Risks of angiotensin-converting enzyme inhibition during pregnancy: experimental and clinical evidence, potential mechanisms, and recommendations for use

OBJECTIVE

To review reports on the use of angiotensin-converting enzyme inhibitors (ACE-I) during pregnancy in order to determine the incidence, nature, and potential mechanisms of fetal complications in an attempt to establish recommendations related to the use of these drugs during gestation.

DATA SOURCES

Relevant English-language articles identified through a Medline search and bibliographies found in recent articles.

STUDY SELECTION

Large number of reports both on animals and on humans have consistently shown a high degree of morbidity and even mortality in fetuses or newborns exposed to ACE-I during pregnancy. The reported complications include oligohydramnios, intrauterine growth retardation, premature labor, fetal and neonatal renal failure, bony malformations, limb contractures, persistent patent ductus arteriosus, pulmonary hypoplasia, respiratory distress syndrome, prolonged hypotension, and neonatal death. A high incidence of fetal complications was related to the use of ACE-I at all trimesters of pregnancy.

CONCLUSION

The gestational use of ACE-I may be associated with a high degree of fetal and newborn morbidity and even mortality. The use of these drugs should be avoided at all trimesters of pregnancy.

Efficacy, risks, and limits of extracorporeal shock wave lithotripsy for salivary gland stones

Stones of the salivary glands may cause recurrent swelling, ascending inflammation, and colic-like pain. Previously, in order to get rid of these stones, the gland usually had to be removed surgically in spite of the associated risks to adjacent structures, especially the facial nerve. We treated 104 salivary gland stones in patients 14 to 78 years old using the Storz Modulith SL 10 lithotripter. Each session (average 3.6 per patient) consisted of 1000 impulses at 2 Hz and 16 to 18 kV. No anesthesia was required. Earplugs were applied to patients being treated for parotid gland stones. With the aid of SWL and drug-induced salivation, 17 (59%) of the patients with parotid gland stones and 42 (56%) of those with submandibular gland stones obtained either total stone clearance or sufficient fragmentation to permit spontaneous passage. Four patients required surgery. The remaining patients are still being treated. The noninvasive SWL for salivary gland stones is noninvasive and painless and has a considerable success rate. It can be performed on an outpatient basis.

Plasma cyclic guanosine monophosphate in chronic heart failure: hemodynamic and neurohormonal correlations and response to nitrate therapy

This study evaluated the relation between plasma cyclic guanosine monophosphate (cGMP) and hemodynamic and neurohormonal parameters in patients with chronic congestive heart failure and assessed the effect of organic nitrate on plasma cGMP levels. Plasma cGMP was fourfold higher in 18 patients with congestive heart failure compared with 15 control subjects (16.7 +/- 9.7 versus 4.0 +/- 1.0 pmol/ml; p < 0.0001) but did not correlate with plasma levels of catecholamines, renin, atrial natriuretic peptide, or with baseline hemodynamic values. The administration of a hemodynamically effective dose of oral isosorbide dinitrate (40 mg) resulted in a transient reduction in plasma cGMP from 16.7 +/- 9.7 pmol/ml at baseline to 13.0 +/- 6.6 pmol/ml at 1 hour (p < 0.05). This change was associated with small and statistically insignificant changes in neurohormonal values and had no relation to any of the hemodynamic changes. We concluded that (1) elevated plasma cGMP in congestive heart failure does not correlate with other neurohormonal or hemodynamic parameters and may be an independent parameter of heart failure, (2) in contrast to previously documented nitrate-mediated increases in intracellular cGMP, nitrate therapy results in a reduction in plasma cGMP, and (3) changes in plasma cGMP cannot serve as a surrogate measurement of changes in intracellular cGMP.

