Showing papers by "Baylor College of Medicine published in 1979"
TL;DR: The hormonal regulation of casein gene expression appears to be an "all or none" process occurring only at the transcriptional or post-transcriptional levels, but may involve a coordinated response at several levels to permit the efficient expression of specialized differentiated functions.
438 citations
TL;DR: Cisplatin is a co-ordination complex of a central platinum atom, two chlordies and two ammonia molecules in the "cis" position that is a prime mechanism of inhibition of tumor growth by cisplatin appears to be inhibition of DNA synthesis.
366 citations
TL;DR: The electroencephalographic seizure pattern was variable, but a marked generalized attenuation of electrical activity was a feature of 71.7% of the attacks.
Abstract: With the use of a time-synchronized video and polygraphic recording system, 5,042 infantile spasms were monitored and analyzed in 24 infants aged 1 to 43 months. Of these, 33.9% were flexor, 22.5% extensor, and 42.0% mixed flexor-extensor. Sometimes the spasms were followed by a period of akinesia and diminished responsiveness lasting up to 90 seconds, and rarely (1.0%) this "arrest" effect constituted the entire seizures. More than one type of seizure occurred in 21 of the 24 infants. In the same number, 78.3% of the seizures occurred in clusters, and the intensity and frequency of the spasms in each cluster often increased to a peak, then progressively decreased until they stopped. Predominantly, the clusters occurred soon after arousal from sleep. The number of seizures occurring at night (55.2%) was similar to the diurnal number (44.8%). The electroencephalographic seizure pattern was variable, but a marked generalized attenuation of electrical activity was a feature of 71.7% of the attacks. Attenuation episodes of similar degree and duration occurred with no evidence of a seizure.
261 citations
TL;DR: Two major silver staining proteins were found which were identified as (molecular weight × 10 −3 /pI) proteins C23 and B23 which are the major acidic proteins in Novikoff hepatoma nucleoli.
236 citations
TL;DR: The greatly unproved survival in those patients with symptomatic coronary disease who had a coronary artery bypass prior to or at the same time as carotid endarterectomy, and the absence of permanent neurological deficit in the 51 of these 135 patients who had simultaneous carotids endartrectomy and coronary arteries bypass suggests that significantly improved survival can be achieved in these high risk patients by the use of simultaneous coronary artery coronary bypass surgery.
Abstract: The significant risk of fatal myocardial infarction after carotid endarterectomy in patients with coronary disease long has been recognized. In 1,546 consecutive carotid endarterectomies performed in 1,238 patients over the last 10 years, angina pectoris was present in 17% (212/1,238) of patients; a further 32% (396/1,238) of patients were asymptomatic, but had a history of myocardial infarction. The perioperative mortality (30 day) in the 1,306 consecutive endarterectomies in 1,026 patients without symptomatic coronary artery disease was 1.5% (15/1,026 patients). Of the 212 patients with symptoms, 85 carotid endarterectomies were performed in 77 patients without prior coronary bypass operation with an operative mortality of 18.2% (14/77 patients). The remaining 135 patients had 155 carotid endarterectomies but were treated by either prior coronary artery bypass (84 patients) or simultaneous carotid endarterectomy and coronary artery bypass (51 patients) with an operative mortality of 3% (4/135 patients). The greatly improved survival in those patients with symptomatic coronary disease who had a coronary artery bypass prior to or at the same time as carotid endarterectomy, and the absence of permanent neurological deficit in the 51 of these 135 patients who had simultaneous carotid endarterectomy and coronary artery bypass suggests that significantly improved survival can be achieved after carotid endarterectomy in these high risk patients by the use of simultaneous coronary artery bypass surgery.
235 citations
TL;DR: Because the attack rates for serious neonatal infections associated with Escherichia coli and other maternally acquired coliform organisms have been constant since 1960, the appearance of the group B Streptococcus resulted in an absolute increase in the incidence of neonatal bacterial disease during the past decade in many hospitals in this country.
