Association of artery wall hypoxia and cellular proliferation at a vascular anastomosis

BACKGROUND

We hypothesize that arterial wall hypoxia incites the pathologic formation of intimal hyperplasia at an artery anastomosis. We have determined from previous studies performed in our laboratory, the oxygen tension profiles of the artery wall at various times after vascular anastomosis. The purpose of this study is to determine the rate of cellular proliferation at an artery anastomosis when the artery wall is most hypoxic.

MATERIALS AND METHODS

Expanded polytetrafluoroethylene (ePTFE) grafts were placed end to end in the infrarenal aorta of 27 New Zealand white rabbits. The anastomotic aortic wall oxygen (O(2)) tensions were measured with an O(2) microelectrode in rabbits 0, 7, 14, 28, and 42 days after surgery. O(2) tensions were also measured in 4 control rabbits for comparison. 5-Bromo-2'-deoxyuridine (BrDU) was injected intraperitoneally 24 h prior to rabbit sacrifice. After O(2) tension measurements, the rabbits were sacrificed and the aortic grafts were harvested. Bioquant morphometrics was used to measure cells with BrDU counterstaining and intimal thickness in 17 rabbits: in control (n = 4), Day 0 (n = 4), 7 (n = 5), and 42 (n = 4). Student's t test was used to compare O(2) tensions, cellular proliferation, and intimal hyperplasia between days.

RESULTS

The pO(2) levels at the outer layers of the aorta, 1 mm distal to the distal aortic graft anastomosis, were 61.0 +/- 2 (+/-SE) mm Hg for controls, 19.8 +/- 1 mm Hg for Day 7 (P < 0.0001), 19.0 +/- 1 mm Hg for Day 14, 39.2 +/- 1 mm Hg for Day 28, and 58.5 +/- 1 mm Hg for Day 42 aortic grafts. BrDU-staining ratios in the intima were significantly higher in the Day 7 aortic grafts, 28.6 +/- 3%, versus BrDU-staining ratio, 1.4 +/- 1%, in Day 42 aortic grafts (P < 0.0002).

CONCLUSIONS

Cellular proliferation is highest at Day 7 when the artery wall is most hypoxic and returns to baseline as O(2) tensions normalize.

Preparation and determination of structure of L-3-deoxymimosine-containing peptides

L-3-Deoxymimosine-containing decapeptides were prepared for the development of protein tyrosine kinase (PTK) inhibitors. During the preparation of peptides, several side products were formed. Identification and determination of major peptides generated were reported.

Comparing patency rates between external iliac and common iliac artery stents

PURPOSE

Placement of intraluminal stents in the common iliac artery (CIA) and external iliac artery (EIA) has become an accepted therapy for treating localized arterial stenoses. The purpose of this study was to compare anatomic patency rates of stents placed in the EIA and CIA for occlusive disease.

METHODS

A radiologic computer database was used to identify 69 consecutive male patients at the Minneapolis Veterans Affairs Medical Center from February 1, 1993, through January 31, 1999, who underwent placement of 98 stents (82 Wallstents and 16 Palmaz stents) for physiologically significant iliac artery occlusive disease and varying degrees of chronic limb ischemia. Patients were followed up with surveillance duplex ultrasound scanning examinations 1 day after procedure, 3 months after procedure, and then at 6-month intervals after stent placement. Follow-up angiograms were performed for patients with duplex ultrasound scans that revealed velocities greater than 300 cm/s. Patient risk factors, iliac artery runoff, concomitant outflow procedures, and anatomic patency rates were compared between patients receiving EIA stents and those receiving CIA stents.

