Synthesis, structure, and stability of the zinc complex of the dimethyl ester of meso-2,3-dimercaptosuccinic acid

The dimethyl ester of meso-2,3-dimercaptosuccinic acid (meso-DiMeDMSA) reacts with Zn2+ ions to form protonated and polynuclear complexes. The species [Zn2L3H]- and [Zn2L3]2- are formed at pH values between 3 and 6.5 and have overall formation constants of 10(37.53) and 10(32.52), respectively, whereas the mononuclear complex [ZnL2]2- is formed at physiological pH and has a formation constant of 10(18.06). The mononuclear complex was synthesized and isolated as an ion association complex with the tetramethylammonium ion, [(Me)4N]2[Zn(DiMeDMSA)2], and its structure in solution was determined by low-temperature 1H and 13C NMR spectroscopy. In this structure the Zn2+ ion is tetrahedrally coordinated to four thiolate groups from two meso-DiMeDMSA molecules.

Shape of the relationship between hypertension and the rate of progression of renal failure in autosomal dominant polycystic kidney disease

The effect of hypertension on the rate of progression of renal failure was analyzed in 26 patients with autosomal dominant polycystic kidney disease relating the slopes of progression (linear regression of the reciprocal serum creatinine on time) with the average mean arterial pressure, systolic and diastolic pressure, derived over the entire follow-up period for each patient. Hypertension was found in 19 of the 26 patients. Using simple linear regression, there was no significant correlation between the two variables in any case. Using polynomial regression (quadratic and cubic), this relationship fits a sigmoid (for diastolic pressure) or a negative parabolic curve (for mean arterial pressure and systolic pressure); i.e. the lowest and the highest values of mean arterial pressure and systolic pressure were associated with faster rates of progression. Thus, an appropriate model to study this relationship is not the linear but the polynomial regression.

The dimethyl ester of meso-2,3-dimercaptosuccinic acid and its interactions with Cd2+ and rabbit liver metallothionein I

The ion association complex formed with the cadmium chelate of the dimethyl ester of meso-2,3-dimercaptosuccinic acid and the tetramethylammonium cation, [(Me)4N]2[Cd(Di-MeDMSA)2], has been synthesized. The structures of the ion association complex and of the ligand (meso-DiMeDMSA) were determined by single-crystal X-ray diffraction. The two methyl ester groups and the two sulfhydryl groups in meso-DiMeDMSA were in a staggered conformation. The anion [Cd(DiMeDMSA)2]2- is essentially a distorted tetrahedron, with a mononuclear CdS4 kernel. The structure of the [Cd(DiMeDMSA)2]2- anion in solution was found to be similar to its structure in the solid state by multinuclear (1H, 13C, 113Cd) magnetic resonance spectroscopy. In the presence of rabbit liver metallothionein I (MT), meso-DiMeDMSA was found to coordinate Zn2+ and Cd2+ ions. 1H NMR spectroscopy proved to be an effective analytical technique for monitoring the competition between meso-DiMeDMSA and the protein for these metal ions. This was accomplished by probing the tertiary structure of MT with 1H NMR spectroscopy after incubation with meso-DiMeDMSA. In addition, the 1H NMR spectra of rabbit liver metallothionein I demonstrated that MT is more susceptible to oxidation at physiological pH after the metal ions have been removed. It appears that intra- as well as intermolecular disulfide cross-linkages are formed upon oxidation. When rabbit liver metallothionein I was incubated with meso-DiMeDMSA in a 20:1 (meso-DiMeDMSA:MT) mole ratio, 32% of the cadmium and 87% of the zinc bound to MT were removed.

Hemodynamic changes in hemodialyzed patients during treatment with recombinant human erythropoietin

Evolution of cardiac index in 12 patients with severe renal anemia on regular hemodialysis (hematocrit 19.9 +/- 2.8%) was studied during the first 4 months of treatment with recombinant human erythropoietin (rhEPO). At the end of the study period, hematocrit rose to 31.1 +/- 3.5% (p less than 0.001) and cardiac index significantly decreased (5.34 +/- 1.25 vs. 3.81 +/- 0.84 liters/min/m2, p less than 0.001). Cardiac index fell mainly because of reduction of stroke volume (108 +/- 27 vs. 81 +/- 25 ml, p less than 0.001), while heart rate did not change during the study period. Before starting rhEPO cardiac index was elevated in 11 out of the 12 patients, whereas after 4 months of treatment this was only maintained in 4 of them. We conclude that substitution with rhEPO in hemodialysis patients significantly decreases cardiac index, confirming anemia as the main factor for hyperdynamic circulatory state in these patients. Whether this reduction in cardiac index will ameliorate cardiac morbidity or not and hematocrit levels for achieving the major benefits require further studies.

