Association of poor clinical status and heavy exposure to tobacco smoke in patients with cystic fibrosis who are homozygous for the F508 deletion

We examined the association between clinical status and exposure to tobacco smoke in 44 patients homozygous for the F508 cystic fibrosis mutation. Heavy exposure to tobacco smoke was significantly associated with lower Shwachman scores, poorer results of pulmonary function tests, and a fivefold increase in the number of pulmonary-related hospitalizations during the previous year.

Attenuation of atherosclerosis in a modified strain of hypercholesterolemic Watanabe rabbits with use of a probucol analogue (MDL 29,311) that does not lower serum cholesterol

Probucol is a drug that lowers plasma cholesterol in both humans and animals. In low density lipoprotein (LDL) receptor-deficient Watanabe rabbits, probucol reduces the progression of atherosclerosis. This effect may be attributed to the antioxidant and/or the cholesterol-lowering properties of the drug. In the present report we studied the antiatherogenic effect of a probucol analogue (MDL 29,311) that possesses antioxidant activity but that does not lower cholesterol. Modified Watanabe rabbits (11-12 weeks of age) produced by crossing British Brown and Japanese Watanabe rabbits were fed normal chow (n = 8), chow containing 1% probucol (n = 9), or chow containing 0.1% (n = 9), 0.5% (n = 8), or 1% (n = 6) probucol analogue. After 70 days serum cholesterol levels and the percent area of sudanophilic lesions in the thoracic region of aortas were determined. Total serum cholesterol was significantly lowered (p less than 0.05) in the probucol group (560 +/- 54 mg/dl) compared with that of controls receiving no drug (731 +/- 67 mg/dl) but was not lowered in the analogue groups (722-802 mg/dl). The lesioned area (mean% +/- SEM) in the probucol group (16 +/- 3) was significantly lower (p less than 0.01) than in the controls (52 +/- 8). There were 43 +/- 7%, 33 +/- 8%, and 35 +/- 5% of lesions for the 0.1%, 0.5%, and 1% analogue groups, respectively. After combining the data for the 0.5% and 1% analogue groups, the value (34%) was lower than that of the controls and almost reached significance (p = 0.066). The mean serum drug concentration in the 1% probucol group was 58 +/- 4 micrograms/ml compared with 13 +/- 2, 44 +/- 8, and 74 +/- 8 micrograms/ml for the 0.1%, 0.5%, and 1% analogue groups, respectively. Thus, the decreased effectiveness of the probucol analogue in preventing atherosclerosis could not be explained by a lack of bioavailability. LDLs isolated from rabbits treated with the drug were resistant to Cu(2+)-induced lipid peroxidation, as determined by thiobarbituric acid-reactive substances. The resistance within the analogue groups was dependent on the number of antioxidant molecules per LDL particle. However, there was no significant difference in atherosclerotic lesions between these two groups, suggesting, although not definitively, that the maximal antiatherogenic effect had been reached. Our data suggest that the antioxidant activity of this class of compounds may play an important role in reducing atherosclerosis, but not in reducing cholesterol levels, and that hypocholesterolemic and possibly other activities of probucol might further enhance its antiatherogenic activity.

Population aging patterns: the expansion of mortality

We used the hypothesis of mortality compression as a framework to examine patterns of mortality from 1962 to 1984. Data from national vital statistics records were used for analysis of the changing age at death for percentiles of the population. Data from the Social Security Administration and the U.S. Census Bureau were used to calculate the force of mortality. The mean age at death for all percentiles, including the oldest groups, has risen during the interval. Examination of the coefficient of variation for the mean age at death suggests that there is a relative increase in the variability of age at death among the oldest old. The available data do not fit a hypothetical sequence of normal density distributions with an increasing mean and declining standard deviation. The force of mortality in those over 85 years appears to be decreasing in a pattern similar to that for those under 85 years. Current mortality patterns suggest an "expansion," rather than compression, of mortality at the oldest ages. Further refinement of these observations, with improved data on mortality among the oldest old, will be helpful in delineating mortality patterns.

Relationship between the human sperm hypo-osmotic swelling test and sperm penetration assay

The hypo-osmotic swelling (HOS) test has been proposed as a useful assay in the diagnosis of the infertile male. A good correlation between the HOS test and the sperm penetration assay (SPA) in fertile and normal semen samples was initially found, but subsequently, no significant correlation was demonstrated with fertile and infertile patients. To validate the potential clinical usefulness of the HOS test, we evaluated 92 ejaculates using the HOS test, SPA, and traditional semen parameters. The methodology originally described by Jeyendran et al (1984) was used for the HOS test. The SPA was performed by the original procedure using an 18-hour preincubation period, and for 28 ejaculates, a modified procedure using TEST-yolk buffer was performed. Values of 60% or more for the HOS and 1% or more for the SPA were considered positive, and less than 60% for HOS and 0% for SPA were considered negative when the standard SPA was performed. For the TEST-yolk buffered SPA, values of 20% or more were considered positive. The sensitivity of the HOS test was 87%, but the specificity was 36%. The association of the two tests over and above that expected by chance (Kappa) was only 0.23. Using logistic regression, both sperm count (P less than 0.001) and morphology (P less than 0.025) were significant predictors of the SPA classification, but the HOS test did not improve the predictive results (P greater than 0.50).(ABSTRACT TRUNCATED AT 250 WORDS)

Synthesis, biological profile, and quantitative structure-activity relationship of a series of novel 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors

A series of 9,9-bis(4-fluorophenyl)-3,5-dihydroxy-8-(alkyltetrazol-5-yl)- 6,8-nonadienoic acid derivatives 1 were synthesized and found to inhibit competitively the enzyme 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase. The analogues having 1N-methyltetrazol-5-yl attached to the C8-position (3a, 4a, R1 = R2 = F) are the most active in suppressing cholesterol biosynthesis in both in vitro and in vivo models: the IC50 for the chiral form of 3a is 19 nM, Ki = 4.3 x 10(-9)M when Km for HMG-CoA is 28 x 10(-6) M;1 the ED50 (oral) value corresponding to the lactone derivative (4a, BMY 22089) is approximately 0.1 mg/kg. Further, BMY 21950 is nearly 2 orders of magnitude more active in parenchymal heptaocytes, from which most of the serum cholesterol originates, than in other cell preparations (such as spleen, testes, ileum, adrenal, and ocular lens epithelial cells; Table III). This apparent tissue specificity may be highly beneficial since the blocking of cholesterol biosynthesis in other vital organs could eventually lead to undesirable side effects. In addition to the chemical synthesis and biological evaluation, a theoretical study aimed at relating the HMG-CoA reductase inhibitory potency to the three-dimensional structure of the inhibitors was undertaken. With a combination of molecular mapping and 3D-QSAR techniques, it was possible to determine a logical candidate for the conformation of the bound inhibitor and to quantitatively relate inhibitory potency to the shape and size of both the binding site and the C8-substituent.