RESULTS

The mean age for the EIA stent group was 69 +/- 1 years versus 66 +/- 1 years (P =.03) for the CIA stent group. Mean follow-up was 21.4 +/- 2.1 months (+/- SE) for all patients. Patients with EIA stents had more ischemic lower limbs when compared with patients who had CIA stents (P =.05). No differences were found between groups in risk factor analysis (P = not significant). Lesion lengths were similar between groups: EIA, 4.6 +/- 0.6 cm, and CIA, 5. 3 +/- 0.8 cm (P = not significant). The following differences were noted on primary patency rates (EIA group vs CIA group): 1 year (93% vs 88%), 2 years (91% vs 85%), and 3 years (90% vs 78%) (Cox proportional hazards; P =.13).

CONCLUSIONS

Anatomic patency rates for EIA and CIA stents appear to be similar despite the fact that patients with EIA stents were older and had more ischemic limbs compared with the patients who had CIA stents.

Antitumor action of physiological estradiol on tamoxifen-stimulated breast tumors grown in athymic mice

The estrogen receptor (ER)-positive MCF-7 breast cancer cell line can be transplanted into athymic mice and grown into tumors with estradiol (E2) support. Tamoxifen (TAM) blocks E2-stimulated tumor growth; however, continuous TAM treatment results in transplantable tumors within a year that will grow with either E2 or TAM (M. M. Gottardis and V. C. Jordan, Cancer Res., 48: 5183-5187, 1988). Although this model may represent the development of TAM resistance for the treatment of advanced breast cancer, no laboratory model exists to study the exposure of breast cancer to 5 years of adjuvant TAM therapy. We have addressed this issue and report the development and characterization of two tumor lines, MCF-7TAM and MT2, which have been serially transplanted into TAM-treated athymic mice for >5 years. The MCF-7TAM tumor rapidly regresses in response to E2 and then about 50% of tumors regrow in response to E2. Interestingly, tumor regression does not occur if TAM treatment is stopped, probably because E2 levels are too low in ovariectomized athymic mice. The development of the antitumor effect of E2 was documented for MT2 tumors over a 1-year period; TAM-stimulated tumor growth was retained, but E2 caused progressively less of a stimulatory effect. Most importantly, E2-stimulated tumors that regrew after initial tumor regression in both MCF-7TAM and MT2 lines were again responsive to TAM to block E2-stimulated growth. Unlike MCF-7 tumors, the MT2 tumor line contains a single point mutation, Asp351Tyr, in the ER, which was retained after the development of E2-stimulated regrowth. The mutation is associated with increased estrogen-like actions for the TAM-ER complex (A. S. Levenson et al., Br. J. Cancer, 77: 1812-1819, 1998), but we conclude that the mutant ER is not required for TAM resistance. On the basis of the new breast cancer models presented, we propose a cyclic sensitivity to TAM that may have important clinical implications: (a) it is possible that a woman's own estrogen may produce an antitumor effect on the presensitized micrometastatic disease after 5 years of TAM. Long-term antitumor action occurs because the drug is stopped, but resistance accumulates and tumors start to grow if adjuvant therapy is continued; and (b) although in the clinic TAM-resistant tumors respond to second-line therapies that cause estrogen withdrawal, e.g., pure antiestrogens or aromatase inhibitors, estrogen therapy may also be effective and return the tumor to TAM responsiveness. In this way, a hormone-responsive tumor may be controlled longer in the patient with advanced disease.

Design and synthesis of anticonvulsive agents as gamma-vinyl GABA-based potential dual acting prodrugs and their biological activities

For the development of new anticonvulsive agents, gamma-vinyl GABA (vigabatrin) and GABA mimetics derivatives were covalently coupled as potential dual acting prodrugs and evaluated for their anticonvulsive activities. Among the prepared compounds, 11 showed the most potent anticonvulsive activity, a shorter onset time and a broader spectrum compared to vigabatrin.

