Effects of methionine sulphoximine on protein transients during heterocyst differentiation in Anabaena and Cylindrospermum spp

Heterocystous blue-green algae normally do not develop heterocysts if grown in the medium enriched with ammonium compounds. If such cultures are resuspended in a medium lacking combined nitrogen, the heterocysts differentiate within 24 h. L-methionine-DL-sulphoximine (MSO) has been reported to induce heterocysts even in the presence of ammonium chloride. The changes in gel electrophoresis protein profiles of cultures developing heterocysts, in the ammonium chloride enriched medium supplemented with MSO suggest that heterocyst differentiation in the presence of ammonium chloride and MSO may be due to derepression of heterocyst formation genes by MSO.

Adrenergic receptors in the hypothalamus concerned with control of arterial blood pressure: elicited by electrical and chemical stimulation

The study was made with the help of a chemitrode placed in various areas of the hypothalamus by the stereotaxic technique, for electrical and chemical stimulation (noradrenaline or isoprenaline) before and after microinjection of respective blockers (phenoxybenzamine or practalol). The results indicated the presence of both alpha and beta-adrenoreceptors in the anterior and dorsomedial hypothalamus producing a depressor response, and, the presence of alpha adrenoreceptors in the posterior and lateral hypothalamus producing a pressor response.

Effect of rifampicin on the heterocyst pattern in Anabaena ARM 314

Alteration in the pattern of heterocysts is observed when suspending ammonia-grown filaments of Anabaena ARM 314 in a medium devoid of combined nitrogen source but supplemented with rifampicin. Paired as well as strings of 3--9 heterocysts were noticed. The electrophoretic protein pattern of non-heterocystous, heterocystous and multiple heterocystous filaments revealed that multiple heterocystous filaments are characterized by the presence of two additional protein transients. It is speculated that rifampicin may lead to an alteration in the enzyme system involved in the synthesis of inhibitory substances or, alternatively, to the formation or activation of enzyme systems involved in the sequestering of inhibitory substances.

Protein-transients during heterocyst differentiation in Anabaena circularis and Cylindrospermum sp

The programme of protein synthesis accompanying cellular differentiation to the heterocyst following transfer of the blue-green algae Anabaena circularis and Cylindrospermum sp. (CBSC 1755) from ammonia-enriched medium to nitorgen-free medium was determined by polyacrylamide gel electrophoresis of whole proteins during successive intervals of differentiation. Besides this, total proteins and soluble amino acids were determined quantitatively. At least 4 sets of proteins can be distinguished on the basis of the time at which they are synthesized. Besides this, differentiation is distinguishable on the basis of the time at which their synthesis is turned off. The postmaturation stages revealed the synthesis of two sets in A. circularis andone in Cylindrospermum so. (CBSC 1755).

Clear cell carcinoma of cervix and vagina in progeny of women who received diethylstilbestrol: three cases with scanning and transmission electron microscopy

Three cases of clear cell carcinoma of the cervix and vagina in progeny of women administered diethylstilbestrol (DES) were studied ultrastructurally. The patients were young and had a positive history of maternal ingestion of DES during pregnancy. Similar ultrastructural features were observed in all cases. The neoplastic cells were arranged in solid nests or glands. Ultrastructural findings in these cases were similar to those of previously reported clear cell carcinomas of the ovary and endometrium, which seems to indicate a common Müllerian origin11, 16 as opposed to a mesonephric origin. 10 A transition between vaginal adenosis and the neoplasm was not observed.

The usefulness of the posterior oblique views in perfusion lung imaging

A total of 116 perfusion lung images, with and without posterior oblique views, were compared by four trained observers. There was a significant increase in the number of perfusion defects detected when the posterior oblique views were included. Pairs of projections of 89 lung images were read by the four observers. The percentage of correct readings for the posterior oblique views was 78% compared with 63% and 56% for the lateral views and AP views, respectively. Inclusion of the posterior oblique views as a routine part of the examination is recommended.

