the neonatal period, the polymerase chain reaction was positive in five of seven infants in whom the acquired immunodeficiency syndrome (AIDS) later developed (a mean of 9.8 months after the test). The test was also positive in one of eight newborns who later had nonspecific signs and symptoms suggestive of HIV infection (mean follow-up, 12 months). No proviral sequences were detected in neonatal samples from nine infants who remained well (mean follow-up, 16 months). HIV proviral sequences were detected in samples obtained during the postneonatal period (median age, five months) in all of 6 infants tested who later had AIDS and in 4 of 14 infants with nonspecific findings suggestive of HIV infection. No proviral sequences were detected in 25 infants who remained well (mean follow-up, 17 months) after being born to HIV-seropositive mothers, or in 15 infants born to HIV-seronegative mothers. We conclude that the polymerase chain reaction will be a useful technique to diagnose HIV infection in newborns and to predict the subsequent development of AIDS. However, larger studies will be required to determine the sensitivity and specificity of the test.
This 57-month study evaluated the use of automatic external defibrillators (AEDs) in the homes of high risk cardiac patients (survivors of out-of-hospital ventricular fibrillation [VF]). The goal was to determine the utility of these devices by trained lay persons in actual cardiac arrest episodes. Ninety-seven survivors of out-of-hospital VF were enrolled in the study; 59 patients received AEDs, and 38 patients served as a control group. During the study period, 7 deaths occurred in the hospital without preceding out-of-hospital cardiac arrest or from noncardiac causes. There were 14 out-of-hospital cardiac arrests, 10 in the AED group and 4 in the control group. There was 1 long-term survivor in the control group. In the AED group, among the 10 cardiac arrests for which the device was available, it was used in 6. Only 2 patients were in VF; 1 was resuscitated with residual neurologic deficits and survived several months. This study observed a small potential for AEDs to save high risk patients.
The clinical and pathologic records of 12 patients with pancreatic lymphoma were reviewed retrospectively to determine distinguishing clinical features. Radiologically, all patients had large abdominal masses in the region of the pancreas. Preoperative percutaneous cytologic biopsy specimens failed to make the diagnosis, and two specimens were interpreted incorrectly as poorly differentiated adenocarcinoma. The diagnosis was difficult to make in two cases, even at laparotomy. Four patients underwent a biliary bypass, and two underwent a concomitant gastric or duodenal bypass. Two patients died postoperatively. Four patients responded well to chemotherapy and/or radiation therapy, and two did not have any recurrences at 3 and 7 years postoperatively. Although rare, lymphoma should be considered in patients with undiagnosed pancreatic masses. The diagnosis may only be made with appropriate preoperative or intraoperative suspicion, and treatment may be rewarding, particularly in comparison with pancreatic adenocarcinoma.
Thirty patients who chose extradural analgesia for elective Caesarean section were pretreated, by random selection, with cimetidine 400 mg, ranitidine 150 mg or no H2-blocker. Following the administration of 0.5% bupivacaine, no significant difference was found between peak plasma bupivacaine concentrations or area under the plasma bupivacaine concentration-time curve (AUC) in these three groups. This study shows that a single dose of cimetidine or ranitidine does not affect significantly the disposition of bupivacaine in the obstetric patient.
The authors analyzed data from 106 adults with chronic renal failure [(CRF), serum creatinine (Scr) greater than 132.6 mumol/l (1.5 mg/dl)], to define the precision of, and effects of covariables on, the relationship between anemia and CRF. We excluded dialyzed or patients who had received transplants and those with obvious potential nonrenal causes of anemia. Hct was a linear function of BUN and Scr (r = -0.48, and r = -0.67, respectively), and a curvilinear function of creatinine clearance (r = 0.68), all p less than .0001. Confidence interval analysis revealed a +/- 10 volume percent variation in Hct at any level of renal function. Sex was the only covariable that affected Hct independently of CRF. This study suggests that CRF may have a different effect on Hct in males and females and indicates that the range of Hct possible at a given level of CRF precludes attributing anemia to CRF with assurance.
