[Aseptic meningitis. Demonstration of bacterial DNA in cerebrospinal fluid by gene amplification]

OBJECTIVE

To develop a diagnostic tool to recognize whether a postoperative meningitis occurring in neurosurgical patients is of bacteriological origin or not, in detecting in CSF bacterial DNA with the polymerase chain reaction (PCR) technique.

STUDY DESIGN

Laboratory study.

PATIENTS

Twenty-seven neurosurgical ICU patients associating, in the postoperative period, the CDC criteria of meningitis and a neutrophil polymorphonuclear count over 100 cells.mm-3 were allocated either into the MB+ group (n = 7) when their CSF culture was positive or in the MB- group (n = 20) when the culture was sterile. The CSF of 43 neurosurgical ICU patients without postoperative clinical and biological features of meningitis acted as controls. Sixteen specimens out of the 43 were inoculated with bacteria at a known concentration.

METHODS

The CSF specimens of all patients were tested for the presence of eurcaryote DNA using the PCR technique. Beforehand its sensitivity had been assessed using the inoculated CSF of control group: a positive amplification at 20 cycles was equivalent to 10(5) CFU.mL-1 and a positive amplification at 25 cycles to 10(3) CFU.mL-1.

RESULTS

In the 43 sterile control CSF specimens the amplification was negative in all at 20 cycles and in 42 at 25 cycles. In the 16 previously sterile control specimens supplemented with bacteria, as well as in the CSF of all 7 patients of MB+ group the amplification was positive at 20 and 25 cycles. In those of MB- group the amplification was negative in all at 20 cycles, but was positive in 19 out of 20 at 25 cycles. Southern blot with specific procaryote probes was positive with amplification products from CSF of MB+ and MB- groups and negative with control CSFs and human DNA.

DISCUSSION

The presence of bacteria in CSF of patients sustaining a meningitis can be accurately detected through their DNA. Postoperative aseptic meningitides may have a bacterial origin. PCR can be used as a routine technique to provide a diagnosis of bacterial meningitis in less than 6 hours. Additionally specific oligonucleotides allow to identify the bacteria in less than 12 hours.

CD11b/CD18 expression, adherence, and chemotaxis of granulocyte in adult respiratory distress syndrome

The accumulation of granulocytes in the pulmonary microvasculature is generally thought a cardinal event in the pathology of adult respiratory distress syndrome (ARDS). However, the mechanism by which granulocytes are sequestered in the pulmonary vascular bed remains largely unknown. Because the CD11b/CD18 membrane receptors mediate various adhesion-dependent functions, their expression was investigated in granulocytes from patients during the course of ARDS development in relation to adherence and chemotaxis. CD11b expression of ARDS resting granulocytes was increased within 24 h of ARDS onset by a factor of two in comparison with control patients (p < 0.05) and remained significantly increased 72 to 120 h later. In contrast, the stimulated expression was significantly decreased only within 24 h of ARDS onset. Adherence was not modified within 8 h of the onset of ARDS, but was increased at Days 1, 3, and 5. The time course of granulocyte chemotaxis shows a decreased chemotaxis capacity during the first 3 d of ARDS, followed by normalization at Day 5. The dynamic changes observed in the various functions studied indicate a possible relationship between the modulation of the CD11b expression and a hyperadhesive state of granulocytes in ARDS. These sticky granulocytes may potentially contribute to the microvascular injury.

