Measurement of porphobilinogen in urine by a simple resin method with use of a surrogate standard

In this method for urinary porphobilinogen (PBG), urine is added to Bio-Rad AG1-X2 (200-400 mesh) acetate resin under alkaline conditions and mixed. After two water washes, the adsorbed PBG is eluted with acid and reacted with Ehrlich's reagent (p-dimethylaminobenzaldehyde). Quantification is by comparison of the color developed with that of a PBG standard similarly treated or of a calibrated methyl red solution. The precision of assay of PBG at 20 and 50 mumol/L is 1.4% and 0.9% within-batch and 4% and 3.9% between-batch, respectively. The analytical recovery is about 90%, a proportion that appears to be inherent in the resin method. The proposed method (y) agreed well with the method of Mauzerall and Granick (x; J Biol Chem 1956;19:435-46), yielding the regression equation y = 0.957x + 2.9 (r = 0.993, n = 26). Good agreement was achieved with results determined from the PBG and the methyl red standards. The proposed method is inexpensive, simple to perform, and suitable for routine and emergency use.

E. G. Boring's review of Brigham's A study of American intelligence: a case-study in the politics of reviews

In 1923, Carl Brigham published A Study of American Intelligence. E. G. Boring was asked by R. M. Yerkes to review the book; Boring agreed, saying that he would write a favourable review. Instead, he published a highly critical review in the New Republic. Contrary to the impression that psychologists and educators in the main supported Brigham's book, Boring's assessment of American Intelligence was in step with other reviews at that time. What remains open to question is why Boring agreed in the first place to write a positive review. Although this question remains unresolved, we lay out the specific details that led Boring to alter his review. Indeed, it is the `small' politics among professionals, and not the social politics of race, that persuaded Boring to pan Brigham's book.

Urine hydroxyproline: a potential error in quantification and a proposed procedure for its measurement

A modification of the colorimetric method of Bergman and Loxley for the measurement of urinary hydroxyproline using external aqueous hydroxyproline standards instead of individual internal standards is described. We show that this modification leads to an underestimation (average 32%) of hydroxyproline because suppression of colour development occurs in urine samples but not in aqueous standards. Use of an internal standard for each urine test corrects for this suppression. Recovery of hydroxyproline (250 mumol/L) added to 12 patient urine samples averaged 99% and the overall imprecision for the assay was then less than 5%. Modifications to the original hydrolysis and colour development procedures allow linearity to 1500 mumol/L. Details of our procedure are given.

Limited heterogeneity of rearranged T-cell receptor V alpha transcripts in brains of multiple sclerosis patients

The identification of activated T cells in the brain of individuals with multiple sclerosis (MS) indicates that these cells are critical in the pathogenesis of this disease. In an attempt to elucidate the nature of the lymphocytic infiltration, we used the polymerase chain reaction to amplify T-cell antigen receptor (TCR) V alpha sequences from transcripts derived from MS brain lesions. In each of three MS brains, only two to four rearranged TCR V alpha transcripts were detected. No V alpha transcripts could be found in control brains. Sequence analysis of transcripts encoded by the V alpha 12.1 region showed rearrangements to a limited number of J alpha region segments. These results imply that TCR V alpha gene expression in MS brain lesions is restricted.

Ward and laboratory assessment of two second-generation blood-glucose monitoring systems

We present an assessment of two blood-glucose monitoring systems--the Ames Glucostix reagent strips read on the Glucometer II and the Boehringer-Mannheim BM-Test-Glycemie 20-800 test strips read on the Reflolux II meter. Many nurses in the wards and a technologist in the laboratory assessed the systems. All operators achieved good precision with both systems at various glucose levels, the coefficients of variation for the technologist being less than 8% and those for the nurses being less than 11%. The Boehringer-Mannheim system gave good agreement with the laboratory values, with a mean bias of +0.14 mmol/L and limits of agreement between -1.38 mmol/L and +1.66 mmol/L. The Ames system gave poorer agreement, with a bias of +0.80 mmol/L and limits of agreement between -2.12 mmol/L and +3.72 mmol/L. Our study shows that both systems are capable of providing clinically-acceptable results when used by trained personnel. Although it took longer to use, the operators unanimously preferred the Boehringer-Mannheim system because generally it was easier to handle. This is due to a smaller amount of blood being needed which is easier to apply and to remove from the strip, and the cleaning material is not as likely to be left on the strip. Also, strip insertion is easier and there is sufficient time for this after the removal of blood.

