Investigating dysregulation of TGF-β1/SMAD3 signaling in atopic dermatitis: a molecular and immunohistochemical analysis

Atopic dermatitis (AD) is a persistent and recurring inflammatory condition affecting the skin. An expanding corpus of evidence indicates the potential participation of transforming growth factor-β1 (TGF-β1) in the modulation of inflammation and tissue remodeling in AD. The primary objective of this study was to examine the aberrant modulation of TGF-β1/small mothers against decapentaplegic homolog 3 (SMAD3) signaling through a comprehensive analysis of their molecular and protein expression profiles. The study encompassed an aggregate of 37 participants, which included 25 AD patients and 12 controls. The assessment of mRNA and protein levels of TGF-β1 and SMAD3 was conducted utilizing quantitative real-time PCR and immunohistochemistry (IHC), whereas serum IgE and vitamin D levels were estimated by ELISA and chemiluminescence, respectively. Quantitative analysis demonstrated a 2.5-fold upregulation of TGF-β1 mRNA expression in the lesional AD skin (P < 0.0001). IHC also exhibited a comparable augmented pattern, characterized by moderate to strong staining intensities. In addition, TGF-β1 mRNA showed an association with vitamin D deficiency in serum (P < 0.02), and its protein expression was linked with the disease severity (P < 0.01) Furthermore, a significant decrease in the expression of the SMAD3 gene was observed in the affected skin (P = 0.0004). This finding was further confirmed by evaluating the protein expression and phosphorylation of SMAD3, both of which exhibited a decrease. These findings suggest that there is a dysregulation in the TGF-β1/SMAD3 signaling pathway in AD. Furthermore, the observed augmentation in mRNA and protein expression of TGF-β1, along with its correlation with the disease severity, holds considerable clinical significance and emphasizes its potential role in AD pathogenesis.

Evaluation of SOCS5 mRNA and its association with serum IL-12 levels and rs41379147 SNP in various subsets of allergic disorders: A case control study

BACKGROUND

The SOCS proteins act as suppressors of cytokine signaling by impeding certain signaling pathways. SOCS5, a constituent of the SOCS family, has been associated with the management of allergic reactions, primarily by impeding the signaling of interleukin-4 (IL-4), which is known to have a cardinal function in accelerating the development of an allergic reaction. The key goal of our research was to explore the probable ramifications of the SOCS5 single nucleotide polymorphism (SNP) namely rs41379147 on the expression of SOCS5 mRNA and serum IL-12 levels, as well as to analyze the interaction between SOCS5 genotypes and various clinicopathological parameters in atopic diseases.

METHODS

The study involved the enrollment of 314 subjects comprising 154 atopic individuals and 160 healthy controls. PCR-RFLP was employed to conduct SNP analysis. Real-Time PCR was employed to quantify SOCS5 mRNA. The enzyme-linked immunosorbent assay (ELISA) technique was used for the quantification of interleukin-12 and total IgE levels in the serum while as chemiluminescence was used to determine Vitamin D levels.

RESULTS

The PCR-RFLP analysis indicated a lack of statistically significant variation in genotypic and allelic frequencies between the cases and controls (p > 0.05) for - 9147 C/T SNP either in total atopy (OR-0.70, 95% CI=0.43-1.12, p =0.15), and on subgroup stratifications of chronic urticaria (OR-0.81, 95 % CI = 0.42-1.59, p = 0.61), allergic rhinitis (OR-0.63, 95 % CI = 0.33-1.19, p = 0.16) and bronchial asthma (OR-0.66,95% CI = 0.29-1.4, p=0.32). There was reduced mRNA expression of SOCS5 in total atopic cases, allergic rhinitis, bronchial asthma and chronic urticaria in comparison to controls which advocates the fact that SOCS5 has a protective role in allergic disease development. Despite the reduced amounts of IL-12 in total atopic cases and different allergic disorders in comparison to controls, IL-12 showed significant positive correlation with SOCS5 mRNA expression (p < 0.05).

CONCLUSION

SOCS5 SNP rs41379147(C/T) does not pose any significant risk towards the development of any allergic disorder and has no impact on the expression of SOCS5 and IL-12. Our study has shown the reduced mRNA expression of SOCS5 among individuals diagnosed with chronic urticaria, allergic rhinitis and bronchial asthma and the expression of SOCS5 showed complete dependence on the cytokine milieu of IL12. The modulation of SOCS5 and IL-12 may represent potential curative targets for treating the menace of allergic diseases and present promising avenues for future investigation.