Psoralen-ultraviolet A-induced erythema: sensitivity correlates with the concentrations of psoralen in suction blister fluid

Since the advent of psoralen-ultraviolet A (PUVA) therapy, the value of plasma 8-methoxypsoralen (8-MOP) concentrations to predict PUVA-induced erythema has been widely investigated. Plasma 8-MOP concentrations have not been proportional to, and cannot alone predict, the degree of PUVA-induced erythema. We assumed that PUVA-induced erythema was related more closely to psoralen concentrations in the skin tissue rather than those within blood vessels. This study was designed to investigate the correlations between the 8-MOP concentrations in suction blister fluid (SBF) and in plasma, with the degree of PUVA-induced erythema. 8-MOP concentrations in plasma and SBF were measured in 15 vitiligo patients and 11 volunteers. Blood and SBF samples were collected 2 h after taking 8-MOP, and 8-MOP concentrations in plasma and SBF were quantified using reverse-phase high-performance liquid chromatography. Eleven volunteers were phototested using a series of doses of ultraviolet A at the time of sampling. The erythema responses were estimated visually to determine the minimal phototoxic dose (MPD). SBF 8-MOP concentrations showed a weak positive correlation with plasma 8-MOP concentrations, which means that we could not predict the exact SBF 8-MOP concentrations using the plasma 8-MOP concentrations. The MPD showed a better correlation with the log of the SBF 8-MOP concentration than with that of the plasma 8-MOP concentration. These results show that plasma 8-MOP concentration cannot represent the exact SBF 8-MOP concentration, and that SBF 8-MOP concentrations, which are representative of the skin tissue 8-MOP level, are more closely related to the erythemal sensitivity during PUVA therapy.

Superficial femoral popliteal vein: An anatomic study

OBJECTIVE

The superficial femoral popliteal vein (SFPV) has been used as an alternative conduit for both arterial and venous reconstructive surgery. Its popularity continues to grow, despite concern about the potential for venous morbidity after harvest. The purpose of this study was to determine an anatomic "safe" length of SFPV for harvest, assuming that the preservation of at least one valve and one significant collateral vein in the remaining popliteal vein (PV) segment can minimize venous morbidity.

METHODS

Forty-four SFPVs were harvested from 39 cadaveric specimens. The length of both the superficial femoral vein (SFV) and PV was measured, and the number and location of valves and significant side branches (more than 2 mm in diameter) of the PV were measured. The Student two-tailed t test was used as a means of comparing vein lengths between the sexes. Correlation coefficients were determined for the effect of patient height on vein length, stratified by means of sex.

RESULTS

Vein length (SFV mean, 24.4 +/- 4 cm; PV mean, 18.8 +/- 4 cm) varied with sex (male SFV mean, 28.1 +/- 5 cm; male PV mean, 21. 5 +/- 3 cm; female SFV mean, 22.6 +/- 4 cm; female PV mean, 18.4 +/- 3 cm; P =.01). Valve number (mean, 1.8 +/- 0.5) and location and collateral vein number (mean, 5 +/- 1.8) and location were variable and independent of height or sex.

CONCLUSION

An anatomic "safe" length of SFPV for harvest to minimize venous morbidity would include all the SFV and 12 cm of PV in 95% of women and 15 cm of PV in 95% of men. We found that the male sex was a significant determinant for a longer safe length of vein that can be harvested.

Incidence of erectile dysfunction after open abdominal aortic aneurysm repair

The aim of this study is to document the incidence of erectile dysfunction (ED) following open abdominal aortic aneurysm (AAA) repair using a modified International Index of Erectile Function questionnaire (IIEF). An IIEF was mailed to 175 married male patients (mean age +/- SD: 71 +/- 8 years) who had an open AAA repair by one of four board-certified vascular surgeons between 1994 and 1998. The IIEFs were anonymous and asked patients to recall their sexual function before and 3 months after repair. ED was defined in patients with IIEF scores <11 (range 1-30). The overall response rate was 39% (68/175). A comparison of the IIEF results showed that 67/68 patients reported worsening erectile function (p < 0.00001); one respondent reported improved erectile function. On the basis of the IIEF scores, 20/68 patients (29%) were found to have ED and 48/68 patients (71%) had normal function prior to repair. Of the 48 patients with normal function prior to surgery, 83% (40/48) had ED after surgery. ED rates were similar between tube grafts 82% (23/28) and bifurcated grafts 85% (17/20) p = ns. The ED rate after open AAA repair is alarmingly high and prospective follow-up with IIEF will be necessary to better assess true ED rates after conventional open AAA repair.

