The effect of oxygen radicals metabolites and vitamin E on glycosylation of proteins

Glycosylation (glycation) of proteins is a major complication of hyperglycemia in diabetes. This study has examined the effect of hydrogen peroxide (H2O2) and tertiary-butylhydroperoxide (TBH) and vitamin E (E) on glycation of hemoglobin (GHb). The RBC (15%) in phosphate-buffered saline were treated with 5-50 mM glucose (G) with and without H2O2 or TBH at 37 degrees C for 1-3 d. Glycation of hemoglobin was assessed by GHb formation using Glyc-affinity columns. There was an increase in the GHb formation with increasing G concentrations. GHb formation increased significantly in the presence of H2O2 at all G concentrations. The increase in GHb was blocked when RBC were pretreated with E. E also inhibited formation of malondialdehyde (MDA), an end product of lipid peroxidation, as assessed by the thiobarbituric acid reactivity. Similar increase in the GHb formation was observed when TBH was used instead of H2O2 to induce oxidant stress to the RBC. To examine any role of MDA per se in increased glycation, RBC were treated ex vivo with and without exogenous standard MDA. GHb formation was significantly higher with G-MDA in contrast to G alone. Thus, increased oxygen radicals activity can initiate per-oxidation of lipids and MDA accumulation, which in turn, can stimulate glycation of proteins in diabetes. E can block the glycation of proteins by inhibiting MDA formation.

Prognostic significance of ras/p21 alterations in human ovarian cancer

Ras/p21 oncoprotein expression and K-ras mutations were analysed by Western blot and/or K-ras oligonucleotide hybridization in 78 primary ovarian cancers, 20 omental metastases, two low malignant potential tumours (LMP), nine benign ovarian tumours and 10 normal ovaries. A cut-off value of an integral of absorbance (i.a.) of 2.20, obtained by receiver operating characteristic (ROC) curve, was shown to be the best cut-off for defining p21 positivity. p21 levels were higher in malignant tumours than in benign tumours (median 2.10 i.a. vs median 1.22 i.a.; P = 0.014) and in omental metastases than in primary ovarian carcinomas (median 2.54 i.a. vs median 2.1 i.a.; P = 0.0089). p21 overexpression did not correlate with any of the clinicopathological parameters examined. Follow-up data were available for 63 patients. A significant relationship was shown between p21 positivity and a shorter overall survival (OS) (P < 0.03) and progression-free survival (PFS) (P < 0.03). In multivariate analysis only the presence of ascites, p21 levels and epidermal growth factor receptor status retained an independent prognostic role. K-ras gene mutations were frequently detected in benign and low malignant potential tumours (71.4%), which were mostly mucinous (P = 0.0152).

Comparison of various maturation treatments on in vitro maturation of goat oocytes and their early embryonic development and cell numbers

In the present study, comparison of 2 different culture media (Ham's F-12 and M-199) for supporting in vitro maturation of goat oocytes, and their subsequent embryonic development was evaluated in the presence or absence of sera (estrous goat serum, EGS and fetal calf serum, FCS) and hormones (FSH, 0.5 ug/ml, LH, 5 ug/ml and estradiol, 1 ug/ml). Neither medium (Ham's F-12 or M-199) when supplemented with EGS and hormones showed any notable changes in the maturation rate nor in cleavage and blastocyst development. The mean cell number for blastocysts was also significantly low (P < 0.05). However, Ham's F-12 medium supplemented with FCS and hormones showed a considerable increase in the maturation rate, but subsequent embryonic development was not appreciably increased. However, maturation, cleavage and blastocyst development rates of oocytes matured in M-199 medium in combination with 10% FCS and hormones were significantly higher (P < 0.05). Mean cell number per blastocyst was also significantly increased in this latter treatment compared with that of the other groups (P < 0.05). The results thus indicated that both the culture medium and serum have a marked effect on maturation and subsequent embryonic development. Further, the results also showed that the combination of M-199 with FSH, LH and E2 supplemented with 10% FCS was the most efficacious medium for in vitro maturation and subsequent embryonic development of the media, sera and hormone combinations studied.