Analysis of intronic SNP (rs4147358) and expression of SMAD3 gene in Atopic Dermatitis: A case-control study

BACKGROUND

Atopic Dermatitis (AD) is a multifactorial cutaneous disorder associated with chronic inflammation of the skin. Growing evidence points to TGF-β/SMAD signaling as a key player in mediating inflammation and the subsequent tissue remodeling, often resulting in fibrosis. This study investigates the role of a core transcription factor involved in TGF-β signaling i.e., SMAD3 genetic variants (rs4147358) in AD predisposition and its association with SMAD3 mRNA expression, serum IgE levels, and sensitization to various allergens in AD patients.

METHODS

A total of 246 subjects including 134 AD cases and 112 matched healthy controls were genotyped for SMAD3 intronic SNP by PCR-RFLP. mRNA expression of SMAD3 was determined by quantitative Real-Time PCR (qRT-PCR), Vitamin-D levels by chemiluminescence, and total serum IgE levels by ELISA. In-vivo allergy testing was performed for the evaluation of allergic reactions to house dust mites (HDM) and food allergens.

RESULTS

A significantly higher frequency of mutant genotype AA (cases: 19.4% vs controls: 8.9%) (OR = 2.8, CI = 1.2 - 6.7, p = 0.01) was observed in AD cases. The mutant allele 'A' also showed a 1.9-fold higher risk for AD compared to the wild allele 'C' indicating that the carriers of the A allele have a higher risk for AD predisposition (OR-1.9, CI = 1.3-2.8, p < 0.001). In addition, quantitative analysis of SMAD3 mRNA in peripheral blood showed 2.8-fold increased expression in AD cases as compared to healthy controls. Stratification analysis revealed the association of the mutant AA genotype with deficient serum Vitamin D levels (p = 0.02) and SMAD3 mRNA overexpression with HDM sensitization (p = 0.03). Furthermore, no significant association of genotypes with SMAD3 mRNA expression was observed.

CONCLUSION

Our study indicates that SMAD3 intronic SNP bears a significant risk of AD development. Moreover, overexpression of SMAD3 mRNA and its association with HDM sensitization highlights the possible role of this gene in AD pathogenesis.

Unveiling the TGF- β1 paradox: Significant implication of TGF- β1 promoter variants and its mRNA and protein expression in atopic dermatitis

BACKGROUND

Atopic Dermatitis (AD) is a chronic inflammatory skin disorder with evidence of lichenification in later stages. There is mounting evidence supporting the role of TGF- β1 in mediating inflammation as well as subsequent tissue remodeling, often resulting in fibrosis. Given the role of genetic variants in the differential expression of TGF-β1 in various diseases, this study seeks to ascertain the role of TGF-β1 promoter variants (rs1800469 and rs1800468) in AD susceptibility, as well as their association with TGF- β1 mRNA expression, TGF- β1 serum levels and skin prick test positivity in Atopic Dermatitis patients.

METHODS

An aggregate of 246 subjects including 134 AD cases and 112 matched healthy controls were genotyped for TGF-β1 promoter polymorphisms by PCR-RFLP. TGF- β1 mRNA was quantified by quantitative Real-Time PCR (qRT-PCR), Vitamin-D levels by chemiluminescence, and serum TGF- β1, and total IgE levels were determined by ELISA. In-vivo allergy testing was performed for the evaluation of allergic reactions to house dust mites and food allergens.

RESULTS

A higher frequency of TT genotypes of rs1800469 (OR = 7.7, p = 0.0001) and GA+AA genotypes of rs1800468 (OR-4.4, p < 0.0001) were observed in AD cases than those in controls. Haplotype analysis demonstrated that TG haplotype carriers had an increased risk of AD (p = 0.013). Quantitative analysis revealed a significant upregulation of both mRNA (p = 0.0002) and serum levels (p < 0.0001) of TGF- β1 with a substantial positive correlation between them (Correlation coefficient=0.504; p = 0.01). Moreover, serum TGF-β1 levels were associated with quality of life (p = 0.03), the severity of the disease (p = 0.03), and House dust mite allergy (p = 0.01) whereas TGF-β1 mRNA levels positively correlated with disease severity(p = 0.02). Stratification analysis revealed that the TT genotype of rs1800469 was associated with higher IgE levels (p = 0.01) and eosinophil percentage(p = 0.007) whereas the AA genotype of rs1800468 correlated with elevated serum IgE levels (p = 0.01). Besides, no significant association of genotypes with mRNA and serum expression of TGF-β1 was observed.

