Vitamin B12 levels in erythrocytes in hypochromic anaemia

Vitamin B(12) levels in erythrocytes were low in untreated hypochromic anaemia, rose to abnormally high levels during therapy with iron alone, and finally slowly fell to normal. These changes were similar to those previously found in pernicious anaemia in response to vitamin B(12) therapy and in folate-deficiency anaemia in response to folic acid, thus changes in erythrocyte B(12) levels are not always due directly to changes in B(12) metabolism but may be secondary to changes in the levels of other haematinic factors.     

Histochemical and immunohistochemical study of diffuse large-cell lymphomas.

Ninety diffuse large-cell lymphomas (diffuse histiocytic lymphoma) were subclassified into B-cell, T-cell, and histiocytic types according to their enzyme histochemical and immunohistochemical characteristics. The B-cell type was characterized by presence of intracellular monoclonal immunoglobulin; negative or weakly positive diffuse acid phosphatase activity; and an occasional focal nodular pattern or preceding nodular lymphoma. The T-cell type was characterized by moderate, focal acid phosphatase activity; convoluted nuclear structure; and frequent preceding cutaneous manifestations. The histiocytic type was characterized by strong nonspecific esterases and diffuse acid phosphatase activity and presence of lysozyme and phagocytic activity. Most of the lesions (74 cases) were of the B-cell type. This group was further subdivided into follicular center cell type and B-cell immunoblastic sarcoma, according to the stage of cellular transformation. Preliminary clinical correlation suggests that the histiocytic type is most resistant to treatment. B-cell immunoblastic sarcomas were much more aggressive than neoplasms of the follicular center cell type.     

Role of volume-stimulated osmolyte and anion channels in volume regulation by mammalian sperm

The ability to maintain cellular volume is an important general physiological function. Swelling induced by hypotonic stress results in the opening of channels, through which ions exit with accompanying water loss (regulatory volume decrease, RVD). RVD has been shown to occur in mammalian sperm, primarily through the opening of quinine-sensitive potassium channels. However, as yet, direct evidence for the participation of anion channels in sperm RVD has been lacking. The chloride channel type ClC-3 is believed to be involved in RVD in other cell types. Using electronic cell sizing for cell volume measurement, the following results were obtained. (i) The anion channel blockers 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB), tamoxifen and 4,4'-diisothiocyanostilbene-2,2'-disulphonic acid (DIDS) increased hypotonic swelling in concentration-dependent fashion, whereas verapamil (P-glycoprotein inhibitor) had little effect. The most potent, NPPB and DIDS, blocked RVD without affecting cell membrane integrity at effective concentrations. (ii) When gramicidin was included to dissipate Na+/K+ gradients, major secondary swelling was observed under hypotonic conditions. This secondary swelling could be reduced by NPPB, and suppressed completely by replacing chloride in the medium with sulphate, an ion which does not pass through chloride channels. It was deduced that the initial hypotonic swelling activated an anion channel through which chloride ions could then enter freely down a concentration gradient, owing to the lack of a counter-gradient of potassium. (iii) Taurine, an osmolyte often involved in RVD, does not appear to play a role in sperm RVD because lengthy preincubation with taurine did not alter sperm RVD response. Our observations provide direct evidence that a chloride channel (possibly ClC-3) is involved in the process of volume regulation in mammalian sperm.     

How useful is weight reduction in the management of hypertension?

A group of previously untreated obese hypertensive patients were started on a weight reduction programme supervised by two dietitians working in a general practice surgery. It was stressed from the beginning of the programme that reducing blood pressure was the purpose of the diet. The results of follow-up after six months are presented together with results for a control group of obese hypertensive patients not receiving dietary advice or drug therapy, but being followed by the general practitioner. The weight, systolic blood pressure and diastolic blood pressure of the dieting hypertensive group were significantly lower than those of the non-dieting group after six months. However, the drop-out rate was significantly higher for the dieting group than for the non-dieting group.

