In vitro selectivity of agonists and antagonists for beta 1- and beta 2-adrenoceptor subtypes in rat brain

A radioreceptor binding assay was developed to determine the selectivity of beta-adrenoceptor agents in rat brain. This was achieved by using the highly selective unlabelled antagonists CGP 20712A and ICI 118-551 to block beta 1- or beta 2-sub-populations respectively in rat cerebral cortex membranes. This permitted the selective labelling of beta-adrenoceptors with the antagonist (-)-[125I]pindolol. Using this method, compounds could be routinely screened and selectivity profiles for binding in the CNS determined with a high degree of sensitivity and resolution.

Independent regulation of beta 1- and beta 2-adrenoceptors

1 The down-regulation of beta-adrenoceptors has been postulated as a biochemical marker of antidepressant efficacy. Here we demonstrate that chronic treatment with desipramine down-regulates beta 1-adrenoceptors in rat cerebral cortex and that beta-adrenoceptor subtypes can be independently regulated by treatment with different beta-adrenoceptor agonists. 2 Desipramine, (+/-)-clenbuterol, prenalterol, corwin (20 mg kg-1 daily) and corwin (10 mg kg-1 daily) were administered to male, Sprague-Dawley rats, over eight days, by means of osmotic Alzet pumps placed subcutaneously and removed 24 h before analysis. Control rats received vehicle only. The beta 1- and beta 2-adrenoceptor populations were measured in cerebral cortex by a modified (-)-[125I]-pindolol receptor binding assay. 3 The conventional antidepressant, desipramine, preferentially down-regulated beta 1-adrenoceptors whereas the non-selective beta-adrenoceptor agonist (+/-)-clenbuterol preferentially down-regulated beta 2-adrenoceptors. The beta 1-selective partial agonist, prenalterol, up-regulated beta 1-adrenoceptors perhaps acting more as an antagonist than as an agonist. Finally, neither dose of corwin had any significant effect on beta-adrenoceptor number.

[Value of nuclear magnetic resonance tomography in the staging of tumors of the urinary bladder]

The accuracy of magnetic resonance imaging (MRI) and computed tomography (CT) in the staging of bladder tumors was evaluated in 46 patients. In the T-staging MRI was superior to CT. With MRI 38 out of the 46 tumors were correctly staged into the four groups T0, T1-T3a, T3b and T4. With CT this classification was only possible in 28 cases. The main advantages of MRI were the capability for multiplanar imaging, which improved evaluation of the bladder base and the bladder dome, as well as a better differentiation between tumor recurrency and fibrosis. In the evaluation of adenopathy MRI and CT proved to be equal and demonstrated a sensitivity of 50%.

[Value of percutaneous diagnosis and therapeutic procedures in obstructive uropathy following kidney transplantation]

Postrenal obstruction is a severe complication after renal transplant. To evaluate side effects and effectiveness we analyzed 71 ategrade pyeloureterographies (AP) and 30 percutaneous and open nephropyelostomies. AP shows a sensitivity of 93% and proved thereby its superiority to alternative diagnostic procedures. Also percutaneous pyelostomy proved its reliability in therapy of obstructive disease. Comparing side effects to those in normal kidneys we found a higher incidence of bleeding (17%). There was no severe complication with loss of graft. In 6 cases of obstructive disease we could prevent an operation by temporary percutaneous nephrostomy. Long term nephrostomy allows to evaluate the function of the kidney accurately which may not be possible until after 1-2 months.

Adjuvant intravesical chemotherapy of superficial bladder cancer with monthly doxorubicin or intensive mitomycin. A comparison of two consecutive series

120 patients with the first occurrence of TNM stage Ta or T1 bladder carcinoma were given adjuvant intravesical treatment in 2 consecutive series. The first 60 received doxorubicin monthly for 6 months, then on the 9th and 12th month following surgery. The second series was given mitomycin weekly for 2 months, then monthly to the end of the first year. Median follow-up is 48 months in the first series and 15 in the second. In the doxorubicin group, 28 patients had recurrences. The recurrence rate is 1.86/100 patient-months. Seventeen of these first relapses occurred within the first year. In the 'intensive' mitomycin series, where 36 patients were observed for 12 months or more, 3 relapsed. The recurrence rate to date is 0.35. The relapse-free survival probability at 12 months is 75% in the first series and 93% in the second. Treatment was stopped due to toxicity in 4 patients in the doxorubicin group and in 10 of the mitomycin group.