Biliary lithotripsy with a new electromagnetic shock wave source. A 2-year clinical experience

During a two-year study period 170 consecutive patients with gallbladder stones, suitable for lithotripsy, were treated with a new electromagnetic lithotriptor (Modulith) and oral bile acids; 142 patients were treated as outpatients. Sufficient fragmentation were obtained in 94% when 2112 +/- 137 shocks in 211 sessions with an energy setting of 17.8 +/- 0.8 kV were administered. Only 4/170 patients needed transient analgesia. Overall, side effects were transient and mild, but three patients developed biliary pancreatitis, which was treated by endoscopic sphincterotomy in two of them. A total of 67/100 patients were free of stones after one year. Subgroup analysis showed that 80% of the patients (stone diameter 5-20 mm), 64% (20-30 mm) and 65% (multiple stones), respectively, can expected to be free of stones after 12 months. In addition, 25 patients with large, endoscopically not extractable common bile duct stones were treated by lithotripsy with the Modulith. After endoscopic placement of a nasobiliary tube, stone targeting was possible by ultrasonography in 14 patients and by fluoroscopy in another 11 cases. In 23 of the 25 patients (92%) stone clearance by endoscopy was achieved after application of 2516 +/- 565 shocks with an energy preset of 18 kV. One patient refused further endoscopic procedures after successful fragmentation and another required local stone dissolution therapy. Side effects occurred more frequently (P < 0.05) after lithotripsy of bile duct stones than of gallbladder stones, but they were without major clinical relevance. The new lithotriptor Modulith thus enables safe and highly effective lithotripsy of gallbladder calculi on an outpatient basis.(ABSTRACT TRUNCATED AT 250 WORDS)

Electromagnetically generated extracorporeal shockwaves for fragmentation of extra-and intrahepatic bile duct stones: indications, success and problems during a 15 months clinical experience

Electromagnetically generated extracorporeal shock waves (without waterbath) were applied after intravenous premedication with 10-15 mg diazepam and 100 mg tramadol in the treatment of 33 patients (aged 32 to 91 years) with multiple intrahepatic stones (n = 4) or huge common bile duct stones (n = 29, 18-30 mm in diameter), which could not be removed by conventional endoscopy. Stone disintegration was achieved in 70% of common bile duct stones and in all intrahepatic concrements after 800-7500 discharges, which were applied during one (n = 21), two (n = 6) or three sessions (n = 6). Apart from mild fleabite-like petechiae at the side of shock wave transmission no other side effects were observed for a total of 51 procedures. We believe electromagnetically generated shock waves are safe, easy to apply, and relatively effective in the therapy of common bile duct and intrahepatic stones.

An analysis of closed obstetric malpractice claims

We reviewed all closed obstetric claims in the records of a major physician-sponsored malpractice insurer that has written policies from 1982 to the present. Of the 54 files closed during the 6.5-year period covered by this study, 21 (39%) involved physician reports of bad outcomes that did not lead to a formal claim. Of the 33 formal claims, 14 (42%) were dismissed, either by the plaintiff's attorney or by the courts. Eighteen of the remaining 19 claims were settled before trial, with an average payment to the plaintiff of $185,000. The one suit that went to trial resulted in a defense verdict. A review of the case histories demonstrated that in the majority of cases when a payment was made, probable medical negligence had taken place. Non-meritorious claims were not compensated. For those cases in which a payment was made, the size of the settlement was commensurate with the seriousness of the injury, which almost always involved damage to the infant. Poor physician judgment was the most common source of error.

Adaptational changes in Staphylococcus aureus MF 31 grown above its maximum growth temperature when protected by sodium chloride: lipid studies

Staphylococcus aureus MF31 was grown to stationary phase in a complex medium at 30, 37, and 43 degrees C in the absence of salt and at 37 and 46 degrees C in the same medium supplemented with 1 M NaCl. The principal phospholipids were cardiolipin, phosphatidylglycerol, aminoacylphosphatidyl glycerol, mono- and di-glycosyldiglyceride, and traces of phosphoglycolipid. The proportion of cardiolipin decreased with increasing growth temperature, but only slightly in the presence of 1 M NaCl, while that of aminoacylphosphatidyl glycerol was unaffected by growth temperature in absence of salt, but was about halved in the presence of 1 M NaCl. The net negative charge per mole phospholipid was greatly increased in the presence of 1 M NaCl. In the absence of salt, temperature had no effect on the total lipid content, but cells from the 46 degrees C culture in 1 M NaCl contained 25% less total lipid. The proportion of phospholipid in the total lipids, both in the absence and presence of salt, declined with increasing growth temperature. The proportion of glycolipids, however, increased with temperature both in the absence and presence of salt. It is suggested that the increase in glycolipid content and in negative charge/mole phospholipid is a part of the adaptation of S. aureus to the combination of high temperature and 1 M NaCl giving its membrane increased stability and possibly helping to exclude Cl- anion from the cell interior.