Expansion rates and outcomes for iliac artery aneurysms

PURPOSE

The expansion rates and outcomes of iliac artery aneurysms (IAAs) were determined.

METHODS

A retrospective chart review was conducted to identify patients in whom IAAs had been diagnosed between June 1990 and March 1999 in a vascular surgery service at a large university-affiliated Veterans Affairs medical center. The patients were veterans, 187 men and two women, in whom the diagnosis of an IAA was made, as defined by the Ad Hoc Committee on Reporting Standards of The Society for Vascular Surgery and International Society for Cardiovascular Surgery, North American Chapter (IAA >/= 1.5 cm). Expansion rates relative to the size of IAAs and clinical outcomes were noted for all patients.

RESULTS

One hundred eighty-nine patients (mean age, 72.3 +/- 0.5 years) with 323 IAAs (mean size, 2.34 +/- 0.7 cm) were found. The mean follow-up (96% of patients with B mode ultrasound scanning) period was 31.4 months, with each patient undergoing a mean of 4.2 studies. The 4-year life-table survival rate was 78.2%, with no patient deaths related to their IAAs. Symptoms were noted in six of 189 patients (3.1%; two ruptures, four chronic pain), who all had IAAs larger than 4 cm. IAAs were repaired in 34 of 189 patients (18%), in 25 of the 34 patients because of their associated abdominal aortic aneurysms and in nine of 34 patients because of their IAAs alone. All nine patients requiring operative treatment of indications related to the IAA had an IAA larger than 4 cm. Expansion rates were slow for IAAs smaller than 3 cm (0.11 +/- 0.02 cm/year) and significantly greater (P <.003) for IAAs 3 to 5 cm (0.26 +/- 0.1 cm/year). The correlation between B mode ultrasound scanning and computed tomography scanning was excellent. The size of the IAAs was underestimated by 0.03 +/- 0. 06 cm by means of B mode ultrasound scanning.

CONCLUSION

The IAAs followed up by this contemporary Veterans Affairs vascular surgery service were small, rarely caused symptoms or rupture, and expanded at a slow rate. IAAs smaller than 3 cm could be followed up safely on an annual basis with B mode ultrasound scanning. IAAs that are 3 cm or larger and smaller than 3.5 cm should be carefully followed with B mode ultrasound scanning at 6-month intervals, whereas elective repair should be considered for IAAs 3.5 cm or larger in good-risk patients. Based on this report and currently available evidence and recommendations, asymptomatic IAAs that are 4 cm or larger and all other symptomatic IAAs should be considered for operative repair. Also, the reported high rupture rate of IAAs that are 5 cm or larger mandates prompt operative repair.

Alopecia neoplastica in a patient with gastric carcinoma

A well-recognized but rare presentation of scalp metastasis is alopecia neoplastica, which occurs as a single or multiple areas of cicatricial alopecia. Alopecia neoplastica is usually a presentation of metastasis from breast cancer, and other primary sites are extremely rare. We report a 36-year-old woman with alopecia neoplastica due to metastasis from gastric carcinoma. She also had pelvic metastases. An asymptomatic erythematous alopecic plaque had developed 10 months before presentation and biopsy was consistent with scalp metastasis. Total abdominal hysterectomy and salphingo-oophorectomy was performed and chemotherapy was proposed.