Effect of modest vitamin E supplementation on blood glycated hemoglobin and triglyceride levels and red cell indices in type I diabetic patients

OBJECTIVE

The glycation of proteins and elevated triglyceride (TG) levels are two of the major risk factors in the development of complications of diabetes. Previous studies have found some beneficial effects of supplementation of pharmacological doses (900-2000 IU/day) of vitamin E in Type II diabetic patients. This study examined whether supplementation with a modest dose of vitamin E (100 IU/day) had any effect on blood glucose, glycated hemoglobin (GHb), TG or red cell counts in Type I diabetic patients.

METHODS

35 diabetic patients were supplemented with either DL-alpha-tocopherol (vitamin E) capsules (orally, 100 IU/day) or a placebo for 3 months in a double-blind clinical trial. Fasting blood was collected from each diabetic patient before and after vitamin E or placebo supplementation. Data were analyzed using paired "t" tests and the Wilcoxon Signed Rank Test.

RESULTS

Levels of GHb (mean +/- SEM) were 11.5 +/- 0.4 and 12.8 +/- 0.9% (p < 0.05); glucose, 8.8 +/- 1.2 and 11.6 +/- 1.3 mM; and TG, 2.2 +/- 0.2 and 2.9 +/- 0.3 mM (p < 0.03) after vitamin E supplementation versus before supplementation. There were no differences in these parameters after supplementation with the placebo. There was no effect on blood RBC, hematocrit, and hemoglobin levels after supplementation of vitamin E or the placebo. There were no differences in ages and duration of diabetes between placebo and vitamin E-supplemented groups.

CONCLUSIONS

This study suggests that modest vitamin E supplementation (100 IU/day) can significantly lower blood GHb and TG levels and does not have any effect on red cell indices in Type I diabetic patients.

Effect of elevated glucose concentrations on cellular lipid peroxidation and growth of cultured human kidney proximal tubule cells

This study has examined whether elevated glucose can induce lipid peroxidation and contribute to the inhibition of cell growth in human kidney proximal tubule(HPT) cells. HPT cells were cultured in media containing glucose concentrations of 8 mM (control), 25 mM, and 50 mM. Lipid peroxidation was assessed by the thiobarbituric acid reactivity and cell growth was assessed by 3H-thymidine uptake. Results show decreased (59%, p < 0.01) growth of HPT cells cultured in 50 mM glucose. Cells cultured in 50 mM mannitol did not show any growth inhibition, suggesting that the decreased cell growth associated with glucose is not due to osmolarity changes. There was an increase (108%, p < 0.02) in lipid peroxidation in cells cultured with high levels of glucose (50 mM) compared with controls and cells cultured with 50 mM mannitol. To examine if membrane lipid peroxidation or malondialdehyde (MDA, an end product of lipid peroxidation) has any role in the inhibition of cell growth, we examined the effect of tertiary butylhydroperoxide (TBH, known to cause lipid peroxidation and generate MDA) on the growth of HPT cells. TBH decreased cell growth (49, 17 and 3% of controls at 0.1, 0.25, and 0.5 mumole TBH/ml medium). Similarly, a marked reduction in the growth was observed with exogenous MDA (72, 69 and 34% of controls at 0.1, 0.25, and 0.5 mumole MDA/ml medium). This suggests that elevated glucose can induce membrane lipid peroxidation and accumulation of MDA, which in turn can inhibit cellular growth and contribute to the altered structure and function of HPT cells in diabetes.