Synthesis and properties of the monomethyl ester of meso-dimercaptosuccinic acid and its chelates of lead (II), cadmium(II), and mercury(II)

The monomethyl ester of meso-dimercaptosuccinic acid (MoMeDMSA) and its chelates with lead(II), cadmium(II), and mercury(II) have been synthesized. The mercury(II) chelate of MoMeDMSA is formed by the coordination of the two sulfur atoms in MoMeDMSA, whereas the lead(II) and cadmium(II) chelates are formed by the coordination of one sulfur and one oxygen atom. The solubilities of the chelates are pH dependent; the mercury(II) chelate dissolves when the uncoordinated carboxylic acid dissociates, but the lead(II) and cadmium(II) chelates are solubilized only after the uncoordinated mercapto group is dissociated. The cadmium(II) chelate is dimeric and the lead(II) and mercury(II) chelates are monomeric at the concentrations and conditions used in this study. The acid dissociation constants of the chelating agent and the uncoordinated groups in its metal chelates have been determined in 50% v/v methanol-water. These acid-base properties in addition to the polarity of the chelating agent contribute to the effectiveness in the in vivo mobilization of intracellular in vivo deposits of cadmium. The biliary excretion of cadmium in rats increased by a factor of 173 upon administration of the relatively toxic, nonpolar dimethyl ester of DMSA whereas the administration of the less toxic, more polar monomethyl ester increased the biliary excretion of cadmium by a factor of 63. On the other hand, meso-DMSA which is highly polar and less toxic is known to be without effect on biliary excretion of cadmium. The monomethyl DMSA, therefore, appears to have properties that are intermediate between those of DMSA and its dimethyl ester, as far as both chelating properties and biliary excretion of cadmium are concerned.

Metabolic effects of cyanate on mice at sea level and in chronic hypobaric hypoxia

In order to evaluate the toxic effects of Sodium Cyanate (NaOCN), it was orally administered to growing mice at sea level (SL-CN) and to mice chronically exposed to intermittent hypobaric hypoxia (IHH-CN). The effects on body weight, in-vivo O2 consumption (VO2) and the respiratory function of liver mitochondria were evaluated. At sea level, the animals on cyanate lost weight in contrast with the controls that gained weight. When exposed to IHH, the controls lost weight and the animals on cyanate regained weight. After 2 months observation the weights of the IHH-CN and IHH-C were similar. The VO2 after one month of treatment was similar in the SL-C and in the SL-CN but it was lower in the IHH-CN when compared with IHH-C. The substrate-stimulated respiration of isolated liver mitochondria (ST4) was not affected by NaOCN, but the ADP-stimulated respiration (ST3) was reduced. The ratio ST3/ST4 (RCR) was also lower. These changes were present in both SL and in IHH and were much larger after three months of treatment. The toxic effects of chronic administration of NaOCN are discussed.

Organophosphate poisoning

Organophosphate compounds insecticides are the most commonly associated with serious human toxicity. We reviewed the adult cases of organophosphate poisoning seen at HURRA from January 1986 to January 1990. We had 14 cases, all male patients. The most common mode of exposure was by ingestion in a suicidal attempt, (8/14 cases). The most common symptom observed was nausea (6/14 patients), and the most common sign was increased bronchial secretions (8/14 patients). Laboratory abnormalities were similar to those previously reported in the literature: leukocytosis (10/14 cases), hyperglycemia (5/14 cases) and hypokalemia (4/14 cases). Patients were treated following accepted guidelines. None of our patients developed seizures nor ventricular arrhythmias. One of our patients developed respiratory failure and required mechanical ventilation. Two patients developed pneumonic processes, requiring intravenous antibiotic therapy. The hospital stay of these two patients was prolonged (7 and 10 days respectively). For the other 12 patients, the hospital stay ranged from 2 to 4 days. We had no mortality in our series. We were able to obtain follow-up interview by telephone with 10 of the 14 patients and we did not find any history of symptoms of delayed clinical toxicity.

Usefulness of a systemic hypertension in-hospital educational program

The effects of an educational program on compliance and blood pressure (BP) control were assessed in 47 hypertensive patients hospitalized for nonhypertension-related diseases. Patients were randomized to receive either a questionnaire and an educational program (group I, 25) or questionnaire only (group II, 22). Baseline clinical characteristics, admission diagnoses and antihypertensive medications were similar between the groups. Antihypertensive medications used by patients before the trial were not changed. Eight weeks after the initial intervention, patients in group I showed a significant reduction in both systolic and diastolic BP (137/89 vs 154/98 mm Hg, p = 0.005 and 0.006, respectively) and improved compliance (96 vs 36%, p = 0.04), compared with patients in group II. An education program in patients with high BP is an effective method to improve compliance and BP control in the short-term.

