DXα gene polymorphism in Graves''disease

An HLA-DX alpha gene polymorphism was analysed by Southern blotting in 49 British patients with Graves' disease and 61 control subjects. Two previously described allelic fragments of Taq I digested genomic DNA at 2.1 kb (U) and 1.9 kb (L) were found. The genotype frequencies for UU, UL and LL did not differ from the controls in Graves' disease, either for the whole groups or when subdivided into HLA-DR3-positive and -negative subjects. There was a significant association of the U allele with HLA-DR3 in both controls (P less than 0.05) and Graves' disease (P less than 0.025). The results indicate that DX alpha polymorphism is not primarily associated with Graves' disease. The findings differ from recent studies which showed that DX alpha polymorphisms may contribute to susceptibility in other DR3-associated autoimmune diseases.     

Role of actin microfilament in osmotic stretch-induced increase of voltage-operated calcium channel current in guinea-pig gastric myocytes

 Using the whole-cell patch clamp technique, the role of actin microfilament in hyposmotic increase of voltage-operated calcium channel current (I _Ba) was studied in guinea-pig gastric myocytes. Hyposmotic superfusate (212 mOsm) increased peak I _Ba amplitude by 32.7 ± 6.5%; when cytochalasin-D (Cyt-D, 20 μM), an actin cytoskeleton disruptor, was used, an increase of only 9.7 ± 3.1% was seen. I _Baresponse to osmotic stress was potentiated (45.1 ± 4.1% increase) by 20 μM phalloidin, an actin microfilament stabilizer. However, colchicine (100 μM), an microtubule cytoskeleton disruptor, had no effect on either I _Ba or its response to hyposmotic solution. Phalloidin also induced a rightward shift of the I/V relationship of I _Ba, while Cyt-D itself had no effect. These results suggest that actin cytoskeleton may mediate hyposmotic stretch-induced I _Ba increase in gastric smooth muscle. Received: 26 March 1997 / Received after revision: 28 May 1997 / Accepted: 3 June 1997     

Differential effects of intravitreal optic nerve and sciatic nerve grafts on the survival of retinal ganglion cells and the regeneration of their axons

We have investigated the effects of intravitreal sciatic nerve (SN) and/or optic nerve (ON) grafts on the survival and the axonal regeneration of retinal ganglion cells (RGCs). Following transection of the ON, approximately 40% RGCs survived at 7 days post-axotomy (dpa). Results showed that the intravitreal ON graft significantly promoted the survival of RGCs at 7 dpa (39,063 vs 28,246). Intravitreal SN graft, however, did not rescue axotomized RGCs at 5, 7 or 14 dpa. Axotomized RGCs could be induced to regenerate axons along a segment of SN graft attached to the proximal stump of ON. On average, 608 axotomized RGCs were induced to regenerate axons along the attached SN graft. The presence of intravitreal SN graft promoted about 100% increase in the number of regenerating RGCs (1,227) relative to the control groups. The intravitreal ON graft, surprisingly, also induced about 100% more regenerating RGCs (1220) than in the control group. When SN and ON grafts were co-transplanted into the vitreous, about 200% more regenerating RGCs (1916) were observed than in the control group. These findings illustrated that the intravitreal ON graft rescued axotomized RGCs and enhanced the regeneration of retinal axons. This is the first report to show that ON promotes RGC axonal regeneration. The intravitreal SN graft did not rescue RGCs but promoted axonal regeneration. The differential effects of intravitreal ON and SN grafts on the survival and the RGC regeneration suggest that these might be two independently operating events.     

Expression and deletion analysis of the Trypanosoma brucei rhodesiense cysteine protease in Escherichia coli.

Trypanosoma brucei, the cause of African sleeping sickness, differentiates in the mammalian bloodstream from a long, slender trypanosome into a short, stumpy trypanosome. This event is necessary for infection of the tsetse fly and maintenance of the life cycle. We have previously shown that the stumpy form contains 10- to 15-fold-greater cysteine protease activity than either the slender form or the insect midgut procyclic, and we have isolated a cDNA encoding the protease. In order to determine whether the cDNA encodes the developmentally regulated cysteine protease, we have purified the protease from trypanosomes and have made a polyclonal antiserum against it. The trypanosomal protease gene was then expressed in Escherichia coli with three different methionines within the pre- and propeptides acting as initiation sites. In each case, a protein was synthesized that was recognized by an antiserum specific for the developmentally regulated trypanosomal cysteine protease. The protein synthesized from the more upstream initiation site within the propeptide was proteolytically active. The recombinant protease and the trypanosomal enzyme were identical with respect to peptide substrates and protease inhibitors. The protein remained active when synthesized in a truncated form lacking the nine consecutive prolines and carboxy-terminus extension, indicating that the terminal 108 amino acids are not necessary for proteolytic activity.     

