Drug-induced papillary necrosis: electrolyte excretion and nephron heterogeneity

The functional expression of papillary necrosis was investigated in rats following administration of 2-bromoethylamine hydrobromide (BEA). The percentage of filtering superficial and juxtamedullary nephrons was assessed using the qualitative Hanssen technique. There was a marked decrease in the percentage of filtering juxtamedullary nephrons 24 h after the induction of papillary necrosis (as compared with control rats), which was blunted in salt-loaded animals. The percentage of filtering superficial nephrons was the same in all three groups. BEA administration to normal rats was associated with a significant increase in sodium, chloride, phosphate, and calcium excretion. BEA administration to rats on a chloride-restricted diet was associated with chloride wastage. These animals also failed to adapt to a low chloride diet as late as 7 days after the administration of BEA. The phosphaturia observed in intact rats treated with BEA was abolished by parathyroidectomy. BEA-treated rats were able to adapt to a low phosphate diet and to a low magnesium diet. These data demonstrate that papillary necrosis is associated with profound impairment of juxtamedullary nephron filtration and with chloride wastage. In the absence of the papillary structures adaptation to phosphorus or magnesium deprivation is still possible.

Use of ganglioside affinity filters to identify toxigenic strains of Clostridium botulinum types C and D

Clostridium botulinum neurotoxin is synthesized by toxic clones grown anaerobically on ganglioside affinity filters. The toxin binds to the filters and is detected by reaction with 125I-immunoglobulin G from type-specific antitoxin. Toxin spots from culture filtrates were similarly identified. The C. botulinum type C and D strains were selected for developing this affinity filter assay because synthesis of the C1 and D toxins is bacteriophage dependent. Toxigenic clones were distinguished from prophage-cured atoxigenic derivatives. These studies represent a first step toward the development of a general nonbiological screening procedure for identifying botulinal toxin and toxigenic cells. The affinity filter methodology should facilitate genetic analysis of the basis of C. botulinum toxicity.

Ultrasound in the evaluation and diagnosis of jaundice

Our experience in the evaluation and diagnosis of jaundice by ultrasound in a consecutive series of patients examined in the past year is reported. A final diagnosis is available in 49 patients with obstructive jaundice and 41 patients with nonobstructive jaundice. The accuracy of separation into these two groups is 97% in this series. We would like to stress the value of ultrasound as a complete investigation in many jaundiced patients. In this series a full diagnosis of the cause of jaundice was achieved in 58% of patients.

Control of bacteriophage lambda repressor establishment transcription: kinetics of l-strand transcription from the y-cII-oop-O-P region

The kinetics of lambda l-strand repressor establishment RNA synthesis were measured from the y-cII region of induced tof- prophage. The activity of the repressor is epistatic to the expression of gene tof coding for the antirepressor (Tof). The activity of Tof, is epistatic to the expression of repressor gene cI transcription from Prm and the expression of repressor establishment transcription from a site 600 to 800 nucleotides upstream from Prm. Three modes of l-strand rex-cI-tof-y-cII-oop transcription occur: (a) Prm promoted cI-rex mRNA synthesis from noninduced prophage, (b) coordinate lit and oop synthesis from induced tof+ prophage and (c) establishment transcription from induced tof- prophage. The synthesis or stability of oop RNA is much reduced from induced tof-, compared with tof+ prophage. The oop transcription from tof- prophage is not coordinate with RNA synthesis from the y-cII interval. The y-cII-(oop) portion of the establishment transcript appears more unstable than the translated downstream copy of genes rex-cI. The initiation of any repressor establishment transcription requires the products of lambda genes cIII, cII, P and Escherichia coli genes dnaB, dnaG, but not actual lambda DNA synthesis. This result demonstrates that common factors, i.e. replication gene products, are required for the initiation of establishment transcription, lambda replication and lit, oop RNA synthesis; and explains why cIII+ cI+ cII+ replication defective phage lysogenize poorly at low multiplicities of infection. The cIII and cII products were shown to act after an earlier replication initiation or activation event. Repressor establishment transcription and repressor mRNA synthesis from Prm (from induced cI- tof-, cIII- cI- tof- or cI- tof- cii- prophage) are amplified by gene dosage. The extent of lysogenization of E. coli by lambda cIII-, cII- or replication minus mutants, defective for initiation of establishment synthesis, is attributed to gene dosage dependent transcription from Prm. The mechanism by which Tof inhibits the initiation of establishment transcription does not appear to require repression of RNA synthesis from PL and PR. RNA synthesis from these promoters is blocked by renaturation of the repressor 5 min after induction, before establishment transcription is detected; however, establishment RNA synthesis measured between 12-13 min after induction, i.e. 7 min after renaturation of the repressor, is only partially reduced.