Resurfacing of facial angiofibromas in tuberous sclerosis patients using CO2 laser with flashscanner

BACKGROUND

Angiofibromas are a common presentation of tuberous sclerosis. They cause considerable cosmetic and hygienic morbidity for patients. Treatments of angiofibromas have included curettage, cryosurgery, chemical peel, dermabrasion, shave excision, and 13-cis retinoic acid. Results from these modalities in many cases were not satisfactory from a cosmetic standpoint. Copper vapor, argon, pulsed dye, and CO2 lasers have been used with success in isolated cases.

OBJECTIVE

The purpose of this study was to evaluate the efficacy of CO2 laser resurfacing with flashscanner in the treatment of facial angiofibromas.

METHODS

Two patients with angiofibromas on the face were treated with a CO2 laser with flashscanner. The cheek and nose were treated in one patient, and entire face was done in the other.

RESULTS

Both patients showed remarkable cosmetic improvements without scarring. Mild hyperpigmentation was found in both patients, which disappeared in 1 month with the application of topical agents. Facial erythema persisted about 2 months in both patients.

CONCLUSION

A CO2 laser equipped with flashscanner causes less residual thermal damage than conventional CO2 lasers and enables controlled depth vaporization for more precise and regular removal of angiofibromas. In whole-face resurfacing, more cosmetically acceptable results are possible because localized treatment leaves marginal prominences. Laser resurfacing is an effective alternative in the treatment of multiple protuberant angiofibromas even though we cannot permanently clear these lesions due to their nature.

Cholesterol-lowering activity of naringenin via inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase and acyl coenzyme A:cholesterol acyltransferase in rats

The effects of dietary supplementation of a citrus bioflavonoid, naringenin, on the cholesterol metabolism were studied. For 42 days male rats were fed a 1% (wt/wt) high-cholesterol diet with or without a naringenin supplementation (0.1%, wt/wt) to study its effect on plasma lipid levels, hepatic lipid contents, activities of hepatic acyl coenzyme A:cholesterol O-acyltransferase (ACAT) and 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, and the excretion of fecal neutral sterols. Naringenin did not significantly alter the concentration of plasma triglycerides, but lowered the plasma cholesterol (3.80 vs. 3.12 mmol/l) concentration and the hepatic cholesterol content (70.3 vs. 54.0 mg/g) significantly (p < 0.05) compared to those of the controls. HMG-CoA reductase (1,879.0 vs. 1,715.0 pmol/min/mg) and ACAT activities (806.0 vs. 563.0 pmol/min/mg) were significantly lower in the naringenin-supplemented group than in controls. Naringenin supplementation caused a marked decrease in the excretion of fecal neutral sterols (242.9 mg/day) compared to the controls (521.9 mg/day). These results show that naringenin lowers the plasma and hepatic cholesterol concentrations by suppressing HMG-CoA reductase and ACAT in rats fed a high-cholesterol diet.

The effect of N-substituted alkyl groups on anticonvulsant activities of N-Cbz-alpha-amino-N-alkylglutarimides

In order to examine the effects of N-substituted alkyl group on the anticonvulsant activities of N-Cbz-alpha-aminoglutarimides as novel anticonvulsants with broad spectrum, a series of (R) or (S) N-Cbz-alpha-amino-N-alkylglutarimides (1 and 2) were prepared from the corresponding (R) or (S) N-Cbz-glutamic acid and evaluated for the anticonvulsant activities in the maximal electroshock seizure (MES) test and pentylenetetrazol induced seizure (PTZ) test, including the neurotoxicity. The most potent compound in the MES test was (S) N-Cbz-alpha-amino-N-methylglutarimide (ED50=36.3 mg/kg, PI=1.7). This compound was also most potent in the PTZ test (ED50=12.5 mg/kg, PI=5.0). The order of anticonvulsant activities against the MES test as evaluated from ED50 values for (R) series was N-methyl > N-H > N-ethyl > N-allyl; for the (S) series N-methyl > N-H > N-ethyl > N-allyl > N-isobutyl compound. Against the PTZ tests, the order of anticonvulsant activities showed similar pattern; for the (R) series, N-methyl > N-H > N-ethyl > N-allyl; for the (S) series N-methyl > N-H > N-ethyl > N-allyl > N-isobutyl compound. From the above results, N-substituted alkyl groups were thought to play an important role for the anticonvulsant activities of N-Cbz-alpha-amino-N-alkylglutarimides.