Growth-dependent alterations in production of serotype-specific and common antigen lipopolysaccharides in Pseudomonas aeruginosa PAO1

Pseudomonas aeruginosa PAO1 was grown in various media and at different temperatures, and the heterogeneity of the extracted lipopolysaccharide (LPS) was characterized by polyacrylamide gel electrophoresis. The size distributions of the serotype-specific LPS and the common antigen LPS were analyzed on Western blots (immunoblots). Cells grown at high, near-growth-limiting temperatures, at low pH, in low concentrations of phosphate, or in high concentrations of NaCl, MgCl2, glycerol, or sucrose produced decreased amounts of the very long chain population of O-antigen LPS molecules. Lower temperatures and lowered glycerol, lowered sucrose, low sulfate, lower salt concentrations, and elevated pH did not significantly affect the level of this LPS population. The size and amount of common antigen LPS was either unaffected or increased slightly when the cells were grown under the above stress conditions. Cells grown under normal, nonstressed conditions were agglutinated only by serotype-specific antibodies. In contrast, cells grown under stress conditions, in which the long-O-polymer LPS was absent, were agglutinated by both serotype-specific and common antigen-specific antibodies. The results indicate that the long O polymers cover and mask the shorter common antigen. However, specific growth conditions limit the production of the long O polymer, allowing the exposure and reactivity of the common antigen on the cell surface.

Correlation of waist to hips ratio to the prevalence of diabetes and hypertension in black females

Regional fat distribution is an important risk factor for the development of diabetes and hypertension in white females; those with fat cells in the upper part of the body have a higher prevalence of diabetes and hypertension than those with similar degrees of obesity in the lower parts of the body. Whether this observation is relevant for the general population of black females is not known. In this article, we report the results of a study of fat distribution in black females and its correlation with the prevalence of diabetes and hypertension. One hundred black females who attend the Charity Hospital System of Louisiana were studied. Anthropometric measurements were taken, and the prevalence of both diabetes and hypertension determined by review of the medical record and patient interview. In this study, the waist to hips ratio was the index of fat distribution. Waist to hips ratio was found to increase with age. The observed prevalence of diabetes, hypertension, and both together was higher in those with upper body obesity: 40% of those in the lower quartile had diabetes, whereas 80% of those in the highest quartile had diabetes. The mean waist to hips of diabetic patients (0.95) was higher than the ratio for nondiabetics (0.90). Hypertensives also had a higher ratio (0.95) than nonhypertensives (0.89). This is the first study to show that waist to hips ratio in blacks correlates with the prevalence of diabetes and hypertension. This suggests that the measurement of waist to hips ratio is an important part of the physical evaluation and may be a predictor of morbidity.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of adducts of deoxyribonucleic acid in white blood cells of roofers by 32P-postlabeling. Relationship of adduct levels to measures of exposure to polycyclic aromatic hydrocarbons

To assess the utility of adducts of deoxyribonucleic acid (DNA) as biomarkers of exposure to carcinogens in an industrial population, a pilot study of roofers occupationally exposed to polycyclic aromatic hydrocarbons was conducted. DNA isolated from white blood cells of roofers and nonoccupationally exposed comparison subjects matched for age, sex, and smoking status was analyzed for DNA adducts with the use of 32P-postlabeling methods. Occupational exposures to polycyclic aromatic hydrocarbons were assessed by personal air sampling and skin wipes. Ten of the 12 roofers, but only 2 of the 12 comparison subjects, had detectable levels of aromatic DNA adducts in the 32P-postlabeling assay. Among the roofers, the post-shift levels of polycyclic aromatic hydrocarbons in the skin wipes were correlated with the DNA adduct levels. These results suggest that 32P-postlabeling assay may be useful for monitoring internal exposures to complex mixtures of aromatic hydrocarbons in industrial populations.

[Metastatic calcification simulating a sacral tumor in a patient on periodic dialysis]

Renal osteodystrophy is usually a prominent feature in patients undergoing chronic hemodialysis. Metastatic calcifications are a frequent finding when secondary hyperparathyroidism is associated. We present a patient with a sacral soft tissue calcification resembling a malignant tumour.

Necrotizing myositis secondary to Serratia marcescens in a renal allograft recipient

We describe a fatal case of spontaneous necrotizing myositis due to a highly resistant strain of Serratia marcescens in a renal transplant recipient. Though Staphylococcus aureus and Clostridium are the usual agents which cause either pyomyositis or necrotizing myositis, gram-negative bacteria are a dangerous and rarely suspected possibility. Such an aggressive disease should be promptly recognized because immunosuppression in susceptible hosts makes conservative management unsuccessful. The prognosis for myositis in immunodepressed hosts is poor and wide excision of all the necrotic muscles, leaving the wound open, and intensive antibiotic therapy are required.