Distribution of mass within native thick filaments of vertebrate skeletal muscle

The distribution of mass within the vertebrate skeletal thick filament has been determined by scanning transmission electron microscopy. Thick and thin filaments from fresh rabbit muscle were mixed with tobacco mosaic virus (TMV), fixed with formaldehyde, dried onto thin carbon films and viewed in a computer-linked microscope. Electron scattering data from both TMV and thick filaments were analysed with reference to the long axis of the particles so that the distribution of mass within the particles could be determined. While TMV appeared to be a uniform rod at the resolution employed (4.3 nm), the thick filament was clearly differentiated along its length. M-line remnants at the centre of the filament were flanked by regions of low mass per unit length, corresponding to the bare zone of the filament, and then by the more massive cross-bridge regions. The mass per unit length was approximately constant through most of the cross-bridge zone and declined at the filament tips, in a manner consistent with a constant number of myosin molecules per 14.3 nm interval (crown) throughout the cross-bridge zone. Fourier analysis of the data failed to detect the expected 43 nm periodicity of C-protein. The total mass of the thick filament was 184 Mdalton (s.e.m., 1.6 X 10(6); n = 70). The mass of adhering M-line proteins was highly variable but, on average, was about 4 Mdalton. The total mass of the filament and the mass distribution in the cross-bridge zone are consistent with three myosin molecules per crown.

Phase I study of oral idarubicin given with a weekly schedule

Thirty one patients with solid tumors were entered into a phase I trial with idarubicin, a new anthracycline antibiotic with oral antitumor activity in animals. The drug was scheduled to be given for 4 consecutive weeks at doses ranging from 10 to 20 mg/m2. Leukopenia was the dose-limiting toxicity. Thrombocytopenia was occasionally seen. Since several patients could not receive the third and fourth administrations of the drug at 17.5 and 20 mg/m2, higher doses were administered only for 2 consecutive weeks. With this schedule, the maximum tolerated dose was 25 mg/m2 and leukopenia was again the dose-limiting toxicity. With both schedules, myelosuppression was highly variable and could not be related to prior therapy, bone or liver metastases, or performance status. Other toxicities were mild to moderate and were dominated by nausea and vomiting which were observed in 29% of the patients. Alopecia and mucositis were unfrequent and cardiac toxicity was not observed. Starting doses of 15 mg/m2 for 4 consecutive weeks or 20 mg/m2 for 2 consecutive weeks could be proposed for oral phase II studies with idarubicin, under careful pharmacokinetic monitoring.

[Polyneuropathy after cisplatin treatment]

Polyneuropathy developed in 7 of 87 women who had been treated with cis-platinum for ovarian carcinoma. Distal disturbances of sensitivity were clinically prominent, the emphasis being on disturbed vibratory perception and acrognosis. No relevant signs of motor dysfunction were noticed, neither clinically nor neurophysiologically. Sural biopsies taken from two women revealed a primary axonal degeneration, mostly affecting the myelinic fibres of large diameter. In 3 cases mild reversion was seen, and in 4 cases no definite reversion, of the disturbed functions - uncertain gait and clumsiness of the hands - during the follow-up period of 6 to 30 months.

Do vitamin D supplements improve the physical capabilities of elderly hospital patients?

A randomized double-blind controlled trial of the effect of vitamin D supplementation on the abilities of elderly hospital patients to carry out basic activities of daily life is described. Those patients included in the trial had plasma 25-hydroxyvitamin D concentrations which were low or low normal as judged by the normal range in young adults. After 2 to 9 months on the trial there was no significant difference in the performance of the control and treatment groups.