Selective inhibition of cholesterol synthesis in liver versus extrahepatic tissues by HMG-CoA reductase inhibitors

Hepatic specificity of inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase may be achieved by efficient first-pass liver extraction resulting in low circulating drug levels, as with lovastatin, or by lower cellular uptake in peripheral tissues, seen with pravastatin. BMY-21950 and its lactone form BMY-22089, new synthetic inhibitors of HMG-CoA reductase, were compared with the major reference agent lovastatin and with the synthetic inhibitor fluindostatin in several in vitro and in vivo models of potency and tissue selectivity. The kinetic mechanism and the potency of BMY-21950 as a competitive inhibitor of isolated HMG-CoA reductase were comparable to the reference agents. The inhibitory potency (cholesterol synthesis assayed by 3H2O or [14C]acetate incorporation) of BMY-21950 in rat hepatocytes (IC50 = 21 nM) and dog liver slices (IC50 = 23 nM) equalled or exceeded the potencies of the reference agents. Hepatic cholesterol synthesis in vivo in rats was effectively inhibited by BMY-21950 and its lactone form BMY-22089 (ED50 = 0.1 mg/kg p.o.), but oral doses (20 mg/kg) that suppressed liver synthesis by 83-95% inhibited sterol synthesis by only 17-24% in the ileum. In contrast, equivalent doses of lovastatin markedly inhibited cholesterol synthesis in both organs. In tissue slices from rat ileum, cell dispersions from testes, adrenal, and spleen, and in bovine ocular lens epithelial cells, BMY-21950 inhibited sterol synthesis weakly in vitro with IC50 values 76- and 188-times higher than in hepatocytes; similar effects were seen for BMY-22089. However, the IC50 ratios (tissue/hepatocyte) for lovastatin and fluindostatin were near unity in these models. Thus, BMY-21950 and BMY-22089 are the first potent synthetic HMG-CoA reductase inhibitors that possess a very high degree of liver selectivity based upon differential inhibition sensitivities in tissues. This cellular uptake-based property of hepatic specificity of BMY-21950 and BMY-22089, also manifest in pravastatin, is biochemically distinct from the pharmacodynamic-based disposition of lovastatin, which along with fluindostatin exhibited potent inhibition in all tissues that were exposed to it.

The use of protriptyline for respiratory failure in patients with chronic airflow limitation

Treatment of nocturnal hypoventilation in patients with restrictive chest wall disease and respiratory failure, results in improved daytime arterial blood gas tensions, increase in functional ability and longer survival. Success has been achieved with the use of protriptyline which reduces the duration of rapid eye movement (REM) sleep during which nocturnal hypoventilation occurs. Eighteen patients with severe chronic airflow limitation (CAL), took part in a randomized, double-blind, crossover trial of protriptyline and placebo. Seventeen patients completed the study. The use of protriptyline was associated with a fall in the median percentage of total sleep time spent in REM from 16 to 8.8% (p less than 0.01). This was associated with a reduction in the median daytime arterial carbon dioxide tension from 6.4 kPa (range 5.2-8.5 kPa) to 5.8 kPa (range 5.0-8.1 kPa) (p less than 0.01); increased respiratory muscle strength (p less than 0.05), and increased six minute walking distance from a median of 258 m (range 58.5-585 m) to 275 m (range 171-598 m) (p less than 0.02). We found pharmacological treatment of REM-related nocturnal hypoventilation in patients with CAL to be effective, but anticholinergic side-effects, particularly in older male patients, might preclude long-term treatment.

Double-blind, placebo-controlled trial of alternate-day furosemide therapy in infants with chronic bronchopulmonary dysplasia

To test the hypothesis that alternate-day administration of furosemide will result in a sustained improvement in pulmonary function without causing alterations in electrolyte or mineral homeostasis, we conducted a randomized, double-blind, placebo-controlled study of 11 hospitalized, oxygen-dependent, spontaneously breathing infants with chronic bronchopulmonary dysplasia. Infants were randomly selected to receive either furosemide, 4 mg/kg in two divided doses on alternate days orally, or placebo for 8 days, followed by crossover to the alternate-therapy for an additional 8-day period. The two study periods were separated by a 48-hour washout period. Dynamic compliance, total pulmonary resistance, the concentration of electrolytes in serum, and the concentrations of calcium and creatinine in urine were measured on nontreatment days. Alternate-day furosemide therapy increased dynamic lung compliance by 76 +/- 112% and decreased total pulmonary resistance by 20 +/- 39%, compared with placebo (both variables p = 0.032). Alternate-day furosemide therapy did not result in increased urine output, electrolyte abnormalities, or increased urinary calcium excretion. We conclude that this simplified treatment regimen may be useful in the management of infants with chronic bronchopulmonary dysplasia. The results support our previous speculation that furosemide improves pulmonary function by mechanisms unrelated to its diuretic properties.

The use of protriptyline for respiratory failure in patients with chronic airflow limitation

Treatment of nocturnal hypoventilation in patients with restrictive chest wall disease and respiratory failure, results in improved daytime arterial blood gas tensions, increase in functional ability and longer survival. Success has been achieved with the use of protriptyline which reduces the duration of rapid eye movement (REM) sleep during which nocturnal hypoventilation occurs. Eighteen patients with severe chronic airflow limitation (CAL), took part in a randomized, double-blind, crossover trial of protriptyline and placebo. Seventeen patients completed the study. The use of protriptyline was associated with a fall in the median percentage of total sleep time spent in REM from 16 to 8.8% (p less than 0.01). This was associated with a reduction in the median daytime arterial carbon dioxide tension from 6.4 kPa (range 5.2-8.5 kPa) to 5.8 kPa (range 5.0-8.1 kPa) (p less than 0.01); increased respiratory muscle strength (p less than 0.05), and increased six minute walking distance from a median of 258 m (range 58.5-585 m) to 275 m (range 171-598 m) (p less than 0.02). We found pharmacological treatment of REM-related nocturnal hypoventilation in patients with CAL to be effective, but anticholinergic side-effects, particularly in older male patients, might preclude long-term treatment.