Malondialdehyde dosimetry in laser-irradiated tissues sensitized by hematoporphyrin derivative

Photodynamic therapy (PDT) is based on the selective retention of a photosensitizer (hematoporphyrin derivative [HPD]) by tumor tissue and the subsequent irradiation of this tissue with light. Unsaturated phospholipids are important targets of membrane photodamage, and malondialdehyde (MDA), an ultimate marker of lipid peroxidation, can easily be measured by the fluorometric thiobarbituric acid (TBA) assay. To determine whether MDA content represents a reference for PDT intensity, tissue content in 7-week-old male nude mice was studied on biopsy samples after PDT (5 mg/kg HPD injected intravenously 24 hr before irradiation at 632 nm) with or without intraperitoneal injection of WR-2721 40 min before treatment. The FeCl3 method requiring only 15 min of incubation in a 95 degrees C waterbath proved most effective compared with the method involving phosphotungstic acid or the MDA-TBA determination using a commercially available kit. Whatever the method used, the best results were found using a 60-min interval between treatment and freezing. MDA concentration in HPD-PDT-treated samples was significantly higher than in HPD-tested controls (P < .01) and increased at laser irradiation doses ranging from 0 to 50 J/cm2. Administration of WR-2721 intraperitoneally significantly reduced MDA concentration (from 70% to 38%). A maximal effect was obtained with 100 mg/kg for brain (-70%) and 200 mg/kg for muscle (-47%). Higher doses produced no additional changes. The MDA assay is a simple tool for indirect evaluation of PDT, and WR-2721 can decrease MDA content in normal tissue, suggesting the possibility of good protection for normal tissue during PDT.

Nosocomial pneumonia in mechanically ventilated patients receiving antacid, ranitidine, or sucralfate as prophylaxis for stress ulcer. A randomized controlled trial

OBJECTIVE

To assess three anti-stress ulcer prophylaxis regimens in mechanically ventilated patients for bacterial colonization, early- and late-onset nosocomial pneumonia, and gastrointestinal bleeding.

DESIGN

Randomized controlled trial.

PATIENTS

Consecutive eligible patients with mechanical ventilation and a nasogastric tube. Of 258 eligible patients, 244 were assessable.

SETTING

Medical and surgical intensive care units.

INTERVENTION

At intubation, patients were randomly assigned to receive one of the following: antacid (a suspension of aluminum hydroxide and magnesium hydroxide), 20 mL every 2 hours; ranitidine, 150 mg as a continuous intravenous infusion; or sucralfate, 1 g every 4 hours.

MEASUREMENTS

Using predetermined criteria, the incidence of gastric bleeding, gastric colonization, early-onset pneumonia, and late-onset pneumonia was assessed in patients intubated for more than 24 hours.

RESULTS

Of 244 assessable patients, macroscopic gastric bleeding was observed in 10%, 4%, and 6% of patients assigned to receive sucralfate, antacid, and ranitidine, respectively (P > 0.2). The incidence of early-onset pneumonia was not statistically different among the three treatment groups (P > 0.2). Among the 213 patients observed for more than 4 days, late-onset pneumonia was observed in 5% of the patients who received sucralfate compared with 16% and 21% of the patients who received antacid or ranitidine, respectively (P = 0.022). Mortality was not statistically different among the three treatment groups. Patients who received sucralfate had a lower median gastric pH (P < 0.001) and less frequent gastric colonization compared with the other groups (P = 0.015). Using molecular typing, 84% of the patients with late-onset gram-negative bacillary pneumonia were found to have gastric colonization with the same bacteria before pneumonia developed.

CONCLUSION

Stress ulcer prophylaxis with sucralfate reduces the risk for late-onset pneumonia in ventilated patients compared with antacid or ranitidine.

Calbindin-D9k gene expression in the uterus: study of the two messenger ribonucleic acid species and analysis of an imperfect estrogen-responsive element