Replication program of active and inactive multigene families in mammalian cells

In a comprehensive study, the temporal replication of tissue-specific genes and flanking sequences was compared in nine cell lines exhibiting different tissue-specific functions. Some of the rules we have determined for the replication of these tissue specific genes include the following. (i) Actively transcribed genes usually replicate during the first quarter of the S phase. (ii) Some immunoglobulin genes replicate during the first half of S phase even when no transcriptional activity is detected but appear to replicate even earlier in cell lines where they are transcribed. (iii) Nontranscribed genes can replicate during any interval of S phase. (iv) Multigene families arranged in clusters of 250 kilobases or less define a temporal compartment comprising approximately one-quarter of S phase. While these rules, and others that are discussed, apply to the tissue-specific genes studied here, all tissue-specific genes may not follow this pattern. In addition, housekeeping genes did not follow some of these rules. These results provide the first molecular evidence that the coordinate timing of replication of contiguous sequences within a multigene family is a general property of the mammalian genome. The relationship between replication very early during S phase and the transcriptional activity within a chromosomal domain is discussed.

Structure and function of Fc receptors on macrophages and lymphocytes

Cell surface receptors for the Fc portion of immunoglobulin confer on most cells of the immune system the ability to communicate with the humoral antibody response. These Fc receptors are known to be particularly important for the function of various effector cells, such as macrophages, since they are involved in mediating a variety of activities including endocytosis, antibody-dependent cellular cytotoxicity, and triggering the release of potent inflammatory agents. Over the past few years, a considerable amount has been learned about the structure and functions of the Fc receptors expressed by murine and human cells, due to the availability of specific anti-receptor antibodies and the isolation of Fc receptor cDNA clones. In general, these receptors are transmembrane proteins whose extracellular domains contain two immunoglobulin-like regions and are thus members of the immunoglobulin gene family. Their domain structure consists of a glycosylated extracellular domain, a single membrane-spanning segment, and a relatively long cytoplasmic domain. The cytoplasmic tails exhibit a surprising degree of variation in length and amino acid sequence. This review summarizes some recent information concerning the structure and expression of the Fc receptors found on murine and human macrophages and lymphocytes. Particular attention is paid to the functional activities of these receptors, and the possible relationship between receptor function and receptor structure.

Rate of replication of the murine immunoglobulin heavy-chain locus: evidence that the region is part of a single replicon

We measured the temporal order of replication of EcoRI segments from the murine immunoglobulin heavy-chain constant region (IgCH) gene cluster, including the joining (J) and diversity (D) loci and encompassing approximately 300 kilobases. The relative concentrations of EcoRI segments in bromouracil-labeled DNA that replicated during selected intervals of the S phase in Friend virus-transformed murine erythroleukemia (MEL) cells were measured. From these results, we calculated the nuclear DNA content (C value; the haploid DNA content of a cell in the G1 phase of the cell cycle) at the time each segment replicated during the S phase. We observed that IgCH genes replicate in the following order: alpha, epsilon, gamma 2a, gamma 2b, gamma 1, gamma 3, delta, and mu, followed by the J and D segments. The C value at which each segment replicates increased as a linear function of its distance from C alpha. The average rate of DNA replication in the IgCH gene cluster was determined from these data to be 1.7 to 1.9 kilobases/min, similar to the rate measured for mammalian replicons by autoradiography and electron microscopy (for a review, see H. J. Edenberg and J. A. Huberman, Annu. Rev. Genet. 9:245-284, 1975, and R. G. Martin, Adv. Cancer Res. 34:1-55, 1981). Similar results were obtained with other murine non-B cell lines, including a fibroblast cell line (L60T) and a hepatoma cell line (Hepa 1.6). In contrast, we observed that IgCh segments in a B-cell plasmacytoma (MPC11) and two Abelson murine leukemia virus-transformed pre-B cell lines (22D6 and 300-19O) replicated as early as (300-19P) or earlier than (MPC11 and 22D6) C alpha in MEL cells. Unlike MEL cells, however, all of the IgCH segments in a given B cell line replicated at very similar times during the S phase, so that a temporal directionality in the replication of the IgCH gene cluster was not apparent from these data. These results provide evidence that in murine non-B cells the IgCH, J, and D loci are part of a single replicon.

Clonal analysis of Escherichia coli O2:K1 isolated from diseased humans and animals

Forty-six Escherichia coli isolates of serotype O2:K1 from human urinary tract infections, chicken sepsis, and bovine mastitis were obtained from laboratories in England, Denmark, Sweden, and Finland. The bacteria were compared for outer membrane protein (OMP) pattern, lipopolysaccharide pattern, electrophoretic mobilities of enzymes, and flagellar serotype and were tested for fimbriation, biotype, hydroxamate production, hemolysin production, antibiotic resistance, plasmid content, colicin production, and virulence in neonatal rats. Isolates from humans were assigned to two clonal groups; poultry isolates belonged to one of these clonal groups, whereas bovine isolates belonged to the other. Poultry and human isolates of the same clonal group could be distinguished only by their plasmid content. Strains within this group were heterogeneous with respect to biotype, fimbriation, virulence, and flagellar serotype. Human and bovine isolates of the second clonal group were distinguished by a minor change in OMP pattern and by their plasmid content. It is concluded that meaningful clonal groupings are best recognized by the combination of OMP and electrophoretic enzyme patterns. The O:K serotype can aid in the recognition of important subclones, whereas the other microbiological properties tested can vary widely within clonal groupings. Furthermore, we conclude that certain O:K serotypes can contain very different clonal groupings having little genetic relatedness.

