Hb Malm? [beta-97(FG-4)His-->Gln] leading to polycythemia in a Dutch family

We have examined six individuals from a two-generation Dutch family for a suspected hemoglobin (Hb) abnormality. The propositus presented with polycythemia and complained of persistent weakness, headache, and epistaxis. All family members initially showed a normal Hb-electrophoretic pattern, but on isoelectric focusing, three of them displayed a fast-moving band associated with high packed red cell volumes (PCV) and increased red blood cell count. The Hb mutant was analyzed at the DNA level by specific gene fragment amplification (PCR), followed by direct DNA sequencing, and the mutation was confirmed by restriction enzyme analysis. We found a C-->G transversion (CAC-->CAG) at codon 97 of the beta-chain, which corresponded to the His-->Gln amino acid substitution previously described as Hb Malm?. We report here the clinical history of the patient, the effects of phlebotomy treatment, and the effect of subnormal iron conditions on the erythropoietic recovery after phlebotomy. The mechanism responsible for the induction of the higher oxygen affinity is discussed, as are some aspects concerning the occurrence, pathology treatment, and the genetic risk of Hb variants with high O2 affinity.     

Codeine and morphine in extensive and poor metabolizers of sparteine: pharmacokinetics, analgesic effect and side effects

OBJECTIVE: Codeine O-demethylation to morphine is catalysed by the genetic polymorphic sparteine oxygenase (CYP2D6). The objective of the present study was to assess the analgesic effect of codeine on different types of experimental pain in relation to sparteine phenotype. METHODS: Fourteen extensive (EMs) and 14 poor metabolizers (PMs) of sparteine completed a randomized, double-blind, three-way, cross-over study with a single oral dose of codeine (75 or 100 mg) against morphine (20 or 30 mg) and placebo. Pain tests performed before and 1, 2, 3, and 4 h after medication included the cold pressor test and pain thresholds for heat and pressure stimulation. Adverse effects were rated by a structured interview. RESULTS: After morphine, morphine and morphine-6-glucuronide were present in equal amounts in plasma of PMs and EMs. After codeine, neither morphine nor morphine-6-glucuronide could be detected in 13 of the 14 PMs, whereas at least one of the compounds could be detected in all EMs. Peak pain and discomfort rated on a VAS scale during the cold pressor test were significantly reduced by morphine in both EMs and PMs, with a median peak change of 8.5 and 7.0 mm, respectively, for peak pain, and 11.5 and 15.5 mm, respectively, for discomfort. Codeine only reduced these pain measures significantly in EMs, with a median peak change of 5.5 mm for peak pain and 10.5 mm for discomfort. Pain detection and tolerance thresholds to heat and pressure were not consistently altered by either morphine or codeine. In PMs, adverse effects were significantly more pronounced on morphine than on codeine and only showed a slight difference between codeine and placebo. In EMs, there was no difference between codeine and morphine and more pronounced adverse effects on both drugs as compared to placebo. CONCLUSION: This study confirms that codeine O-demethylation depends on CYP2D6; it shows that the 6-glucuronidation of morphine is independent of CYP2D6; it supports the theory that the analgesic effect of codeine depends on its O-demethylation; and it indicates that this is probably also the case for the adverse effects. The results lend no support to the suggestion of a non-opioid analgesic effect of codeine.     

Neuropeptide Y in hamster limbic nuclei: lack of colocalization with substance P

The medial nucleus of the amygdala (Me), bed nucleus of the stria terminalis (BNST), and medial preoptic area (MPOA) regulate copulation in the male hamster. The present study identified neuropeptide Y-immunoreactive (NPY-IR) neurons in the BNST and Me with the greatest concentration in the posteromedial and posteriordorsal subdivisions of these nuclei, respectively. NPY-IR filters are found in all three nuclei with dense plexi of NPY-IR varicosities in the most medial subdivisions. Substance P neurons are also densely concentrated in the posterior BNST and Me; however, no neurons contained both peptides. Thus, NPY and substance P neurons comprise two distinct populations within the BNST and Me of the hamster.     

Coronary artery perforation with rotational coronary atherectomy]

We tried to determine whether women with a urinary tract infection (UTI) were more likely to have had a recent pelvic examination than were women seen for other reasons. We compared 56 women who were diagnosed as having a UTI with 49 controls who had an unrelated complaint (sinusitis). Significantly more women with UTIs had received a pelvic examination within the preceding 2 months (43% vs 16%, P = .01). We conclude that having a pelvic examination is associated with an increased risk of a UTI developing within the following 2 months. This may be due to physical factors related to the examination or to risk factors related to the patients' reasons for obtaining a pelvic examination. Further study is needed to determine if the pelvic examination is an independent risk factor. If so, established preventive measures could reduce this risk.     

Differential suppression of dialysis patients' lymphocyte IFN-gamma production by glucocorticoids and cyclosporine