Abstract: β-Hemolytic streptococci of Lancefield group B have been causally linked to neonatal disease since 1938, but only in the last decade has the group B Streptococcus become the leading etiologic agent for bacteremia and/or meningitis occurring during the first two months of life. Neither the reasons for the emergence of this organism nor the shifts over the past 40 years in the prevalence of various bacteria responsible for neonatal infection has been adequately explained. However, the importance of the group B Streptococcus as a frequent cause of neonatal mortality and morbidity demands a thorough understanding of the epidemiology and pathogenesis, clinical features, diagnostic methods, and management of these infections by physicians caring for newborn infants. INCIDENCE The common occurrence of neonatal group B streptococcal septicemia and meningitis in several geographically distant centers since 1970 has allowed the relatively precise determination of attack rates for early onset type (≤5 days) infection. Reported attack rates have been surprisingly uniform, varying from 1.3/1,000 to 4.0/1,000 live births (Table 1). Because the attack rates for serious neonatal infections associated with Escherichia coli and other maternally acquired coliform organisms have been constant since 1960, the appearance of the group B Streptococcus resulted in an absolute increase in the incidence of neonatal bacterial disease during the past decade in many hospitals in this country.
219 citations
TL;DR: In this paper, a comparative study of a number of different types and strains of human enterovirus and bacteriophages to nine different soil types was studied and it was shown that no single soil can be used as the model for determining virus adsorptive capacity of all soil types.
Abstract: Virus adsorption to soils is considered to be the most important factor in removing viruses after land treatment of wastewater. Most of the studies on virus adsorption to soils have utilized poliovirus as the model system. In the present study, comparative adsorption of a number of different types and strains of human enteroviruses and bacteriophages to nine different soil types was studied. Under the experimental conditions of this study, greater than 90% of all viruses adsorbed to a sandy loam soil except echovirus types 1, 12, and 29 and a simian rotavirus (SA-11), which adsorbed to a considerably lower degree. A great deal of variability was observed between adsorption of different strains of echovirus type 1, indicating that viral adsorption to soils is highly strain dependent. Of the five phages studied, f2 and phi X174 adsorbed the least. In addition to being dependent on type and strain of virus, adsorption was found to be influenced also by type of soil. Thus, soils having a saturated pH of less than 5 were generally good adsorbers. From these results, it appears that no one enterovirus or coliphage can be used as the sole model for determining the adsorptive behavior of viruses to soils and that no single soil can be used as the model for determining viral adsorptive capacity of all soil types.
212 citations
TL;DR: A syndrome consisting of colobomatous microphthalmia, heart disease, abnormalities of the external ear with associated hearing loss, and mental retardation is described.
Abstract: A syndrome consisting of colobomatous microphthalmia, heart disease, abnormalities of the external ear with associated hearing loss, and mental retardation is described. Nine children and one adult were evaluated. There is not race or sex predilection. The syndrome can be heritable, as shown by a mother and daughter who were among the patients. In addition to the four major components enumerated, multiple other anomalies may be associated. In some cases, the syndrome may occur incompletely. Whenever two or more of the four components are recognized, the other systems usually affected should be investigated.
208 citations
TL;DR: A group of studies dealing with migration and illness are reviewed in the context of competing theories about the selection, motivation and adjustment of different migrant groups, and about the meaning of migration as a social and psychological phenomenon.
Abstract: The exploration of environmental influences in the broadest sense offers the most promising leads in explaining variations in risk, both between countries and between social and cultural groups for Coronary Heart Disease and Hypertension, for a number of Cancer sites, and for other diseases as well. A body of literature in several disciplines deals with the health of migrants both before and after migration, and includes comparison of migrants with: (1) their genetic kin; (2) with non-related countrymen who stayed at home; (3) with their own progeny; (4) with those whom they share a social or cultural environment but not a social or cultural background; and (5) with those who migrated at different stages in the life cycle. A group of studies dealing with migration and illness are reviewed in the context of competing theories about the selection, motivation and adjustment of different migrant groups, and about the meaning of migration as a social and psychological phenomenon.
190 citations
TL;DR: In areas where GBS disease is prevalent, screening pregnant women and treating those colonized with GBS (with no history of penicillin hypersensitivity) with intravenous ampicillin during labor is recommended.
Abstract: Early-onset group B streptococcus (GBS) disease in the infant is acquired by vertical transmission from the mother colonized with GBS. Thirty-four women colonized with GBS were treated with intravenous ampicillin sodium during labor. None of their infants were colonized with GBS at birth or within 48 hours. Twenty-four women colonized with GBS received no antibiotic therapy; 14 (58%) of their infants were colonized with GBS at birth or by 48 hours. This difference was highly significant. Mechanisms by which this may have occurred were temporary suppression of GBS vaginal and rectal colonization, high concentration of ampicillin in the amniotic fluid, and transplacental transport of the antibiotic to the infant. In areas where GBS disease is prevalent, we recommend screening pregnant women (34 to 36 weeks' gestation) and treating those colonized with GBS (with no history of penicillin hypersensitivity) with intravenous ampicillin during labor. ( JAMA 241:1245-1247, 1979)
190 citations
TL;DR: It is concluded that calmodulin is more closely associated with the kinetichore-to-pole microtubules than other components of the mitotic apparatus.
