SEX DIFFERENCES IN ANAESTHETIC TOXICITY: FLUROXENE AND TRIFLUOROETHANOL IN MICE

A sex difference in postanaesthetic mortality after fluroxeneanaesthesia was found in Swiss Webster mice. More males succumbedthan females. This toxicity was biotransformation-dependentand could be reversed by pretreatment with "opposite" sex hormones.The toxicity of the fluroxene metabolite trifluoroethanol alsowas more marked in male mice, but was only partially influencedby microsomal enzyme inhibitors or stimulators, or by sex hormones.     

Evaluation of PTEN expression in cervical adenocarcinoma by tissue microarray

PTEN, a tumor suppressor gene, appears to negatively control the phosphoinositide 3-kinase signaling pathway for regulation of cell proliferation and cell survival. Somatic PTEN mutations are involved in a variety of tumors, including endometrial carcinomas, where PTEN expression is diminished. We examined expression of PTEN in a series of cervical adenocarcinomas and precursors, using tissue microarray (TMA) technology. TMA blocks were constructed using paraffin-embedded, formalin-fixed tissues from 273 samples derived from 16 normal cervical biopsies, 119 cases of invasive adenocarcinoma, and 20 high-grade cervical glandular intraepithelial neoplasia (CGIN). Fresh 3-mum sections were cut and immunostained with PTEN, and expression was correlated with clinicopathologic variables, including histologic subtypes of adenocarcinoma. In 137 patients, PTEN expression was positive in 121 (88%). The intensity and distribution of PTEN staining in the tumor tissue were more heterogeneous than those observed in the normal tissues. There were no significant differences in distribution or intensity of PTEN expression between adenocarcinoma in situ and subtypes of invasive adenocarcinoma. Our findings show that unlike the case in most endometrial carcinomas, PTEN expression is retained during the process of carcinogenesis in the glandular cervix. There is, however, evidence of altered distribution and intensity of PTEN expression in cervical adenocarcinoma cells.     

A ward token system: the illustrated version

In the previous issue of Apex (Vol. 1 No. 3,1973) we described how we had set about developing a positive reinforcement system to develop and maintain self-help and social skills in our children using tokens as conditioned reinforcers. This short illustrated note is to show some of the developments in pictorial form.     

CAROTID SINUS HYPERSENSITIVITY AND COMPLETE HEART BLOCK IN REITER'S SYNDROME

We describe a 42-year-old man with Reiter's syndrome who developedcomplete heart block only 5 wee after the onset of his illness.He was also noted to have carotid sinus hypersensitivity andevidence sinoatrial disease. There were no clinical signs orechocardiographic findings to suggest involvement of tl aorticroot or aortic valve. His arrhythmias were treated successfullywith a physiological pacemaker. The combination of sinoatrialand atrioventricular node disease suggests that the inflammatoryprocess Reiter's syndrome can produce widespread involvementof the conducting system. KEY WORDS: Reiter's syndrome, Arthritis, Carotid sinus hypersensitivity, Stokes-Adams attacks     

GROUP G STREPTOCOCCAL OSTEOMYELITIS OF THE SPINE

Two elderly men, one with definite and one with probable malignancy,presented with severe back pain. Both had osteomyelitis of thelumbar spine due to Group G streptococci which responded tochemotherapy. KEY WORDS: Streptococcus G, Spine, Osteitis, Elderly men     

APPLICATION OF MASS SPECTROMETERY TO THE SEQUENCING OF PROTEINS

Mass spectrometry is now established as a viable method for determing the sequence of amino acids in proteins. The approach involves chemical and enzymic digestion of the protein (as in classical methods) to small peptides (ten residues) which are then chemically modified to increase their volatility. The chemical modifications are (i) acetylation of basic nitrogen sites and (ii) Permethylation. The derivatives so obtained may be sequenced in the mass spectrometer as mixtures of several peptides. This is achieved by a temperature gradient in the mass spectrometer source, which effects partial, or total separation of the derivatized peptides according to their volatilities. In this way, much tedious separation work (sometimes the rate-determining factor in classical approaches) may be avoided. The sequencing process is carried out from the N-terminal residue, utilizing the preferential cleavage of the ionized petide at the amide bonds; each amino acid is associated with a characteristic mass increment and thus the sequence can be determined. Mass spectrometry is especially useful in the detection and characterization of novel amino acids which might otherwise be difficult to identify. Although almost all work to date has used electron impact mass spectrometery, in the future it is possible that newer methods of ionization, such as field desorption and chemical ionization, might be profitably used.     

MORTALITY OF JAMAICAN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS

A retrospective study of all patients with systemic lupus erythematosus(SLE) who died at the University Hospital of the West Indiesover a 14-year period is presented. The major cause of deathwas infection followed by renal failure. Gram-negative organismswere the major microbiological agents causing infections. Side-effectsof therapy were common, in particular bone marrow depressionand haemorrhage related to anticoagulants. It appears that controllingsevere lupus activity without increasing the risk of life-threateningcomplications remains an important goal in the treatment ofSLE. KEY WORDS: Systemic lupus erythematosus, Mortality, Infection, Anticoagulants, Jamaica