Clinical features and prognosis of adult polycystic kidney disease

To appraise the prognosis of adult polycystic kidney disease (APKD), 107 patients (58 male and 49 female) were studied retrospectively. The mean age at the time of diagnosis was 45.9 years (ages ranging from 18 to 83 years). Ninety-eight patients had symptomatic APKD. At diagnosis, 30 of these patients had normal renal function, and 68 presented with chronic renal failure (serum creatinine higher than 1.5 mg/dl). Nine of the 107 patients were asymptomatic. Hypertension was the most common feature in symptomatic APKD, present in 51% of these patients as initial manifestation, and was observed in 46% of the patients with normal renal function. Forty of the 107 patients (37%) went into end-stage renal disease (ESRD) at a mean age of 52.7 years. The probability of being alive and not having ESRD, estimated using a time-to-event analysis, was 74% by the age of 50, 51% by the age of 58 and 37% by the age of 70 years. Thus, the prognosis for patients with APKD is better than some reports suggested some years ago.

Kidney transplantation in systemic lupus erythematosus nephritis: a one-center experience

Eight patients with end-stage renal disease secondary to systemic lupus erythematosus (SLE) received 8 cadaveric renal allograft. Patient and graft survival was 100 and 87%, respectively. None of them showed extrarenal manifestations of SLE or recurrence of lupus nephritis after grafting. One graft was lost because of chronic rejection. In another patient, an episode of graft function deterioration due to bad control of arterial hypertension was observed. Three patients were transplanted during their first year on hemodialysis. Two women became pregnant after successful kidney transplantation; one suffered a spontaneous abortion and the other had a successful delivery. In neither of them, was SLE observed during or after pregnancy. Morbidity was low in this series, and infections were the most frequent complication. In summary, our experience with renal transplantation in SLE patients compares, favorably with the general nodiabetic transplanted population.

Lead chelates of meso- and racemic-dimercaptosuccinic acid

Lead chelates of racemic- and meso-dimercaptosuccinic acid (DMSA) were synthesized and isolated from aqueous solutions and characterized by potentiometric measurements and infrared spectroscopy. Two types of lead chelates of racemic DMSA were isolated: one in which racemic-DMSA is coordinated to Pb+2 via one oxygen and one sulfur atom and the other in which the Pb2+ is coordinated via two sulfur atoms. The latter form of the chelate is converted into the former upon dissolution in dimethylsulfoxide. Only one type of Pb2+ chelate of the meso form of the ligand was formed. In this case, meso-DMSA is coordinated to Pb+2 via one oxygen and one sulfur atom. Meso- and racemic-DMSA have very different solubilities in aqueous solutions. Meso-DMSA is slightly soluble in water, whereas racemic-DMSA is very soluble in water even in the presence of strong acids. The solubilities of the chelates were found to be pH dependent. When the uncoordinated sulfhydryl and carboxylic acid groups dissociate, the chelates dissolve and remain in aqueous solution. The infrared spectra of meso- and racemic-DMSA show distinct features that can be used to detect the presence of either diastereoisomer.

Determination and metabolism of dithiol chelating agents. VIII. Metal complexes of meso-dimercaptosuccinic acid

Metal complexes of meso-dimercaptosuccinic acid (DMSA) with Pb2+, Cd2+, and Hg2+ were studied by potentiometric and infrared methods. This dimercapto metal-binding agent was found to form complexes whose structures are dependent on the metal ion to be complexed. In the cases of Pb2+ and Cd2+, one oxygen and one sulfur act as the donor atoms; in the case of Hg2+, two sulfur atoms act as the donors. The solubilities of all metal chelates were found to be pH dependent. Complexes of cadmium and lead are insoluble in the pH range 1.0 to 7.1, but are solubilized when the noncoordinated sulfhydryl and carboxylic acid groups are ionized. The mercury complex is insoluble in the pH range 1.0 to 3.0. It dissolves when one of the noncoordinated carboxylic acid groups is ionized. The dimethyl ester of meso-DMSA (DiMe-meso-DMSA) was synthesized and its acid dissociation constants were determined (pK1 = 6.38 and pK2 = 8.00). Esterification of the carboxyl groups of meso-DMSA changes its coordination properties in that the two sulfur atoms of DiMe-meso-DMSA are used to coordinate with Hg2+, Cd2+, or Pb2+. Esterification of meso-DMSA also changes its biological properties. DiMe-meso-DMSA, when given to rats 3 days after Cd administration, greatly increased the excretion of Cd via bile. In contrast, meso-DMSA was devoid of such activity.