IFN-gamma is a potent pro-inflammatory cytokine involved in the immunologic rejection of transplanted organs. Having previously demonstrated differential suppressive effects of methylprednisolone (MP), prednisolone (P) and cyclosporine (CsA) on dialysis patients' lymphocyte proliferative responses to phytohaemagglutinin (PHA), we studied the effects of these drugs on dialysis patients' lymphocyte IFN-gamma production during mitogenic and allogeneic (MLR) stimulation. The mean +/- SEM 50% inhibitory concentration (ng/ml) on cell proliferation was significantly lower for MP than P in PHA-stimulated haemodialysis (HD) patients' (35 +/- 7 vs 152 +/- 25, P < 0.001) and peritoneal dialysis (PD) patients' (35 +/- 11 vs 134 +/- 33, P = 0.001) cultures and in HD patients' MLR cultures (15 +/- 3 vs 48 +/- 9, P < 0.001). The mean +/- SEM fractional responses (PHA or MLR + drug/PHA or MLR) in culture supernatant IFN-gamma concentrations were significantly lower with 10(-7) M concentrations of MP than P in HD (0.19 +/- 0.05 vs 0.31 +/- 0.06, P = 0.01) and PD (0.30 +/- 0.11 vs 0.46 +/- 0.11, P < 0.05) PHA cultures and in HD MLR cultures (0.15 +/- 0.04 vs 0.28 +/- 0.07, P = 0.01). CsA (400 ng/ml) alone not only caused less than 50% inhibition of IFN-gamma production in 15/27 HD PHA, 6/14 PD PHA and 4/13 HD MLR cultures, but actually stimulated it in 9 HD and 5 PD PHA cultures. The results suggest that: (1) MP has greater immunosuppressive potential than P for renal transplant recipients; (2) the stimulation of IFN-gamma by CsA in some patients could be harmful in patients with initial allograft dysfunction; and (3) pre-transplant in-vitro assessment of recipients' PBMC responsiveness to glucocorticoids and CsA may help individualize the post-transplant immunosuppressive regimen.     

A study of subunit interface residues of fructose-1,6-bisphosphatase by site-directed mutagenesis: effects on AMP and Mg2+ affinities

The structural transformation of fructose-1,6-bisphosphatase upon binding of the allosteric regulator AMP dramatically changes the interactions across the C1-C4 (C2-C3) subunit interface of the enzyme. Asn9, Met18, and Ser87 residues were modified by site-directed mutagenesis to probe the function of the interface residues in porcine liver fructose-1,6-bisphosphatase. The wild-type and mutant forms of the enzyme were purified to homogeneity and characterized by initial rate kinetics and circular dichroism (CD) spectrometry. No discernible alterations in structure were observed among the wild-type and Asn9Asp, Met18Ile, Met18Arg, and Ser87Ala mutant forms of the enzyme as measured by CD spectrometry. Kinetic analyses revealed 1.6- and 1.8-fold increases in kcat with Met18Arg and Asn9Asp, respectively. The K(m) for fructose 1,6-bisphosphate increased about 2-approximately 4-fold relative to that of the wild-type enzyme in the four mutants. A 50-fold lower Ka value for Mg2+ compared with that of the wild-type enzyme was obtained for Met18Ile with no alteration of the Ki for AMP. However, the replacement of Met18 with Arg caused a dramatic decrease in AMP affinity (20 000-fold) without a change in Mg2+ affinity. Increases of 6- and 2-fold in the Ki values for AMP were found with Asn9Asp and Ser87Ala, respectively. There was no difference in the cooperativity for AMP inhibition between the wild-type and the mutant forms of fructose-1,6-bisphosphatase. This study demonstrates that the mutation of residues in the C1-C4 (C2-C3) interface of fructose-1,6-bisphosphatase can significantly affect the affinity for Mg2+, which is presumably bound 30 A away. Moreover the mutations alternatively reduce AMP and Mg2+ affinities, and this finding may be associated with the destabilization of the corresponding allosteric states of the enzyme. The kinetics and structural modeling studies of the interface residues provide new insights into the conformational equilibrium of fructose-1,6-bisphosphatase.     

Dynamic behavior of hepatitis C virus in chronically infected patients receiving liver graft from infected donors

We studied the outcome of hepatitis C virus (HCV) infection in 14 patients with end-stage HCV-related liver disease who received HCV-positive liver allografts. Viral sequences specific for donor and recipient were established by direct sequencing of PCR products from the NS5 region and by single-strand conformation polymorphism. Within a few months after transplantation the donor strain took over the recipient strain in 8 patients while in 6 patients it was the recipient strain which ultimately prevailed. Donor and recipient were infected by identical genotypes in 6 donor/recipient pairs and by different genotypes in the remaining 8 pairs. Subtype 1b and type 1 (1a + 1b) became the predominant strains in all recipient/donor pairs in which they were present. Patients retaining their own strain were found to have significantly more active liver disease than those infected by the donor strain. We show that HCV superinfection and overtake phenomena occur in humans and suggest that genotypes 1b and 1 (1a + 1b) may possess replicative advantages over other genotypes. Furthermore, we provide evidence of the existence of interference preventing simultaneous continuous infection even by the same genotype strains. The development of active liver disease associated with recipient strain infection and mild or no disease associated with infection from the donor suggests various pathogenic abilities of different HCV strains.     

The effect of propionate on lipid synthesis in rat lymphocytes

1. The effect of propionate on lipid synthesis in lymphocytes cultured for 24 hr and incubated for 2 hr was investigated. 2. [1-14C]-propionate was incorporated mainly into phospholipids in both control and concanavalin A (Con A) stimulated cultured lymphocytes. 3. The content of free coenzyme A markedly decreased in 2 hr incubated lymphocytes when propionate was added to the medium at concentrations from 10 to 100 mmol/l. 4. Propionate at 40 mmol/l decreased the incorporation of [1-14C]-palmitate into phospholipids (86%), triacylglycerol (87%) and cholesterol ester (98%) and increased in cholesterol (133%) of cultured lymphocytes. 5. Addition of propionate into the culture medium at 2.5 and 5.0 mmol/l concentrations markedly increased the activity of hydrolases of various acylCoA derivatives. 6. The results suggest that propionate may reduce the content of acylCoA and so its esterification and this might be important for the regulation of lymphocytes proliferation.