Increased survival rate in very low birth weight infants (1500 grams or less): no association with increased incidence of handicaps

The incidence of major handicaps was studied in a selected high-risk population of 1919 very low birth weight (less than or equal to 1500 gm) infants born between 1976 and 1985. Seventy-four percent of these infants were discharged alive. We have handicap information on 632 infants who have been followed for up to 7 years of age; 462 were evaluated at 18 months or later. Patients lost to follow-up represent 55% of the eligible population, but inpatient morbidity factors were available for the entire population and were used to calculate synthetic estimates of handicap rates. The overall incidence of severe major handicaps at 18 months was 18.0% (83/462). Cerebral palsy was found in 7.6%, and 6.5% were mentally retarded (IQ less than or equal to 70). Severe retinopathy of prematurity was present in 5.5%, and 5.4% of the infants had neurosensory hearing loss. Thirty-one infants (6.7%) had more than one handicap, the most common combination being cerebral palsy and mental retardation. Outcome of infants grouped by 250 gm birth weight intervals was compared for two periods (1976 to 1980, and 1981 to 1985); the numbers of survivors in each birth weight group increased during the second period, especially in the 500 to 750 gm and the 751 to 1000 gm groups. The observed incidence of major handicaps decreased from the first 5-year period to the second 5-year period (p less than 0.001). The largest decreases in the observed proportion handicapped occurred in the two lowest birth weight groups. The incidence of multiple handicaps also dropped; again, the two lowest birth weight groups showed the largest decrease. We conclude that an increased survival rate of very low birth weight infants need not be associated with an increased incidence of major handicaps.

Association between respiratory syncytial virus outbreaks and lower respiratory tract deaths of infants and young children

The temporal patterns of respiratory virus isolations from 10 laboratories in the USA were compared with that of deaths of children less than 5 years old from July 1975 through June 1984. Isolations of respiratory syncytial virus (RSV) occurred as yearly winter outbreaks; parainfluenza virus 1 and 2 isolations occurred as well-defined outbreaks every other year in the autumn; parainfluenza virus 3 isolations occurred throughout the year with periodic, increased isolations suggestive of outbreaks; and influenza virus isolations (A, B, or A plus B) occurred as yearly winter outbreaks. After data were controlled for seasonal patterns, RSV isolations were strongly correlated with the winter peaks in lower respiratory tract illness (LRI) deaths of infants 1-11 months old; influenza virus isolations were correlated with the winter peak in LRI deaths of children 24-59 months old. The parainfluenza viruses were not correlated with respiratory deaths. This study supports the idea that RSV is a major contributor to winter peaks in LRI deaths of children 1-11 months old.

The impact of luteal phase inadequacy in an infertile population

A retrospective analysis of patients evaluated and treated for infertility was performed. Luteal phase inadequacy was diagnosed when the late luteal endometrial biopsy pattern was greater than 2 days out of phase in two cycles; in patients treated with clomiphene citrate therapy was changed if one biopsy was out of phase. One hundred ninety-seven patients underwent 242 biopsies. Among 137 women no treated with clomiphene citrate, 24 (17.5%) had out-of-phase biopsy specimens; 7 of 24 (29.2%) repeat biopsies were out of phase, with luteal phase inadequacy in 7 of 137 (5.1%) women. The probability of an out-of-phase biopsy occurring by chance alone was 4.2 of 137 or 3.1%. No woman was diagnosed to have luteal phase inadequacy as the single infertility factor. Fifty-three pregnancies (41%) occurred in 130 women without luteal phase inadequacy and in 2 of 7 (28.6%) diagnosed to have luteal phase inadequacy with other infertility factors. In clomiphene citrate-treated patients, pregnancy occurred in 15 of 26 (57.7%) with corrected luteal phase inadequacy and in 21 of 34 (61.8%) without luteal phase inadequacy. In this population the diagnosis of luteal phase inadequacy was not made more frequently than by chance alone. Moreover, fecundity in patients with treated luteal phase inadequacy is comparable to that in patients without this diagnosis.

Use of mixture models in determining laboratory criterion for identification of seropositive individuals: application to parvovirus B19 serology

Selecting the cut-off value to identify infected individuals requires a trade-off between sensitivity and specificity. The standard technique for selecting a cut-off uses results of a population either known or assumed uninfected. Using mixture models, however, it is not necessary to identify an uninfected population. This technique also provides methods to estimate the probability that an individual will be accurately classified. We illustrate this technique in determining cut-off values for the serological diagnosis of human parvovirus B19 infection.

Flecainide enantiomers: disposition in human subjects and electrophysiologic actions in vitro

The antiarrhythmic agent flecainide is administered as a racemate. The disposition of the individual enantiomers and their electrophysiologic actions are unknown. We therefore determined through plasma levels of S-(+)-flecainide and R-(-)-flecainide in 13 patients who were receiving long-term oral flecainide therapy. In addition, the effects of the enantiomers on action potential characteristics in canine cardiac Purkinje fibers were assessed. Plasma concentrations of R-(-)flecainide were significantly higher than those of the S-(+)-enantiomer (-/+ ratio, 1.10 +/- 0.13,mean +/- SD; range, 0.89 to 1.32, p less than 0.01), suggesting that the drug undergoes enantioselective disposition. In the in vitro experiments, both enantiomers reduced phase 0 action potential Vmax (an index of the fast inward sodium current) and shortened action potential duration at 50% and 90% repolarization, but no differences between the enantiomers were detected. The time constants for development of Vmax depression were significantly longer for S-(+)-flecainide (13.4 +/- 1.5 seconds) compared with R-(-)-flecainide (8.9 +/- 0.6 seconds, p less than 0.001). Thus, although S-(+)-flecainide and R-(-)-flecainide undergo modest enantioselective disposition, they exert similar electrophysiologic effects. These studies have provided no evidence to indicate that administration of a single enantiomer, rather that the racemic drug, would offer any advantage.