Abstract: Indirect immunofluorescence was used to determine the distribution of calmodulin in the mitotic apparatus of rat kangaroo PtK2 and Chinese hamster ovary (CHO) cells. The distribution of calmodulin in PtK2 cells was compared to the distribution of tubulin, also as revealed by indirect immunofluorescence. During mitosis, calmodulin was found to be a dynamic component of the mitotic apparatus. Calmodulin first appeared in association with the forming mitotic apparatus during midprophase. In metaphase and anaphase, calmodulin was found between the spindle poles and the chromosomes. While tubulin was found in the interzonal region throughout anaphase, calmodulin appeared in the interzone region only at late anaphase. The interzonal calmodulin of late anaphase condensed during telophase into two small regions, one on each side of the midbody. Calmodulin was not detected in the cleavage furrow. In view of the differences in the localization of calmodulin, tubulin, and actin in the mitotic apparatus, experiments were designed to determine the effects of various antimitotic drugs on calmodulin localization. Cytochalasin B, an inhibitor of actin microfilaments, had no apparent effect on calmodulin or tubulin localization in the mitotic apparatus of CHO cells. Microtubule inhibitors, such as colcemid and N2O, altered the appearance of tubulin- and calmodulin-specific fluorescence in mitotic CHO cells. Cold temperature (0 degrees C) altered tubulin-specific fluorescence of metaphase PtK2 cells but did not alter calmodulin-specific fluorescence. From these studies, it is concluded that calmodulin is more closely associated with the kinetichore-to-pole microtubules than other components of the mitotic apparatus.
TL;DR: The known chemistry of the actin cross-linking protein (M r = 58,000) and its redistribution during the transformation sequence are consistent with the idea that this protein functions to organize F actin into filopodial cores by cross- linking adjacent actin filaments.
TL;DR: The differential stimulation of type II sites by estradiol and estriol suggests that this is a specific estrogenic response and is highly correlated with uterine growth.
Abstract: Estradiol administration causes an increase in two specific binding components in uterine nuclei of mature ovariectomized rats. One of these sites (type I) represents the estrogen receptor which binds estradiol with high affinity (dissociation constant, 1 nM) and low capacity (1 pmol/uterus) and is translocated from the cytoplasm to the nucleus. The second component (type II) binds estradiol with a higher capacity than type I sites and displays a saturation curve which is sigmoidal. Hence, no accurate estimation of the dissociation constant can be made. The differential stimulation of type II sites by estradiol and estriol suggests that this is a specific estrogenic response and is highly correlated with uterine growth. A single injection of estradiol results in long term retention of type I sites (>6 h), rapid and sustained elevations of type II sites (1-72 h), and true uterine growth. In contrast, estriol injection caused a rapid increase in type I sites which was not accompanied by an increase in typ e...
TL;DR: Results show that rotaviruses and reoviruses can be distinguished by their patterns of inactivation by physical and chemical agents.
Abstract: Summary
The stability of the infectivity of Simian rotavirus, SA11, has been analysed and compared to the stability of reovirus type 1. SA11 infectivity was stable to freeze-thawing, sonication, incubation at 25 °C overnight or at 37 °C for 1 h and to treatment with acid, ether, chloroform and Genetron. In contrast to reovirus, the infectivity of SA11 was more rapidly inactivated by heating at 50 °C. SA11 infectivity was inactivated above pH 10.0 and by heating at 50 °C in 2 m-MgCl2, but was stabilized by heating in 2 m-MgSO4; reovirus 1 infectivity was enhanced by heating in MgCl2. Both SA11 and reovirus 1 were inactivated by freezing in MgCl2. These results show that rotaviruses and reoviruses can be distinguished by their patterns of inactivation by physical and chemical agents.
