Alveolar macrophage surface carbohydrate expression is altered in interstitial lung disease as determined by lectin-binding profiles

Cell-surface-associated glycoconjugates play important roles in cellular functions such as antigen presentation and cell adhesion, functions that may be modulated in patients with interstitial lung disease. Because carbohydrate residues can be recognized by specific lectins, we designed our study to establish baseline data for bronchoalveolar-lavage-derived cells from normal volunteers and to compare the lectin-binding properties of these cells with cells recovered from patients presenting with interstitial lung disease. Cells were obtained from patients with idiopathic pulmonary fibrosis (n = 10), patients with sarcoidosis (n = 20), and patients receiving amiodarone without evidence of clinical lung disease (n = 10) as well as from normal volunteers (n = 8). To determine the pattern of cell-surface glycoconjugate expression on alveolar macrophages (AM), we used a panel of 21 fluorochrome-coupled plant lectins and employed flow cytometry to determine their binding to AM. The labeling profiles of AM were found to be highly reproducible for normal subjects. At the lectin concentrations used for this study, some lectins showed very little binding to AM and some displayed intermediate binding, but the majority of the lectins labeled nearly all AM in samples. Fluorescence intensity varied characteristically for cells labeled with different lectins, providing further refinement and permitting discrimination beyond that provided by data restricted to percent of labeling. AM from patients with interstitial lung disease showed increased binding for the plant-derived lectins PNA, UEA-I, BSL-I, VVL, and SJA compared with AM from normal subjects, being most augmented for AM from patients with idiopathic pulmonary fibrosis. Because peripheral blood monocytes from normal subjects show a higher percentage of labeling with PNA, UEA-I, SJA, and BSL-I than did AM, the increased expression of binding sites for these four lectins by AM from patients with interstitial lung disease may reflect the influx of immature blood monocytes and/or the emergence of a proinflammatory macrophage phenotype. This study demonstrated heterogeneous expression of surface carbohydrate residues by AM and blood monocytes from normal subjects and alterations in carbohydrate receptor expression in interstitial lung disease. Lectin-binding properties may prove useful, therefore, in the evaluation of mononuclear phagocyte populations in interstitial lung disease, especially by the identification of functional subsets and/or changed activation states.

Quantitation of genomic methylation using ligation-mediated PCR

We have developed a new technique for the quantitation of CpG methylation of genomic DNA. This method measures the conversion of a larger amplified DNA fragment to a shorter DNA product correlating with demethylation. The procedure uses pairs of non-isoschizomeric enzymes, one of which is methylation-sensitive, to cleave genomic DNA at closely spaced sites. The extent of cleavage by the methylation-sensitive restriction enzyme is quantitated by amplification of these digestion products with ligation-mediated PCR and radioactive labeling of the product. The ratio of the two amplified fragments correlates with the degree of methylation at the restriction site. The analysis is rapid, quantitative, internally controlled and requires small quantities of genomic DNA.

Specific, temporally regulated expression of the insulin-like growth factor II gene during muscle cell differentiation

We have compared the expression of insulin-like growth factor II (IGF-II) messenger RNA (mRNA) to the expression of other mRNAs encoding proteins known to play pivotal roles during the differentiation of continuously cultured, fusing muscle cell lines. These cell lines respond to changes in culture conditions by undergoing a well characterized alteration in gene expression which leads to a change in their phenotype from dividing, mononucleate myoblasts to fused, multinucleate myotubes. The hallmarks of this differentiation program include the induction of myogenic regulatory genes as well as the genes that encode the contractile proteins. We have found that the differentiation of these cells leads to the production of multiple IGF-II transcripts. In one of the cell lines studied, C2C12, IGF-II mRNA levels were rapidly induced during differentiation. Increases in IGF-II mRNA levels preceded the expression of the contractile protein genes but occurred only after the activation of the myogenic regulatory gene myogenin. The same regulated pattern of IGF-II mRNA expression was seen in both rapidly and slowly fusing subclones of this cell line, indicating a requirement for IGF-II at a specific point during muscle differentiation. These results suggest that IGF-II plays an important role during the terminal differentiation of skeletal muscle cells and are consistent with the existence of an autocrine loop through which IGF-II may act to regulate the differentiation process.