PI 3-kinase activation in BCR/abl-transformed hematopoietic cells does not require interaction of p85 SH2 domains with p210 BCR/abl

BCR/abl is a chimeric oncogene implicated in the pathogenesis of human chronic myelogenous leukemia. Expression of the BCR/abl gene induces hematologic malignancies in transgenic mice and transformation of interleukin-3-dependent hematopoietic cells. The mechanism of BCR/abl-mediated transformation of hematopoietic cells is poorly understood and involves activation of at least two signaling pathways, p21ras and PI 3-kinase. Here we report that PI 3,4-P2 and PI 3,4,5-P3, the enzymatic products of PI 3-kinase, accumulate in metabolically labeled transformed hematopoietic cells, in contrast to our previous report on the lack of accumulation of PI 3-kinase products in nontransformed NIH 3T3 fibroblasts that express p210 BCR/abl. Transformed cells also have increased PI 3-kinase activity in total cell extracts and membrane fractions. Activation of PI 3-kinase occurs by occupancy of SH2 domains of PI 3-kinase regulatory subunit, p85, by phosphorylated YXXM motifs. Therefore, we investigated whether BCR/abl binds to p85 and whether this binding is mediated by interaction of p85 SH2 domains with YXXM motif of BCR/abl. Association of p210 BCR/abl with p85 in immune complexes and with p85 SH2 domains was evident in hematopoietic cells that express the wt p210 BCR/abl. However, the binding of BCR/abl to p85 SH2 domains was abolished in cells expressing mutant, temperature-sensitive (ts) p210 BCR/abl in which the tyrosine in the YXXM motif of p210 BCR/abl was replaced by histidine. Despite lack of direct interaction with p85 SH2 domains, expression of ts p210 BCR/abl resulted in rapid, time-dependent activation of total and membrane-associated PI 3-kinase and increased PI 3-kinase activity in anti-P-tyr and anti-abl immunoprecipitates. These data suggest that BCR/abl-induced activation of PI 3-kinase in hematopoietic cells does not require binding of p85 SH2 domains to BCR/abl gene product and involves interaction with other tyrosine phosphorylated intermediate proteins.

Paraquat induced DNA damage by reactive oxygen species

The redox cycling contact herbicide paraquat (PQ) causes oxidative damage to pulmonary tissue. PQ is reduced enzymatically to PQ radical in lung where it reacts with molecular oxygen, generating reactive oxygen species (ROS). ROS damage various macromolecules including DNA. However, the ability of paraquat to mediate DNA damage is unknown. In this study, Bam H1 site (5'-GGATCC-3') on pBR322 DNA was chosen as the target sequence for a study of the PQ-mediated DNA damage. The incubation of PQ with plasmid DNA in the presence of freshly prepared rat lung microsomes and NADPH resulted in damage to the restriction site. The PQ-treated DNA was not digested with the endonuclease reflected by the digestion pattern of DNA on agarose gels. The effect was dependent on the dose of PQ. The PQ-mediated damage to DNA was comparable to DNA damage caused by ROS generated through the xanthine-xanthine oxidase system. The results of the present study suggest that ROS generated by PQ in vitro under aerobic conditions may lead to a modification of the restriction site on DNA.

Surgery for unilateral bronchiectasis: results and prognostic factors

SETTING

King Khalid University Hospital referral centre for thoracic surgery, Riyadh, Saudi Arabia.

OBJECTIVE

To assess the results of surgery and factors influencing its outcome in patients with unilateral bronchiectasis.

DESIGN

A retrospective analysis of 40 patients with unilateral bronchiectasis who were operated upon consecutively at King Khalid Hospital, between July 1987 and May 1993.

RESULTS

Left-sided disease was seen in 60% (n = 24) and right-sided in 40% (n = 16) of the patients. The entire lung was involved in 30% of cases (n = 12). Of these, the left lung was totally involved in 22.5% (n = 9) and the right in 7.5% (n = 3). A lobectomy was performed on 21 patients, basal segmentectomy with preservation of apical segment on 7, and pneumonectomy on 12. There was no operative mortality in this series. Six patients (15%) developed postoperative complications, bleeding (n = 4) and prolonged air leak (n = 2). During an average follow-up period of 30.7 months (+/- 15.4 months), 29 patients (72.5%) were cured and the remaining 11 (27.5%) improved. No patients with Pseudomonas aeruginosa infection (n = 3) or obstructive airway disease (n = 5) were cured (P = 0.02 and P = 0.002 respectively).