The calbindin D9k (CaBP9k) gene is under strict estrogen control in the rat uterus. This tissue contains two CaBP9k messenger RNA (mRNA) species. We have used primer extension analysis, reverse transcriptase associated with polymerase chain reaction, and RNase H digestion to show that these two mRNA species have the same structural features, including 5'- and 3'-ends, and poly(A) tail length. Our results suggest that the difference in electrophoretic mobilities of the two mRNA species might be due to interaction with another factor. We also analyzed the imperfect estrogen-responsive element (ERE) present on the first 5'-splice site of the rat CaBP9k gene. The oligonucleotide corresponding to the CaBP9k ERE was cloned in the plasmid pBLCAT2 (where the thymidine kinase promoter governs the expression of the chloramphenicol acetyl transferase gene) and transfected into MCF7 cells. This CaBP9k ERE was found to be a hormone-inducible enhancer that worked in an orientation-independent manner on a heterologous promoter and was functional at physiological hormone concentrations. One CaBP9k ERE conferred only weak (about 2-fold) estrogen induction, but two EREs cloned in tandem were strongly synergistic (14- to 16-fold). The CaBP9k ERE also bound to the partially purified estrogen receptor (ER) and to ER expressed in COS cells by gel shift assay. Methylation interference showed that all the guanine residues in both half-sites of the CaBP9k ERE were protected by ER binding. Thus, ER binds to the CaBP9k ERE in a way similar to other EREs. The gel shift assay results indicate that the strong synergistic effect of two EREs cloned in tandem is not due to cooperative binding between the two elements. As the CaBP9k gene is under strong estrogenic control in the uterus in vivo, the imperfect CaBP9k ERE may cooperate with another trans-acting factor to become fully efficient.

[Value of D(-) lactate determination for the fast diagnosis of meningitis after craniotomy. An initial study]

The early diagnosis of postoperative bacterial meningitis (BM) may be difficult. CSF cultures may remain sterile. Clinical features and routine laboratory data often fail to give an evidence. As early antibiotic therapy is essential in such patients, a rapid diagnosis is required. Different authors proposed the D(-) isomer of lactic acid as an early and effective marker of infection in the body fluids (including CSF). D(-) lactate is produced by bacteriae and fungi; L(+) lactate may be produced also by human tissues in anaerobic situations. We conducted a prospective study in a neurosurgical intensive care unit to evaluate this technique for the diagnosis of meningitis following craniotomy. Fifty-four patients were included, 40 in group A (not infected or infected out of the CNS), 4 in group B (suspected BM), 10 in group C (BM with positive CSF cultures). No patient suffered from septicemia, haemodynamic or ventilatory instability, nor metabolic disorder. Clinical data, CSF and blood samples (cytology, conventional biochemistry, D(-) and L(+) lactate, bacteriology) were collected at inclusion and, in group B and C patients, at day 2, 5 and at clinical recovery. D(-) lactate measurements were performed with an enzymatic method adaptated from a Boehringer Mannheim kit (for determination in foodstuff). Statistics were based on the comparison of group A vs C patients. D(-) and L(+) lactate concentrations in the CSF were significantly higher in group C patients, and blood concentrations were similar.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of inspiratory neuromuscular output during synchronized intermittent mechanical ventilation

BACKGROUND

In synchronized intermittent mandatory ventilation, it is generally accepted that the work of the inspiratory muscles is decreased by the ventilator so that their activity can be modulated by the frequency of assisted breaths. We examined the validity of this concept, which recently has been questioned.

METHODS

We studied five patients receiving synchronized intermittent mandatory ventilation because of an acute exacerbation of chronic obstructive pulmonary disease. The level of machine assistance, defined as the percentage of total ventilation delivered by the ventilator, was varied from a high (> 60%) to a medium (20-50%) and to the lowest tolerated value (0% in four patients). Esophageal pressure, air flow, and the electromyograms of the diaphragm and sternocleidomastoid muscles were recorded. At each level of machine assistance, distinguishing assisted from spontaneous breaths, the duration of electrical activation, the integrated electromyograms, and the work of breathing were computed.

RESULTS

The durations of electrical activation and the integrated electromyograms of the diaphragm and sternocleidomastoid were similar in successive spontaneous and assisted breaths. At > 60% of machine assistance, the cumulative values per minute of the integrated electromyograms of the diaphragm and sternocleidomastoid and the work of breathing were reduced only by 38, 32, and 44%, respectively, compared with the lowest tolerated level of machine assistance. The durations of electrical activation did not change with increasing level of machine assistance.