Muscle-specific expression of human insulin receptor in transgenic mice

Variations in skeletal muscle insulin signaling are thought to have important effects on in vivo glucose homeostasis. To address the role of the insulin receptor in insulin action in muscle, we overexpressed human insulin receptors in the skeletal muscle of transgenic mice. A muscle-specific transgene (TMPE/HIR) was constructed by using promotor and enhancer elements derived from the rat MLC1/3 locus coupled to the intact protein-coding region of the human insulin-receptor cDNA. After testing the transgene for expression in cultured C2C12 myotubes, six founder mice transgenic for TMPE/HIR were generated. We determined that one line of mice had significant expression of human insulin-receptor mRNA in skeletal muscle. The analysis of several tissues from these mice by immunoprecipitation of labeled insulin receptors with a human-specific antireceptor antibody, revealed exclusive expression of human insulin receptors in skeletal muscle. Using both human-specific and non--species-specific anti-insulin receptor antibodies, we developed two immunoassays capable of quantitating the relative amounts of human and total insulin receptors in muscle. Compared with nontransgenic littermate controls, the total number of insulin receptors was increased by 30% in heterozygous transgenics and 68% in homozygotes. Human insulin-receptor protein contributed substantially to the total insulin-receptor pool present in transgenic muscle (42% for heterozygotes, 61% for homozygotes). Intraperitoneal glucose and insulin tolerance tests were performed with homozygous transgenic and nontransgenic littermate mice. Results with both approaches were significantly different for the two groups of mice, suggesting that the modest increase in insulin receptors in the muscle of transgenic mice causes a direct increase in insulin responsiveness.(ABSTRACT TRUNCATED AT 250 WORDS)

Preliminary data on the metabolic brain pattern of patients with winter seasonal affective disorder

The brain metabolic pattern of patients with winter seasonal affective disorder with and without light treatment was determined by positron emission tomography. Compared with controls, patients with seasonal affective disorder with and without light treatment had globally lower metabolic rates, relatively lower superior medial frontal cortex rates, and somewhat higher basal ganglia rates. Patients receiving light treatment had a relatively higher rate in an occipital region of interest containing the primary visual cortex. Patients without light treatment had relatively higher metabolic rates in right parietal and medial orbitofrontal cortex and lower rates in the left parietal cortex. Patients not receiving light treatment had a hemispheric metabolic asymmetry (left greater than right) for the midprefrontal cortex located 67 mm above the canthomeatal line. The right side of this region, previously found reduced in manic-depressive illness and schizophrenia, was decreased primarily in patients with seasonal affective disorder with fewer atypical depressive symptoms. These "abnormal" prefrontal and parietal cortex regions appeared highly "coupled" in the patients with seasonal affective disorder.

A transgene target for positional regulators marks early rostrocaudal specification of myogenic lineages

In transgenic mice, muscle-specific regulatory elements from the myosin light chain (MLC) 1/3 locus drive graded expression of a linked CAT reporter gene in selected fast muscles along the anteroposterior axis of the adult animal. The gradient of MLC-CAT transcripts is established early in development, during the generation of somites from the paraxial mesoderm and the activation of myogenic factor gene expression, and is not reflected in the expression of the endogenous MLC1 gene. At later embryonic stages, the gradient of MLC-CAT transcripts persists in intercostal and intervertebral muscles, but is not maintained in other axial muscles. Profiles of CAT transgene activity reveal that the gradient is generated during the maturation of increasingly caudal somites, opposite to the direction of somite development, and is retained in dissociated somite cultures. We propose that coexpression of myogenic factors is necessary but not sufficient to regulate expression of the MLC-CAT transgene, which is responsive to additional positional cues in the embryo.