The results of a separate comparison between a control group of obese normotensive patients following the same dietary programme and the group of dieting obese hypertensive patients are also presented. Attendance rates and weight loss achieved were significantly better for the hypertensive group than for the normotensive group after 12 months.

Weight reduction appears to be an effective first-line therapy for approximately 50% of obese patients with mild to moderate hypertension, and raised blood pressure appears to provide motivation for such patients to attend a dietitian's clinic and to lose weight.

     

Quality assurance programme for necropsies.

One hundred and eight consecutive necropsies were entered into a quality assessment of the necropsy service in this hospital using a previously published American protocol. Our results were similar to those of the American series, with confirmation of the major clinical diagnosis in 75%, but a higher rate of unsuspected diagnosis (44%). Necropsy was helpful in 58% of cases. The presentation of selected cases at a monthly conference on causes of death was valuable in correlating clinical and pathological findings, and in helping integrate both services.     

Colonization and maintenance of murine embryonic stem cells on poly(alpha-hydroxy esters)

The aim of this study was to determine the ability of various poly(alpha-hydroxy esters) to support the in vitro propagation of murine embryonic stem (ES) cells in an undifferentiated state. To this end, ES cell colonization, growth and Oct-4 immunoreactivity following a 48 h culture period upon poly((D,L)-lactide), poly((L)-lactide), poly(glycolide) and poly((D,L)-lactide-co-glycolide) (PLGA) were assessed. By the analysis of live and dead cell number indices and Oct-4 immunoreactivity, ES cell colonization rate during a 48 h culture period was found to be significantly greater on PLGA compared to all the other unmodified poly(alpha-hydroxy esters) tested. Surface treatment of all polymers with 0.1m potassium hydroxide revealed a significant increase in ES cell live numbers when compared to all unmodified polymers, thus revealing a correlation between polymer content, hydrophilicity and colonization rate. These data suggest that surface treated poly(alpha-hydroxy esters) may be employed for ES cell scale up procedures and in tissue engineering applications requiring the colonization of scaffolds by ES cells in an undifferentiated state. According to such applications, once the designated scaffold has been colonized, ES cell directed differentiation into the desired and fully differentiated, functional adult tissue may then be effected.     

Differential diagnosis of Taenia saginata and Taenia solium infection by PCR

We have designed species-specific oligonucleotides which permit the differential detection of two species of cestodes, Taenia saginata and Taenia solium. The oligonucleotides contain sequences established for two previously reported, noncoding DNA fragments cloned from a genomic library of T. saginata. The first, which is T. saginata specific (fragment HDP1), is a repetitive sequence with a 53-bp monomeric unit repeated 24 times in direct tandem along the 1, 272-bp fragment. From this sequence the two oligonucleotides that were selected (oligonucleotides PTs4F1 and PTs4R1) specifically amplified genomic DNA (gDNA) from T. saginata but not T. solium or other related cestodes and had a sensitivity down to 10 pg of T. saginata gDNA. The second DNA fragment (fragment HDP2; 3,954 bp) hybridized to both T. saginata and T. solium DNAs and was not a repetitive sequence. Three oligonucleotides (oligonucleotides PTs7S35F1, PTs7S35F2, and PTs7S35R1) designed from the sequence of HDP2 allowed the differential amplification of gDNAs from T. saginata, T. solium, and Echinococcus granulosus in a multiplex PCR, which exhibits a sensitivity of 10 pg.     

Monocytoid B cell lymphoma.

The clinical, light microscopic, ultrastructural, immunocytochemical and cytogenetic features of a case of monocytoid B cell lymphoma were investigated. The tumour initially affected the cervical and supraclavicular nodes, but 33 months later affected the left parotid salivary gland. The patient had subclinical Sjögren''s syndrome. The neoplastic cells showed characteristic morphological features and had peri- and interfollicular distribution in the node. Immunocytochemically the tumour cells were L26, 4KB5, MB2, CD19, CD20, CD22 and IgM/kappa positive. Prominent plasmablastic plasmacytoid differentiation was present in the recurrent tumour, suggesting an origin from post-follicular B cells. The lymphoma cells showed unusual cytogenetic abnormalities.