CONCLUSION

Curative resection for selected patients with unilateral bronchiectasis can be performed safely with good results and low morbidity. Pseudomonas aeruginosa infection and obstructive airway disease have an adverse effect on postoperative cure.

The effect of modest vitamin E supplementation on lipid peroxidation products and other cardiovascular risk factors in diabetic patients

Among many factors, elevated lipids and lipid peroxide levels in blood are major risk factors in the development of cardiovascular disease in diabetic patients. This study has examined whether oral supplementation of vitamin E, an antioxidant, has any effect on blood lipid peroxidation products (LP) and lipid profile of diabetic patients. Thirty-five diabetics(D) were supplemented with DL-alpha-tocopherol (E) capsule (orally, 100 IU/d) or placebo (P) for three months in double-blind clinical trials. Plasma E was analyzed by HPLC and LP by the thiobarbituric acid-reactivity; serum lipids by auto-analyzer. Data were analyzed using paired t-test and Wilcoxon Signed Rank Test. Vitamin E supplementation significantly lowered LP and lipid levels in diabetic patients; there were no differences in these parameters after P supplementation. There were no differences in the duration of diabetes and ages of D between P- and E- supplemented groups. This study suggests that vitamin E supplementation significantly lowers blood LP and lipid levels in diabetic patients.

Vitamin E and vitamin E-quinone levels in red blood cells and plasma of newborn infants and their mothers

OBJECTIVE

Vitamin E is a physiological antioxidant and protects cell membranes from oxidative damage. This study has determined whether vitamin E level in RBC of newborns has any relationship with its level in their mothers. We have also examined levels of vitamin E and vitamin E-quinone, an oxidized product of vitamin E, in paired samples of red blood cells (RBC) and plasma of newborns and their mothers.

METHODS

Blood was collected from 26 mothers and their full-term placental cords at delivery. Vitamin E and vitamin E-quinone levels were determined in RBC and plasma by HPLC.

RESULTS

Newborn-plasma had significantly lower vitamin E levels compared with maternal-plasma both when expressed as nmole/ml (5.5+/-0.4 vs 26.1+/-1.1, p = 0.0001) or nmole/mumole total lipids (1.9+/-0.1 vs 2.6+/-0.1, p = 0.0001). Vitamin E level in the newborn-RBC was similar to that of maternal-RBC when expressed as nmole/ml packed cells (2.77+/-0.14 vs 2.95+/-0.13), but was significantly lower when expressed as nmole/mumole total lipids (0.56+/-0.03 vs 0.64+/-0.04, p = 0.03) from that of maternal-RBC. Vitamin E-quinone levels are significantly elevated in newborns compared with their mothers both in RBC (29.4+/-2.1 vs 24.1+/-1.2, p = 0.04) and plasma (39.9+/-5.3 vs 25.3+/-4.2, p = 0.006) when expressed as nmole/mmole total lipids but not when expressed as nmole/ml. There was a significant correlation of vitamin E between newborn-plasma and newborn-RBC (r = 0.65, p = 0.0002 for nmole per ml packed RBC;r = 0.63, p = 0.0007 for nmole per mumole total lipids). The relationship between maternal plasma and newborn plasma was significant when vitamin E was normalized with nmole/mumole total lipid (r = 0.54, p = 0.007 but not when expressed as nmole/ml (r = 0.09, p = 0.64). However, vitamin E in the RBC of maternal and newborn had significant correlation when expressed as per ml packed cells (r = 0.61, p = 0.001) and per total lipid (r = 0.46, p = 0.02). There was no relationship of vitamin E-quinone levels between RBC and plasma of newborns and their mothers.