Adaptational changes in Staphylococcus aureus MF31 grown above its maximum temperature when protected by NaCl: physiological studies

Staphylococcus aureus MF31 can grow at 46 degrees C, 2 degrees C above its normal maximum temperature of growth if 1 M NaCl is added to the medium. In the present work we show that monosodium glutamate, proline, threonine, aspartic acid, and betaine (in order of decreasing effectiveness) also enabled cells to grow at 46 degrees C. Cells grown at 46 degrees C in he presence of salt (protected or P cells) accumulated glutamate more rapidly than cells grown at 37 degrees C without salt (normal or N cells) and contained an increased amino acid pool. The principal constituents of this pool were dicarboxylic amino acids and proline. Turbidimetric evidence suggests that NaCl caused plasmolysis in S. aureus. The P cells, although grown in 1 M NaCl, had about the same Cl- and K+ content as the N cells grown without added NaCl. P cells had increased heat resistance but high concentrations of CaCl2 in the heating menstruum reduced their D55 value from a maximum of 214 min to less than 30 s. We suggest that growth at 46 degrees C in 1 M NaCl can be explained, in part at least, by the increased amino acid pool internal to the cell and the external osmotic support given by Cl- anions excluded by the cell.

Failure of nisin to inhibit outgrowth of Clostridium botulinum in a model cured meat system

Up to 550 ppm (550 micrograms/ml) of nisin in combination with 60 ppm (60 micrograms/ml) of nitrite failed to prevent outgrowth of Clostridium botulinum spores in pork slurries adjusted to pH 5.8. Reducing the pH enhanced nisin activity. Proteolytic and nonproteolytic type B spores were equally resistant to nisin.

The protective effect of some food ingredients on Staphylococcus aureus MF31

The upper limiting temperature of growth of Staphylococcus aureus MF31 in heart infusion broth (HI) was about 44 degrees C but addition of monosodium glutamate (MSG) and soy sauce permitted the organism to grow above this temperature. This effect is similar to that of NaCl. Tomato ketchup, Worcestershire and HP sauces added to HI did not allow growth at the non-permissive temperature of 46 degrees C but death was delayed. Staphylococcus aureus died in unsupplemented chicken meat slurry at 46 degrees C but grew at 48 degrees C in slurry supplemented with 5.8% NaCl and survived incubation for 18 h at 50 degrees C in slurry supplemented with 5.8% NaCl and 5% MSG. Cultures grown at 37 degrees C had a D60 value of 2 min in 50 mmol/l Tris (pH 7.2) buffer. Cultures grown at 46 degrees C in HI containing 5.8% NaCl had a D60 value of 8 min in Tris buffer. Addition of 5.8% NaCl plus 5% MSG to the buffer increased the D60 by a factor of about 7 for both cultures. In storage experiments at room temperature, the culture grown at 37 degrees C and at 46 degrees C plus 5.8% NaCl died at about the same rate in salami. In milk powder, however, the count of 37 degrees C culture decreased from 10% g to 10(6)/g in 5 weeks while the count of 46 degrees C culture remained unchanged. In cottage cheese, freeze-dried rice and macaroni, the 37 degrees C cultures also died more rapidly. It is suggested that cultures grown at 46 degrees C plus 5.8% NaCl may be suitable for experiments with artificially contaminated foods.