Bowen's diseases and basal cell carcinomas in a patient

Bowen's disease is a well-known precancerous lesion, in which invasive squamous carcinoma may develop. However, it is rare that Bowen's disease, basal cell carcinoma, and internal malignancy develop in a single patient. We report a case of a 54-year-old male patient with Bowen's disease, basal cell carcinoma of the skin, and squamous cell carcinoma of the lung. Multiple scaly erythematous patches had developed several years earlier and were diagnosed as Bowen's disease by skin biopsy. The number of lesions increased and, five months ago, a right lower lobectomy was done for squamous cell carcinoma which was detected on a chest X-ray. Skin biopsies of two different sites revealed Bowen's disease and basal cell carcinoma. The arsenic level was increased in his hair specimen. Cryotherapy was applied.

Unilateral renal cystic disease in adults

Unilateral renal cystic disease (URCD) is morphologically indistinguishable from autosomal dominant polycystic kidney disease (ADPKD) except for its unilaterality. Unlike ADPKD, URCD patients show neither a genetic background nor progressive deterioration in renal function; thus, the differential diagnosis of URCD from ADPKD is important. Only a few cases of URCD have been reported. This study reports two cases of URCD in adults together with a literature review. We identified these two cases using abdominal computerized tomography and family screening with renal ultrasonography.

Presence of circulating antibodies to a disease-specific antigen on cultured human dermal microvascular endothelial cells in patients with Behçet's disease

Behçet's disease is a chronic, multisystem disorder characterized by a recurrent inflammatory reaction. Antiendothelial cell antibodies have been detected in the serum from patients with autoimmune diseases with presenting vasculitis and it is assumed that they can induce damage to the endothelial cells. In this study, we detected antiendothelial cell antibodies in the serum from patients with Behçet's disease using an enzyme-linked immunosorbent assay, electrophoresis and immunoblotting. The cytolysis of human dermal microvascular endothelial cells (HDMEC) was measured using a cytotoxicity assay. The serum from 37.4% of Behçet's disease patients showed IgM antibodies against unstimulated HDMEC while the serum from 18.4% of patients showed an increase in IgM antibody titer after IFN-gamma pretreatment. The frequency of vasculitis was higher in the IgM-positive Behçet's disease patients than in the IgM-negative patients. In Western blotting, IgM-positive Behçet's disease serum reacted with the 44 kDa HDMEC surface antigen, whereas IgM-positive systemic lupus erythematosus serum reacted with the 81 kDa HDMEC surface antigen. The reactivity to the 44 kDa protein band was also observed in cultured human umbilical vein endothelial cells but not in fibroblasts, A431 cells or SK-MEL-2 cells. Serum from Behçet's disease patients incubated with human complement or mononuclear cells produced no significant lysis of HDMEC, and cultured HDMEC were resistant to antibody-dependent cell-mediated cytotoxicity. The results suggest that antibodies against antigens on the surface of endothelial cells may play a role in inducing vasculitis in Behçet's disease, not through a direct toxic effect of an antiendothelial cell antibody but by an indirect effect involving the activation of endothelial cells to produce cytokines.

