Do big breasts disadvantage women with breast cancer?

The present study was undertaken in order to discover whether patients with breast cancer in large breasts experienced a delay in the detection of their cancer due to the bulk of the breast and consequently presented with more advanced tumours compared with women with small breasts. Mastectomy specimens were weighed and their dimensions measured, in particular recording breast mass and breast thickness (anterior-posterior depth). Tumour diameter, the number of involved lymph nodes and the oestrogen and progesterone receptor levels were measured as prognostic indices. Although there was no difference in receptor status of tumours from large and small breasts, on presentation, patients with big breasts had larger tumours and more involved lymph nodes than women with small breasts, whether breast size was assessed by weight or thickness. Women with large breasts may therefore be expected to fare worse than those with small breasts.

Phorbol ester-mediated enhancement of hippocampal noradrenaline release: which ion channels are involved?

Enhancement of neurotransmitter release following phorbol ester-induced activation of protein kinase C (PKC) may be mediated by changes in ion conductance through the presynaptic membrane. This question was studied with rabbit hippocampal slices preincubated with [3H]noradrenaline ([3H]NA). NA release was evoked by pulses of either high K+ or Ca2+ (in the presence of high K+), or by electrical field stimulation. 4 beta-Phorbol 12,13-dibutyrate (PDB) increased and polymyxin B (PMB) reduced the K+-evoked NA release independent of the K+ concentration used for depolarization. The effects of PDB and PMB were not reduced by tetrodotoxin. PDB still enhanced the NA release triggered by short Ca2+ pulses in depolarized, axon terminal membranes (30 mM K+ and no Ca2+). The electrically evoked NA release was markedly enhanced by PDB even in the absence of Cl- in the medium or in the presence of the K+ channel blockers, tetraethylammonium, 4-amino- and 3,4-diaminopyridine. The inhibitory effect of the Ca2+ channel blocker, Cd2+, remained almost unchanged in the presence of PDB. It is concluded that PKC activation facilitates NA release in the hippocampus but not via presynaptic changes in Na+, K+ or Cl- currents. Whether phorbol ester mediates an increased intracellular Ca2+ availability, or whether a triggering 'normal' Ca2+ influx simply initiates, and synergistically supports, the PKC-mediated reactions leading to enhanced exocytosis, cannot be decided from the results of the present experiments.

Protein kinase C and presynaptic modulation of acetylcholine release in rabbit hippocampus

1. The involvement of protein kinase C in the presynaptic modulation of stimulated acetylcholine release was investigated in rabbit hippocampus. 2. Slices of the rabbit hippocampus, labelled with [3H]-acetylcholine, were superfused with medium and stimulated electrically during superfusion. 3. The protein kinase C activating phorbol ester 4 beta-phorbol 12,13-dibutyrate (4 beta-PDB) enhanced the electrically evoked tritium overflow in a concentration-dependent manner. Its biologically inactive 4 alpha-isomer was without any effect on transmitter release. 4. The protein kinase C inhibitor polymyxin B decreased the stimulation-evoked tritium overflow and counteracted the enhancement of release caused by 4 beta-PDB. 5. The stimulation-evoked tritium overflow was facilitated when the muscarine receptor antagonist atropine was present. The effects of both atropine and 4 beta-PDB, given in combination, were additive. 6. The net inhibition of the evoked tritium overflow caused by the muscarine receptor agonists carbachol and oxotremorine was similar, irrespective of whether 4 beta-PDB was present or not. 7. Similar results to those for muscarine autoreceptor-mediated inhibition, were obtained for inhibition of the stimulated tritium overflow caused by the adenosine receptor agonist (-)-N6-(R-phenylisopropyl)-adenosine ((-)-PIA) and the opioid receptor agonist ethylketocyclazocine (EKC). The net inhibition of both agonists was independent of the presence of the phorbol ester. 8. The above results provide further evidence for participation of a presynaptically located protein kinase C in the modulation of acetylcholine release. However, the modulatory mechanisms which are coupled to presynaptic receptors and mediate inhibition of release seem not to be directly affected by protein kinase C.