PET studies of parkinsonian patients treated with autologous adrenal implants

Transplantation of autologous adrenal medulla tissue into the striatum has recently been proposed as a treatment for Parkinson's disease. We report the use of positron emission tomography (PET) to evaluate patients who had adrenal implants placed into the right caudate. 6-[18F] fluoro-L-dopa (6-FD) scans were performed to study the integrity and activity of the implant, and the nigrostriatal dopamine system before and six weeks after transplantation surgery. [68Ga] Gallium-ethylenediaminetetraacetate (Ga) scans were also performed to assess the blood brain barrier. The Ga scans performed on two patients showed increased permeability of the blood brain barrier at the surgical site. 6-FD PET scans in five patients did not show a consistent change in striatal uptake following adrenal medullary implantation after six weeks. Further assessment of implant viability with 6-FD PET scans after longer follow up may provide useful information if the blood-brain barrier becomes re-established with the passage of time.

The box plot: a simple visual method to interpret data

Exploratory data analysis involves the use of statistical techniques to identify patterns that may be hidden in a group of numbers. One of these techniques is the "box plot," which is used to visually summarize and compare groups of data. The box plot uses the median, the approximate quartiles, and the lowest and highest data points to convey the level, spread, and symmetry of a distribution of data values. It can also be easily refined to identify outlier data values and can be easily constructed by hand. We apply box plots to tabular data from two recently published articles to show how readers can use box plots to improve the interpretation of data in complex tables. The box plot, like other visual methods, is more than a substitute for a table: It is a tool that can improve our reasoning about quantitative information. We recommend that the box plot be used more frequently.

Adrenal medullary transplantation to the caudate nucleus in Parkinson's disease. Initial clinical results in 18 patients

Results from a pilot study of adrenal medullary autotransplantation for Parkinson's disease are presented. Eighteen patients were studied; 12 were followed up for 1 year, and 6 were followed up for 6 months. Four of 12 patients showed distinct improvement in the signs and symptoms of their disease, as assessed using the Columbia Rating Scale, at 1 year; none showed distinct deterioration. The 6 patients who were followed up for only 6 months were an average of 20 years older and generally more severely affected. None distinctly improved. Morbidity was considered to be minor and transient among the first 12 patients, while 4 of the last 6 patients experienced alteration in mental status lasting as long as several months. This problem has led us to conclude that older patients with preexisting cognitive impairment should not be included in future studies until the benefits are more clearly established. However, we believe that the distinct and persistent improvement seen in some of the younger patients warrants the initiation of a well-designed, randomized, and controlled trial of adrenal medullary autotransplantation for the purpose of confirming these results and assessing the effect of the procedure on the natural progression of Parkinson's disease.

Luteinizing hormone and ovulation timing in a therapeutic donor insemination program using frozen semen

A series of 110 therapeutic donor insemination cycles was analyzed to determine the impact on fecundity when a urinary luteinizing hormone detection kit was used to plan inseminations. To prevent the transmission of human immunodeficiency virus, frozen semen, thawed after a 90-day quarantine, was used. The minimum standard for insemination with cryopreserved semen was a total of 24 x 10(6) motile sperm per milliliter after thawing. Fecundity was 0.12 when insemination timing was based on cervical mucus evaluation and basal body temperature charts and 0.13 when a urinary luteinizing hormone kit was also used to predict ovulation. Life table analysis with the log rank test showed no statistically significant difference in the number of cycles required to achieve conception between the group of patients using conventional methods of ovulation timing and the group of patients using the urinary luteinizing hormone kit. Urinary luteinizing hormone testing offers no advantage over conventional methods, such as cervical mucus examination and evaluation of basal body temperature, when ovulation is being timed for insemination with frozen donor semen.

Phosphorylation of native 97-kDa 3-hydroxy-3-methylglutaryl-coenzyme A reductase from rat liver. Impact on activity and degradation of the enzyme

Immunoprecipitation of native rat liver microsomal 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, phosphorylated by [gamma-32P]ATP in the presence of reductase kinase, revealed a major 97-kDa 32P band which disappeared upon competition with pure unlabeled 53-kDa HMG-CoA reductase. A linear correlation between the expressed/total HMG-CoA reductase activity ratio (E/T) and the fraction of 32P released from the 97-kDa enzyme established the validity of the E/T ratio as an index of HMG-CoA reductase phosphorylation state in isolated microsomes. Incubation of rat hepatocytes with mevalonolactone resulted in a rapid increase in phosphorylation of microsomal reductase (decrease in E/T) followed by an enhanced rate of decay of total reductase activity which was proportional to the loss of 97-kDa enzyme mass determined by immunoblots. Inhibitors of lysosome function dampened both basal and mevalonate-induced reductase degradation in hepatocytes. In an in vitro system using the calcium-dependent protease calpain-2, up to 5-fold greater yields of soluble 52-56-kDa fragments of reductase (immunoblot and total activity) were obtained when the substrate 97-kDa reductase was phosphorylated before proteolysis. Immunoblots of unlabeled phosphorylated reductase compared with gels of immunoprecipitated 32P-labeled reductase resolved a 52-56-kDa doublet which contained 32P solely in the upper band. These data suggest that a major phosphorylation site of HMG-CoA reductase lies within the "linker" segment joining the membrane spanning and cytoplasmic domains of the native 97-kDa protein.

Analysis of surveillance data with Poisson regression: a case study

One way to examine the ability of a statistical technique to detect changes in surveillance data is to analyse data sets with known changes and observe how accurately these changes can be detected. The elimination of restrictions on legal abortions should have reduced mortality associated with abortions, particularly mortality associated with illegal abortions. The sensitivity of Poisson regression to detect changes in abortion associated mortality from 1962 to 1984 was assessed for the entire United States of America and for specific states. Although it is clear that this change occurred using data from the entire United States, only the largest of the individual state data sets examined (370 events over 23 years) consistently demonstrated the expected pattern. Inconsistent patterns were found in data sets from two states with between one-fourth and one-half this number of events. The legal change was not detected at all in three states with a small number of events (1 event per year or less). From this case study, a minimum of two or three events per year seems to be necessary before Poisson regression can detect outliers. Comparisons of the four tests used suggest that tests based on model deviance are superior to tests based on comparison of observed and expected number of events.

Thyroid hormone resistance in a large kindred: physiologic, biochemical, pharmacologic, and neuropsychologic studies

PURPOSE

Thyroid hormone resistance affects the pituitary gland and a variety of other tissues. We studied a large kindred with this disorder and measured a number of clinical markers of tissue metabolism to determine if these markers were useful in elucidating the sites and degree of resistance.