Use of histidine dipeptides and myoglobin to monitor adulteration of cooked beef with meat from other species

A new high performance liquid chromatography (HPLC) method was used to monitor the adulteration of cooked beef products with meat from other species. The ratio of the histidine dipeptides anserine and carnosine which are present in skeletal muscle, are so different between sheep, cattle, horse and kangaroo that detection of adulteration can be rapidly achieved by chromatography on a Partisil-10 SCX column with 0.2 M lithium formate, pH 2.9. To obtain a definitive identification of the adulterant it was necessary to also examine the electrophoretic mobility of myoglobin in sodium dodecylsulphate gels. One brand of "beefsteak" pie was found to actually be a mixture of mutton and beef.

Acute lethal graft-versus-host disease stimulates cellular proliferation in the adult rat liver

The present investigation was designed to analyse the effects of acute lethal graft-versus-host disease (GVHD) in adult (DA x LEW)F1 rats on cellular proliferation within the liver. The influence of the host thymus on GVHD-induced proliferation was also assessed. From 1-28 days after initiation of GVHD [3H]thymidine ([3H]-TdR) was injected i.v. and rats were killed one hour later. Percentage labelled cells (LI) of periportal infiltrating cells (PIC), hepatocytes (H), and sinusoidal lining cells (SC) were counted. Mean values for control rats were 0.3 +/- 0.1% (H), 0.4 +/- 0.1% (SC) and 0.2 +/- 0.1% (PIC). GVHD rats demonstrated a significant increase in LI of PIC (days 1-21), SC (days 2-17) and H (days 2-17). Most labelled cells in PIC were large lymphocytes. Peak LI values were 7.0 +/- 1.0% PIC (day 17), 6.8 +/- 0.9% SC (day 17), and 5.2 +/- 0.9% H (day 7), with all cellular compartments returning to near normal LI values by day 28. Stimulation of cellular proliferation occurred in all three liver cell compartments in neonatally thymectomized (TXM) rats. The intensity of GVHD-induced cell proliferation was significantly decreased at day 7 in all compartments and PIC was dramatically decreased at day 21 in TXM-GVHD rats as compared to non-TXM-GVHD rats. It is hypothesized that the general stimulation of hepatocyte cell proliferation in GVHD is related to the secretion of lymphokines by primarily donor and secondarily host T cells in the periportal infiltrate.

Breaststroker's knee: pathology, etiology, and treatment

Twenty-three breaststroke swimmers (ranging in age from 6 to 30 years old) with painful knees were examined. Underwater movies of these swimmers were taken. Eighteen swimmers had tenderness under the medial facet of the patella and over the medial femoral intercondylar ridge. Five of these 18 swimmers also had tenderness along the tibial collateral ligament. Five swimmers had tenderness just along the tibial collateral ligament. The onset of knee pain usually occurred within 3 years of the swimmers' beginning the breaststroke. Initially, the knees were only symptomatic when the swimmers performed the whipkick. As the swimmer continued the breaststroke, in spite of discomfort, the knees became symptomatic during other athletic and nonathletic activity. Breaststroke who had been using the whipkick for more than 8 years had clinical evidence of patellofemoral osteoarthritis. The site of pain in the knee was related to the way in which the whipkick was performed. Breaststroke without knee pain used a whipkick with characteristics that were consistently different than those of the symptomatic swimmers. Treatment of breaststroke's knee should be directed toward correcting the swimmer's whipkick. This approach is most likely to be successful if applied as soon as the swimmer becomes symptomatic.

The effects of iopodate on the serum iodothyronine pattern in normal subjects

The ingestion by normal subjects of 3 g of sodium iopodate, which is widely used in routine oral cholecystography, resulted in significant decreases of serum total and free T3 to a nadir on day 4 which averaged 43% and 40%, respectively, below initial mean values. Total and free rT3 increased markedly to a peak on day 3, 244% and 189%, respectively, above initial mean values. Total and free T4 and free T4 index rose to a maximum on day 4, but these changes were not statistically significant. A marked TSH increase was also seen, most evident on day 3. All these changes reverted to baseline values by day 14 at a time when serum total iodide was still markedly elevated. It is concluded that the changes observed after iopodate were not due to alterations in serum binding proteins nor to an effect on thyroid gland by the large iodine component of iopodate, but were consistent with an effect on the peripheral metabolism of T4. Difficulty in interpreting routine thyroid function tests may occur for up to 14 days after oral cholecystography with iopodate.