Polycyclic aromatic hydrocarbon (PAH) residues on skin in relation to air levels among roofers

To assess the utility of skin wipes as an index of exposure to polycyclic aromatic hydrocarbons (PAHs), simultaneous skin wipe and breathing zone air samples were obtained for 10 roofers. Samples were obtained during removal of an old coal-tar pitch roof and application of a new asphalt roof. Skin wipes were obtained immediately before and after the workshift. Anthracene was present in air but not skin samples. In air samples, the relative concentrations of seven PAHs were fluoranthene greater than pyrene greater than benzanthracene greater than benzo[a]pyrene greater than benzo[b]fluoranthene greater than benzo[ghi]perylene greater than benzo[k]fluoranthene. A similar pattern, or rank concentration, was observed in matching skin wipe samples. The amount (ng) of PAH (either total or individual compounds) found in skin wipes taken after the workday was significantly correlated with that in air samples (micrograms/m3, time-weighted average) for 8 of the 9 cases with air and skin samples taken the same day (r = 0.99 for total PAH). Skin wipe PAH residues were not significantly correlated with air samples taken 4 d earlier. These findings suggest that skin wipes can provide a useful measure of exposure to PAH.

Analysis of a common-antigen lipopolysaccharide from Pseudomonas aeruginosa

Lipopolysaccharide isolated from Pseudomonas aeruginosa PAO1 (O5 serotype) was separated into two antigenically distinct fractions. A minor fraction, containing shorter polysaccharide chains, reacted with a monoclonal antibody to a P. aeruginosa common antigen but did not react with antibodies specific to O5-serotype lipopolysaccharide. In contrast, fractions containing long polysaccharide chains reacted only with the O5-specific monoclonal antibodies. The shorter, common-antigen fraction lacked phosphate and contained stoichiometric amounts of sulfate, and the fatty acid composition of this fraction was similar to that of the O-antigen-specific fraction. The lipid A derived from the serotype-specific lipopolysaccharide cross-reacted with monoclonal antibodies against lipid A from Escherichia coli, while the lipid A derived from the common antigen did not react. We propose that many serotypes of P. aeruginosa produce two chemically and antigenically distinct lipopolysaccharide molecules, one of which is a common antigen with a short polysaccharide and a unique core-lipid A structure.

Enhanced binding of polycationic antibiotics to lipopolysaccharide from an aminoglycoside-supersusceptible, tolA mutant strain of Pseudomonas aeruginosa

The lipopolysaccharide (LPS) of the aminoglycoside-supersusceptible Pseudomonas aeruginosa tolA mutant PAO1715 was compared with its parent strain PAO1670 and tol+ revertant PAO1716. Electrophoretic separation of purified LPSs from the three isolates showed similar LPS banding patterns. Analysis of the Western blots of these LPSs from the three isolates with O-antigen-specific monoclonal antibody indicated that the ladder pattern consisted of doublet bands, which presumably reflected a modification of core or lipid A; the level of one of the bands in the doublet was in much lower amounts in the isolate from the tolA mutant than in that from the parent or revertant. Results of competitive displacement experiments, in which the cationic spin probe 4-dodecyldimethylammonium-1-oxyl-2,2,6,6-tetramethylpiperidine bromide was displaced from its LPS-binding site by polycations, revealed that the tolA mutant had a much higher affinity for gentamicin, polymyxin, Ca2+, and Mg2+ than did the parent or revertant. The order of affinity for all samples was polymyxin B much greater than gentamicin C much greater than Ca2+ greater than Mg2+. Both gentamicin and polymyxin induced rigidification of all of the LPS samples, but for the sample from the tolA mutant, rigidification occurred at substantially lower concentrations. Dansyl polymyxin titration experiments with intact cells demonstrated that the increased affinity of the LPS from the tolA mutant for polycations was reflected in an increase in the affinity of binding to the cell. Together these data suggest that the tolA mutant is supersusceptible to aminoglycosides by virtue of an LPS change which increases the binding affinity of the LPS for polycations, including gentamicin.

Heterogeneity of lipopolysaccharides from Pseudomonas aeruginosa: analysis of lipopolysaccharide chain length