Survival in foods of Staphylococcus aureus grown under optimal and stressed conditions and the effect of some food preservatives

Staphylococcus aureus was grown in a rich peptone medium which became alkaline with continued incubation. Cells were grown at 37 degrees C and in the same medium containing 1 M NaCl at 46 degrees C, a temperature at which this organism can grow only when protected by NaCl. Cells of these cultures are hereafter called 37 degrees C-cells and 46 degrees C-cells, respectively. The 37 degrees C-cells harvested when the pH was 7.1 to 7.7 had decimal reduction times (D60-value) of 1.8 to 3.1 min in 50 mM pH 7.2 Tris buffer. The D60 value of 46 degrees C-cells tested in the same way, harvested from cultures at pH 6.6 to 7.6, ranged from 5.3 to a maximum of 12.8 min. In milk, green beans, peas, or beef slurry, the D60-value of 46 degrees C-cells was about four times higher than that of 37 degrees C-cells. Length of survival after freeze-drying in skim-milk powder exposed to air was longest for the cells with the highest D-value. In freeze-dried peas and media acidified with acetic and lactic acids, 46 degrees C-cells survived longer than 37 degrees C-cells. However, the sensitivity of the two kinds of cells to potassium sorbate, sodium benzoate, and sodium propionate was essentially the same, but the 46 degrees C-cells were more resistant to butylated hydroxyanisole and sodium nitrite.

N-Acetylprocainamide kinetics and clinical response during repeated dosing

Kinetics of and clinical responses to N-acetylprocainamide (NAPA) were evaluated in 10 patients with chronic ventricular arrhythmias who had not responded to usual doses of currently available antiarrhythmic drugs. Kinetic data analysis was by measured NAPA concentrations (n = 149) collected during repeated dosing. Response was evaluated with serial 24-hr ambulatory ECGs. An a priori kinetic model based on earlier studies predicted NAPA concentrations well (r = 0.94, SEE = 3.6 mg/l). The capability for defining patient-specific estimates for drug disposition with six or seven serum concentrations measured at the outset of therapy was subsequently confirmed with larger data sets from the same patients. Mean values for elimination rate (0.082 hr -1 +/- 0.017) and volume of distribution (1.25 l/kg +/- 0.28) were of the same order as in earlier single-dose studies. A substantial degree of interpatient and intrapatient variability in the absorption rate for NAPA was observed. NAPA was not found to be clinically effective in any of the 10 patients, although two patients demonstrated a greater than 70% reduction in frequency of premature ventricular contractions. There were adverse effects in all patients, which frequently required dose reduction or cessation of therapy. In this group of patients with resistant arrhythmias, NAPA was no more effective than baseline therapy, and adverse effects often limited complete evaluation. The kinetic analysis demonstrated the feasibility of a strategy for developing patient-specific kinetic models that may have applications to other antiarrhythmic drugs.

Salt extends the upper temperature limit for growth of food-poisoning bacteria

Inclusion of NaCl into the growth medium raised the upper temperature limit of growth of the following organisms: Staphylococcus aureus (two strains), Salmonella senftenberg, S. typhimurium, Escherichia coli, Streptococcus faecalis, Bacillus cereus, Clostridium sporogenes, C. perfringens (two strains). The magnitude of the response varied with the culture, the largest being 3.5 degrees with B. cereus cells. The spores of B. cereus were not protected by salt but clostridial spores behaved as the vegetative cells (response of 2.5 degrees). The optimal salt concentration for the protective effect varied with the organism ranging from 0.2 M for the Gram-negative organisms to 1.0 M for S. aureus.

Repair of salt tolerance and recovery of lost D-alanine and magnesium following sublethal heating of Staphylococcus aureus are independent events

Sublethal heating of Staphylococcus aureus S6 in potassium phosphate buffer caused loss of salt tolerance, D-alanine, and magnesium. During incubation in rich complex media all three of the damaged sites were repaired. Repair occurred more slowly but went to completion in a dilute synthetic medium (DSM), free of D-ala. DSM plus penicillin or D-cycloserine allowed repair of salt tolerance but recovery of normal levels of D-ala or Mg was prevented. When DSM-repaired cells were cultured into fresh rich medium they grew rapidly after a short lag. Cells which had acquired their salt tolerance in DSM plus cycloserine and were D-ala and Mg deficient grew slowly and had a lag of 3 h. We suggest that heat damage has two separate primary targets in S. aureus cells: the membrane, which is manifested by loss of salt tolerance, and a second site, possibly teichoic acids, manifested by loss of D-ala and Mg.