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We studied whether an intravenous bolus of cimetidine altered the disposition of extradurally administered lignocaine in the parturient. Mothers who requested extradural analgesia for elective Caesarean section were randomly pretreated with either cimetidine 200 mg intravenously (n = 5) or no H2-receptor antagonist (n = 5). No difference was found between peak plasma lignocaine levels or area under the plasma concentration/time curve between the two groups after administration of 6 mg/kg lignocaine 2% with adrenaline 1:200,000. There was no evidence for an effect of a single intravenous dose of cimetidine on lignocaine disposition in the obstetric patient. In addition, the extradural administration of 6 mg/kg lignocaine produces plasma levels well below toxic levels.
Two comparable series of 21 patients who had elective Caesarean section had general anaesthesia induced by thiopentone sodium 4.53 (SD 0.65) mg/kg or propofol 2.15 (SD 0.26) mg/kg. Maintenance was similar for both groups. Blood pressure was lower in the propofol group during the induction-delivery interval. Umbilical/maternal vein ratios for thiopentone and propofol were 8.5 and 7.2 respectively. Infant wellbeing as judged by Apgar score and cord blood analysis showed little difference between the two induction agents. Factors associated with uterine relaxation and bleeding were similar in the two groups.
Various antacid or antisecretory agents are used to reduce the risk to patients of aspiration of gastric contents during general anaesthesia and a trial of the gastric proton pump inhibitor, omeprazole, is reported here. Twenty women admitted for elective Caesarean section under general anaesthesia received a single 80-mg oral omeprazole dose at 2000 hours on the evening before surgery. Intragastric pH and volume were measured immediately after induction of anaesthesia and on completion of surgery. Eighty-five percent of pH measurements at induction and extubation and 80% and 95% of volume measurements at induction and extubation respectively met the defined success criteria (pH greater than or equal to 2.5, volume less than 25 ml). Omeprazole treatment was well tolerated by the women and Apgar scores and subsequent progress of the babies were acceptable. These results indicate that gastric acidity and volume were acceptable in the majority of women after omeprazole treatment, but the interval from drug administration to induction of anaesthesia may have been too long in some cases and resulted in unacceptably low pHs.
Gastric pH and volumes were measured in 84 women who had general anaesthesia for emergency Caesarean section. Forty-eight received only 20 ml 8.4% sodium bicarbonate immediately before induction of anaesthesia and 36 ranitidine 150 mg 6-hourly during labour in combination with NaHCO3. Gastric pH was less than 2.5 in four women who received only bicarbonate. All aspirates from the ranitidine plus bicarbonate group had a pH greater than 2.5. Mean volumes of gastric content aspirated were 87 (SD 87.4) and 60 (SD 46.3) ml for the bicarbonate alone and bicarbonate plus ranitidine series respectively. These differences were not significant. Twenty millilitres of 8.4% NaHCO3 cannot be recommended as a single dose antacid for emergency Caesarean section. Ranitidine plus bicarbonate is considered a reliable antacid regimen to ensure elevation of gastric pH to safe levels.
We studied whether a single oral dose of either cimetidine or ranitidine affects the disposition of epidurally administered lidocaine in the parturient. Patients given epidural analgesia for elective caesarean section were randomly pretreated with either cimetidine 400 mg (n = 5), ranitidine 150 mg (n = 7) or no H2 receptor antagonist (n = 5). Following the administration of 400 mg of lidocaine 2% with adrenaline 1:200,000 no difference was found in peak plasma lidocaine levels or area under the plasma concentration/time curve (AUC) between the three groups. A single oral dose of cimetidine or ranitidine does not affect lidocaine disposition in the obstetric patient.
Eighty California quail (Callipepla californica), collected from the E. E. Wilson Wildlife Area near Monmouth, Oregon (USA) during a 22 mo period, were examined for gastrointestinal helminths. Eight birds were infected with three species of nematodes, Heterakis isolonche, Dispharynx nasuta, and Capillaria sp., and two species of cestodes, Rhabdometra odiosa and Davainea sp. Except for D. nasuta, prevalence did not exceed 5% despite mesic conditions in the collection area. Two mountain quail (Oreortyx pictus) were collected from Lane County, Oregon (USA), near Blue River Reservoir; both were infected with the nematode Trichostrongylus tenuis.