Lipopolysaccharide (LPS) from smooth strains of Pseudomonas aeruginosa 503, PAZ1, PAO1715, PAO1716, and Z61 was fractionated by gel filtration chromatography. LPS samples from the first four strains, all PAO1 derivatives, separated into three major size populations, whereas LPS from strain Z61, a Pac K799/WT mutant strain, separated into two size populations. When column fractions were applied to sodium dodecyl sulfate-polyacrylamide gels in their order of elution, molecules of decreasing size were resolved, and the ladder of molecules with different-length O antigens formed a diagonal across the gel. The LPS from the PAO1 derivatives contained two distinct sets of bands, distinguished on the gels as two sets of diagonals. The set of bands with the faster mobility, the B bands, was found in column fractions comprising the three major amino sugar-containing peaks. In the sample from strain 503, a fourth minor peak which contained B bands was resolved. The slower-moving set of bands, the A bands, were recovered in a minor peak. LPS from strain Z61 contained only one set of bands, with the higher-molecular-weight molecules eluting from the column in a volume similar to that of the B bands of the PAO1 strains. Analysis of the fractions of LPS from all strains indicated that less than 8% of the LPS molecules had a long, attached O antigen. Analysis of the peak that contained mainly A bands indicated a lack of reactive amino sugar and phosphate, although heptose and 2-keto-3-deoxyoctulosonic acid were detected. Reaction of isolated fractions with monoclonal antibody specific for the PAO1 O-antigen side chain indicated that only the B bands from the PAO1 strains were antigenically reactive. The bands from strain Z61 showed no reactivity. The data suggest that the A and B bands from the PAO1 strains are antigenically distinct. We propose that PAO1 strains synthesize two types of molecules that are antigenically different.

Efficacy of two insertions of 100-minute releasing quinacrine hydrochloride pellets for non-surgical female sterilization

Extensive research has been undertaken to develop a simple method of non-surgical female sterilization. Zipper and associates identified quinacrine hydrochloride as a drug likely to produce tubal occlusion when placed into the uterus. Zipper's early work with a solution of quinacrine led to the development of quinacrine pellets, a delivery system that was designed to bring the quinacrine into prolonged contact with the tubal ostia through extended uterine retention. Three transcervical uterine insertions of 10-minute releasing quinacrine hydrochloride pellets performed at monthly intervals have produced a 12-month pregnancy rate of 3.3 per 100 women. The ultimate goal is to develop an effective, single insertion procedure, but the performance of the quinacrine pellets in occluding tubes has necessitated more than one insertion. FHI developed a 100-minute extended release pellet system with the expectation that more prolonged drug exposure would produce a higher rate of tubal closure. A study of the 100-minute releasing pellet system has been conducted in Santiago, Chile. Two monthly insertions in 112 women has resulted in a 12-month pregnancy rate of 2.0 per 100 women. Postprocedure problems occurring within the first year were reported by 13% of the women; most were minor and transitory.

Psychological response of firefighters to a chemical fire

Samples of firefighter subjects (n = 80) and a comparison group (n = 15) were contrasted on a number of postincident psychological distress measures in the aftermath of a polyvinyl chloride (PVC) fire. Using a structured, self-administered questionnaire, firefighter subjects were found to be more psychologically distressed on demoralization, specific emotional distress, and perceived threat to physical health. After controlling for baseline characteristics on which subjects and the comparison group differed, these between-group effects remained significant. The three outcome scales, while correlated, measure different components of psychological distress.

Neutron scattering analysis of bacterial lipopolysaccharide phase structure. Changes at high pH

The aggregate structure of lipopolysaccharide isolated from an Re strain of Escherichia coli was examined at different pH values using small angle neutron scattering. At pH values of 6 and 7.4, angle-averaged scattering of the sodium salt of this isolate was consistent with randomly coiled tubular micelles approximately 100 A in diameter. At pH 9.1, however, Kratky analysis of the scattering data was distinctly different and consistent with pairing of uniform tubular micelle sections of length 1440 and 110 A in diameter. Contrast variation measurements of the micelles yielded an average micellar weight of the sample at pH 9.1 of approximately 1.11 X 10(7) daltons and suggested that the aggregates were tubular micelles of size and length similar to that derived from the scattering intensity data. Anisotropic scattering patterns of samples under shear indicated a rigidification of the micelles as the pH was increased to 9.1 and the temperature decreased from 25 to 10 degrees C. The rotational diffusion constants deduced from the observed shear anisotropy indicate that the structure at pH 9.1 must have smallest and largest dimensions which differ by at least an order of magnitude, ruling out spherical or moderately ellipsoidal structures. Analysis of the shear rate needed to induce anisotropic scattering indicated that the stiffness length of the micelles at pH 9.1 was approximately 1000 A and decreased at higher and lower pH values.

Branhamella catarrhalis as a lower respiratory tract pathogen in patients with chronic lung disease

To determine the possible role of Branhamella (formerly Neisseria) catarrhalis as a respiratory pathogen, we screened quality sputa (defined by cellular criteria) that showed numerous gram-negative cocci on Gram's stain for the presence of B catarrhalis. In an eight-month period, 52 isolates of B catarrhalis were identified in adults attending a hospital for chest diseases. During this period B catarrhalis was the third most common potential pathogen isolated from sputa. Twenty-two patients (42%) had associated patchy bronchopneumonic or lobar infiltrates. All had negative blood cultures and a generally mild clinical course. The majority of strains (73%) of B catarrhalis produced beta-lactamase and were resistant to penicillin and ampicillin. Isolates (including beta-lactamase-producing strains) were susceptible to erythromycin, tetracycline, and trimethoprim-sulfamethoxazole. These studies demonstrate that in patients with chronic lung disease, the presence of B catarrhalis in sputum can be suspected on the basis of a Gram's stain and may be associated with the development of new pneumonic infiltrates. Since these organisms frequently produce beta-lactamase, empiric antimicrobial therapy should include agents other than the penicillins.