Nisin: a possible alternative or adjunct to nitrite in the preservation of meats

Nisin at 75 ppm (75 microgram/g) was superior to 150 ppm of nitrite in inhibiting outgrowth of Clostridium sporogenes PA3679 spores in meat slurries, which had been heated to simulate the process used for cooked ham. The inhibitory activity of nisin decreased as the spore load or pH of the slurries increased. Unlike nitrite, inhibition by nisin was unaffected by high levels of iron either as a constituent of meats or when added as an iron salt. In slurries treated with 75 ppm of nisin, refrigerated storage for 56 days resulted in depletion of nisin to a level low enough to allow outgrowth within 3 to 10 days if the slurries were subsequently abused at 35 degrees C. In contrast, a combination of 40 ppm of nitrite and either 75 or 100 ppm of nisin almost completely inhibited outgrowth in these slurries. The nisin-nitrite combination appeared to have a synergistic effect, and the low concentration of nitrite was sufficient to preserve the color in meats similar to that of products cured with 150 ppm of nitrite.

The effect of NaCl on the upper temperature limit for growth of and enterotoxin synthesis by Staphylococcus aureus

The upper temperature limit for growth of an enterotoxin A producing strain (MF31) and of an enterotoxin B producing strain (S6) was about 44-45 degrees C in either a peptone-based medium or heart infusion broth. In the presence of NaCl, growth and production of enterotoxin, coagulase, and thermostable nuclease occurred up to 2 degrees C higher. The optimal concentration of NaCl for the temperature elevation effect was 1 M.

Mechanism of the temperature protective effect of salts on Staphylococcus aureus

In the previous paper we reported that the maximum temperature for growth of Staphylococcus aureus was about 2 degrees C higher in media supplemented with NaCl. We now show that MgCl2 was the most effective protectant at 0.4 M. NaCl and KCl were as effective as MgCl2 when tested at 1 M. NH4Cl was less effective at all concentrations and LiCl was not protective. Sucrose and glucose (1M) gave about half the biomass of 1M NaCl. Glycerol, Na2SO4, NaNO2, NaNO3, and CH3COONA were not protective. Protection is probably due to the nonpenetrating solute (sucrose) or the nonpenetrating Cl- anion. Mg2+ had an effect additional to that attributable to Cl- because MgSO4 and to a slight extent (CH3COO)2Mg were protective. The morphology of the cells grown at 45 degrees C in 1 M NaCl was abnormal: septation became irregular, cell walls were thickened, and the cells occurred in irregularly sized clumps surrounded by capsular material.

Stability of ribosomes of Staphylococcus aureus S6 sublethally heated in different buffers

Cells of Staphylococcus aureus heated at 52 degrees C in magnesium-chelating buffers [pH 7.2, 50 mM potassium phosphate or 50 mM tris(hydroxymethyl)-aminomethane containing 1 mM ethylenediaminetetraacetic acid] leaked 260-nm absorbing material, shown to be RNA, and suffered destruction of their ribosomes. These cells did not regain their salt tolerance when repair was carried out in the presence of actinomycin D (5 microgram/ml). Cells similarly heated in magnesium-conserving buffers [pH 7.2, 50 mM tris(hydroxymethyl)aminomethane containing 10 mM MgCl2 or piperazine buffer] did not leak RNA, suffered no ribosomal damage when heated for 15 min, and recovered, at least partially, in the presence of actinomycin D. Ribosomal damage, is therefore, a consequence of Mg2+ loss and is not an effect of heat per se. Cells suspended in either Mg2+-chelating or Mg2+-conserving buffers lost salt tolerance to about the same extent during heating at 52 degrees C. Therefore, sublethal heat injury can not be attributed to ribosomal damage.