TL;DR: It is shown that in the goldfish retina, GAD is localised in specific interneurones: type H1 horizontal cells and probably type Ab pyriform amacrine cells, which have been shown to be both pre- and postsynaptic to red-sensitive cones and red- sensitive centre-depolarising bipolar cells, respectively.
Abstract: A DIRECT way to examine whether certain neurones may use γ-aminobutyric acid (GABA) as a neurotransmitter is to determine by immunocytochemistry if L-glutamic acid decarboxylase (GAD), the enzyme responsible for GABA synthesis, is localised in these cells. We have been studying GABA-ergic pathways in the goldfish retina by autoradiographic and biochemical methods1–3. It would therefore be of interest to localise the GAD-containing cells in this system immunocytochemically. However, although GAD has been purified from mouse brain4 and antibodies against the enzyme have been obtained, these antibodies do not cross-react with the GAD found in neural tissues of teleosts5. Thus, before immunocytochemical studies of GAD-containing neurones in the goldfish retina were possible, we had to purify GAD from teleost brain and obtain a specific antibody against this enzyme. Such an antibody has now been obtained6. We show here that in the goldfish retina, GAD is localised in specific interneurones: type H1 horizontal cells and probably type Ab pyriform amacrine cells. These cell types have been shown to be both pre- and postsynaptic to red-sensitive cones and red-sensitive centre-depolarising bipolar cells, respectively3,7–9.
TL;DR: Oral penicillin treatment of couples is not an effective means of reducing maternal colonization at the time of delivery, as demonstrated in a study of women colonized with GBS in Houston, Texas.
TL;DR: Subjective gastrointestinal complaints generally correlated with endoscopic pathology; however, nine volunteers had evidence of severe injury to the gastric mucosa with no symptomatology, confined to the patients on indomethacin, naproxen, and ibuprofen.
Abstract: The effects of various nonsteroidal antiinflammatory drugs on the gastric mucosa were endoscopically evaluated in 40 normal volunteers. Eight groups, each containing five subjects were designed: aspirin (3600 mg/d); placebo; ibuprofen (1600 mg/d); ibuprofen (2400 mg/d); indomethacin (100 mg/d); indomethacin (150 mg/d); naproxen (500 mg/d); and naproxen (750 mg/d). All volunteers took medication for seven days and gastroscopy was carried out on day one and day eight. All findings were documented by photography. Severe gastric mucosal injury occurred with aspirin (P<0.05), both doses of indomethacin, and the higher dose of naproxen. Lesser changes were seen with the lower dose of naproxen, both doses of ibuprofen and placebo. The higher doses of ibuprofen, indomethacin, and naproxen caused a greater degree of gastric mucosal injury, but statistical significance was achieved only with naproxen (P<0.01). Subjective gastrointestinal complaints generally correlated with endoscopic pathology; however, nine volunteers had evidence of severe injury to the gastric mucosa with no symptomatology. This was confined to the patients on indomethacin, naproxen, and ibuprofen. Aspirin patients all had some degree of symptomatology but to a lesser degree than expected in view of the endoscopic findings.
TL;DR: To determine if high intratesticular concentrations of testosterone are essential for completion of spermatogenesis, intact 90-day-old Charles River CD rats were treated with testosterone propionate (TP), and morphological changes failed to occur because the period of treatment was too short.
Abstract: To determine if high intratesticular concentrations of testosterone are essential for completion of spermatogenesis, intact 90-day-old Charles River CD rats were treated with testosterone propionate (TP). Pilot studies indicated that sc administration of 100 /xg TP/100 g BW-day caused maximum suppression of testicular testosterone. This dose was administered for 13 days and animals were killed 24 h after the last injection. Intrastesticular levels of testosterone were reduced 30- fold from 0.295 ± 0.04 to 0.01 ± 0.001 ng/mg testis, and serum levels of FSH were suppressed 33% from 238 ± 15 to 195 ± 5 ng/ ml (P < 0.001). However, testicular weight only fell from 1.598 ± 0.058 to 1.482 ± 0.026 g, and qualitatively, spermatogenesis was normal. To examine the possibility that morphological changes failed to occur because the period of treatment was too short, a second group of animals were treated with the same dose of TP for 39 days. Once again, the intratesticular concentration of testosterone was suppressed...
TL;DR: In this article, the authors evaluated four children, including two sisters, with junctional ectopic tachycardia; intracardiac electrophysiologic recordings were performed in three of them.