CONCLUSIONS

The degree of inspiratory muscle rest achieved by synchronized intermittent mandatory ventilation is not proportional to the level of machine assistance; furthermore, the inspiratory motor output is not regulated breath by breath but rather is constant for a given level of machine assistance.

N-acetylcysteine enhances recovery from acute lung injury in man. A randomized, double-blind, placebo-controlled clinical study

OBJECTIVE

To determine the effects of intravenous N-acetylcysteine (NAC) on the development of severe adult respiratory distress syndrome (ARDS) and mortality rate in patients with mild-to-moderate acute lung injury and to analyze the duration of ventilatory support and FIO2 required as well as the evolution of the lung injury score.

SETTING

Three university hospital ICUs and one regional ICU in Switzerland.

PATIENTS

Sixty-one adult patients presenting with mild-to-moderate acute lung injury and various predisposing factors for ARDS received either NAC, 40 mg/kg/d, or placebo intravenously for 3 days.

MEASUREMENTS

Respiratory dysfunction was assessed daily according to the need for mechanical ventilation and FIO2, the evolution of the lung injury score, and the PaO2/FIO2 ratio. The cardiovascular state, liver function, and kidney function were also monitored. Data were collected at admission (day 0), during the first 3 days, and on the day of discharge from the ICU.

RESULTS

The NAC and placebo groups (32 and 29 patients, respectively) were comparable at ICU admission for severity of illness assessed by the simplified acute physiology score (SAPS) (10.8 +/- 4.6 vs 10.9 +/- 4.8) and lung injury score (LIS) (1.39 +/- 0.95 vs 1.11 +/- 1.08) (mean +/- SD). Three patients in each group developed ARDS. The 1-month mortality rate was 22 percent for the NAC group and 35 percent for the placebo group (difference not statistically significant). At admission, 22 of 32 patients (69 percent) in the NAC group were mechanically ventilated compared with 22 of 29 (76 percent) in the placebo group. At the end of the treatment period (day 3), 5 of 29 (17 percent) in the NAC group and 12 of 25 (48 percent) in the placebo group were still receiving ventilatory support (p = 0.01), The FIO2 was 0.37 less than admission value (day 0) in the NAC group, and 0.20 less in the placebo group (p < 0.04); the oxygenation index (PaO2/FIO2) improved significantly (p < 0.05) from day 0 to day 3 only in the NAC-treated group. The LIS showed a significant regression (p = 0.003) in the NAC-treated group during the first 10 days of treatment: no change was observed in the placebo group. No adverse effects were observed during the treatment with NAC.

CONCLUSIONS

Intravenous NAC treatment during 72 h improved systemic oxygenation and reduced the need for ventilatory support in patients presenting with mild-to-moderate acute lung injury subsequent to a variety of underlying diseases. Development of ARDS and mortality were not reduced significantly by this therapy.

[The pulmonary manifestations of diving accidents]

Scuba diving is associated with risks of drowning, lung barotrauma and decompression sickness. In case of near-drowning, irreversible neurologic lesions or death may follow an acute hypoxemia or a cardiopulmonary arrest. Therefore, victims of drowning should benefit from an immediate and prolonged cardiopulmonary resuscitation. Lung barotrauma are due to the failure of expanding lung gases to escape during ascent; they are likely to be complicated by arterial gas embolism. They can follow a panic ascent even from a shallow depth. Most of decompression procedures induce the formation of asymptomatic venous gas bubbles, normally filtrated and eliminated by the lungs. In case of massive intravenous bubbling, the filtering capacity of the lungs can be overwhelmed and the lung microcirculation damaged up to the point of provoking a cardio-respiratory failure.

