Zinc supplementation in infants born small for gestational age reduces mortality: a prospective, randomized, controlled trial.

BACKGROUND: Low birth weight infants have been noted to have low zinc concentrations in cord blood, and zinc deficiency in childhood is associated with reduced immunocompetence and increased infectious disease morbidity. This study investigates whether zinc supplementation of infants born full term and small for gestational age affects mortality. METHODS: A randomized, double-blind, controlled trial with 2-by-2 factorial design enrolled 1154 full-term small for gestational age infants to receive in syrup 1 of the following: riboflavin; riboflavin and zinc (5 mg as sulfate); riboflavin, calcium, phosphorus, folate, and iron; or riboflavin, zinc, calcium, phosphorus, folate, and iron. A fixed dosage of 5 mL per child was given daily from 30 to 284 days of age. Household visits were made 6 days per week to provide the syrup and conduct surveillance for illness and death. When a child's death was reported, parental reports and medical records were used to ascertain the cause. The effects of zinc and of the combination of iron, folate, calcium, and phosphorus were analyzed by intent to treat. The mortality analysis was performed using a survival analytic approach that models time until death as the dependent variable; all models had 2 terms as independent variables: 1 for the zinc effect and 1 for the vitamin and mineral (calcium and phosphorus, folate and iron) effect. RESULTS: Zinc supplementation was associated with significantly lower mortality, with a rate ratio of 0.32 (95% confidence interval: 0.12-0.89). Calcium, phosphorus, folate, and iron supplementation was not associated with a mortality reduction, although a statistically nonsignificant trend toward reduction was observed with a rate ratio of 0.88 (95% confidence interval: 0.36-2.15). CONCLUSIONS: Zinc supplementation in small for gestational age infants can result in a substantial reduction in infectious disease mortality.

Inhibition of hepatitis-B-virus core promoter by p53: implications for carcinogenesis in hepatocytes.

The incidence of hepatocellular carcinoma (HCC) is particularly high in regions of Asia and sub-Saharan Africa where rates of infection with human hepatitis-B virus (HBV) and aflatoxin-B1 contamination of food are high. In HCC tumors occurring in inhabitants of these regions, a G-to-T mutation frequently occurs at position 249 of the tumor-suppressor gene p53. This suggests that HBV and p53 mutation may collaborate in the carcinogenic process in liver. We have examined the effect of the HBV protein HBX in HCC lines with exogenous wild-type p53 or mutated p53 on transactivation of 2 different reporter genes. Transfection of HCC lines with wild-type p53 and a reporter with the promoter from the p53-responsive gene WAF1/p21 resulted in a high level of expression, as expected. When cells were co-transfected with a reporter gene driven by the HBV core promoter and with the HBX gene, expression was enhanced in the Hep 3B, HLE, PLC/PRF/5 and HuH 7 lines, but not in the HuH 1 line. Co-transfection of the reporter with a plasmid containing wild-type p53 resulted in significant inhibition of the HBV core promoter in all of the lines, whereas the mutated p53 gene had no effect. Our results indicate that wild-type p53 can inhibit transcription from the HBV core promoter. In similar experiments, both HBX and p53 were co-transfected into HCC lines with the WAF1/p2l reporter gene. HBX inhibited p53-induced expression in 4 of the 6 lines (Hep 3B, HuH 1, HuH 7 and HLE), there was no effect in one line (HLF), and enhancement was evident in PLC/PRF/5. Our results indicate that inhibition of p53 transcriptional activity by HBX does occur in HCC, but is highly cell-context-dependent. Inhibition of transcription from the HBV core promoter by wild-type p53 appears to be more universal, and may represent a mechanism by which wild-type p53 can protect against the carcinogenic process in liver.

Cell cycle-dependent modulation of telomerase activity in tumor cells.