Evaluation of Copper I IUD's

The development of the Copper 1 IUD (Cu 1) was an attempt to decrease the incidence of unpleasant side effects (primarily pain and bleeding) associated with IUD use, by reducing the size of the vector carrying the copper. The Cu 1 consists of a straight stem with crossarms in an "X" configuration, designed to anchor the IUD in place. The device was tested in 98 interval women in the Hospital Barros Luco in Santiago, Chile who were asked to return at 1, 3, 6, and 12 months post-insertion for follow-up examinations. There was only 1 removal for bleeding and pain; however, both pregnancy and expulsion rates were high at 9.0 and 16.0 respectively after 12 months. The crossarms did not keep the device in place as expected. The high pregnancy rate may have been due to the reduced size of the IUD and to increased displacement/expulsion. Future efforts to decrease IUD size will be dependent on designing an IUD which will be less easily expelled or displaced.

Endemic infantile hypothyroidism in a severe endemic goitre area of central Africa

Thyroid function and exposure to dietary goitrogenic factors (iodine deficiency and thiocyanate overload) were studied at birth and from birth to 7 years in 200 neonates and 347 children living in the severe endemic goitre area of Ubangi, Northern Zaire. Serum T4 was at the lower limit of normal at birth (104 +/- 4 nmol/l) and stayed at that level during the first year of life (123 +/- 9) (NS), but decreased to 75 +/- 8 (P less than 0.001) at 2-4 years and to 62 +/- 6 (P less than 0.001) at 5-7 years of age. Mean serum FT4 decreased from 10.4 +/- 0.9 pmol/l during the first year to 8.2 +/- 1.0 (NS) at 2-4 years (NS) and to 7.7 +/- 0.9 (P less than 0.05) at 5-7 years. Mean serum TSH was 10.4 (8.4-12.9) mU/l (geometric mean +/- 1 SEM) during the first year, 10.1 (7.5-13.7) (NS) at 2-4 years and 24.3 (18.5-31.9) (P less than 0.05) at 5-7 years. Mean serum T3 was 3.23 +/- 0.12 nmol/l during the first year and remained stable thereafter. The frequencies of low T4 (T4 less than 77 nmol/l), high TSH TSH (TSH greater than 50 mU/l), and low T4 and T3 (T3 less than 1.69 nmol/l) were twice as high at 5-7 years as in the first year (respectively 65%, 42% and 15%). The urinary iodide concentration of the children was stable and low throughout the study period. By contrast, serum thiocyanate concentration which was high at birth (129 +/- 5 mumol/l) decreased to normal values between 3 and 12 months of age and increased again during and after weaning (1 to 3 years of age) to reach a value of 138 mumol/l which was comparable to that observed in adults in the same area. Thiocyanate concentration was high (133 +/- 7 mumol/l) in the mothers' serum but low in the mothers' milk (57 +/- 3 mumol/l) (P less than 0.001). Multivariate analysis showed that both iodine deficiency and thiocyanate overload were explanatory factors of the serum levels of T4, FT4 and TSH in children. In conclusion, our results show that infantile hypothyroidism is much more frequent at 5-7 years of age than at birth or during the first year of life. The deterioration in thyroid function during and after weaning is linked to persistent iodine deficiency accompanied by an increase in thiocyanate overload. The variability in the age of onset, the severity, and the duration of infantile hypothyroidism might explain the wide range of psychomotor and physical abnormalities observed in a large proportion of subjects in this area.

Distal coronary power injection during percutaneous transluminal coronary angioplasty

A modification of the standard percutaneous transluminal coronary angioplasty (PTCA) procedure is described using a power injector instead of a hand-held syringe for distal coronary contrast injections. This system was used in 215 dilatations without complications related to the power injector. We found this system to simplify the PTCA procedure and allowed for improved distal visualization even with the steerable PTCA catheters containing an intraluminal guide wire.

Propranolol as a novel, effective spermicide: preliminary findings

The efficacy and tolerability of 80 mg propranolol tablets as a vaginal contraceptive were studied in 198 fertile women for 11 months. The calculated one year life table pregnancy rate was 3.4/100 women and the Pearl index was 3.9/100 women years. No major adverse effects were encountered. The findings suggested that propranolol is an effective vaginal contraceptive whose failure rate compares favourably with that of other methods of contraception. Further study of propranolol and similar compounds is warranted.