[NMR tomography in urology. Principles--technics--risks--areas of use]

NMR tomography is a new imaging method based on nuclear magnetic resonance. It is possible to obtain sectional views of the human body in all three planes without ionizing radiation. NMR can differentiate soft tissue better than CT, and large blood vessels can be simultaneously evaluated without using contrast medium. The pathological process could be imaged exactly in every examination. Due to the lack of image clarity caused by breathing movement, NMR is not superior to CT when using contrast medium in the epigastrium. Calculation of relaxation times T1 and 2 shows clear differences between tumor and normal tissue. However, contrary to initial expectations. NMR did not permit a type-specific diagnosis to be made. Three-dimensional images improve the process of staging tumors, especially in the retroperitoneal space and in the pelvis. As with CT, metastatic lymph nodes can only be demonstrated when they have reached a size of at least 1 cm. Further studies will be necessary to evaluate the validity of this new imaging method.

Measurement of plasma group I pepsinogens

Plasma group I pepsinogen (PG I) concentration is now a readily available non-invasive marker of gastric secretory function, with several potentially useful applications. Ninety-eight percent of control subjects had a plasma PG I below 115 ng/ml while values above this level were seen in 43% of duodenal ulcer patients. Plasma PG I levels below the observed normal lower limit of 30 ng/ml were seen consistently in patients with documented achlorhydria or pernicious anaemia. In 48 patients with a variety of upper gastrointestinal disorders there was a significant correlation between PG I pepsinogens and pentagastrin-stimulated maximal acid output. Changes in plasma PG I promise to be useful in evaluating both operations on the vagus and newer anticholinergic drugs, whilst in epidemiological and family studies these measurements seem well suited to explore duodenal ulcer heterogeneity.

Histone positions within the nucleosome using platinum labeling and the scanning transmission electron microscope

An approach to studying the organization of macromolecular complexes using heavy-atom labeling has been developed and applied to the problem of determining the positions of the histone proteins within the nucleosome. The approach is based on the capability of the scanning transmission electron microscope to image heavy atoms. Nucleosomes containing histones labeled with heavy atoms were prepared by lysine modification of selected histones with methyl (methylthio)acetimidate, followed by reconstitution of the modified histones into nucleosomes, and reaction of the reconstituted nucleosomes with chloroglycyl-1-methioninatoplatinum (II). Micrographs of the platinum-labeled nucleosomes were obtained using the scanning transmission electron microscope, and analyzed using both computer and manual techniques. The results of the analysis were 24 A resolution maps of the distribution of high electron scattering density picture elements (representative of platinum atoms) indicating the position of each histone. The significance of those results and the general applicability of the platinum-labeling techniques are discussed. Finally, a description of the histone positions within the nucleosomes is presented and discussed in relation to the current literature on nucleosome structure.

[Clinical significance of nuclear magnetic resonance tomography in urology. Initial experiences]

NMR tomography, which is based on nuclear magnetic resonance, enables the production of sectional images of the human body without ionising radiation. In particular, the field of urology places great hopes on this new procedures, since the contrast in soft tissue is considerably better than that of computer tomography. Our first clinical results confirm the advantages of the soft tissue differentiation as well as the possibility to judge the large vessels safely and simultaneously without contrast medium, which is advantageous in the detection of tumours in the retroperitoneum and in the region of the kidneys. An improvement of the preoperative staging of urological tumours can be achieved by means of primary three-dimensional images. Only after several years of experience with NMR tomography and all its variations will it be able to evaluate properly, to what extent clinically relevant diagnostic possibilities are offered by the analysis of relaxation values.

Incidence of metabolic bone disease in rheumatoid arthritis and osteoarthritis

Bone biopsy specimens from the iliac crest were obtained during surgical operations from 45 patients with rheumatoid arthritis (RA) and 41 with osteoarthritis (OA). Control material was obtained from 20 cases of sudden death due to cardiovascular disease. By both conventional histology and image analysis techniques about a quarter of all patients showed some osteoporosis. This was equally common among the OA and RA patients. It was more common among those with transparent skin and those taking corticosteroids. The only case showing mild osteomalacia suffered from OA. No gross differences were apparent between the groups in relation to plasma biochemical studies, diet, or exposure to sunlight. These results are in striking contrast to the high incidence of osteomalacia in RA reported from the west of England; moreover they do not confirm reports of hypercalcaemia among rheumatoid subjects. We conclude that the differences regarding osteomalacia are due to selection of cases. We find no evidence that osteomalacia is specifically associated with RA.