X-linked severe combined immunodeficiency syndrome: the first Korean case with gamma c chain gene mutation and subsequent genetic counseling

X-linked severe combined immunodeficiency (X-SCID) is a rare, life-threatening immune disorder, caused by mutations in the gamma c chain gene, which encodes an essential component of the cytokine receptors for interleukin-2 (IL-2), IL-4, IL-7, IL-9, IL-15, and IL-21. A 13-month-old boy with recurrent infections who had reduced serum immunoglobulin levels and decreased numbers of CD3, CD16/56 cells was evaluated for gamma c chain gene mutation and protein expression. The patient had a C-to-T point mutation at nucleotide position 690, one of the hot spots, resulting in a single amino acid substitution of cysteine for arginine (R226C), as determined by direct sequencing and PCR-RFLP. The patient's mother was a heterozygous carrier. Percutaneous umbilical cord blood sampling was performed at the 6-month of gestation in a subsequent pregnancy. As the immunophenotype of the fetus showed an identical pattern, the pregnancy was terminated and genetic analysis of the abortus confirmed recurrence. This is the first report of the molecular diagnosis of X-SCID in Korea. Genetic analysis of the gamma c chain gene is useful for definite diagnosis and genetic counseling for X-SCID.     

Coincidence of hereditary angioedema (HAE) with Crohn's disease

A patient with two diseases, based presumably on different immunopathological mechanisms, hereditary angioedema (HAE) and Crohn's disease, was followed for 8 years. For more than three years of this observation period, detailed laboratory data were also available and could be analyzed. Both diseases had severe courses requiring chronic treatment with danazol and sulfasalazine, respectively. During exacerbation of Crohn's disease, the levels of C4 was found to be significantly lower than during the periods free of symptoms of both diseases. This drop was probably due to an impaired C1-inhibitor activity. HAE attacks and acute exacerbation of Crohn's disease never occurred simultaneously. This finding may be a mere chance but may also indicate that the different immunopathological processes underlying HAE and Crohn's disease influence each other.     

Background nonselective cationic current and the resting membrane potential in rabbit aorta endothelial cells

The ion channel conductances that regulate the membrane potential was investigated by using a perforated patch-clamp technique in rabbit aorta endothelial cells (RAECs). The whole-cell current/voltage (I-V) relation showed a slight outward rectification under physiological ionic conditions. The resting membrane potential was -23.3 +/- 1.1 mV (mean +/- SEM, n = 19). The slope conductances at the potentials of -80 and 50 mV were 31.0 +/- 4.0 and 62.8 +/- 7.1 pS pF(-1), respectively (n = 15). Changes in the extracellular and intracellular Cl(-) concentrations did not affect the reversal potential on I-V curves. The background nonselective cationic (NSC) current was isolated after the K(+) current was suppressed. The relative permeabilities calculated from the changes in reversal potentials using the constant-field theory were P(K):P(Cs):P(Na):P(Li) = 1:0.87:0.40:0.27 and P(Cs):P(Ca) = 1:0.21. Increases in the external Ca(2+) decreased the background NSC current in a dose-dependent manner. The concentration for half block by Ca(2+) was 1.1 +/- 0.3 mM (n = 7). Through the continuous recording of the membrane potential in a current-clamp mode, it was found that the background NSC conductance is the major determinant of resting membrane potential. Taken together, it could be concluded that the background NSC channels function as the major determinant for the resting membrane potential and can be responsible for the background Ca(2+) entry pathway in freshly isolated RAECs.     

Comparison of haemoglobin H inclusion bodies with embryonic zeta globin in screening for alpha thalassaemia.

AIMS--To compare the haemoglobin (Hb) H inclusion test with immunocytochemical detection of embryonic zeta chains in screening for alpha thalassaemia. METHODS--Blood samples from 115 patients with relevant clinical history and hypochromic microcytic indexes were screened using the HbH inclusion test and the Variant Hemoglobin Testing System (BioRad, Hercules, CA, USA). RESULTS--The HbH inclusion test was positive in 61 of 115 cases, three of whom had HbH disease confirmed by electrophoresis. The remaining 58 had alpha thalassaemia 1. All three HbH cases and 56 of 58 cases of alpha thalassaemia 1 expressed embryonic zeta chains, giving a specificity of 96.7%. Fifty four of 115 cases had a negative HbH inclusion test, of whom 50 had beta thalassaemia trait and three had iron deficiency. No diagnosis was reached for the remaining patient. CONCLUSION--The immunocytochemical test is as sensitive as the HbH inclusion test in screening for alpha thalassaemia. The presence of zeta chains is highly specific for alpha thalassaemia 1 incorporating the (--/SEA) deletion. The specificity and simplicity of the immunocytochemical test make it the test of choice in screening for alpha thalassaemia.     

Idiopathic infant pyoceles

Three infants presented with acute scrotal swelling, erythema, and a tender irreducible firm mass within the scrotum. All patients were operated upon with the preoperative diagnosis of testicular torsion. At operation, grossly purulent fluid was found in a hydrocele sac. In all the cases, the testes were normal and no source of the scrotal infection was identified. A variety of bacterial organisms were cultured and responded readily to antibiotics. Follow-up has documented survival of the testes without apparent atrophy. "Idiopathic" infant pyocele is rarely described and consequently, not included in the differential diagnosis of patients with acute surgical conditions of the inguinoscrotal region.