Control of lambda repressor prophage and establishment transcription by the product of gene tof

Control of expression of the bacteriophage lambda (lambda) repressor was studied by measuring repressor transcription in noninduced and derepressed lambda lysogens. Three distinct modes of leftward transcription were observed from cI and the adjacent genes associated with the control of repressor synthesis: The prophage or maintenance mode Prm-cI-rex-ti repressor transcript occurs from repressed lysogens; the oop (Po-oop-to) transcript, and the lit (lit-ti) RNA, from the distal half of gene rex, both occur from induced tof+ prophage; the repressor establishment mode of transcription is observed throughout the rex-cI-tof-y-cII-oop interval between Po and ti from induced tof- prophage. The overall level of establishment mRNA synthesis is partially template dependent. However, the actual initiation step for repressor establishment transcription requires the participation of the lambda cIII, cII products, and also either requires the activity of Escherichia coli replication proteins, or is triggered by a replication initiation event. The cII cIII products do not positively stimulate de novo initiation of establishment transcription, but rather act after an initial replication-dependent step. Initiation of the establishment mode of repressor transcription is totally inhibited by more than 125-fold, in an all or none fashion, by the lambda antirepressor (Tof), the product of gene tof (cro). Since Tof only reduces the in vivo rightward transcription of cII from Pr by about 2-fold, we suggest that Tof inhibits repressor establishment transcription by either uncoupling the replication and cII-cIII dependent events, or by inhibiting the activity rather than the expression of the cIII, cII products. Our results do not fully support either of the present hypotheses that establishment transcription is initiated from the hypothetical Pre promoter in the y-interval, or arises through antitermination of the oop RNA. Since the initiation and control of the establishment mode of repressor transcription parallels the control of lit RNA synthesis, we propose a common mechanism underlies the initiation of these transcripts.

Measurement of serum TSH and thyroid hormones in the management of treatment of thyroid carcinoma with radioiodine

1. Serum levels of TSH, thyroxine (T4) and triiodothyronine (T3) have been measured during treatment and follow-up of patients with thyroid carcinoma. 2. Serum TSH and thyroid hormone levels were initially normal. Three weeks after total thyroidectomy, TSH was elevated in about 50% of patients and after a subsequent therapy dose of 131I it exceeded 30 mU/l in 90% of patients. Occasionally, TSH did not rise until after the second dose of 131I. Low serum T4 and T3 concentrations were associated with the increase of TSH. 3. Withdrawal of l-thyroxine replacement treatment in athyreotic patients for four weeks before test doses of 131I, led to falls of serum T4 and T3 concentration and a progressive rise of serum TSH after the first weeks but there was considerable variation in the final level reached. In the majority, values greater than 30 mU/l were attained despite some patients having received l-thyroxine for many years. A few patients on prolonged thyroxine maintenance had little or no increase in TSH despite considerable reduction in serum T4 and T3 concentrations. 4. The 131I concentration (muCi/g) developed in tumour tissue was also examined in relation to the serum TSH level. In general a tumour should not be considered as incapable of concentrating 131I adequately until serum TSH levels have exceeded 30 mU/l.

A successful medium for maintaining earthworms

Several different culture media were tested for their effect on weight and viability of earthworms ( Lumbricus terrestris). A medium containing pulverized newspaper, pelletted rabbit food, walnut meal, peanut oil, topsoil and coffee grounds supported life and growth for 62 weeks, and improved the condition of degenerated worms.

The detection of Clostridium botulinum type E in smoked fish products in the Pacific Northwest

A total of 240 samples of smoked fish products, including salmon, sturgeon, black cod, and others, produced by 28 small processors in the Pacific Northwest, were purchased from retail outlets and examined culturally for the presence of Clostridium botulinum. The culture filtrates from 47 of the samples (19.6%) were toxic to mice and in 11 samples (4.6%) type E botulinal toxin was identified by means of specific antitoxin. No other type of botulinal toxin was found. Pure cultures of the organism were isolated from three samples.

Incidence of Clostridium botulinum type E in salmon and other marine fish in the Pacific Northwest

Salmon, sole, cod, oysters, clams, and crabs from ocean waters along the coast of Oregon and Washington were examined for the presence of Clostridium botulinum type E. The organism was detected by identification of the type E toxin in enrichment cultures of the viscera of individual fish. Of 369 salmon specimens, 48 yielded cultures containing toxin lethal to mice, and almost half of the toxic cultures were shown to contain botulinal toxin, chiefly type E. Eighteen of 113 sole and cod specimens, 4 of 22 Dungeness crab specimens, 5 of 16 oyster specimens, and 27 of 115 clam specimens gave rise to cultures containing botulinal toxin which was usually type E, although types A and B were occasionally encountered.