Single catheter technique for accurate cardiac outputs from left ventricle

We report our experience in cardiac output measurements using a single catheter for left ventricular green dye injection with sampling from the side arm of a femoral artery introducer sheath. This technique is compared to thermal dilution (20 patients) and pulmonary artery green dye injection (20 patients). There were no significant differences between the single catheter left ventricular method and the other two accepted methods for measuring cardiac output.

Pseudomonas aeruginosa mucoid strain. Its significance in adult chest diseases

Isolation of mucoid strains of Pseudomonas aeruginosa from bronchial secretions has occurred usually in the setting of cystic fibrosis. This association has been so strong that it is considered a sign of the presence of cystic fibrosis. We reviewed the records of 31 patients in whom this strain was isolated; in contract to previous experiences, we found that only 2 of our patients could be considered to have cystic fibrosis. The remainder all had a chronic pulmonary disease, and common to all was the presence of bronchiectasis. We conclude that isolation of mucoid strains of Pseudomonas aeruginosa from bronchial secretions of adults with a chronic pulmonary process indicates the presence of underlying bronchiectasis.

Antibiotic therapy of acute exacerbations of chronic bronchitis. A controlled study using tetracycline

We conducted a double-blind, randomized, placebo-controlled trial in 40 patients to evaluate the need for antibiotics in acute exacerbations of chronic bronchitis. All patients were sufficiently ill to require hospitalization although none needed ventilatory support; the presence of pneumonia was excluded. Treatment consisted of bronchodilators, corticosteroids, and either tetracycline, 500 mg, or placebo by mouth every 6 hours for 1 week. Arterial blood gases, spirometric tests, bacteriologic evaluation of sputum, and patient and physician evaluation of the severity of illness were assessed at the beginning and end of the study. All patients improved both symptomatically and by objective measures of lung function. At the end of the study period there were no differences between those patients receiving tetracycline and those receiving placebo. We conclude that antibiotic therapy is not needed in moderately ill patients with exacerbations of chronic bronchitis.

Placidyl abuse: a dimorphic picture

Eleven patients with documented intoxication with ethchlorvynol were evaluated for clinical and laboratory manifestations. All of the 7 patients who ingested the drug were severity neurologically depressed; 3 were hemodynamically unstable and 1 developed pulmonary edema documented to be noncardiogenic 40 h after admission. All of the remaining patients (including 1 who also ingested a small amount) presented with pulmonary edema in the absence of neurological changes, soon after injection of 2--3 capsules iv; hemodynamic measurements in one of these demonstrated a noncardiogenic etiology. The clinical manifestations in these 2 groups of patients seem to be clearly separable, depending on the dose and route of administration.

Trimellitic anhydride Toxicity. A cause of acute multisystem failure

A person exposed to trimellitic anhydride (TMA) an epoxy resin widely used in industry, experienced respiratory failure, anemia, and gastrointestinal bleeding. A lung biopsy specimen demonstrated intra-alveolar hemorrhage and damage to alveolar lining cells. The patient and six co-workers were examined. Results indicated the presence of hemolytic antibodies directed against TMA-haptenized erythrocytes, IgG, IgA, and IgM antibodies directed against TMA-erythrocyte complexes, and antibodies against TMA-human serum albumin. Antibody levels in the patient were greater than in the co-workers. The elevated antibody levels demonstrate the antigenic potential of TMA. However, the cause of the pulmonary and hematologic damage remains uncertain and may represent either immunologic or direct toxic effects of TMA. In patients with multisystem failure of this nature, occupational hazards should be added to the differential diagnosis.

Tricyclic antidepressant overdose: clinical and pharmacologic observations

Forty-seven patients with confirmed TCA overdoses were thoroughly evaluated with regard to clinical and electrocardiographic findings. In 22 patients plasma levels of the primary TCA and the desmethyl metabolite were determined. We found that both neurologic and cardiovascular complications were common, but independent of each other. While plasma levels of the parent of TCA compound correlated best with the neurologic disturbances, cardiac abnormalities were more related to the desmethyl metabolite level. Although plasma levels correlate with the clinical findings, sufficient overlap between normal and abnormal levels and findings exist that we do not feel that routine measurement of plasma levels is clinically useful at this time.

Quinacrine hydrochloride pellets: preliminary data on a nonsurgical method of female sterilization

The efficacy of transcervical insertions of quinacrine hydrochloride pellets to produce tubal occlusion has been evaluated in a study of 139 women in Santiago, Chile. At one year, the pregnancy rate was 3.1%, an acceptable rate for a nonsurgical method of female sterilization.