Abstract: Junctional tachycardia due to an automatic ectopic focus occurs in children in one of two clinical settings: (1) in the immediate postoperative period after surgery, near the atrioventricular (A-V) junction, and (2) spontaneously, causing chronic supraventricular tachycardia. In the surface electrocardiogram, Junctional ectopic tachycardia appears as a narrow QRS tachycardia with A-V dissociation. This study evaluated four children, including two sisters, with Junctional ectopic tachycardia; intracardiac electrophysiologic recordings were performed in three of them. In each child, ventricular depolarization was preceded by a His bundle potential and a normal H-V interval. Neither overdrive pacing nor programmed premature stimulation of the atria or the ventricles influenced the tachycardia. Digoxin failed to alter the tachycardia, but alleviated congestive heart failure in all four patients. Propranolol slowed the rate of tachycardia in two patients, as did reserpine and phenytoin in one patient each. Chlorpromazine resulted in sinus rhythm in one patient. Quinidine and lidocaine were ineffective. Two patients died, one from low cardiac output associated with uncontrolled tachycardia, the other suddenly and unexpectedly while receiving digoxin and propranolol. The third patient's tachycardia regressed after repair of a ventricular septal defect. She has had sinus rhythm for 9 months without medication. The tachycardia of the fourth patient is uncontrolled despite treatment with digoxin, propranolol and phenytoin. On the basis of this study, acute treatment of Junctional ectopic tachycardia is recommended in the immediate postoperative period with intravenous propranolol (with a ventricular pacemaker available to treat bradycardia) and long-term treatment with oral digoxin plus either propranolol, phenytoin or Chlorpromazine.
TL;DR: A sensitive, quantitative and reproducible plaque assay for the measurement of the simian rotavirus SAII is described, finding that MA-104 cells were the most sensitive.
Abstract: A sensitive, quantitative and reproducible plaque assay for the measurement of the simian rotavirus SAII is described. Plaque formation required the presence of the facilitators pancreatin or trypsin and diethylaminoethyl-dextran in the agar overlay. SAII produced plaques in three continuous primate cell lines: MA-104, CV-1 and LLC-MK2. MA-104 cells were the most sensitive.
TL;DR: Growth curves of the simian rotavirus SA11 in a variety of cell cultures are presented and observable cytopathic effect was found to correlate with the percentage of infected cells in the culture.
Abstract: Understanding the basic virology of rotavirus infections has been hampered by the fastidiousness of most isolates and by the lack of a rapid quantitative assay method The growth characteristics of the simian rotavirus SA11 were studied because it grows to high titers in tissue culture and infectivity can be quantitated by plaque assay SA11 replication was analyzed in a variety of primary cell cultures or continuous cell lines derived from both homologous and heterologous hosts Viral replication was observed in each of the cell cultured examined The individual cell cultures demonstrated marked variability in their susceptibility to rotavirus infection The highest titers were obtained with MA104, BSC-1, CV-1, and BGM cells Observable cytopathic effect was found to correlate with the percentage of infected cells in the culture This study presents growth curves of the simian rotavirus in a variety of cell cultures
TL;DR: Lay persons trained in cardiopulmonary resuscitation were evaluated six months after completion of a four-hour basic life support course to determine the degree to which CPR cognitive and psychomotor performance skills were retained.
Abstract: Lay persons trained in cardiopulmonary resuscitation (CPR) were evaluated six months after completion of a four-hour basic life support course to determine the degree to which CPR cognitive and psychomotor performance skills were retained. Evaluation criteria were based on the American Heart Association's recommended standards. The data disclosed a significant decrease in the resuscitators' retention of CPR knowledge and skills. ( JAMA 241:901-903, 1979)
TL;DR: Current bacteriological standards for determining the safety of shellfish and shellfish-growing waters do no reflect the occurrence of enteroviruses, and no significant statistical relationship was demonstrated between virus concentration in oysters and the bacteriological and physiochemical quality of water andshellfish.