Serum concentration of the soluble interleukin-2 receptor in vitiligo patients

Serum levels of sIL-2R can be used to monitor in vivo immune activation and its elevation have been shown to be correlated with T cell mediated immune disease such as atopic dermatitis, psoriasis, lymphoma and systemic sclerosis. Vitiligo is the disease of depigmentation caused by destruction of melanocytes, and there have been extensive studies on the immune pathogenesis. If the pathogenesis of vitiligo is correlated with the activation of T lymphocytes, the change of IL-2R will be detected compared with that of normal control. Therefore we sought the change in sIL-2R to determine whether T lymphocytes from patients with vitiligo show abnormal biological behavior. The quantitation of sIL-2R was done by sandwich enzyme-linked immunosorbent assay (ELISA) from the sera of 79 vitiligo patients and 40 normal controls. The results were summarized as following. The sIL-2R level in vitiligo patients (671.91 +/- 368.59 U/ml) was significantly increased compared with that of controls (370.8 +/- 71.8 U/ml; P < 0.005). According to clinical types, sIL-2R level in focal type of vitiligo patients was significantly higher than those in other types (segmental or generalized; P < 0.05). The sIL-2R level in patients less than 1 year duration was significantly higher than in patients more than 1 year duration (P < 0.05). The sIL-2R levels were not significantly different between active and inactive group. There was no significant differences among sIL-2R levels according to sex or age of onset. Our study showed that sIL-2R level was higher in vitiligo patients compared with that of normal controls, so the activation of T lymphocytes would be an important component in the pathogenesis of vitiligo. The higher sIL-2R levels in recent onset group would suggest that sIL-2R level might be an acute immunologic marker in vitiligo patients.

Chitin synthase II inhibitory activity of ursolic acid, isolated from Crataegus pinnatifida

Two triterpenoid compounds, ursolic acid and uvaol, were isolated from Crataegus pinnatifida Bunge leaves. Ursolic acid inhibits chitin synthase II from S. cerevisiae with an IC50 value of 0.84 microgram/ml and the inhibition appears to be selective for chitin synthase II, whereas uvaol has no inhibitory activity up to 280 micrograms/ml. Oleanolic acid, alpha-hederin hydrate, and betulic acid inhibited the chitin synthase II activity under the same conditions with an IC50 of 5.6, 64.3, and 98.7 micrograms/ml, respectively.

A novel glutamic acid to aspartic acid mutation near the end of the 2B rod domain in the keratin 1 chain in epidermolytic hyperkeratosis

We report a mutation in a mild case of epidermolytic hyperkeratosis that results in a glutamic acid to aspartic acid substitution in a novel location, codon 477 or position 106 of the 2B rod domain of the keratin 1 chain. This residue has been conserved in all intermediate filament chains and lies near the beginning of the highly conserved helix termination sequence and just prior to the predicted molecular overlap region. Keratin filaments assembled in vitro from chains bearing this substitution are abnormal, indicating that the glutamic acid residue is critically involved in ionic interactions in intermediate levels of filament structure.

Arginine in the beginning of the 1A rod domain of the keratin 10 gene is the hot spot for the mutation in epidermolytic hyperkeratosis

Keratin intermediate filaments are expressed in specific type I/type II pairs in the stage of differentiation of keratinocytes. The mutations in the keratin genes expressed in the epidermis are etiologically responsible for several epidermal genetic skin diseases, such as epidermolysis bullosa simplex, epidermolytic hyperkeratosis (EHK), ichthyosis bullosa of Siemens, palmoplantar keratoderma, pachyonchia congenita and white sponge nevus. The mutations of keratins 1/10 which are expressed in spinous and granular layers are confirmed to cause EHK. There are several trials to correlate between the clinical phenotypes and sites of mutations of the keratin genes. One of these is that EHK is divided into two groups: the palms and soles involvement (PS) group and the non-palms and soles (NPS) group. So far the PS group had the mutations in the keratin 1 and the NPS group in keratin 10. Most of the mutations of the NPS group were reported in the beginning of the 1A rod domain and over 2/3 of the mutations in the 1A rod domain were the base pair substitution of arginine. Here we find two different mutations in two unrelated Korean kindreds classified as NPS group-R156C and R156H-in the 1A rod domain of keratin 10. Our results are compatible with the above classification and suggest that the arginine in the beginning of the 1A rod domain is the hot spot for the mutation of the keratin 10 gene.