The myosin light chain enhancer and the skeletal actin promoter share a binding site for factors involved in muscle-specific gene expression

The myosin light chain (MLC) 1/3 enhancer (MLC enhancer), identified at the 3' end of the skeletal MLC1/3 locus, contains a sequence motif that is homologous to a protein-binding site of the skeletal muscle alpha-actin promoter. Gel shift, competition, and footprint assays demonstrated that a CArG motif in the MLC enhancer binds the proteins MAPF1 and MAPF2, previously identified as factors interacting with the muscle regulatory element of the skeletal alpha-actin promoter. Transient transfection assays with constructs containing the chloramphenicol acetyltransferase reporter gene demonstrated that a 115-bp subfragment of the MLC enhancer is able to exert promoter activity when provided with a silent nonmuscle TATA box. A point mutation at the MAPF1/2-binding site interferes with factor binding and abolishes the promoter activity of the 115-bp fragment. The observation that an oligonucleotide encompassing the MAPF1/2 site of the MLC enhancer alone cannot serve as a promoter element suggests that additional factor-binding sites are necessary for this function. The finding that MAPF1 and MAPF2 recognize similar sequence motifs in two muscle genes, simultaneously activated during muscle differentiation, implies that these factors may have a role in coordinating the activation of contractile protein gene expression during myogenesis.

Rostrocaudal gradient of transgene expression in adult skeletal muscle

Transgenic mice were produced in which expression of the reporter gene chloramphenicol acetyltransferase (CAT) is controlled by regulatory elements of a rodent myosin light chain gene. CAT activity was readily detectable in muscles of these mice but negligible in a variety of nonmuscle tissues. Unexpectedly, levels of CAT expression varied greater than 100-fold from muscle to muscle, forming a gradient in which a muscle's position in the rostrocaudal axis was correlated with its level of CAT enzyme activity and abundance of CAT mRNA. Thus, rostral muscles (innervated by cranial nerves) had the lowest levels of CAT, thoracic muscles had intermediate levels, and caudal muscles (innervated through lumbar and sacral roots) had the highest levels. We established that myosin light chain sequences are responsible for the gradient of CAT expression but observed no strong gradient of endogenous myosin light chain expression. We argue that elements that are silent or masked by other sequences in their native context are revealed in the transgene and that the rostrocaudal gradient of gene expression they produce reveals the existence of a positionally graded endogenous regulator of gene expression. These transgenic mice provide evidence that cells in adult mammals retain "positional information" of a sort hitherto studied largely in embryos. The transgene they express may provide a means for determining how such positional values are generated and maintained.

Progesterone binding in a clinical isolate of Pseudomonas aeruginosa

We have undertaken the characterization of progestin binding component(s) in the cytosol prepared from Pseudomonas aeruginosa isolated from an immunocompromised patient. Incubation of P. aeruginosa cytosol aliquots at 0 degrees C with 20 nM [3H]R5020 (a synthetic progestin) revealed the presence of saturable binding. The [3H]R5020 binding reached an equilibrium after 1 h at 0 degrees C and showed saturation at 30-50 nM with a Kd value of 7.7 nM. At 0 degrees C, beta-mercaptoethanol increased the [3H]R5020 binding by 20% but sodium molybdate had no effect. The [3H]R5020-macromolecular complex was stable for up to 4 h at 37 degrees C. Steroid binding specificity analysis revealed that [3H]R5020 binding could be eliminated in the presence of 2 microM progesterone, estradiol, or dihydrotestosterone but that the synthetic glucocorticoid, triamcinolone acetonide, did not compete. Postlabeling of the cytosol fractions obtained after 10-30% glycerol gradient analysis demonstrated association of the radioactivity with a molecule that sedimented as a 6-8 S protease-sensitive moiety which was unaltered in the presence of RNase or DNase. When cells were grown in the presence of 100 nM progesterone, a 50% inhibition in the number of resulting colonies was observed. In addition to its evolutionary significance, the presence of this steroid binding molecule suggests a potential in the endocrine manipulation in the treatment of infections caused by P. aeruginosa.