CONCLUSIONS

Elevated blood levels of vitamin E-quinone suggest increased oxidative stress and utilization of vitamin E in newborns compared to their mothers. Because vitamin E levels in RBC of newborns are lower and significantly related to vitamin E levels in RBC of their mothers, an increase in vitamin E supplementation to mothers during pregnancy may increase vitamin E levels in the newborn and help impede the effect of extrauterine oxygen toxicity.

Hyperinsulinemia in nondiabetic Asian subjects using specific assays for insulin, intact proinsulin, and des-31, 32-proinsulin

OBJECTIVE

To investigate the contributions of intact proinsulin and of des-31,32-proinsulin to fasting concentrations of insulin-like molecules in nondiabetic subjects from two ethnic groups (Asian and white) and to see whether Asian subjects are hyperinsulinemic compared with white subjects using highly specific assays for insulin.

RESEARCH DESIGN AND METHODS

We investigated subjects with normal glucose tolerance (NGT) (82 Asian and 67 white) and impaired glucose tolerance (IGT) (16 Asian and 13 white), diagnosed by using standard World Health Organization criteria. Highly specific monoclonal antibody-based assays were used to measure insulin, intact proinsulin, and des-31,32-proinsulin. An index of insulin secretion was derived as a ratio of incremental insulin to incremental glucose concentrations from 0 to 30 min during an oral glucose tolerance test.

RESULTS

Asian subjects with NGT, despite being significantly thinner than whites (BMI 24.4 +/- 3.5 vs. 25.7 +/- 3.7 kg/m2, P = 0.04), had a more central distribution of obesity (subscapsular-to-triceps skinfold ratios 1.36 +/- 0.69 vs. 1.17 +/- 0.41, P = 0.047). Asian subjects with NGT showed significant hyperinsulinemia 2 h after oral glucose load (plasma insulin median 274 pmol/l [range 26-1,505] vs. 186 pmol/l [27-720], P < 0.005) compared with whites. Asian subjects with NGT also had significantly higher insulin increments (P < 0.02) compared with white subjects and significantly higher fasting concentrations of intact proinsulin (median 2.7 pmol/l [range 0.9-14.1] vs. 2.1 [0.8-7.9], P < 0.02) but not of des-31,32-proinsulin. The ratio of proinsulin-like molecules to the total sum of three insulin-like molecules, however, was similar between Asian and white subjects with NGT and IGT.

CONCLUSIONS

These results indicate that when specific assays for insulin are used, Asian subjects show postglucose load hyperinsulinemia and fasting hyperproinsulinemia compared with white subjects, suggesting increased insulin secretion and/or the presence of underlying insulin resistance in this ethnic group. The contribution of proinsulin-like molecules to total insulin-like molecules was similar between Asian and white subjects with NGT and IGT, and there was no contribution to hyperinsulinemia in Asian subjects.

Plasminogen activator inhibitor (PAI-1) activity is elevated in Asian and Caucasian subjects with non-insulin-dependent (type 2) diabetes but not in those with impaired glucose tolerance (IGT) or non-diabetic Asians