Telomerase is a ribonucleoprotein complex that is thought to add telomeric repeats onto the ends of chromosomes during the replicative phase of the cell cycle. We tested this hypothesis by arresting human tumor cell lines at different stages of the cell cycle. Induction of quiescence by serum deprivation did not affect telomerase activity. Cells arrested at the G1/S phase of the cell cycle showed similar levels of telomerase to asynchronous cultures; progression through the S phase was associated with increased telomerase activity. The highest level of telomerase activity was detected in S-phase cells. In contrast, cells arrested at G2/M phase of the cell cycle were almost devoid of telomerase activity. Diverse cell cycle blockers, including transforming growth factor beta1 and cytotoxic agents, also caused inhibition of telomerase activity. These results establish a direct link between telomerase activity and progression through the cell cycle.

Association between diarrheal duration and nutritional decline: implications for an empirically validated definition of persistent diarrhea.

In an empiric approach to develop the definition of persistent diarrhea, we evaluated the relationship between diarrheal duration and risk of ensuing clinically significant decline in nutritional status, in a cohort of 395 children < 24 mo. Weights were obtained at the onset of diarrhea (wt I) and after three months interval (wt II). The occurrence of an adverse outcome (AO) was defined as a decline of -- 5% in NCHS weight for age (% WFA) between weights I and II or death in this interval. The risk of AO was similar for episodes of / or > 7 days while it was substantially higher in episodes with > 14 days duration (45%) than for shorter duration episodes, relative risk (RR) = 2.5 (p < 0.001). Relative risk remained similar for duration thresholds of 21 (2.3) and 28 days (2.6). As episode durations greater than 14 days are associated with substantial elevation of the risk of clinically cogent sequelae, such episodes may be termed 'persistent' at least in terms of poor prognostic expectations.

Inhibition of type 1 human immunodeficiency virus replication by a tat antagonist to which the virus remains sensitive after prolonged exposure in vitro.

The transactivator of transcription, Tat, of human immunodeficiency virus type 1 (HIV-1) is required for viral replication. Inhibition of Tat function could have the potential to keep integrated provirus in dormancy. In the presence of Tat, Ro 24-7429, an analog of Ro 5-3335, inhibited expression of indicator genes controlled by the HIV-1 long terminal repeat promoter in transient transfection assays and in a constitutive cell line at noncytotoxic concentrations. Reduction of steady-state mRNA of the indicator gene by the compound correlated with reduction of the gene product in the constitutive cell line. Ro 24-7429 has broad activity against several strains of HIV-1 in different cell lines, peripheral blood lymphocytes, and macrophages (IC90 = 1-3 microM). Importantly, Ro 24-7429 inhibited viral replication in both acute and chronic infection in vitro, a characteristic expected of a Tat antagonist and not shared by viral reverse transcriptase inhibitors. Consistent with this, the compound reduced cell-associated viral RNA and proteins and partially restored cell-surface CD4 in chronically infected cells. After 2 years of continued weekly passage of the virus in fresh CEM cells grown in the presence of the compound at 1 or 10 microM, the virus did not develop resistance to the drug. These results indicate that the compound's action might involve a cellular factor.

Mania in the elderly: a 5-7 year follow-up.

A 5-7 year follow-up study of elderly individuals hospitalized on an acute psychiatric inpatient service for bipolar disorder, manic phase, demonstrates that the prognosis of mania has improved in the past 30 years. A majority of those hospitalized for mania are alive and living independently 5 years after hospitalization. However, eight of 25 (32%) patients have experienced a decline in Mini-Mental State Exam score to below 24, suggesting a clinically significant cognitive disorder. Mortality rates were higher in the manic group than expected from population norms. Compared to a group of similarly aged individuals hospitalized for unipolar depression, patients with bipolar disorder had an earlier age of onset and a lesser likelihood of being rehospitalized.

Fine structure mapping and phenotypic analysis of five temperature-sensitive mutations in the second largest subunit of vaccinia virus DNA-dependent RNA polymerase.