Cardiac arrest: prognostic factors and outcome at one year

This study was designed to determine by multivariate statistical methods the influence of 38 variables on outcome after cardiopulmonary resuscitation (CPR) and to assess neuropsychological status in long-term survivors. The charts of 181 consecutive patients resuscitated in a 1,100-bed University Hospital over a 2-year period were analyzed retrospectively. Of the 181 resuscitated patients, 23 (13%) could be discharged. Outcome was significantly affected by the following variables: presence of shock or renal failure before cardiac arrest (CA) (odds ratio = 10.6; 95% confidence interval = 1.3-85.8 and odds ratio = 13.8; 95% confidence interval = 1.7-109.2, respectively), administration of epinephrine (odds ratio = 11.2; 95% confidence interval = 3.2-39.2) or prolonged CPR (> 15 min) (odds ratio = 4.9; 95% confidence interval = 1.7-13.7). By contrast, when CA occurred in uncomplicated acute myocardial infarction a significantly better prognosis could be demonstrated (odds ratio = 0.2; 95% confidence interval = 0.0-0.6). The 10 long-term survivors investigated lead an independent life and all returned to former occupation. The most common complaint was moderate memory disturbance (five patients). The conclusion is that this study confirms the critical influence of cellular anoxia on prognosis and allows the improved delineation of the situations in which cardiopulmonary resuscitation appears to be hopeless or likely to be successful. The follow up in a small number of survivors has shown a good quality of life and minor neuropsychological sequellae.

Estrogen-induced calbindin-D 9k gene expression in the rat uterus during the estrous cycle: late antagonistic effect of progesterone

Progesterone modulates estrogen-stimulated responses in the uterus. Calbindin-D 9k (CaBP9k), a 17 beta-estradiol-responsive gene expressed in the uterus, was used as a marker to examine the interactions between endogenous progesterone and estradiol in the rat. The variations in uterine CaBP9k messenger RNAs (mRNAs) during the rat estrous cycle indicated that CaBP9k gene expression was greatest during the estrogen-dominated phases (proestrus and estrus) and became totally repressed during diestrus, when progesterone predominates. Estradiol was found to be the major controlling factor of CaBP9k gene expression in vivo, progesterone antagonizing estrogen-induced CaBP9k gene expression. The inhibitory role of progesterone was further examined in two experiments. Mature cyclic rats were injected with the progesterone antagonist RU486 before the progesterone surge of proestrus, and the estrous cycle was mimicked in ovariectomized rats by sequential injections of estrogen and progestin. Progesterone did not appear to be involved in the rapid decrease in CaBP9k mRNA during estrus but was implicated in the down-regulation of the estrogen-stimulated CaBP9k gene expression at the end of estrus and during diestrus. This delayed effect of progesterone was confirmed in the ovariectomized rat model. CaBP9k mRNA accumulation in estrogen-primed ovariectomized rats was suppressed by estrogen followed 1 h later by the progesterone agonist R5020. This effect occurred more than 24 h after progestin treatment. The inhibition of the estrogen-induced CaBP9k gene expression in the rat uterus by progesterone is certainly mediated by the progesterone receptor, because progesterone had no effect without estrogen priming or when the antagonist RU486 was used. The delayed progesterone effect probably does not involve depletion of nuclear estrogen receptors, the major rapid mechanism proposed for estrogen inhibition by progesterone in the rodent uterus, or control of estrogen receptor synthesis, as shown by Northern blot analysis of estrogen receptor mRNA.

[Contribution of imaging techniques in acute neonatal renal pathology]

Ultrasound is the first imaging modality used to evaluate acute renal disease in neonates. Normal findings and abnormalities seen in venous or arterial thrombosis, hemodynamic shock, or sepsis are reviewed. Transient changes due to intoxications, tubular disorders, or congenital nephrotic syndrome are considerably less common.