PATIENTS

A kindred of 89 persons in four generations was identified; 44 had thyroid function tests, and 14 (five to 67 years old) were found to have thyroid hormone resistance.

RESULTS

The inheritance pattern was autosomal dominant, with no common HLA haplotype. Physiologic measurements in five affected members showed marked heterogeneity. Four patients had normal baseline cardiac contractility, but only two experienced a shortening of their QKd interval into the hyperthyroid range with triiodothyronine (T3) therapy. Intrathyroidal 127I content was increased in two patients and was normal in two. Bone mineral content was normal in two men, but two women had marked osteopenia. The propositus, hypothyroid after inappropriate 131I therapy, had a hypothyroid ventilatory response to hypercapnea. This response became low normal during T3 (100 micrograms/day) administration but not during long-term thyroxine (T4) (300 micrograms/day) administration. Three other patients had values within normal limits and one had a hyperthyroid ventilatory response. Peripheral biochemical markers of thyroid hormone action were measured in 13 affected and 19 unaffected family members. Sex hormone-binding globulin was increased in zero of 13 affected patients (versus 19 of 20 hyperthyroid, chi 2:p less than 0.001); ferritin was elevated in two of 13 patients (versus 11 of 20 hyperthyroid, p less than 0.02); angiotensin converting enzyme activity was increased in one of 13 patients (versus 12 of 20 hyperthyroid, p less than 0.025). The eldest patient had marked cardiac sensitivity despite normal biochemical markers. We attempted to suppress the integrated thyroid-stimulating hormone (TSH) response to thyrotropin-releasing hormone (TRH) using T3 (72 and 100 percent suppression in two patients), dopamine (40 percent suppression in one), 3,5,3'-triiodothyroacetic acid (TRIAC) (94 percent suppression in one), and verapamil (10 percent and 40 percent suppression in two). Neuropsychologic function was studied in 14 individuals (11 affected, three unaffected). Although mild impairments were detected, they were not specific for thyroid hormone resistance.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison of late luteal phase endometrial biopsies using the Novak curette or PIPELLE endometrial suction curette

The late luteal phase endometrial biopsy is an important part of the evaluation of patients with recurrent spontaneous abortion or infertility. The procedure can be painful and, if an adequate amount of tissue is not obtained, may have to be repeated. In this report, the results of endometrial biopsies performed in the late luteal phase with either the Novak curette or the PIPELLE Endometrial Suction Curette were analyzed retrospectively. The two techniques did not differ in the number of biopsy specimens found to have inadequate tissue for diagnosis; however, patients who underwent biopsy with the PIPELLE recalled significantly less pain associated with the procedure. When used in premenopausal patients undergoing endometrial biopsy during the late luteal phase, the PIPELE provided adequate tissue with preservation of glandular, stromal, and capsular architecture.

Phosphorylation and degradation of HMG CoA reductase

3-Hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase is the limiting enzyme step in cholesterol formation in mammalian liver and other tissues. It is a glycoprotein of 97,000 daltons embedded in the endoplasmic reticulum with a long cytoplasmic extension that is the site of catalytic conversion of HMG CoA to mevalonate. The enzyme is subject to both long-term (induction/repression; degradation) and short-term control (reversible phosphorylation) mediated by endocrine signaling (insulin, glucagon) and through negative feedback by metabolic products of mevalonate (e.g., cholesterol). The catalytic capacity of microsomal reductase falls rapidly in the presence of several protein kinases (reductase kinase, protein kinase-C, calmodulin-dependent protein kinase). Activity is restored with various protein phosphatases. Increased phosphorylation of reductase in intact cells after addition of glucagon or mevalonate is followed by enhanced degradation of the enzyme. In an in vitro model system, phosphorylated, native microsomal reductase is more rapidly cleaved by the calcium-dependent, neutral protease calpain than the dephosphorylated from of reductase. Our present research which centers on the mechanism of the in vitro model system is reviewed. Calpain in the presence of Ca2+ cleaves the cytosolic domain of phosphorylated 97 kDa reductase at two points giving rise to two fragments of nearly the same size that appear as a 52-56,000 dalton doublet by electrophoresis and immunoblotting. In the same system native reductase labeled with [gamma-32P]ATP generates a doublet with 32P solely in the upper (heavier) band. This indicates that serine phosphorylation sites lie between the two calpain cleavage loci. These are positioned in the "linker" region of the long carboxy-terminal cytosolic domain near the membrane. This segment possesses five invariant serine residues and two PEST sequences (constellations of proline, glutamate, serine and threonine) that are characteristic of proteins with short half-lives. If phosphorylation of HMG CoA reductase is confined to the linker region, we must look to this domain in order to interpret the resulting conformational changes that markedly influence reductase catalytic activity and prepare the enzyme for degradation.

The effect of intermittent positive-pressure hyperinflation in restrictive chest wall disease

The effects of intermittent positive-pressure hyperinflation on lung volumes, arterial blood gas tensions and respiratory muscle performance have been assessed in 10 patients with severe scoliosis (vital capacity 22-43% predicted). Hyperinflation was carried out 2-3 times a day for 5 min aiming to double the spontaneous tidal volume with each delivered breath. A volume-preset, time-cycled device was used in 6 patients and a pressure-cycled, patient-triggered machine in 4 cases. Progressive reduction in lung volume was reversed by the volume-preset device which increased the mean vital capacity from 29 to 33% predicted after 3 months (p less than 0.05) with improvement maintained after 9 months. This machine offered a significant advantage over the pressure-cycled device which at maximum or near maximum inflation pressures produced less hyperinflation and had no beneficial effect on lung volumes. The improvement in vital capacity was correlated with the degree of hyperinflation (r = 0.65; p less than 0.05). The effect of hyperinflation on arterial blood gas tensions was transient and not accompanied by an increase in accessible alveolar volume.

Identifying important results from multiple statistical tests

When many statistical tests are performed simultaneously, the overall chance of a type I error (incorrect rejection of a true null hypothesis) can substantially exceed the nominal error rate used in each individual test. Numerous techniques exist to adjust results of individual tests to control this problem. In general, these techniques apply a more stringent criterion of statistical significance (a smaller P-value) to each individual test than normally needed to maintain the experimentwise type I error. With an analysis that seeks to identify results for further research, however, such a conservative technique may not be appropriate. We present a new approach that uses a mixture of several distributions to model the set of P-values or of test statistics. One component models the results consistent with a failure to reject the null hypothesis, while the other distribution(s) in the mixture represent results inconsistent with the null hypothesis. These latter results may not achieve statistical significance based on a conventional P-value. We illustrate the use of the method on national mortality data and on several data sets analysed previously.