We have used plasmid clones spanning the region encoding the 132-kDa subunit of the cowpox virus RNA polymerase (CPV rpo 132) to marker rescue each of five vaccinia virus (VV) temperature sensitive (ts) mutants, ts 27, ts 29, ts 32, ts 47, and ts 62, which together constitute a single complementation group. The experiments fine-map the vaccinia mutations to a 1.3-kb region containing the 3' end of the CPV rpo 132 gene. Phenotypic characterization shows that all five mutants are affected to varying extents in their ability to synthesize late viral proteins at the nonpermissive temperature, similar to other ts mutants with lesions in the 22- and the 147-kDa subunits of the VV RNA polymerase. Two mutants, ts 27 and ts 32, exhibit a delay in the synthesis of late viral proteins at both the permissive and the nonpermissive temperatures. We conclude that the five VV mutants affect the 132-kDa subunit of the VV RNA polymerase. Additional genetic experiments demonstrate intragenic complementation between ts 62 and three other members of this complementation group, ts 27, ts 29, and ts 32.

Fine structure mapping of five temperature-sensitive mutants in the 22- and 147-kilodalton subunits of vaccinia virus DNA-dependent RNA polymerase.

We have mapped the temperature-sensitive (ts) lesions of three mutants, ts51, ts53, and ts65, and two other mutants, ts7 and ts20, to regions on the vaccinia virus genome that encode the 147- and 22-kilodalton subunits of the viral DNA-dependent RNA polymerase, respectively. Plasmid and bacteriophage clones from the HindIII J region and the region spanning the HindIII J-H junction were used in marker rescue experiments to map the mutations. Sequence analysis of the region encoding the 22-kilodalton subunit in the wild-type, ts7, and ts20 viruses revealed a single base change in the mutants compared with that in the wild-type virus. The identification of these RNA polymerase mutants provides us with tools to understand transcription and its regulation in vaccinia virus.

Detailed phenotypic characterization of five temperature-sensitive mutants in the 22- and 147-kilodalton subunits of vaccinia virus DNA-dependent RNA polymerase.

We have carried out detailed phenotypic characterization of five temperature-sensitive (ts) mutants of vaccinia virus, the ts lesions of which have previously been mapped to two different subunits of the viral RNA polymerase. We have also attempted to determine the mechanism of temperature sensitivity in these mutants. Phenotypic characterization of each of the mutants showed that at the nonpermissive temperature, all five mutants exhibited normal levels of early viral mRNA and protein synthesis, but for an extended period of time, all mutants accumulated normal levels of DNA in abnormally large pools in the cell cytoplasm; all mutants were defective in the synthesis of late viral mRNA and proteins and in viral morphogenesis. In an attempt to address the mechanism of temperature sensitivity in these mutants, we measured the effect of a temperature shift on the ability of the mutants to direct late viral protein synthesis. If infected cells were shifted down from a nonpermissive temperature late during infection, late protein synthesis was initiated after a lag period of 1 to 2 h. If infected cells were shifted up from a permissive temperature early during infection, late protein synthesis continued to be defective. If infected cells were shifted up to the nonpermissive temperature after late protein synthesis had commenced, late protein synthesis was maintained at the nonpermissive temperature at the level observed when the temperature was shifted up. We interpret these results to mean that once a functional RNA polymerase has been assembled at the permissive temperature during a mutant infection, it remains functional at the nonpermissive temperature, but that the ts mutants are defective in the assembly of a newly synthesized RNA polymerase at the nonpermissive temperature. This interpretation implies that the virion RNA polymerase is responsible for early viral transcription and that a newly synthesized RNA polymerase transcribes late viral genes.

Anesthetic induction with fentanyl and intravenous lidocaine for coronary artery surgery.