Paired MyoD-binding sites regulate myosin light chain gene expression

The muscle-specific enhancer element located downstream of the myosin light chain (MLC) locus encoding MLC1 and MLC3 contains three binding sites (A, B, and C) for the myogenic determination factor MyoD. A 173-base-pair region of the MLC gene enhancer, including these three sites, retains full enhancer function when transfected into muscle cells. Whereas mutation of either upstream MyoD binding site (A or B) has a mild effect on muscle-specific enhancer activity, mutation of the third MyoD binding site (C) substantially weakens the enhancer, both in muscle cells or in nonmuscle cells cotransfected with a MyoD, myogenin, or myf5 expression vector. Site C is necessary but insufficient, since double mutation of two MyoD binding sites (A plus B) abrogates enhancer activity. Thus, site C requires either site A or B for enhancer function. This study shows a hierarchy of function among the three MyoD binding sites in the MLC enhancer. We propose that a protein-DNA complex is formed with at least two of these sites (A and C or B and C) to effect activation of the locus encoding MLC1/3 during myogenesis.

Effect of diabetes on Na(+)-H+ exchange by single isolated hepatocytes

We used the fluorescent dye 2',7'-bis-(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF) to examine intracellular pH (pHi) regulation in single hepatocytes isolated from control rats and rats with either spontaneous or drug-induced diabetes mellitus (DM). In the absence of CO2-HCO3-, both control and DM cells recovered from cellular acid loads applied by the NH4+ prepulse technique. Because the pHi recovery was blocked by either Na+ withdrawal or ethylisopropylamiloride in both control and DM cells, it was presumably mediated by Na(+)-H+ exchange. In the control cells, the pHi threshold above which the rate of change of pHi (dpHi/dt) was zero was 7.06, and the slope of the dpHi/dt-pHi relationship was -0.030 s-1. In the DM cells, the pHi threshold was 7.22 and the slope was -0.017 s-1. Thus, at pHi values below approximately 6.9, the pHi recovery was slower in the DM cells. Inasmuch as we observed no difference in the cellular buffering power between control and DM cells, diabetes inhibits Na(+)-H+ exchange within this low pHi range. At pHi values above approximately 6.9, however, Na(+)-H+ exchange was apparently stimulated by diabetes. Thus diabetes induces two distinct alterations of Na(+)-H+ exchange, an alkaline shift in pHi threshold and decrease in slope. Treatment of diabetic rats with insulin for 48 h restored both Na(+)-H+ exchange parameters to normal. On the other hand, insulin added in vitro to DM cells for 2-5 h shifted the threshold toward the control value without affecting the slope, thus leading to a further inhibition of Na(+)-H+ exchange over the entire pHi range.(ABSTRACT TRUNCATED AT 250 WORDS)

A highly conserved enhancer downstream of the human MLC1/3 locus is a target for multiple myogenic determination factors

A potent muscle-specific enhancer element, originally described in the rat myosin light chain (MLC) 1/3 locus located downstream of the coding region, is found in an analogous position in the human MLC1/3 gene. When linked to a CAT reporter gene and transfected into muscle or non-muscle cells, the human MLC enhancer directs high levels of muscle-specific gene expression from homologous or heterologous promoters, irrespective of position or orientation relative to the CAT transcription unit. A significant degree of sequence homology (over 85%) in the 3'-flanking regions of the two MLC genes is restricted to a 200 bp sequence which lies approximately 1.5 kb downstream of the polyadenylation site in both species. The human enhancer sequence includes binding sites for human myogenic determination factors containing a common basic helix-loop-helix motif, and it can be trans-activated to varying degrees in non-muscle cells by these factors. This study establishes the MLC enhancer as an evolutionarily conserved, integral component of the MLC1/3 locus which constitutes a novel target for the action of myogenic determination factors.

Myf-6, a new member of the human gene family of myogenic determination factors: evidence for a gene cluster on chromosome 12