Day-care center attendance and hospitalization for lower respiratory tract illness

To identify risk factors associated with hospitalization for acute lower respiratory tract illness, 102 children less than 2 years of age admitted to four Atlanta metropolitan area hospitals between December 1984 and June 1985 with the diagnosis of lower respiratory tract illness were studied. The most common causative agent associated with illness was respiratory syncytial virus, followed by other respiratory viruses, Haemophilus influenzae, and Streptococcus pneumoniae. The 102 case-patients were compared with 199 age- and sex-matched controls. A parent or guardian for each patient and control was interviewed by telephone regarding demographic data, care outside the home, breast-feeding, previous medical history, allergies, and smoking and illness in household members. Five factors were associated with lower respiratory tract illness in both a univariate analysis and a multiple logistic regression model (P less than .05). These factors were the number of people sleeping in the same room with the child, a lack of immunization the month before the patient was hospitalized, prematurity, a history of allergy, and regular attendance in a day-care center (more than six children in attendance). Care received outside of the home in a day-care home (less than or equal to six children in attendance) was not associated with lower respiratory tract illness. The suggestion made by our study and other studies was that for children less than 2 years of age, care outside of the home is an important risk factor for acquiring lower respiratory tract illness, as well as other infectious diseases, and that this risk can be reduced by using a day-care home instead of a day-care center.

Isolation and characterization of mevinolin resistant mutants of Saccharomyces cerevisiae

Mutant of Saccharomyces cerevisiae resistant to mevinolin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme-A (HMGCoA) reductase (EC1.1.1.34) were isolated and one mutant (MV71) was extensively characterized. While growth of resistant strains in the presence of mevinolin was growth. Diploids produced by mutant/wild-type matings showed levels of mevinolin resistance which indicated incomplete dominance. Sterol synthesis in the presence of mevinolin was inhibited in strain MV71 but to a lesser degree than seen in the wild-type strain. All mevinolin resistant mutants also demonstrated a slight resistance to the antibiotic nystatin. The subcellular location of HMGCoA reductase activity in MV71 and the wild-type strain were determined and it was shown that yeast HMGCoA reductase is not regulated by a dephosphorylation mechanism as has been shown for mammalian reductases. In vivo and in vitro studies of strain MV71 and the wild-type indicated that mevinolin resistance did not result in changes in HNGCoA reductase activity as has been demonstrated in mammalian systems. Based on growth data, sterol analysis, and the lack of detection of HMGCoA reductase activity differences between strain MV71 and the wild-type, mevinolin resistance is concluded to result possibly from a mutation in HMG2, one of the two functional yeast HMGCoA reductase genes, which accounts for a minor (up to 17%) amount of total cellular reductase activity.

Preexposure immunization with intradermal human diploid cell rabies vaccine. Risks and benefits of primary and booster vaccination

Intradermal human diploid cell rabies vaccine (ID HDCV) was licensed for preexposure use in the United States on May 30, 1986. We studied the safety and efficacy of this newly approved route and dose of administration. Serologic results were available from 112 (90%) of the 124 persons who participated in an HDCV low-dose preexposure study in which five different ID, intramuscular (IM), and subcutaneous primary immunization regimens were administered. Three 1.0-mL IM doses of vaccine resulted in titers similar to those from three 0.1-mL ID doses when compared 49 days, one year, and two years after primary immunization. Uniformly high postbooster titers occurred in all five groups when ID boosters were administered at one year or two years. Adverse reactions were similar following both ID and IM vaccination. Although ID HDCV can be a cost-effective substitute for IM vaccine, excessive use of unnecessary preexposure booster doses by any route may be inadvisable because of systemic allergic reactions. In addition, poor immune responses to HDCV have been documented in persons vaccinated in some developing countries. This may limit the use of low-dose regimens in some places.

Sample size for individually matched case-control studies

The standard formulas used to calculate sample size for an individually matched case-control study assume a constant probability of exposure throughout the pool of possible controls. We propose new formulas that allow for heterogeneity in the probability of exposure among controls in different matched sets. Since matching factors are suspected of being confounders, they are expected to divide the total population into subgroups with different proportions exposed. Thus, the assumption of homogeneity of exposure among controls, made by the currently used formulas, is inconsistent with the assumptions used to design a matched study. The proposed formulas avoid this inconsistency. We present an example to illustrate how heterogeneity can affect the required sample size.

Detection of antibodies and antigens of human parvovirus B19 by enzyme-linked immunosorbent assay

Acute-phase serum from a patient with aplastic crisis provided sufficient human parvovirus B19 to make a monoclonal antibody against B19 and to develop antigen and immunoglobulin M (IgM) and IgG antibody detection enzyme-linked immunosorbent assays (ELISAs). The indirect capture antibody method was used for all three assays. Antigen was detected in 8 of 29 sera drawn within 2 days of onset of illness from patients with aplastic crisis. These sera had high titers of virus by electron microscopy and DNA hybridization and had no detectable B19 antibody. Antigen was not detected in serum specimens that had low titers of B19 DNA and had B19 antibody. With the IgM ELISA, we detected B19 IgM in over 85% of clinical cases of aplastic crisis and fifth disease and less than 2% of controls. The prevalence of B19 IgG antibodies increased with age. Approximately 2% of children less than 5 years of age and 49% of adults greater than 20 years of age had B19 IgG antibodies. The B19 antibody ELISAs are sensitive and specific tests to detect B19 infections.

Effects of protriptyline on sleep related disturbances of breathing in restrictive chest wall disease

The effects of protriptyline on sleep stage distribution and gas exchange have been assessed in eight patients with nocturnal hypoventilation secondary to restrictive chest wall disease. At a dose of 10-20 mg taken when they retired the total sleeping time was unaltered but the proportion of rapid eye movement (REM) sleep fell from 22% to 12% (p less than 0.05). The total time spent at an arterial oxygen saturation of less than 80% decreased (p less than 0.01) and the magnitude of the fall correlated with the reduction in REM sleep (r = 0.67, p less than 0.05). There was also a reduction in the maximum carbon dioxide tension reached during the night (p less than 0.01). The arterial oxygen tension measured diurnally increased (p less than 0.05) from a median of 8.0 kPa (60 mm Hg) to 9.0 kPa (67.5 mm Hg), but the carbon dioxide tension and base excess were unchanged. Anticholinergic side effects were experienced by most patients but did not limit treatment.