Discrimination of collagen types by methionine-specific stain

Chloroglycyl-L-methioninatoplatinum (II) (Pt-GLM) specifically labels methionine residues in collagen. Rat Type I and calf Type III collagen segment long spacing aggregates show differences in Pt-GLM bands, in agreement with known methionine positions. Reconstituted fibers formed from the same two collagens again demonstrate some differences in band pattern, which can be understood in terms of the amino acid sequences and the known packing of molecules in the fiber. Native collagen fibers have been extracted from rat and chick tendon (predominantly Type I collagen). These have been stained with Pt-GLM and studied in the Johns Hopkins STEM and a CTEM. Density profiles along the collagen fibers have been obtained, and those for successive 670-A repeats averaged, by computer programs. The position of peaks in the average density profiles for these various fibers show very good correlation with the known locations of Met residues. The band patterns and density profiles for native and reconstituted Type I fibers are very similar and differ from those of reconstituted Type III fibers.

Phase I study of carboplatin given on a five-day intravenous schedule

Twenty-six adult patients were entered in a phase I trial of carboplatin, a new cisplatin derivative with reduced potential for nephrotoxicity. All patients had solid tumors and the median World Health Organization performance score was 2 (0-3). Twelve patients had not received prior chemotherapy. The drug was administered as a 15-minute IV infusion, without pre- or posthydration, at daily doses of 40-125 mg/m2 for five consecutive days. Antiemetics were given only if needed. Thrombocytopenia and neutropenia were dose related and dose limiting. One patient died from septic shock at the highest dose level. Nonhemolytic anemia was also encountered. Nausea and vomiting were experienced by most patients but gastrointestinal intolerance was severe in only two patients. One patient had hypercreatininemia, which was minor and rapidly reversible. Other toxic effects consisted of negligible fatigue, paresthesia, pruritus, local pain, stomatitis, headache, and alopecia. Although none of the patients achieved a partial or complete response, antitumor effect was strongly suggested in two patients with thyroid and cervix cancer, respectively. Carboplatin is an attractive candidate for phase II trials. In good-risk patients, such trials could be initiated at a daily dose of 100 mg/m2 for five consecutive days every five to six weeks.

A phase II study of cisplatin in advanced gastric cancer

Twenty patients with recurrent or metastatic gastric adenocarcinoma and prior chemotherapy were treated with cisplatin, 60-120 mg/m2 as a 6-hr infusion repeated every 3 weeks. There were 4 partial responses in 18 evaluable patients. Seven patients had stable disease. Time to progression ranged from 6 to 28 weeks. Median WBC nadir was 3.2 X 10(3)/mm3 (range, 1.5-7.1) and platelet nadir 120 X 10(3)/mm3 (range, 13-220). A transient increase in serum creatinine was observed in 6 cases, and nausea and vomiting in all. We conclude that this drug is active in stomach cancer and that it warrants further trials in combination chemotherapy.

The evolution of Japanese management: lessons for U.S. managers

To find the key to the success of Japanese economic performance since World War II, Marsland and Beer explore five main "environmental" factors used by Japanese firms to build a successful human resources management approach: Japanese social values, the structure of private enterprise, the structure of labor markets, the historic development of the Japanese employment system, and the structure of Japanese management. This discussion shows that post-war Japanese management, faced with rapid change, introduced new concepts and techniques that reinforced and maintained certain social values and traditions that fit well with human resources management objectives. This skillful blend of new ideas with traditional values enabled the Japanese to achieve superior economic performance.

Concurrent or sequential use of cytotoxic chemotherapy and hormone treatment in advanced breast cancer: report of the Swiss Group for Clinical Cancer Research

In a trial of combined hormone treatment and cytotoxic chemotherapy 464 patients with advanced breast cancer were randomly allocated to either concurrent or sequential treatment. Cytotoxic drugs were given only if the antitumour activity of the hormone treatment was inadequate. Hormone treatment consisted of oophorectomy for premenopausal and tamoxifen administration for postmenopausal patients. Length of survival was better, though not significantly, in premenopausal patients (p = 0.29) treated concurrently and in postmenopausal women (p = 0.17) treated sequentially; the difference was highly significant (p = 0.003) only for postmenopausal women in the low-risk category. The findings suggest that postmenopausal women with metastatic breast cancer should probably be treated primarily by carefully monitored hormone treatment.