In a randomized, double-blind trial, 59 patients undergoing coronary artery surgery received fentanyl 10, 15, or 25 microg/kg infused over 5 minutes for anesthetic induction. Half of the patients received intravenous lidocaine, 1.5 mg/kg, 1 minute before laryngoscopy. Efficacy of induction as judged by loss of consciousness was evaluated, and hemodynamic values during induction, laryngoscopy, and tracheal intubation were recorded each minute for 10 minutes. Plasma fentanyl concentrations were determined after termination of the fentanyl infusion. Opioid induction with fentanyl was successful in 90% (18 of 20) of patients receiving 25 microg/kg, 89% (17 of 19) of patients receiving 15 microg/kg, but only 55% (11 of 20) of patients receiving 10 microg/kg (P < .01). While plasma fentanyl concentrations were proportional to the dose infused (25 ng/mL, 18 ng/mL, and 14 ng/mL in the 25, 15. and 10 microg/kg fentanyl groups, respectively), there was no relationship between plasma fentanyl concentration and hemodynamic response to laryngoscopy or intubation. Opioid induction caused a gradual decrease in blood pressure that was restored with intubation. Lidocaine partially blocked this restoration (systolic blood pressure 122 +/- 5 v 138 +/- 5 mmHg, lidocaine v placebo, 1 minute after laryngoscopy, P < .05). Fentanyl, 15 or 25 microg/kg, intravenously, is an effective induction agent for patients with coronary artery disease. Supplementation with intravenous lidocaine, 1.5 mg/kg, will obtund the increase in blood pressure that occurs with laryngoscopy and intubation and help prevent infrequent hypertensive responses seen with this opioid technique.

Differential spread of blockade of touch, cold, and pinprick during spinal anesthesia.

The differential levels of sensory blockade of pinprick, cold, and touch were monitored throughout the course of spinal anesthesia administered to 50 patients to determine variations in the degree of spread during onset, plateau, and regression, and to establish the effects of epinephrine and the effect of posture during injection. A significant difference was observed between the dermatomal level of sensory loss of touch and the dermatomal level of loss of either pinprick or cold during onset, at 5 min in patients given tetracaine with epinephrine, at time of maximum spread in patients given tetracaine with epinephrine or in the sitting position, and in all groups during regression. Loss of touch began later, never extended as far cephalad, and regressed sooner. The extent of this difference was greatest during regression, when the anesthetic was given to patients in the sitting position, after epinephrine. The level at which the sense of touch was lost seemed to mark the limits of the zone of solid spinal anesthesia; these limits could not be assessed effectively using pinprick. We propose that loss of touch sensation be used to assess whether anesthesia is adequate to avoid tourniquet pain. If there is loss of touch sensation above the L1 dermatome, it is unlikely that tourniquet pain will occur.

Role of pepsin in species differences in erosive gastritis.

This controlled study shows that the rabbit is more vulnerable to erosive gastritis after stress of operation, weight loss, and hypersecretion or acute ischemia than is the cat. Rabbit gastric juice also produces more erosions in the Shay rat preparation after four hours than does cat gastric juice (P less than .05). In vitro, rabbit pepsin has 1.5 times greater specific activity and possesses other kinetic differences. The deleterious effect of these qualitative differences on gastric mucosa may also be augmented by quantitative differences. Hypersecretion of pepsin has been reported once the mucosa is damaged. We conclude that demonstration of species-related differences in pepsin activity helps to explain an apparent discrepancy noted by others--namely, why the rabbit is so much more susceptible to stress-produced erosions than the cat or other experimental animals.

Peripheral dissemination of bacteria in contaminated wounds; role of devitalized tissue: evaluation of therapeutic measures.

The role of available therapeutic agents in the management of infection has long been a continuing source of debate. This study assessed the rapidity of lateral dissemination of three common pyogenic organisms from wounds. The Streptococcus spreads peripherally with greater speed than the Staphylococcus or E. coli. Appraisal of the role and effectiveness of jet wound irrigation, debridement, and penicillin provides firm evidence that, of these three therapeutic agents, the only one that can control bacterial proliferation in a contaminated wound is the antibiotic. The primary role of energized jet irrigation is to remove clots and wound debris. The specific function of debridement is removal of devitalized tissue, in which role it has no effective competitor. These studies demonstrate that devitalized tissue in a contaminated wound quickens the rapidity of peripheral spread of all three micro-organisms. Systemic penicillin plus saline irrigation is the most effective therapeutic measure at both the second and fourth postinoculation hours in nondevitalized contaminated wounds. Debridement proved to be the most effective therapeutic device at the second, fourth, and sixth postinoculation hours in devitalized wounds.