Mass and in situ molar activity of tyrosine hydroxylase in the median eminence. Effect of thyroidectomy and thyroid hormone replacement

The effects of thyroidectomy and thyroid hormone replacement on the mass and in situ molar activity of tyrosine hydroxylase (TH) in the median eminence (ME) and superior cervical ganglia (SCG) of male rats were investigated. The tissue specificity of these effects were evaluated by comparing the ME with the superior cervical ganglion (SCG). All animals were thyroparathyroidectomized (Tx) or sham Tx. Tx rats were treated daily for 3 weeks with 0.15 M NaCl (solvent vehicle) or L-thyroxine (T4). Two doses of T4, 10 and 100 micrograms/day/kg BW, were used. Sham Tx rats were treated with 0.15 M NaCl. All animals were studied on the day following the last treatment. The mass of TH was determined using an immunoblot assay, and the in situ activity of TH was calculated from the rate of intracellular accumulation of L-dihydroxyphenylalanine (DOPA) after administration of an inhibitor of DOPA decarboxylase activity. In the ME, thyro-parathyroidectomy resulted in a 40% increase in the mass and a 100% increase in the in situ molar activity of TH over that of sham Tx rats. Compared to Tx animals given 0.15 M NaCl, Tx rats treated with a low dose of T4 (10 micrograms/day/kg BW) had a reduced quantity of TH in the ME, but the molar activity of the enzyme was increased. Treatment of Tx rats with a high dose of T4 (100 micrograms/day/kg BW) restored TH mass but not the in situ activity of TH in the ME to the level seen in sham Tx rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Structural analysis of poly(3-alkylthiophene)s

Poly(3-hexylthiophene) (PT6), poly(3-octylthiophene) (PT8), poly(3-decylthiophene) (PT10) and poly(3-dodecylthiophene) (PT12) were synthesized by electrochemical and chemical polymerization. Investigation of these polymers by means of gel permeation chromatography indicates that the polymers prepared from the different monomers under similar conditions do not differ substantially considering molecular weight and molecular weight distribution. Bimodal distributions were found for electropolymerized polymers, and with increasing polymerization time, the high-molecular-weight and probably highly branched fraction increased relatively to the low-molecular-weight fraction. The microstructure of the polymers was investigated by nuclear magnetic resonance, and it has been found that the polymers exhibit more types of structural units than expected from a simple coupling of adjacent thiophene moieties in 2,5′-positions. Chemical oxidation with iron trichloride in chloroform gave soluble, high-molecular-weight poly(3-alkyl-thiophene)s with a rather low amount of irregular couplings, and these more regular polymers exhibited a higher degree of crytallinity. Room temperature conductivities of the oxidized polymers were between 0,1 and 30 S/cm depending on the polymerization conditions, but these values were rather independent of the length of the alkyl substituent.     

Examination of spinal cord in diseases of the craniocervical junction and high cervical spine.

A simple necropsy technique for the removal of the craniocervical junction was devised: a relatively small specimen comprising part of the clivus, the foramen magnum, and cervical vertebral canal is removed in one piece with the medulla and spinal cord inside, and examined systematically after fixation. This method, used in a series of patients with chronic craniocervical instability, allows both good clinicopathological correlations to be made and histological changes in the lower medulla or upper cervical cord segments to be related to sites of extrinsic compression.     

Mortality study of asbestos cement workers

The present study describes cause-specific mortality of asbestos cement workers in the Emilia Romagna region of Italy. The cohort included workers in ten factories, most of which started operating between 1955 and 1965. Asbestos, mainly chrysotile, constituted 10%–20% of the dry component of the mixture. Crocidolite range between 5% and 50% of total asbestos. Asbestos concentrations up to 44 ff/cc were reported prior to 1975, while in recent years they have usually been below 0–1 ff/cc. The cohort included 3341 workers who had at some time been employed in the ten factories under study. Their mortality experience was compared with that of the population resident in Emilia Romagna. Vital status was ascertained at 1989. Seventy-three subjects were lost to followup (2.2%). Mortality from all causes and from all types of cancer was increased in the cohort. Malignant neoplasms of the respiratory tract showed a significant increase (SMR: 134; 90% confidence interval: 101–175; 40 observed) due to lung cancer (SMR: 124; 90% confidence interval: 91–166; 33 observed) and neoplasms of the pleura, mediastinum, and other parts of the respiratory tract (SMR: 602; 90% confidence interval 237–1267; 5 observed). The discrepancy between observed and expected mortality mainly concerned subjects with at least 20 years of employment in the factories. Five more cases of histologically confirmed mesothelioma occurred after the end of follow-up.     

Complications of intravesical bacillus Calmette-Guerin: a case report.

Bacillus Calmette-Guerin (BCG) is the most effective agent currently available to treat superficial bladder cancer. However, this form of therapy is not without potential serious or fatal complications. In addition to the potentially toxic systemic side effects attributed to hematogenous absorption of the bacillus, direct upper tract seeding may occur in patients with vesicoureteral reflux. We report on a patient treated with intravesical BCG for bladder cancer in whom unilateral necrotizing granulomatous pyelonephritis developed. Although severe, this complication is rare and we conclude that reflux is not a contraindication for intravesical BCG therapy.     

Genetic ablation of the t-SNARE SNAP-25 distinguishes mechanisms of neuroexocytosis.

Axon outgrowth during development and neurotransmitter release depends on exocytotic mechanisms, although what protein machinery is common to or differentiates these processes remains unclear. Here we show that the neural t-SNARE (target-membrane-associated-soluble N-ethylmaleimide fusion protein attachment protein (SNAP) receptor) SNAP-25 is not required for nerve growth or stimulus-independent neurotransmitter release, but is essential for evoked synaptic transmission at neuromuscular junctions and central synapses. These results demonstrate that the development of neurotransmission requires the recruitment of a specialized SNARE core complex to meet the demands of regulated exocytosis.     

Myxoglobulosis of the appendix

Myxoglobulosis is a rare morphologic variant of appendiceal mucocele characterized by intraluminal mucinous globules of the appendix. Most reported cases have presented clinically as an acute abdomen or as an incidental laparotomy or autopsy finding. We report a case of myxoglobulosis in a 32-year-old man who presented with an extra-appendiceal mass following a 10-year symptomatic course. Laparotomy disclosed a pericecal collection of opaque, white globules originating from a perforated appendix walled off by fibrous adhesions. The globules exhibited some histologic and staining properties at variance with those described in previous reports. These findings suggest that myxoglobulosis may be more heterogeneous pathogenetically than the distinctive gross appearance of the lesion would indicate.