[Simultaneous or sequential hormono/chemotherapy and a comparison of various polychemotherapies in the treatment of metastatic breast cancer]

Since in the treatment of advanced breast cancer chemotherapy and the various hormonal manipulations seem recently to have reached a plateau of effectiveness when used alone, it is widely assumed that the combination of both treatment modalities could improve therapeutic results. The outcome is reported of a study encompassing 109 pre- and 297 postmenopausal evaluable cases with previously untreated metastatic breast cancer. The patients were randomized either to a concurrent chemo/hormonotherapy or to the hormonal treatment alone, chemotherapy being delayed until the occurrence of tumor progression. All patients were further randomized to 3 chemotherapy regimens (LMFP, LMP/FVP, LMFP/ADM) representing three different degrees of intensity. Pre-menopausal patients tend to live longer with the concurrent combination of both modalities, whereas postmenopausal patients fare better when chemotherapy is delayed until the occurrence of tumor progression with hormonotherapy alone. However, the differences in survival are statistically significant only in postmenopausal patients with a less aggressive tumor ("low-risk"). The more aggressive cytotoxic combinations elicit higher response rates than "minimal chemotherapy", but the differences translate only marginally into different survivals. These findings are discussed with regard in particular to their importance in establishing widely acceptable therapeutic rules for the treatment of advanced breast cancer.

Pharmacokinetics of VP16-213 given by different administration methods

Plasma pharmacokinetics of VP16-213 were investigated after a 30-60 min infusion in 14 adult patients and six children. In adult the elimination half-life (T1/2 beta), plasma clearance (Clp) and volume of distribution (Vd) were respectively 7.05 +/- 0.67 h, 26.8 +1- 2.4 ml/min/m2, and 15.7 +1- 1.8 l/m2; in children 3.37 +/- 0.5 h, 39.34 +1- 6.6 ml/min m2, and 9.97 +/- 3.7 l/m2. After repeated daily doses no accumulation of VP16-213 was found in plasma. The unchanged drug found in the 24 h urine after administration amounted to 20-30% of the dose. In eight choriocarcinoma patients plasma levels of VP16-213 were measured after oral capsules and drinkable ampoules. The bioavailability compared to the i.v. route was variable, mean values being 57% for capsules and 91% for ampoules. In one further patient, with abnormal d-Xylose absorption results, VP16-213 was not detectable in plasma after the oral ampoule dose. Steady state levels investigated in three patients after 72 h continuous VP16-213 infusion (100 mg/m2/24h) were around 2-5 micrograms/ml. Levels of VP16-213 were undetectable in CSF after i.v. or oral administration.

Johns Hopkins University, Baltimore, Maryland

The STEM can be used in one of three modes: 1) to image individual atoms; 2) to measure mass or molecular weight; 3) to collect electron energy loss spectra or x-ray fluorescence data. Heavy atom imaging is used to identify chemical groups in a molecule or macromolecules in an assembly. Specific labels have been developed for bases in nucleic acids. These permit localization of bound proteins on single strand nucleic acids. Pt(gly-L-met)Cl is a specific label for methionine residues of proteins as shown with the SLS aggregate of collagen. Lysine can be labeled as well if first methyl (methyl-thio-acetimidate) is coupled. This labeling procedure permits the localization of individual histones within a nucleosome. Mass determination can be used to answer crucial questions about biological assemblies. This is demonstrated by examples from muscle structure.

Performance appraisal: dilemmas and possibilities

Citing avoidance by the supervisor and defensiveness from the subordinate as the two main barriers to effective performance appraisal, the author suggests ways to minimize both. The emphasis is on discussing performance evaluation in a nonevaluative manner.