Abstract: The presence of enteroviruses in oysters and oyster-harvesting waters of the Texas Gulf coast was monitored over a period of 10 months. Viruses were detected in water and oyster samples obtained from areas both open and closed to shellfish harvesting. Viruses were detected periodically in waters that met current bacteriological standards for shellfish harvesting. No significant statistical relationship was demonstrated between virus concentration in oysters and the bacteriological and physiochemical quality of water and shellfish. Viruses in water were, however, moderately correlated with total coliforms in water and oysters and with fecal coliforms in oysters. Total coliforms in water were realted to total coliforms in sediment were related only to total coliforms in sediment. Among the physiochemical characteristics of water, turbidity was related statistically to the organic matter content of water and to fecal coliforms in water. There was a marked effect of rainfall on the bacteriological quality of water. Of a total of 44 water samples, 26 yielded virus in concentrations from 4 to 167 plaque-forming units per 100-gallon (ca. 378.5-liter) sample. Of a total of 40 pools of 10 to 12 oysters each, virus was found in 14 pools at a concentration of 6 to 224 plaque-forming units per 100 g of oyster meat. On five occasions, virus was found in water samples when no virus could be detected in oysters harvested from the same sites. This study indicates that current bacteriological standards for determining the safety of shellfish and shellfish-growing waters do no reflect the occurrence of enteroviruses.
TL;DR: In this article, a series of 79 headache patients were tested (18 classic, I complicated, 37 common, 16 cluster and 7 muscle contraction), and cerebral vasomotor responsiveness was likewise tested in 48 age and sex matched healthy volunteers.
Abstract: SYNOPSIS
Cerebral vasomotor responsiveness to 5% CO 2 or 100% 0 2 inhalation or hyperventilation was tested in groups of patients with either migraine or cluster headache. Regional cerebral blood flow was measured by the 133 Xe inhalation method before and during hypercapnia, hypocapnia or hyperoxia. A series of 79 headache patients were tested (18 classic, I complicated, 37 common, 16 cluster and 7 muscle contraction). For purposes of comparison, cerebral vasomotor responsiveness was likewise tested in 48 age and sex matched healthy volunteers. CO 2 responsiveness was expressed as D%Fg (gray matter blood flow) per mmHg PECO 2 (end-tidal CO 2 tension). Normal response was 3.6 ± 0.8% during 5% CO 2 inhalation and 3.0 ± 0.9% during hyperventilation. Inhalation of 100% O 2 inhalation reduced mean hemispheric Fg by 9.4 ± 5.4%. During the prodrome of migraine (N = 1) there was bilateral impairment of hemispheric CO 2 responsiveness. During the headache phase of migraine (N = 5) CO 2 responsiveness was impaired throughout both hemispheres but recovery occurred 24 hours after headache had subsided. During the headache-free interval of migraine (N = 21) there was excessive cerebrovascular CO 2 responsiveness (5.1 ± 2.2%). The cerebral hemisphere on the side of predominant head pain showed significantly greater excessive CO 2 response than the “non-headache” hemisphere. During cluster headache (N = 2) hemispheric CO 2 responsiveness was similarly impaired, but returned to normal immediately after the headache subsided. Unlike migraineurs, during cluster headache the cerebral vasoconstrictive response to 100% O 2 was excessive with marked reduction of Fg (33 ± 11%), with relief of headache. Two different types of abnormality in cerebral vascular receptor sites are hypothesized, which make it possible to differentiate migraine from cluster headache.
TL;DR: Analysis of the supernatant fraction of nucleoli extracts by polyacrylamide gel electrophoresis indicates that, although more than one nucleolar protein can bind silver, only one protein is associated with the staining of active ribosomal cistrons.
TL;DR: A simple radiographic finding is described, visible on the routine anteroposterior knee x-ray, which indicates severe lateral capsular injury and should alert the examiner to the high probability of anterior cruciate and medial ligamentous damage.
Abstract: The purpose of this presentation is to describe a simple radiographic finding, visible on the routine anteroposterior knee x-ray, which indicates severe lateral capsular injury and should alert the examiner to the high probability of anterior cruciate and medial ligamentous damage. Basic capsular anatomy is reviewed first, then the lesion itself is described in detail. Two cases are presented, one which
TL;DR: The results indicate the presence of a protein in the plasma membrane of cells transformed or infected by simian virus 40 that is immunologically indistinguishable from nuclear tumor antigen.