The Myf-6 gene, a novel member of the human gene family of muscle determination factors has been detected by its highly conserved sequence coding for a putative helix-loop-helix domain. This sequence motif is a common feature of all Myf factors and other regulatory proteins. The new Myf gene is located on human chromosome 12, approximately 6.5 Kb upstream of the Myf-5 locus in a closely linked cluster of myogenic determination genes. Myf-6 cDNAs were isolated from human and mouse skeletal muscle, the only tissue in which expression of the corresponding mRNA was observed. In contrast to human primary muscle cell cultures which express moderate levels of Myf-6 mRNA, most established rodent muscle cell lines completely lack this mRNA. Myogenic 10T1/2 cells, however, induced by the expression of either pEMSV-Myf-4 or pEMSV-Myf-5 activate their endogenous mouse Myf-6 gene. Constitutive expression of Myf-6 cDNA in C3H 10T1/2 fibroblasts establishes the muscle phenotype at a similar frequency to the previously characterized myogenic factors. Moreover, muscle-specific CAT reporter constructs containing either the human myosin light chain (MLC) enhancer or the promoter of the embryonic myosin light chain gene are activated in NIH 3T3 fibroblasts or in CV1 kidney cells by cotransfection of Myf-6 expression vehicles. This transcriptional activation occurs in the absence of any apparent conversion of the cellular phenotype of the recipient cells. Glutathione-S-transferase fusion proteins with Myf-3, Myf-4 or Myf-5 specifically bind to a MEF-like consensus sequence present in the human MLC enhancer and the MLC1 emb promoter. In contrast, the Myf-6 hybrid protein interacts weakly with the same sequences showing lower affinity and reduced specificity. Since co-expressed pEMSV-Myf-6, nevertheless, is able to activate transcription of the MLC-CAT reporter constructs in non-muscle tissue culture cells, the different DNA binding properties in vitro might suggest that transactivation of gene expression by Myf-6 involves distinct binding sites and/or additional protein factors.

Construction and applications of DNA probes for detection of polychlorinated biphenyl-degrading genotypes in toxic organic-contaminated soil environments

Several DNA probes for polychlorinated biphenyl (PCB)-degrading genotypes were constructed from PCB-degrading bacteria. These laboratory-engineered DNA probes were used for the detection, enumeration, and isolation of specific bacteria degrading PCBs. Dot blot analysis of purified DNA from toxic organic chemical-contaminated soil bacterial communities showed positive DNA-DNA hybridization with a 32P-labeled DNA probe (pAW6194, cbpABCD). Less than 1% of bacterial colonies isolated from garden topsoil and greater than 80% of bacteria isolated from PCB-contaminated soils showed DNA homologies with 32P-labeled DNA probes. Some of the PCB-degrading bacterial isolates detected by the DNA probe method did not show biphenyl clearance. The DNA probe method was found to detect additional organisms with greater genetic potential to degrade PCBs than the biphenyl clearance method did. Results from this study demonstrate the usefulness of DNA probes in detecting specific PCB-degrading bacteria, abundance of PCB-degrading genotypes, and genotypic diversity among PCB-degrading bacteria in toxic chemical-polluted soil environments. We suggest that the DNA probe should be used with caution for accurate assessment of PCB-degradative capacity within soils and further recommend that a combination of DNA probe and biodegradation assay be used to determine the abundance of PCB-degrading bacteria in the soil bacterial community.

Myosin light chain enhancer activates muscle-specific, developmentally regulated gene expression in transgenic mice

The rat myosin light chain (MLC)1/3 gene locus contains a potent muscle-specific enhancer, located downstream of the coding region, greater than 24 kilobases away from the MLC1 transcription start site. To assess the role of this enhancer in the activation of MLC expression during development, transgenic mice were generated carrying multiple copies of a MLC1 promoter-chloramphenicol acetyltransferase (CAT) transcription unit linked to a genomic fragment including the enhancer. CAT expression was detected in four mouse lines, up to 1000-fold higher in skeletal muscles than in other tissues. Activation of endogenous MLC1 transcription in these animals 4 days before birth was reflected in the onset of CAT transgene expression. This study identifies the transcriptional control elements necessary to activate the 21-kilobase MLC1/3 locus at the appropriate fetal stage and indicates that the MLC enhancer is sufficient to induce developmentally regulated expression from the MLC1 promoter exclusively in skeletal muscle cells.

[Computerized tomography studies of the lower legs of patients with chronic venous insufficiency and arthrogenic venous stasis syndrome]

Transverse computed tomography of the lower legs in patients with chronic venous insufficiency reveals changes in the extravasal connective tissue. In the subcutaneous fat there is fibrosis - sometimes with ossification - that may extend to the periachilloregion and then embeds the Achilles tendon. The Achilles tendon has a reduced cross-section and reduced density with circumscribed, hypodense areas that are a sign of degeneration. In the muscles, areas of atrophy with lipomatous degeneration can be found as well. In the bones there are signs of increased osteoporosis; the periosteum shows osseous proliferation. The extent of these changes correlates with the degree of venous insufficiency and is most often seen in patients with the arthrogenic stasis syndrome.