Radionuclide bone imaging in the surgical treatment planning of odontogenic keratocysts

Locally aggressive benign lesions of the jaws, such as odontogenic keratocysts and ameloblastomas, require complete excision in view of the high incidence of recurrence after incomplete surgical removal. Because of the limitations of conventional radiology as the sole technique for determining the extent of these lesions, the use of 99m-technetium-labeled bone-imaging agents is suggested. This method of defining the location of surgical margins is based on the agent's sensitivity as an indicator of subtle changes in bone metabolism. A case of an unusually large recurrent odontogenic keratocyst is presented in which the planning of the surgical procedure was predicated on the results of a bone scan of the jaws in addition to conventional radiology. This diagnostic procedure, especially when used in conjunction with conventional radiology, appears to be of considerable value in defining the extent of a variety of oral-maxillofacial bony lesions.

A histologic study of the placentas of patients with saline- and prostaglandin-induced abortion

A comparative histologic study of plancentas aborted after infusion of hypertonic saline or prostaglandin F2alpha into the amniotic cavity toinduce abortion is presented. Five placentas from spontaneous abortions served as controls. Saline abortion produced edema of the membranes; congested,dilated, thrombotic blood vessels; and subchorionic necrosis. Prostaglandin did not produce edema, but created marked vasospasm as evidenced by thickened vessels without subchorionic necrosis. The absence of serious sepsis and defibrination in prostaglandin-induced abortions is probably related to the absence of tissue necrosis.

Malignant melanoma of the cervix uteri

Primary malignant melanoma of the uterine cervix in a 70-year-old Negro female is reported. Only 9 other cases have been reported in the literature. The diagnosis, prognosis, and modern trends in therapy for this lesion are discussed.

Dual radionuclide study of myocardial infarction. Relationships between myocardial uptake of potassium-43, technetium-99m stannous pyrophosphate, regional myocardial blood flow and creatine phosphokinase depletion

The dual radionuclide myocardial distributions of imaging agents potassium-43 (43K) and technetium-99m stannous pyrophosphate (99mTc-PYP) were studied in a 24-hour closed chest canine infarct preparation. In multiple myocardial biopsies in 20 dogs, tissue levels of both radionuclides were compared to either an index of tissue viability (myocardial creatine phosphokinase [CPK] depletion), or to estimates of regional myocardial blood flow as measured by the microsphere technique. Myocardial 43K uptake in the ischemic and infarcted zone correlated well with both CPK depletion (r = 0.73) and microsphere estimates of relative blood flow. The correlation with microspheres was excellent in the transmural sample (r = 0.93) as well as endocardial (r = 0.97) and epicardial (r = 0.86) portions. On the other hand, 99mTc-PYP myocardial uptake did not correlate with the extent of CPK depletion. Maximal uptake was frequently noted in border zones with only moderate CPK depletion, while lesser degrees of 99mTc-PYP uptake were noted in the central infarct zone where CPK activity was lowest. The relationship of 99mTc-PYP uptake to microsphere regional flow estimates demonstrated that 99mTc-PYP uptake was maximal at flows of 0.3 to 0.4 of normal. At lower flows, 99mTc-PYP uptake fell toward normal levels. A similar relationship was noted between the distributions of 99mTc-PYP and 43K. In relatively high flow border segments (larger than or equal to 0.80 of normal), abnormal 99mTc-PYP uptake of five to six times normal persisted. The transmural distribution of 99mTc-PYP demonstrated that in low flow regions 99mTc-PYP uptake was primarily epicardial, while in the higher flow ischemic periphery of the infarct endocardial uptake predominated. Thus, while there is a direct correlation between cationic 43K myocardial uptake and regional myocardial viability and blood flow, no such direct relationship exists for 99mTc-PYP. This is in part based on the necessity for delivery of the radioactive tracer to the infarct zone.

Prostaglandins in mice with neuroblastoma

Male albino mice, with and without transplanted neuroblastoma C1300, had tissues analyzed for prostaglandins by radioimmunoassay. Highest prostaglandin concentrations occurred in tumor tissue, lungs, spleen, and kidneys. Tritiated prostaglandins A1 or E1 and tritiated arachidonic acid were injected intravenously. The concentration (organ/tumor) was higher at 1 hr than at 6 or 24 hr. Prostaglandin E1 and arachidonic acid localized principally in the kidney (likely the excretory organ) whereas prostaglandin A1 showed highest concentration in the liver.