Risk factors for outbreaks of influenza in nursing homes. A case-control study

To determine risk factors for outbreaks of influenza virus infections in chronic-care facilities for the elderly, the authors compared the characteristics of two groups of nursing homes in Genesee County, Michigan, in 1982-1983, following a community-wide epidemic caused by A/Bangkok/1/79-like (H3N2) viruses: seven homes in which an outbreak occurred (case homes) and six homes with sporadic illnesses only (control homes). The two groups were similar in many respects, including the physical characteristics of the facilities, visitation and staffing patterns, infection control practices, and demographic and clinical profiles of residents. Case homes, however, had larger resident populations than control homes (median 160 vs. 92, respectively; p = 0.028) and a lower proportion of residents who had been vaccinated with A/Bangkok antigen the previous autumn (median 51% vs. 81%, respectively; p = 0.047). Based on a retrospectively determined estimate of the efficacy of influenza vaccine in preventing illness (43%), the number of residents presumed to be susceptible to the epidemic strain was higher in case homes than in control homes (median 102 vs. 61, respectively; p = 0.0047) and was the most important factor selected by a stepwise, multivariate logistic regression model (p less than 0.0005). These findings are consistent with mathematical models of vaccine-induced herd immunity in closed populations and suggest that high rates of vaccination can reduce the risk of influenza outbreaks in this setting.

The early kinetics of the neutralizing antibody response after booster immunizations with human diploid cell rabies vaccine

Persons immunized in developing countries were recently shown to have low titers after pre-exposure immunization with human diploid cell rabies vaccine (HDCV). An investigation into the response to HDCV boosters was conducted to determine if immunologic sensitization had occurred and if there was a response difference in persons immunized in and outside of the United States. Intramuscular (im) booster doses of vaccine were administered to 113 persons previously immunized outside the United States and 47 persons immunized in the United States. The post-exposure booster regimen of a single 1.0-ml im booster, as recommended by the World Health Organization for all but the most severe bites, produced a one-dilution (5-fold) rise in antibody titer in 14 (11%) of 123 persons tested 5 days after booster and in 56 (89%) of 63 persons studied 7 days after booster. Persons immunized in the United States and those immunized outside the United States had similar responses. Persons with low pre-booster titers were more likely to exhibit a 5-fold rise in antibody titer 5 days after booster (P = 0.03) than persons with higher pre-booster titers. The post-exposure booster regimen of 2 1.0-ml im doses (one each on days 0 and 3), recommended in the United States, produced a more rapid response than the single booster regimen in only some persons; a 5-fold response occurred in 6 (50%) of 12 persons 5 days after booster.(ABSTRACT TRUNCATED AT 250 WORDS)

Impact of hormonal contraceptives vis-à-vis non-hormonal factors on the vitamin status of malnourished women in India and Thailand. World Health Organization: Special Programme of Research, Development and Research Training in Human Reproduction. Task Force on Oral Contraceptives

The effects of combined oral contraceptives containing 30 or 50 micrograms ethinyl oestradiol and 150 micrograms levonorgestrel or a 3-monthly injectable preparation depo-medroxyprogesterone acetate (DMPA) on the vitamin status of low-income group women from two urban centres in India (Bombay and Hyderabad) and one rural centre in Thailand (Chiang Mai) were examined in a follow-up study over a period of 1 year. The magnitude of malnutrition in the study population vis-à-vis a middle-income reference group was assessed by comparing the baseline data on the two groups. Effects of time-related variables such as lactation and season were also examined by a cross-sectional analysis of the baseline data on the study population. In all three centres the majority of the study population suffered from biochemical riboflavin and/or pyridoxine deficiency even before initiating contraception. Lactation appeared to have an effect on the vitamin status, which varied among the different populations. Seasonal effects were seen, but showed inconsistent trends in the three centres. Both the oral contraceptive pills and DMPA tended to increase serum vitamin A and blood folate. The thiamin, riboflavin and pyridoxine status of the women who were already deficient did not deteriorate further with the use of hormonal contraception, as judged by enzyme saturation tests. Some deterioration in the riboflavin status of the normal women of Hyderabad was seen with the use of oral pills. Women who were biochemically deficient prior to the use of oral contraceptives tended to show some improvement in B-vitamin status, over the 1-year period of hormonal contraception.

Case-control studies and Bayesian inference

We outline the methods of Bayesian inference for applications to case-control studies. These methods appear as the natural way of making inferences, since much of the controversy that surrounds a specific case-control study is subjective. We derive conjugate prior distributions of exposure, posterior distributions of the ratio of the odds of being incident with a disease both with and without exposure to a potential causal agent, and convenient approximations. In particular, we show how one may carry out 'case-control studies' without necessarily having a control group. We illustrate these ideas with the data that first showed the relationship between in utero exposure to diethylstilbestrol and cancer of the vagina in young girls.

Immune complex-like disease in 23 persons following a booster dose of rabies human diploid cell vaccine

Following a routine 0.1 ml booster dose of Merieux rabies human diploid cell vaccine (HDCV), administered intradermally, 23(10.2%) of 226 persons had signs and symptoms compatible with an immune complex-like disease. The disease had its onset from 3-13 days after the injection, lasted 1-5 days, and consisted primarily of urticaria (78.3%), macular rash (65.2%), angiooedema (39.1%), and arthralgia (17.4%). None of the cases were considered severe, and all recovered with no sequelae. There were significant differences in attack rates between men (78.3% of all cases) and women, and between those receiving vaccinations on different days. Similar reactions have been reported following intramuscular booster doses of HDCV. Since the Merieux HDCV is used worldwide, physicians administering HDCV must be aware of these adverse reactions and warn patients. Appropriate therapy should be instituted as warranted by severity of reactions.