In order to study the plasminogen activator inhibitor activity (PAI-1) in subjects at different risk of non-insulin-dependent diabetes and ischaemic heart disease we examined 89 subjects with diet controlled NIDDM (49 Caucasian, 40 Asian), 29 with impaired glucose tolerance (IGT) (13 Caucasian, 16 Asian), and 149 with normal glucose tolerance (67 Caucasian, 82 Asian). Diabetes was diagnosed by WHO criteria and highly specific, monoclonal antibody-based assays were used to measure insulin, intact proinsulin, and des 31,32 proinsulin. Subjects with NIDDM were significantly more obese, had more central distribution of obesity, higher fasting plasma specific insulin concentrations (NIDDM median 74 pmol l-1 vs IGT 41 pmol l-1, p < 0.01 and vs normals 34 pmol l-1, p < 0.001) and higher PAI-1 activity than normals and those with IGT (NIDDM 23.0 +/- 6.9 vs IGT 16.8 +/- 5.0, p < 0.001 and vs normals 17.1 +/- 6.9 AU ml-1, p < 0.001). However, PAI-1 activity was not significantly different between Asian and Caucasian normals (17.5 +/- 7.3 vs 16.5 +/- 6.4 AU ml-1, p = ns) and diabetic (22.8 +/- 7.3 vs 23.1 +/- 6.6 AU ml-1, p = ns) subjects. In addition to relationships with obesity and plasma triglyceride, PAI-1 activity, after controlling for age, sex, body mass index, and waist-hip ratio, was related to fasting insulin (partial r = 0.22, p < 0.001), intact proinsulin (partial r = 0.36, p < 0.001), and des 31,32 proinsulin concentrations (partial r = 0.33, p < 0.001) as measured by highly specific assays. The association of PAI-1 with diabetes was weakened but remained statistically significant (p = 0.042) after controlling for age, sex, ethnicity, obesity, plasma triglyceride, and all insulin-like molecules. We conclude that, although PAI-1 activity is raised in subjects with diet-treated NIDDM, it is normal in subjects with IGT and non-diabetic Asians, populations at high risk of NIDDM and ischaemic heart disease. Raised PAI-1 activity may play an important role in the pathogenesis of macrovascular disease in subjects with NIDDM, but is unlikely to explain excess risk of ischaemic heart disease in Asians and those with impaired glucose tolerance.

Lyophilized aqueous based polymer matrices for transdermal delivery of captopril

Transdermal system(s) bearing captopril were developed using a low temperature casting method and aqueous based polymers viz., eudragit RL-100 and polyvinyl pyrrolidone (PVP). The developed system(s) were subjected to an in vitro characterization study. The results were compared with the transdermal systems of the same composition prepared at room temperature. The study revealed that the system(s) prepared using the low temperature casting method performed better in comparison to those prepared at room temperature. The developed system(s) followed zero order release kinetics.

Relationship between elevated lipid peroxides, vitamin E deficiency and hypertension in preeclampsia

Preeclampsia or pregnancy-induced hypertension is a major cause of both maternal and fetal-neonatal morbidity and mortality. The deficiency of vitamin E can cause accumulation of lipid peroxidation products, which, in turn, can induce vasoconstriction. This study has examined any evidence of increased cellular lipid peroxidation and accumulation of malonydialdehyde (MDA, an end product of lipid peroxidation) in pregnancy-induced hypertension and any relationship between the elevated MDA and lower vitamin E levels with hypertension in pregnant women. EDTA-Blood was collected from pregnant women at the time of delivery. Plasma vitamin E was determined by HPLC; MDA by the thiobarbituric acid-reactivity. Subjects with diastolic blood pressure (DBP) > or = 90 mm Hg were considered hypertensive (HT) and with < 90 mm Hg normotensive (NT). Data (Mean +/- SE) from 49 NT and 11 HT women show that HT has significantly lower vitamin E (22 +/- 1 vs 27 +/- 1 nmole/ml, p < 0.03) and elevated MDA levels (0.56 +/- 0.06 vs 0.43 +/- 0.02 nmole/ml, p < 0.03) compared to NT; the ages and gestational ages of women were similar. Among all women, there was a significant positive relationship between DBP and MDA levels (r = 0.27, p < 0.05), and a significant negative relationship between vitamin E levels and DBP (-0.36, p < 0.005), and a significant negative relationship between MDA and vitamin E levels (r = 0.27, p < 0.05). Thus, HT women's plasma has significantly lower E and higher MDA levels, and DBP significantly correlates with the extent of vitamin E deficiency and increased MDA levels. This study suggests a relationship between elevated lipid peroxidation and lower vitamin E levels and hypertension in pregnancy (preeclampsia).

