Carbonic anhydrase activity in the blood of adult sheep, fetal sheep and lambs

The activity of carbonic anhydrase (E.C.4.2.1.1) (CA) has been measured in the blood of adult and fetal sheep and lambs. The mean activity in adult sheep was 0.89 enzyme units (EU) per 100 micrograms of Hb. The activity in fetal sheep aged 90 days was just below 20% of this and in fetuses near full term was just under 40% of the mean adult level. The regression line gave an increase of CA activity (per 100 micrograms Hb) of 0.004 EU/day. The appearance of CA in fetal blood normally occurred before any detectable production of adult Hb. One aberrant fetus showed early development of the adult pattern in the red cells, having adult type Hb and adult levels of CA during the period of 116-128 days of fetal age. In the period after birth the CA level in the blood rose rapidly, reaching the adult level 30 days after birth. During this period activity per 100 micrograms HB increased by 0.014 EU/day, significantly faster than during fetal life.     

Virus protein changes and RNA termini alterations evolving during persistent infection

Cloned infectious vesicular stomatitis virus isolated following 5 years of persistent infection of BHK21 cells in vitro exhibits a number of peptide map changes in the G protein (spike glycoprotein), the M protein (membrane matrix protein) and the N protein (nucleocapsid structural protein). Only slight alterations have occurred in the peptide maps of the two VSV polymerase-associated proteins L and NS. Dideoxy sequencing of the 3′ ends of the cloned virus originally used to establish the persistent infection, and of the cloned virus recovered following 5 years of persistence, shows one base substitution in the three base junction between the 3′ leader sequence and the N protein-coding region. Repeated lytic passages of virus recovered from persistent infection led to no oligonucleotide map changes after 30 passages, but two map changes were present after 102 and remained after 133 lytic passages in BHK21 cells in vitro. Only one of these represented reversion to the original map position, and this “mutant” virus still exhibited a temperature-sensitive small plaque phenotype. Finally, the mutated virus recovered after more than $\text{5}\text{1}\text{2}$ years of persistent infection is now so slow-growing that it can establish persistent infection of BHK21 cells in the absence of DI particles (although DI particles are present constantly once the cells recover from the initial cytopathology).     

Hyperthermic treatment of chromomycosis with disposable chemical pocket warmers

A case of chromomycosis in which hyperthermia proved effective is reported. The patient was a 56-year-old male bean curd maker who, without any previous history of minor trauma, developed on the extensor side of the left upper arm an eczematous lesion that underwent gradual radial expansion. The lesion showed a well-defined, 7×10 cm infiltrated erythematous plaque with the central area healed and, at the upper and lower borders, adherent scales and crusts on the surface. Histological examination revealed granulomatous changes in the dermis, as well as sclerotic cells within giant cells and microabscesses. On culturing,Fonsecaea pedrosoi was isolated. The patient was treated with disposable chemical pocket warmers, which were secured over the lesion with a rather tight elastic bandage, so that they kept the affected area warm for 24 hours a day. After a month of such hyperthermic treatment, the erythema and infiltration had decreased considerably, and microscopic examination and culture of the crusts both yielded negative results. Examination of biopsy specimens of the lesion after the third month showed that it had cicatrized. The treatment was stopped after 4 months, and no relapse occurred. We also summarize the published results of local hyperthermic treatment of chromomycosis in Japan.     

Selecting representative model micro-organisms

Background  

Micro-biological research relies on the use of model organisms that act as representatives of their species or subspecies, these are frequently well-characterized laboratory strains. However, it has often become apparent that the model strain initially chosen does not represent important features of the species. For micro-organisms, the diversity of their genomes is such that even the best possible choice of initial strain for sequencing may not assure that the genome obtained adequately represents the species. To acquire information about a species' genome as efficiently as possible, we require a method to choose strains for analysis on the basis of how well they represent the species.     

Low-density lipoprotein preparation by combined diafiltration and ultracentrifugation

A method for isolating low-density lipoprotein by combining diafiltration and ultracentrifugation is described. Diafiltration separates plasma components by use of an ultrafiltration membrane that excludes particles of molecular weight greater than 300,000. The retentate is concentrated three- to fourfold by ultrafiltration, allowing large-scale preparation of low-density lipoprotein. Low-density lipoprotein prepared in this manner is similar in physical, chemical, and biologic properties to low-density lipoprotein isolated by sequential density ultracentrifugation alone. When low-density lipoprotein, prepared by either method, was added to human umbilical vein endothelial cell cultures, no cytotoxicity was observed. The techniques described reduce the demand on multiple rotors and ultracentrifuges for large-scale preparation of low-density lipoprotein suitable and often needed for tissue culture studies.     

Red–blue plots for detecting clusters in count data

A new index and four new graphical displays, termed "red–blue" plots, are presented to study and measure clustering in spatially referenced count data. The index can detect clusters in the form of patches, comprising several nearby large counts, and in the form of gaps, comprising several nearby small counts. The new methods quantify the degree to which the count for each sample unit contributes towards the overall degree of clustering, either as part of a patch or as a gap; provide tests of nonrandomness to detect clustering; and facilitate a comprehensive definition of the size and dimension of a cluster. The methods are illustrated using aphid field data.     

Identification of HLA-B44 subtypes associated with extended MHC haplotypes

The HLA class I antigen B44 is found in each of two different extended major histocompatibility haplotypes (allele combinations of HLA-B, HLA-DR, and complement genes BF, C2, C4A, and C4B in linkage disequilibrium). Using isoelectric focusing, two variants of HLA-B44 were identified. The basic variant was found in all cell lines with the extended haplotype HLA-B44, DR7, FC31, and the acidic variant in all cell lines with the extended haplotype HLA-B44, DR4, SC30. The occurrence of each antigen variant with a unique extended haplotype explains previous observations concerning the nonrandom association of B44 variants with DR antigens.