Temporal and geographic patterns of isolates of nonpolio enterovirus in the United States, 1970-1983

Surveillance data on nonpolio enterovirus (NPEV) from the Centers for Disease Control (Atlanta, Georgia) for the United States from 1970 to 1983 were analyzed for the temporal and geographic patterns of the most common types of NPEV isolated. The number of isolates varied from year to year, partly because of variation in the number of reporting laboratories and partly because of true variation in the rate of isolation. The most common types isolated also varied from year to year, yet the 15 most common types over the entire 14-year period accounted for 65%-89% of isolates for a given year. The 15 most common types of NPEV had two basic patterns of isolation, one in which a type had periodic epidemic years and the other in which it did not. In 11 of the 14 years there was one or more epidemic types, each accounting for greater than or equal to 20% of all isolates of NPEV that year. The six most common isolates in March, April, and May predicted an average of 59% of the total isolates detected in July-December of that year.

Phosphorylation state of HMG CoA reductase affects its catalytic activity and degradation

The expressed catalytic activity of liver microsomal HMG CoA reductase, the limiting enzyme in cholesterol synthesis, is reversibly diminished by phosphorylation in vitro. In intact hepatocytes the expressed activity of HMG CoA reductase is enhanced by incubation of cells with insulin, and diminished by treatment with glucagon or with mevalonate. In the latter situations the level of total reductase activity falls following initial inactivation (phosphorylation) of the enzyme. This observation suggested that the phosphorylated form of HMG CoA reductase is more sensitive to proteolysis. HMG CoA reductase is a 97,000 dalton (97 K) integral protein of the endoplasmic reticulum with a cytosolic domain that includes the catalytic site and serine residues that may be reversibly phosphorylated. In vitro the Ca2+-activated proteolytic enzyme, calpain, generates two catalytically-active fragments: a membrane bound 62 K and a soluble 53 K form of the enzyme which are quantified by specific immunoblot procedures. Cleavage of the native 97 K HMG CoA reductase is enhanced by pretreatment (inactivation) of microsomes with ATP (Mg2+) and liver reductase kinase compared to microsomes pretreated with protein phosphatase. This is reflected in a loss of 97 K reductase and an increase in the soluble 53 K form of the enzyme. Degradation of HMG CoA reductase in hepatocytes is partially blocked by lysosomotropic agents and insulin. A steady state model for the turnover of proteins subject to reversible phosphorylation has been developed which recognizes fractional degradative rate constants for the phosphorylated and dephosphorylated species.

Pre-exposure rabies immunization with human diploid cell vaccine: decreased antibody responses in persons immunized in developing countries

In November 1982, a U.S. Peace Corps volunteer in Kenya completed pre-exposure rabies prophylaxis with a standard 3 dose intradermal (ID) series of human diploid cell rabies vaccine (HDCV). In May 1983, she was bitten by a dog and died of rabies 3 months later. An initial investigation revealed that the patient, as well as 9 of 11 others immunized at the same time, had no rabies antibody titers (less than 1:5). We therefore instituted investigations into the immunogenicity of pre-exposure HDCV both in the United States and in developing countries. A serosurvey revealed unexpectedly low rabies titers in both Peace Corps volunteers and others immunized in developing countries. Antibody titers measured 2-3 weeks after ID immunization were compared in 9 groups totaling 271 persons in the United States and Kenya. There was no statistically significant difference in antibody titers in the 6 U.S. groups immunized from 1980-1984 (P greater than 0.15); however, groups immunized in the United States had significantly higher titers than a group of Kenyan nationals (P less than or equal to 0.0001), and the Kenyans had significantly higher titers than 2 Peace Corps groups immunized in Kenya (P less than or equal to 0.0001). No single hypothesis proposed (laboratory error, vaccine potency, vaccination technique, or specific immune suppression) accounted for the observed differences. Although we cannot fully explain the poor response to HDCV, it is probably due to multiple factors. We conclude that persons immunized with ID pre-exposure HDCV in developing countries should have rabies antibody titers determined to ensure their seroconversion; for persons immunized in the United States, such titers need not be routinely determined.

Efficacy of influenza vaccine in nursing homes. Reduction in illness and complications during an influenza A (H3N2) epidemic

From December 10, 1982, to March 4, 1983, when influenza A (H3N2) viruses circulated in Michigan, outbreaks of influenza-like illness were identified in seven nursing homes in Genesee County; 272 (27%) of 1,018 residents were affected. Unvaccinated residents were more likely than vaccinated residents to become ill (risk ratio [RR], 2.6; 95% confidence interval [Cl], 1.8-3.6) and were subsequently more likely to be hospitalized (RR, 2.4; 95% Cl, 1.2-4.8), develop roentgenographically proven pneumonia (RR, 2.9; 95% Cl, 1.6-5.3), or die (RR, 5.6; 95% Cl, 1.2-9.1). Similar observations were made during investigations in six of the eight remaining nursing homes in Genesee County, in which 57 (12%) of 458 residents became ill sporadically. These findings suggest that influenza vaccine can reduce the incidence and severity of influenza virus infections among the elderly and chronically ill and underscore the importance of vaccination programs for those in nursing homes and in the general community.

Assessment of percussion, vibratory-shaking and breathing exercises in chest physiotherapy

While gravity-assisted positions (postural drainage) and the forced expiratory technique are known to promote sputum clearance, the additional value of percussion, vibratory-shaking and breathing exercises individually in chest physiotherapy is uncertain. These modalities have been evaluated in 8 patients with copious sputum production (mean: 44 g/day), using an inhaled radioaerosol technique. Tracheobronchial clearance was unaffected by the addition of either vibratory-shaking or percussion with and without breathing exercises to postural drainage. There was however a significant (p less than 0.01) increase in the dry weight of sputum produced during each of these treatments. The combination of postural drainage used in conjunction with the forced expiration technique is responsible for the majority of mucus mobilisation and should form the basis of routine chest physiotherapy programmes; the other modes appear to be of lesser value.

Phosphorylation of microsomal HMG CoA reductase increases susceptibility to proteolytic degradation in vitro

Conversion of native, 97-100 kDa rat liver microsomal HMG CoA reductase to membrane-bound 62 kDa and soluble 52-56 kDa catalytically active forms was catalyzed in vitro by the calcium-dependent, leupeptin- and calpastatin-sensitive protease calpain-II purified from rat liver cytosol. Cleavage of the native 97-100 kDa reductase was enhanced by pretreatment (inactivation) of microsomes with ATP(Mg2+) and liver reductase kinase (compared to protein phosphatase-pretreated controls). This was reflected in a loss of the 97-100 kDa species and an increase in the soluble 52-56 kDa species (total enzyme activity and specific immunoblot recovery).