A muscle-specific enhancer is located at the 3' end of the myosin light-chain 1/3 gene locus

Two skeletal myosin light chains, MLC1 and MLC3, are generated from a single gene by transcription from two different promoters and alternate splicing of the pre-mRNAs. To define DNA sequences involved in MLC transcriptional control, we constructed a series of plasmid vectors in which segments of the rat MLC locus were linked to a CAT gene and assayed for expression in muscle and nonmuscle cells. Whereas sequences proximal to the two MLC promoters do not appear to contain tissue-specific regulatory elements, a 0.9-kb DNA segment, located greater than 24 kb downstream of the MLC1 promoter, dramatically increases CAT gene expression in differentiated myotubes but not in undifferentiated myoblasts or nonmuscle cells. The ability of this segment to activate gene expression to high levels, in a distance-, promoter-, position-, and orientation-independent way, defines it as a strong muscle-specific enhancer element.

In vivo induction of the lymphokine-activated killer phenomenon: interleukin 2-dependent human non-major histocompatibility complex-restricted cytotoxicity generated in vivo during administration of human recombinant interleukin 2

The availability of purified human recombinant interleukin 2 (IL-2) has enabled clinical trials to test its in vivo effects. We report here the immunological effects of 7 consecutive days of IL-2 treatment given to 25 patients with cancer in a clinical Phase I study. Peripheral blood lymphocytes obtained from patients following therapy with IL-2 had enhanced proliferative responses to IL-2 and enhanced direct cytotoxic activity on K562 target cells. This lytic activity was further augmented by the addition of IL-2 during the 51Cr release assay. Fresh peripheral blood lymphocytes from some patients who had just completed treatment at the higher IL-2 dose levels were able to kill both the natural killer-resistant Daudi cell line and fresh tumor cells while pretreatment samples and peripheral blood lymphocytes from healthy controls were not. This lytic activity was best detected when IL-2 was present in the in vitro effector assay. These results demonstrate that the administration of IL-2 to patients with cancer induces a population of effector cells able to directly destroy natural killer-resistant target cells, when assayed in the presence of IL-2.

The causes of morbidity and mortality among infants born at term

Previous studies have reported on the pathologic spectrum of perinatal mortality; however, in our opinion, the problems pertaining to the term newborn have not been emphasized sufficiently. We reviewed the autopsies of all term infants up to 2 months of age in a ten-year period (July 1975 to July 1985). These 342 patients comprised 20% of all pediatric autopsies. The patients were grouped according to cause of death in the following categories: congenital anomalies (59%); infection (10%); perinatal injury, including meconium aspiration (9%); maternal-placental problems (11%); and miscellaneous (5%). In 4% of the cases, mainly stillbirths, the cause of death was unclear. Of the congenital anomalies, the cardiovascular system was most affected (57%). Hyaline membrane disease and intraventricular hemorrhage, usually frequent in series involving many preterm patients, were seldom seen. This study emphasizes the different pathologic spectrum of mortality between premature and term newborns.

Characterization of glutamine transport by liver plasma membrane vesicles

Plasma membrane vesicles were prepared from livers of fed normal and diabetic rats and used to characterize the membrane transport process responsible for glutamine uptake by the liver cell. In vesicles from normal rats the initial velocity of glutamine uptake was fourfold more rapid (0.20 +/- 0.02 vs. 0.05 +/- 0.02 nmol X mg protein-1 X 10 s-1) when Na+ replaced K+ in the extravesicular buffer. In the presence of a Na+-gradient glutamine uptake by vesicles was saturable, with a Km of 1.3 +/- 0.5 mM and a Vmax of 10 +/- 2.3 nmol X mg-1 X min-1. Lithium could fully substitute for Na+ in stimulating glutamine entry. In the presence of an imposed K+-gradient glutamine uptake was a linear function of its extravesicular concentration. In accord with the sodium-stimulated uptake of glutamine occurring via a sodium symport process, we observed that glutamine stimulated the initial rate of 22Na+ entry into vesicles by four- to fivefold. We further observed that glutamine entry was more rapid when lipophilic anions accompanied sodium in the incubation buffer, suggesting that Na+-glutamine flux is electrogenic. Preloading of vesicles with glutamine did not effect subsequent entry of labeled glutamine (no transstimulation), whereas intravesicular alanine did enhance alanine but not glutamine entry. Alloxan diabetes, which is known to stimulate the Na+-alanine cotransporter in these vesicles did not increase glutamine entry at any concentration tested.(ABSTRACT TRUNCATED AT 250 WORDS)