Studies in monkeys of attenuated hepatitis A variants

Three HAV variants, H2M20(35 degrees C), H2M20(35 degrees C) and H2M20K5(32 degrees C), were developed by passage in different tissue culture cells and at different temperatures. Virulence for monkeys was assessed by inoculating each of the variants into four monkeys. Weekly bleeding through 16 weeks post-inoculation was assayed for anti-HAV titers and SGPT as well as LDH5 activities. And in some monkeys liver biopsies were also studied. Seroconversion was induced in all of the inoculated monkeys. The anti-HAV titers tested at 16 weeks post-inoculation were: 40-640 with H2M20(35 degrees C), 40-160 with H2M20(32 degrees C) and 20-40 with H2M20K5(32 degrees C). These variants showed different levels of virulence/attenuation for monkeys. Variant H2M20(35 degrees C) showed no evidence of attenuation, variant H2M20(32 degrees C) retained slight virulence and variant H2M20K5(32 degrees C) showed no evidence of virulence for monkeys. Criteria are proposed for assay of HAV virulence tested in monkeys.

The effect of copper IUD on microcirculation of blood flow in rabbit uterus

A survey of the rabbit's normal microcirculation of blood flow volume in the endometrium and myometrium with or without a copper intrauterine device (IUD) was made. It was found through statistical analyses that the IUD stimulated the endometrium so that microcirculation of blood flow volume in the endometrium increased significantly, but it did not change the microcirculation of blood flow volume in the myometrium and in the opposite uterus.

Protein kinase C activation and alpha 2-autoreceptor-modulated release of noradrenaline

1 Effects of phorbol esters on the evoked noradrenaline release were studied in slices of the rabbit hippocampus, labelled with [3H]-noradrenaline, superfused continuously with a medium containing the reuptake inhibitor cocaine and stimulated electrically for 2 min (stimulation parameters: 2 ms, 24 mA, 5 V cm-1, 3 or 0.3 Hz). 2 The electrically-evoked overflow of [3H]-noradrenaline in the slices was increased in a concentration-dependent manner by the protein kinase C (PKC) activators 12-O-tetradecanoylphorbol 13-acetate (TPA) and 4 beta-phorbol 12,13-dibutyrate (4 beta-PDB). Phorbol esters, which do not activate PKC, 4-O-methyl-TPA and 4 alpha-PDB, showed no effect on neurotransmitter release. The effect of 4 beta-PDB was abolished in the presence of tetrodotoxin and in the absence of calcium. The PKC inhibitor polymyxin B inhibited the evoked noradrenaline release. 3 In the presence of 4 beta-PDB the inhibitory effects of the alpha 2-adrenoceptor agonist clonidine or the facilitatory effects of the alpha 2-adrenoceptor antagonist yohimbine seemed to be modified only by changes in the concentration of noradrenaline in the synaptic region. At a stimulation frequency of 3 Hz the inhibitory action of clonidine was reduced whereas the facilitatory effect of the yohimbine was even slightly enhanced by the phorbol ester. At 0.3 Hz and in the presence of 4 beta-PDB the effect of clonidine remained and that of yohimbine was strongly enhanced. 4 Pretreatment of the slices with islet-activating protein or N-ethylmaleimide significantly reduced the enhancement of noradrenaline release caused by 4 beta-PDB. It is possible that a regulatory N-protein is involved in steps following PKC activation. 5 These results suggest that PKC participates in the mechanism of action-potential-induced noradrenaline release from noradrenergic nerve terminals of the rabbit hippocampus and that effects on the autoinhibitory feedback system were not responsible for the 4 beta-PDB-induced increase of neurotransmitter release.

Studies on the transmission of human hepatitis A virus to stump-tailed monkey

The newly-caught stump-tailed monkeys (Macaca speciosa) with negative antibody to hepatitis A were inoculated with human hepatitis A virus. The following findings were observed in the monkeys after inoculation: (i) the elevation of activities of the serum glutamic-pyruvic transaminase, lactate dehydrogenase and its isoenzyme (LDH5), (ii) the seroconversion of antibody to hepatitis A virus. (iii) the shedding of hepatitis A antigen in feces. These findings show that the stump-tailed monkey (Macaca speciosa) is susceptible to infection of human hepatitis A virus. The virus recovered from the feces of the infected monkey, named as Hang-zhou A-1A strain of hepatitis A virus, has experienced two generations of successful transmission in monkeys.

Susceptibility of monkeys to human hepatitis A virus

A stump-tailed monkey, newly caught and without antibody to hepatitis B virus (HAV), was successfully infected with human HAV. The following alterations were observed in the monkey's functions: (1) elevation in activities of serum glutamic pyruvic transaminase, lactate dehydrogenase, and its type 5 isoenzyme (electrophoretically the fastest moving); (2) development of antibody to HAV; and (3) shedding of HAV antigen in feces. The virus isolated from the monkey, designated the Hangzhou A-1A strain of HAV, was serially transmitted to two other stump-tailed monkeys. Thus, the stump-tailed monkey (Macaca speciosa) is susceptible to infection with human HAV.