Direct proof of autoreactive T-lymphocytes in experimental allergical encephalomyelitis (EAE)

A microcytotoxicity assay to prove directly against myelin basic protein directed cytotoxic T cells has been developed. Spleen and lymph node cells of myelin basic protein immunized strain 13 guinea pigs were restimulated in vitro with basic protein for 5 days and used as attacking cells. Autologous spleen cells were coated with about 10(7) molecules basic protein by hydrophobic attachment, labelled with 51Cr and used as targets. Concentration dependent lysis (74% corrected lysis) was measured with attackers gained 12 days post immunization. Controls performed using unspecific (PHA) stimulated attackers and non BE coated target showed no lysis. Lysis was shown to be MHC restricted. The test may serve as a tool for the assay of human demyelinating diseases.

Effects of obstruction on single-kidney function: clinical and experimental results with 131I-hippurate and 99mTc-DMSA

In 35 patients, renography with 131I-o-hippurate (OIH) and static renal imaging with 99mTc-dimercaptosuccinic acid (DMSA) were used to measure differential renal function (DRF). The results were compared. Depth correction was applied in both methods. In non-obstructed kidneys (19 patients), both methods revealed nearly identical kidney function (r = 0.98). For completely obstructed kidneys (16 patients), OIH gave a significantly better DRF (14 ml/min) than DMSA. This small difference was of no clinical value. Because DMSA is reported to give unreliable results in unilateral obstructed kidneys, the right ureter was ligated in 8 dogs for 10 days and DRF was measured before and after opening an ureteral fistula. The difference in DRF was about 1% and could be accounted for by the amount of urinary radioactivity collected from the pelvic system after the ligature had been opened. Although DMSA appears to give reliable values in determining DRF, even in obstructed kidneys, OIH is preferred since total clearance values and postrenal urinary dynamics can be determined simultaneously.

[Phase-II-study with vindesine (desacetyl-vinblastine-amide-sulfate) in advanced malignant diseases]

53 patients with advanced and measurable cancerr were treated with vindesine in doses of 3 mg/m2 (pretreated) and 4 mg/m2 (non pretreated) i.v. once weekly. 48 patients are evaluable for response: of 14 patients with squamous cell carcinoma of the lung, 1 partial remission (PR), 1 minor response (MR) and 1 no change (NC) were observed. In 5 patients with large cell carcinoma of the lung: 1 NC. In 3 with adenocarcinoma of the lung: 1 MR. One patient with nasopharyngeal carcinoma had progressive disease. Stable disease was observed in a patient with carcinoma of the tongue and in a patient with adenocarcinoma of the esophagus. Four patients with colorectal carcinoma had progressive disease. One MR was observed in a patient with breast cancer, while all of the other 3 patients had progressive disease. One carcinoma of the penis was stable. One MR was observed in a patient with Hodgkin's disease. One PR was observed in a case with no-Hodgkin's lymphoma. A patient with acute leukemia had progressive disease. Among 9 patients with malignant melanoma, 3 had an MR and 1 patient had stable disease. A patient with fibrosarcoma had progressive disease. Observed toxicity included leukopenia, thrombocytopenia, anemia, paresthesias, constipation, jaw pain, nausea, stomatitis, alopecia, loss of taste, pruritus and skin rash, weakness and fatigue.

High-resolution scanning transmission electron microscope at Johns Hopkins

The scanning transmission electron microscope constructed at Johns Hopkins follows the general layout of the first instrument at the University of Chicago. It is currently operating at 50 kV with a resolution of about 3 A. Its detector scheme consists of scintillation crystals coupled to photomultipliers in such a way as to eliminate introduction of unnecessary statistical noise. A unique alignment scheme utilizes the spherical aberration of the objective lens.

Osmium-labeled polynucleotides: reaction of osmium tetraoxide, with poly-1,N6-ethenoadenylic acid

Osmium tetraoxide, in the presence of ligands such as pyridine and bipyridine, adds across the etheno bridge of 1,N6-etheno-9-methyladenine and poly-1,N6-ethenoadenylic acid. The Os:P ratio in the labeled polynucleotide was approximately equal to 1 when bipyridine was used as the stabilizing ligand. A similar study with polycytidylic acid, which had been partially modified with chloroacetaldehyde so that some bases were converted to 3,N4-ethenocytosine, gave an OS:P ratio of approximately equal to 1.3. Calf-thymus DNA, in which the adenine and cytosine bases were modified by chloroacetaldehyde, gave an Os:P ratio of approximately equal to 1 after 24 h. These results suggest that 3,N4-ethenocytosine will add two Os labels.