Abstract: The distribution of simian virus 40 large tumor antigen in subcellular fractions from simian virus 40-transformed hamster (H-50) and mouse (VLM) cells and from simian virus 40-infected monkey cells was determined. Solubilized [35S]-methionine- or 32Pi-labeled surface membrane and nuclear fractions were prepared, immunoprecipitated with hamster anti-T serum, and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Tumor antigen with an apparent molecular weight of ~96,000 was detected in both subcellular fractions. Minor components of ~68,000 and ~56,000 with anti-T reactivity which labeled with [35S]methionine were also detected in both fractions from H-50 cells, as were components of ~140,000 and ~56,000 from VLM cells. The 56,000 component appeared to be greatly reduced in 32Pi-labeled surface membrane fractions. Normal cells or cells transformed with a heterologous agent, such as polyoma virus or a chemical carcinogen, lacked immunoprecipitable tumor antigen. Cell fractionation was monitored by [3H]thymidine labeling, NADH-diaphorase activity, and Na+-K+-dependent ATPase activity. These analyses revealed only trace contamination of surface membranes by nuclei, extremely low levels of nuclear rupture during homogenization, and an approximate 10-fold enrichment of surface membrane. Reconstruction experiments demonstrated that soluble tumor antigen failed to associate or copurify with surface membranes during fractionation procedures. These results indicate the presence of a protein in the plasma membrane of cells transformed or infected by simian virus 40 that is immunologically indistinguishable from nuclear tumor antigen.
TL;DR: The current studies demonstrate the feasibility of using fluorescent reconstituted LDL in conjunction with the cell sorter to isolate mutant cells lacking functional LDL receptors, and a population of normal fibroblasts could be distinguished from a populations of FH fibro Blasts.
Abstract: Previous studies have shown that the cholesteryl ester core of plasma low density lipoprotein (LDL) can be extracted with heptane and replaced with a variety of hydrophobic molecules. In the present report we use this reconstitution technique to incorporate two fluorescent probes, 3-pyrenemethyl-23, 24-dinor-5-cholen-22-oate-3 beta-yl oleate (PMCA oleate) and dioleyl fluorescein, into heptane-extracted LDL. Both fluorescent lipoprotein preparations were shown to be useful probes for visualizing the receptor-mediated endocytosis of LDL in cultured human fibroblasts. When normal fibroblasts were incubated at 37 degrees C with either of the fluorescent LDL preparations, fluorescent granules accumulated in the perinuclear region of the cell. In contrast, fibroblasts from patients with the homozygous form of familial hypercholesterolemia (FH) that lack functional LDL receptors did not accumulate visible fluorescent granules when incubated with the fluorescent reconstituted LDL. A fluorescence-activated cell sorter was used to quantify the fluorescence intensity of individual cells that had been incubated with LDL reconstituted with dioleyl fluorescein. With this technique a population of normal fibroblasts could be distinguished from a population of FH fibroblasts. The current studies demonstrate the feasibility of using fluorescent reconstituted LDL in conjunction with the cell sorter to isolate mutant cells lacking functional LDL receptors.
TL;DR: Disk diffusion susceptibility testing appears to be a simple and reliable means of predicting susceptibility results for M. fortuitum and most isolates of M. chelonei by the agar dilution method.
Abstract: Although recent studies have suggested that some antibacterial agents have good activity against the rapidly growing mycobacteria Mycobacterium fortuitum and Mycobacterium chelonei, an easily applicable method for susceptibility testing of clinical isolates is not yet available. We evaluated a disk diffusion method with Mueller-Hinton agar and 48-h readings with 59 strains of M. fortuitum and 11 strains of M. chelonei and compared the results to agar dilution susceptibilities for nine antimicrobial agents. All isolates were susceptible to 16 micrograms of amikacin or kanamycin per ml with minimum zone diameters of 14 and 18 mm, respectively. Amikacin inhibited 100% of isolates of M. fortuitum at 2 micrograms/ml, whereas 10 of 11 (91%) of M. chelonei strains had minimum inhibitory concentrations of 4.0 micrograms/ml or greater. Doxycycline and minocycline had almost identical activities, inhibiting 44% of strains at 4.0 micrograms/ml, and both allowed easy differentiation between susceptible and resistant strains by disk diffusion. Although most isolates of M. chelonei grew better on 7H10 agar, this media gave two- to eight-fold higher minimum inhibitory concentrations than were obtained with Mueller-Hinton agar. Disk diffusion susceptibility testing appears to be a simple and reliable means of predicting susceptibility results for M. fortuitum and most isolates of M. chelonei by the agar dilution method.
TL;DR: The data suggest that if medical suppressive therapy is to be used in conjunction with conservative surgery to enhance fertility, it should be used preoperatively rather than postoperatively, and that surgery is efficacious.