Heat-mediated selective delivery of liposome-associated melphalan in murine melanoma

Malignant melanoma is notable for its resistance to chemotherapy, and multimodality approaches are being investigated to improve therapeutic efficacy. Melphalan and dacarbazine are commonly used for treatment of melanoma and their effect is potentiated by hyperthermia. The present study attempts to enhance the antitumour effect of melphalan by encapsulating it in temperature-sensitive liposomes and using it in combination with localized hyperthermic treatment of tumours for targeted delivery. Small unilamellar vesicles made of synthetic lipids (distearoyl phosphatidyl choline and dipalmitoyl phosphatidyl choline), showing gel to liquid crystalline phase transition at 42 degrees C, were used for encapsulation of melphalan. In vivo antitumour efficacy of the combination of liposomal melphalan and hyperthermia was determined using B16F10 murine melanoma transplanted into C57Bl/6 mice. A significant reduction in tumour volume and increased survival time was observed in tumour-bearing mice treated with a combination of hyperthermia and thermosensitive liposome-encapsulated melphalan compared with animals treated with an equivalent dose of free melphalan with or without hyperthermia. These results suggest that hyperthermia in combination with temperature-sensitive liposome-encapsulated melphalan may serve as a useful targeted drug delivery system for more effective management of melanoma.

Cost effective computerised analysis of biological signals

A data acquisition system--using self designed and assembled A/D and D/A converter board and appropriate software--has been developed for the International Business Machine (IBM) Personal Computer and has been used for spectral analysis of bio-electric signals. Spectral analysis of EEG signals was performed and the reliability confirmed by analysis of the same data by a standard systemdeveloped by Dynalog Inc, USA. The cutting edge of the system however, lies in its extreme low cost, combined with the versatility offered due to it being a computer based system.

Deposition kinetics, metabolism and urinary excretion of sulfathiazole following oral administration in sheep

Deposition kinetics, metabolism and urinary excretion of sulfathiazole were investigated in German black head sheep following single oral administration (100 mg/kg). Kinetic evaluation of plasma levels was performed using a two-compartment best fit model. Sulfathiazole is significantly metabolized to N4-acetyl metabolite in the rumen fluid. The drug is very poorly absorbed since the minimum effective concentration in plasma was not attained at any time following oral administration. The prolonged elimination half-life in sheep may be due to a low rate of drug absorption from the rumen and gastro-intestinal tract. Sulfathiazole was mainly excreted in the urine as free drug and N4-acetyl metabolite.

Epididymal histoplasmosis diagnosed by isolation of Histoplasma capsulatum from semen

An autochthonous case of epididymal histoplasmosis masquerading as tuberculosis in a 55-year-old male patient is reported from India. It was diagnosed by culture of Histoplasma capsulatum from semen and by demonstration of the fungus upon re-examination of epididymal biopsy sections previously misinterpreted as tuberculous granuloma. The patient's main complaints were painful epididymal swelling, occasional fever and cough. He was treated successfully by excision of epididymis and vas deferens combined with amphotericin B therapy. This is believed to be the first case of epididymal histoplasmosis to be reported outside the American continent and the fourth of its type reported in the English literature. The case is also noteworthy in that H. capsulatum was isolated for the first time from semen, and it underlines the importance of mycological culture of semen specimens for diagnosis of genitourinary infections of obscure etiology.

Pattern and surgery for oesophageal carcinoma in Saudi Arabia

Forty-three patients with carcinoma of the oesophagus are presented, 30 of whom were male and 13 female, with ages ranging from 42 to 88 years. Mean duration of symptoms was 4.6 months. Of patients, 65.2% were in stage III and 30.2% in stage IIA. Stages I and IV were encountered in one patient each. Twenty-five were Saudis and 14 non-Saudis. Of the Saudi patients, 64.3% were from the Qaseem region. 48.8% had subtotal oesophagectomy with neck anastomosis and 51.2% had limited oesophagectomy with intrathoracic anastomosis. The mortality rate was 11.6% The 5-year survival rate was 33.3%. We found sex, histology, stage of disease and extent of oesophageal resection influence long-term survival.