Electron microscopic determination of the binding sites of ribosomal proteins S4 and S8 on 16S RNA

Specific complexes.early in the assembly of Escherichia coli ribosomes were examined in the electron microscope. Complexes between ribosomal protein S4 or S8 and 16S RNA were fixed gently with formaldehyde and then denatured for protein-free spreading. Binding of each protein was found to preserve an easily recognized configuration in the RNA that allows the sites of protein binding to be determined. S8--16S RNA complexes have a single hairpin loop near the middle of the 16S RNA, 798 +/- 21 bases from one end and 657 +/- 26 bases from the other. S4-16S RNA complexes have two adjacent loops at one end with 250--450 bases. This structure probably arises from the simultaneous binding of S4 to three noncontiguous sites on the RNA. Measurements of these complexes place the binding sites near the 5' end, at more than one site 250--585 nucleotides from the 5' end and 645 +/- 45 bases from the 3' end. The latter site has not been recognized previously as a distinct S4 binding site. This approach allows the binding sites to be determined without knowledge of the nucleotide sequence and gives insight into the configuration of the rRNA in the assembling ribisome.

Vitamin-D metabolism in nephrotic syndrome

Plasma concentrations of 25-hydroxy-cholecalciferol (25-OHD3) and vitamin-D-binding globulin (V.D.B.G.) were significantly reduced in ten nephrotic subjects. V.D.B.G., which is undetectable in normal urine, was present in substantial amounts in the urine of each nephrotic subject. Administration of 3H-labelled cholecalciferol to three subjects resulted in the rapid appearance of the labelled vitamin in the urine, mainly as the 25-hydroxylated metabolite bound to V.D.B.G. in amounts which could largely account for the low plasma-25-OHD3. The plasma half-life of 25-OHD3 was substantially reduced in the nephrotic syndrome.

Osmium-labeled polynucleotides. The reaction of osmium tetroxide with deoxyribonucleic acid and synthetic polynucleotides in the presence of tertiary nitrogen donor ligands

Osmium tetroxide in the presence of pyridine or 2,2'-bipyridine has been found to react completely with the pyrimidine moieties (thymine, uracil, and cytosine) in polynucleotides. Pyrimidine osmate ester moieties, L2OSO4-pyrimidine, were formed. The OSO4 has added across the 5,6 double bond and L=pyridine or 1/2-bipyridine. The pyridine derivatives were not stable and decomposed slowly after the OSO4-pyridine reagent was removed by gel chromatography. Labeled poly(uridylic acid) lost osmium completely during gel chromatography unless the eluent contained a high concentration of pyridine. The products formed between OSO4-bipyridine and polynucleotides were much more stable and the OS label was retained during and after gel chromatography. Both the OSO4-pyridine and OSO4-bipyridine reagents reacted more rapidly than the OSO4-CN-reagent.

[Tubular response to antidiuretic plasma activity in the transplanted kidney (author's transl)]

Reabsorption of osmotically free water (TmcH2O) was studied in 10 patients after renal transplantation. A rising or constant free water reabsorption was observed under hydropenia and increasing tubular solute load. These findings suggest that in the transplanted kidney the functioning nephrons respond in a normal way to plasma ADH-activity. The excretion of plasma-hypotonic urine reflects decreased antidiuretic activity as in overhydration rather than tubular unresponsiveness to ADH. The excretion of plasma-hypertonic urine indicates tubular reabsorption of osmotically free water due to ADH, and this in general rules out overhydration. Daily estimation of urinary and plasma osmolality will be useful in judging the actual state of hydration after renal transplantation.

Vitamin-D status in long-stay geriatric patients

Very low concentrations of plasma-25-hydroxycholecalciferol, 25(OH) D3, were found in patinets in a long-stay geriatric hospital.