Comparison of results of intravenous infusion of anistreplase versus streptokinase in acute myocardial infarction

This randomized study compares the coronary perfusion rate in patients with acute myocardial infarction (AMI) treated with 2 different intravenous thrombolytic agents: streptokinase 1.5 million U given over 60 minutes and anisoylated human plasminogen streptokinase activator complex (anistreplase) administrated as a bolus of 30 U over 5 minutes. One hundred seventy-five patients (149 men and 26 women, mean age 54 years) have been included in this study. Eighty-nine patients were treated with anistreplase and 86 patients with streptokinase. AMI was inferior in 54 patients (61%) in the anistreplase group and in 54 patients (63%) in the streptokinase group. It was anterior in 35 (40%) and 32 (37%) patients, respectively. Coronary angiography and ventriculography were performed at a mean time (+/- SEM) of 207 +/- 11 minutes after the beginning of thrombolysis in 170 patients. A perfusion score grade of 2 or 3 according to the Thrombolysis in Myocardial Infarction trial was found in 63 patients (72%) in the anistreplase group and in 56 patients (68%) in the streptokinase group (p = NS). Severe bleeding occurred in 7 patients (8%) after anistreplase and in 6 patients (7%) after streptokinase. No cerebral hemorrhage occurred. Nine patients (5%) died during their hospital stay: 6 after anistreplase and 3 after streptokinase. It is concluded that intravenous administration of anistreplase or streptokinase is efficient and safe. Coronary patency 207 minutes after fibrinolysis, incidence of adverse events and mortality are similar in both groups.

Colon cancer in seven siblings

In a case-control study of cancer of the colon it was found that 96 out of 332 (29%) cases had a positive family history of cancer of the colon (2 cases and more) as compared with 19 out of 473 (4%) controls. 3 colon cancer cases reported that 6 of their respective relatives were also affected with the same cancer. We were able to do a complete follow-up study of one family where 7 out of 12 sibling (P < 0.05) had confirmed pathological diagnoses of cancer of the colon. The mean age at diagnosis among these familial colon cancer cases was 64 years (60 years for females and 73 years for males) and all tumours were located in the caecum or right colon (a common characteristic of colon cancer in this family). There was no history of familial adenomatous polyposis in this family. It is unlikely that the significantly high proportion of familial colon cancer found could be due to chance. This suggests that both environmental and genetic factors play an important role in the aetiology of colon cancer.

Calbindin-D9K gene expression in the lung of the rat. Absence of regulation by 1,25-dihydroxyvitamin D3 and estrogen

Calbindin-D9K (CaBP9K) is classically considered to be the molecular expression of 1,25-dihydroxyvitamin D3. The hormone is known to regulate the rat CaBP9K gene in duodenal tissue at transcriptional and posttranscriptional levels. This study shows that the CaBP9K gene is expressed in the rat lung, and that this expression is probably not vitamin D- or estrogen-dependent. The CaBP9K gene is not expressed in alveolar macrophages, but CaBP9K messenger RNA (mRNA) was localized by in situ hybridization in alveolar epithelial cells. CaBP9K mRNA was detected as early as the 20th day of gestation. The quantity of CaBP9K mRNA gradually increased during growth, from 1-77 days after birth, whereas the CaBP9K concentration dramatically increased from day 19 to day 20 of gestation. Vitamin D-deficient male rats (8 weeks old) were given a single injection of 1,25-dihydroxyvitamin D3 (650 pmol/100 g body wt) and killed 1 h and 24 h after injection. The hormonal treatment resulted in a rise in duodenal CaBP9K mRNA, but no significant change in lung extracted CaBP9K mRNA. Mature ovariectomized rats were injected with 17 beta-estradiol (0.5 microgram/100 g body wt) and killed 24, 48, and 72 h later. The CaBP9K mRNA concentration in the uterus was markedly dependent on estrogen; that of the lung was not. The factors regulating the CaBP9K gene expression in the lung remain to be determined.