Elevations in circulating 1,25-dihydroxyvitamin D in three patients with lymphoma-associated hypercalcemia

Three patients with hypercalcemia associated with malignant lymphoma and elevations in plasma 1,25-dihydroxyvitamin D [1,25-(OH)2D] are described. In addition to the elevation of circulating 1,25-(OH)2D, these three patients were characterized by suppressed immunoreactive PTH levels and urinary cAMP excretion, elevated fasting urinary excretion of calcium, and absence of adenylate cyclase-stimulating activity in the tumor extracts. Bone marrow biopsy and skeletal radionuclide scans were negative for lymphoma in two patients. Surgical excision of a solitary splenic lymphoma in one patient and medical therapy in another patient resulted in rapid normalization of the serum calcium and plasma 1,25-(OH)2D levels. These findings confirm an earlier observation that elevated plasma levels of 1,25-(OH)2D may occur in certain patients with lymphoma and suggest that this vitamin D metabolite may act as a humoral or systemic mediator of hypercalcemia. Proof that this is the case and identification of the source of 1,25-(OH)2D production will require further study.

BK viral enhancer element and a human cellular homolog

Comparison of two closely related primate papovaviruses, simian virus 40 (SV40) and human BK virus (BKV), reveals that the only region of extensive divergence, the tandem sequences adjacent to the origins of DNA replication, is responsible in SV40 for enhancing early gene expression. This study demonstrates a similar enhancer function for the analogous repeated region in BKV. The dissimilarity in sequence of the BKV and SV40 enhancer elements suggests that they may have been acquired since SV40 and BKV diverged. A locus cloned from the human genome homologous to the BKV tandem repeats has been shown to function as low level enhancer element in mammalian cells. These data support the hypothesis that viral enhancer sequences may be evolutionarily related to host cell sequences.

Circadian rhythm disturbances in manic-depressive illness

Clinical features of manic-depressive illness, such as diurnal variation in mood, early morning awakening, and cyclicity and seasonality of recurrences, have led to speculation that the circadian system may be involved in its pathophysiology. At least three types of circadian rhythm abnormalities have been described in such patients: blunting of circadian rhythms' amplitudes, advanced position (or even nonentrainment) of circadian rhythms' phases, and doubling of the length of the sleep-wake cycle from 24 to 48 h. Several types of experiments indicate that alterations in the timing of sleep and wakefulness relative to other circadian rhythms (i.e., changes in internal phase relationships) may trigger the onset or offset of episodes of depression and mania. Whether drugs used to treat manic-depressive illness act through their effects on the circadian system is currently being investigated. Direct manipulations of the circadian system are also being investigated as new approaches to treatment.

Electroconvulsive treatment and lithium carbonate. Their effects on norepinephrine metabolism in patients with primary, major depressions

Effects of electroconvulsive treatment (ECT) and lithium carbonate on norepinephrine metabolism were investigated in eight patients with primary, major depressions. A series of 12 ECTs reduced urinary norepinephrine and normetanephrine output significantly, and showed a tendency to reduce urinary vanillylmandelic acid output as well as whole-body norepinephrine turnover. Treatment with lithium carbonate significantly reduced urinary norepinephrine, normetanephrine, 3-methoxy-4-hydroxyphenylglycol, and vanillylmandelic acid output as well as whole-body norepinephrine turnover. These findings point to a common effect of antidepressant treatments since they are similar to results produced by administration of three other types of antidepressant drugs: clorgiline, a specific monoamine oxidase A inhibitor; desipramine, a relatively specific norepinephrine reuptake Inhibitor; and zimelidine, a relatively specific serotonin reuptake Inhibitor. These drugs reduce total production of norepinephrine and/or its major metabolites in depressed patients. Thus, five antidepressant treatments with different mechanisms of action have a common overall effect on the system.