Recombinant human platelet-activating factor acetylhydrolase reduces the frequency of diabetes in the diabetes-prone BB rat

Platelet-activating factor (PAF) has been implicated in the development of type 1 diabetes. Our previous studies have suggested that PAF inhibitors reduce insulitis and the frequency of diabetes in BB rats. In this study, serum PAF levels were reduced to address the hypothesis that PAF is important for the development of insulitis. From the age of 35 days on, DP-BB rats were treated with human recombinant PAF acetylhydrolase (rPAF-AH), which efficiently inactivates PAF. Our data indicate that intraperitoneal injections of rPAF-AH reduce the incidence of diabetes in the DP-BB rat. Daily intraperitoneal injections of 6.0 mg/kg body wt rPAF-AH reduced the frequency of diabetes in saline-injected rats from 90% (27/30) to 57% (17/30) (P = 0.004). As found by morphometric analysis on pancreatic islets, DP-BB rats protected from diabetes had less severe degrees of insulitis in a dose-dependent manner. DP-BB rats protected by rPAF-AH also had a higher percentage of insulin-positive cells in pancreas sections compared with those from diabetic animals. We therefore speculated that the beta-cells were protected from insulitis by rPAF-AH.

Mutations in the 1A rod domain segment of the keratin 9 gene in epidermolytic palmoplantar keratoderma

Palmoplantar keratodermas (PPK) constitute a heterogeneous group of diseases marked by the thickening of palms and soles of affected individuals. They are divided into autosomal dominant and autosomal recessive groups by the mode of transmission. The autosomal dominantly transmitted group is further divided into epidermolytic (EPPK, Voerner) and non-epidermolytic (NEPPK, Unna-Thost) types according to the histopathologic findings. Recent development of molecular approaches has confirmed that EPPK and NEPPK are caused by the mutations in keratin 9 and 1 genes, respectively. We have studied three families of EPPK to find the mutation in the keratin 9 gene. DNA sequence analyses revealed single base changes in sequences encoding the highly conserved 1A rod domain segment of the keratin 9 gene in two of the three families. These mutations caused Arg (CGG) to Glu (CAG; R162Q) and Arg (CGG) to Try (TGG; R162W) substitutions. The same arginine position has been mutated in the keratin 10 gene in epidermolytic hyperkeratosis, the keratin 14 gene in epidermolysis bullosa simplex, and the keratin 9 gene in hereditary EPPK in Western patients. In this study we show that unrelated Korean patients have similar mutations.

A glutamate to lysine mutation at the end of 2B rod domain of keratin 2e gene in ichthyosis bullosa of Siemens

Ichthyosis bullosa of Siemens is a rare autosomal dominant skin disorder whose clinical findings are quite similar to those of epidermolytic hyperkeratosis. The differences between those two diseases include absence of erythroderma and different distributions in the skin in ichthyosis bullosa of Siemens. Recent studies have confirmed that ichthyosis bullosa of Siemens is caused by the mutation in the keratin 2e (K2e) gene, which is expressed in the upper spinous and granular layers. We have identified a sporadic case of ichthyosis bullosa of Siemens; based on diagnosis by histopathological findings, the K2e gene of the patient was analysed. Direct sequencing of PCR products revealed a single base change in sequences encoding the highly conserved end of the 2B rod domain segment of the K2e gene. This mutation results in substitution of the codon for glutamic acid by a codon for lysine in position 493 in K2e (E493K). Mutations of the K2e gene involving five different residue positions (Q187P, T485P, L490P, E493D, E493K and E494K) are known to cause ichthyosis bullosa of Siemens. Of these sites, E493, which is conserved in type I and type II keratin genes, is the most frequently altered amino acid in the K2e gene. These data together suggest that this codon constitutes a hot spot for mutations in the K2e gene.