Study of serum prealbumin and serum alpha fetoprotein in cases of fulminant hepatic failure

We studied serum prealbumin (SPA) and serum alpha fetoprotein (AFP) to assess liver cell injury and prognosis in patients with fulminant hepatic failure (FHF). We studied 21 patients of FHF of viral etiology, 10 acute viral hepatitis (AVH) and 10 healthy controls. Initial (on the day of admission) AFP levels were significantly elevated in FHF group (30.28 +/- 63.58 ng/ml, p < 0.01 compared to AVH and control group in whom it was undetectable. Serum AFP correlated well with deranged Liver Functions (LFT). In the Survivors (n = 4) of FHF, serial estimations (on Day 5 and Day 10 of admission) revealed declining AFP Levels, correlating with clinical recovery. SPA on admission was significantly reduced in FHF group (15.10 +/- 9 mg/dl p < 0.05) compared to AVH (37.0 +/- 9.34 mg/dl) and control group (40.25 +/- 5.92 mg/dl). Low SPA also correlated with deranged LFT. Serial estimations in the survivors (Day 5, Day 10) revealed rising SPA which correlated with clinical recovery.

In vitro metabolism of sulfathiazole in rumen fluid and its metabolism and disposition kinetics following intraruminal administration in sheep

The antimicrobial agents may undergo a change in the complex stomach particularly in the rumen as a result of microbial fermentation in ruminants. Present investigation deals with the influence of ruminal fluid probably the role of ruminal microorganisms on the degradation of sulfathiazole in vitro and its metabolism and disposition following its single intraruminal administration (100 mg/kg) in adult german black head sheep. Sulfathiazole is metabolized to N4-acetyl sulfathiazole in the rumen fluid after its in vitro incubation at different concentrations (10-60 micrograms/ml) for varying time intervals (1-6 h) at a temperature of 38 +/- 0.5 degrees C. Likewise in vivo it is significantly metabolized to its N-acetyl metabolite in the rumen after an intraruminal administration. The levels of sulfathiazole are maintained above minimum effective therapeutic concentration (40 micrograms/ml) for more than 24 h in rumen fluid. The drug is poorly absorbed into the circulation after intraruminal administration since the levels in plasma could not reach up to minimum effective therapeutic concentration at any time. The biological half-life of sulfathiazole was found to be 16.7 h following single intraruminal administration. Results of this investigation suggest that oral or intraruminal application of sulfathiazole has only local effects in the rumen fluid. A systemic treatment is not possible after this path of application.

Occurrence of three-stranded DNA within a RecA protein filament

A RecA protein-generated triple-stranded DNA species can be observed by electron microscopy, within narrowly defined conditions. Three-stranded DNA is detected only when initiation of normal DNA strand exchange is precluded by heterologous sequences within the duplex DNA substrate, when ATP is hydrolyzed, and when the DNA is cross-linked with a psoralen derivative prior to removal of RecA filaments. When adenosine 5'-O-(thiotriphosphate) is used, only the product hybrid duplex DNA can be cross-linked within the RecA filament. The third strand is either displaced or interwound in a conformation that does not permit cross-linking. When ATP is hydrolyzed by RecA, all three strands are cross-linked within the filament in a complex pattern that suggests a dynamic structure. This structure is altered when RecA protein is removed before cross-linking. Hsieh et al. (1990) and Rao et al. (1991, 1993) have proposed, on the basis of nuclease protection and chemical modification studies, that a stable triple-stranded DNA species can persist after removal of RecA protein. We have been unable to visualize these triple-stranded structures by the methods used in the present investigation. When RecA removal was followed immediately by interstrand cross-linking, only the two strands of the hybrid duplex DNA were cross-linked.