The structure of rat preproinsulin genes

In rat there are two nonallelic insulins, I and II. We have cloned and sequenced double stranded cDNA copies of both preproinsulin mRNA I and II. Using the cloned sequence as probe, we established by the Southern blotting technique a restriction map of the two chromosomal genes. This map indicates that an intron exists within the insulin II gene. To examine this in more detail, we have isolated both genes from a library of rat DNA cloned in phage lambda. Restriction endonuclease analysis and direct DNA sequencing revealed that gene II contains two introns: a 490 base pair intron between the region encoding amino acids 38 and 39 of proinsulin, and a 119 base pair intron, which is 17 base pairs upstream from the initiation codon. Gene I is not interrupted within the protein coding region, but possesses an intron homologous to the 119 base pair intron of insulin II. We are studying the structure of insulin genes from other species to determine if the 490 base pair intron was lost or inserted in the duplicated gene. We have identified nuclear RNA molecules larger than preproinsulin mRNA which contain the transcribed intronic sequences. These molecules represent a new precursor in insulin biosynthesis.

Evolution of two major chorion multigene families as inferred from cloned cDNA and protein sequences

Complete or partial sequences are reported from six chorion cDNA clones of the silkmoth Antheraea polyphemus. The proteins encoded belong to the two major chorion protein classes, A and B, each of which is encoded by a multigene family. The sequence comparisons define some major features of the families and suggest how these genes may be evolving. Deletions and insertions might be involved in expanding or contracting internally repetitive regions. Sequence divergence is localized, thus defining sequence domains of distinct evolutionary properties and presumably distinct functions.

The structure and transcription of four linked rabbit beta-like globin genes

Rabbit chromosomal DNA contains a cluster of four linked beta-like globin genes arranged in the orientation 5'-beta 4-(8kb)-beta 3-(5 kb)-beta 2-(7-kb)-beta 1-3'. Determination of the nucleotide sequence of gene beta 1 confirms that this gene corresponds to the second type of two common co-dominant alleles encoding the adult beta-globin chain. With the exception of two nucleotide substitutions in the large intervening sequence (intron), the intron and flanking sequences are identical with the nucleotide sequence of the first type determined by Weissmann et al. (1979). A 14S polyadenylated transcript containing large intron sequences (possibly a mRNA precursor) is detected in the bone marrow cells of anemic rabbits. Gene beta 2 has limited sequence homology to adult and embryonic beta-globin probes and lacks a detectable mRNA transcript in the erythropoietic tissues examined. It contains at least one intervening sequence analogous to the large intron in gene beta 1. Genes beta 3 and beta 4 both contain an intron of 0.8 kb. Partial DNA sequence analysis indicates that the large intron in beta 4 is located between codons for amino acids lysine and leucine in an analogous position to that of the large intron in beta 1. In addition, a second smaller intron interrupts the 5' coding sequences of gene beta 4. Both genes beta 3 and beta 4 are transcribed in embryonic globin-producing cells. Their DNA sequence homology is limited, however, to a segment of approximately 0.2 kb located on the 5' side of the large intron.

The structure and evolution of the two nonallelic rat preproinsulin genes

In the rat, there are two nonallelic genes for preproinsulin. The insulin end products are very similar and are equally expressed. We have isolated clones carrying these genes and their flanking sequences, and characterized them by DNA sequencing and electron microscopic analysis. We have established the primary structure of the preproinsulin mRNAs and the signal peptides of these two proteins. One of the genes contains two introns: a 499 bp intron interrupting the region encoding the connecting peptide and a 119 bp intron interrupting the segment encoding the 5 noncoding region of the mRNA. The introns are transcribed and present in a preproinsulin mRNA precursor. The other gene possesses the smaller, but not the larger, of the two introns. Calculations based on the divergence of the two preproinsulin nucleotide and amino acid sequences indicate that these genes are the products of a recent duplication. Thus one of the genes gained or lost an intron since that time.

Simple Achlorhydric Anemia

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