CONCLUSION

Our study indicates that TGF-β1 promoter SNPs bear a significant risk of AD development. Moreover, upregulation of TGF-β1 mRNA and serum levels and their association with disease severity, quality of life, and HDM allergy suggests its role as a diagnostic/prognostic biomarker that could help in the development of new therapeutic and prevention strategies.

Gene variants and mRNA expression analysis of SOCS3 and its association with serum IL-4 levels in atopic diseases

BACKGROUND

The suppressors of cytokine signaling (SOCS) are a class of negative regulators for several aspects of cytokine signaling that have been attributed to the pathophysiology of inflammatory disorders. Given the role of the SOCS3 gene in regulating Th2 cell proliferation, our study aimed to analyze two SOCS3 SNPs viz. rs8074003 and rs7222391, and their potential influence on IL-4 levels and SOCS3 mRNA expression besides analyzing the interaction of the SOCS3 genotypes with the various clinicopathological parameters.

METHODS

A total of 314 subjects including 154 atopic cases and 160 healthy controls were genotyped for SOCS3 polymorphisms by PCR-RFLP. SOCS3 mRNA was quantified by Real-Time PCR. The serum IL-4 and total IgE levels were determined by ELISA and Vitamin-D levels were quantified by chemiluminescence.

RESULTS

The CC genotype of rs8074003 was more frequent in atopic cases and posed a 3- fold risk of atopy (p = 0.001) whereas CG and GG genotypes were widespread in the controls (p = 0.1). For the other SNP rs7222391, there was no difference in genotypic and allelic distribution. The SOCS3 mRNA expression and serum IL-4 levels were substantially increased in the atopic cases with a significant positive correlation between them (p < 0.05).

CONCLUSION

SOCS3 SNP rs8074003 poses a convincing risk of atopic disease development. The SOCS3 expression and IL-4 levels were up-regulated in total atopy and in its different presentations. It seems plausible to target SOCS3 and IL-4 as a potential target for the diagnosis of atopy and for the development of reliable personalized therapeutic strategies to control atopic conditions.

Biochemical Factors associated with Breast Cancer in Bangladeshi Women

Breast Cancer is the commonest maligrancy in woment. A study was carried out in the Department of Biochemistry, Dhaka Medical College to investigate some of the biochemical features that are associated with breast cancer occurring in Bangladeshi women. Thirty diagnosed breast cancer patients and thirty healthy women were selected. A questionnaire was used for collecting information regarding age, family history, physical activity and exercise, BMI, diet, smoking, alcohol abuse, addiction, details of menstrual and obstetric history, breast-feeding, parity, use of contraceptives and HRT. Blood samples were collected and tested for fasting lipid profiles, serum estrogen and progesterone. The study has revealed that high levels of serum total cholesterol (P<0.05), TAG (P<0.05), LDL-C (P<0.05) and low level of serum and HDL-C (P<0.05) were found to be associated with breast cancer. The study further reveals that blood levels of estrogen (P<0.05) and progesterone (P<0.05) were found to be lower than that of the controls. DOI: http://dx.doi.org/10.3329/bjmb.v6i2.17644 Bangladesh J Med Biochem 2013; 6(2): 58-62

Risk factors of acute coronary syndrome among Bangladeshi people

Two hundred consecutive patients of acute coronary syndrome aged 30-80 years (inclusive) admitted to the coronary care unit of National institute of Cardiovascular Diseases, Dhaka, were prospectively recruited as cases. Two hundred controls were prospectively selected either from individuals attending in the Shaheed Suhrawardy Medical College Hospital, admitted for elective surgery or in medicine ward for conditions that were unlikely to confound a comparative analysis. The Cases had significantly lower yearly incomes than controls, and significantly higher number of cases is occupied as sedentary worker. Smoking was an important risk factor. About 70% of cases and 45% of controls smoked previously cigarettes. Consumption of non smoke tobacco is another risk factor. The high risk of IHD in developing countries attributed to low consumption of fruit and vegetables, and in our study regular consumption of fruits (taking fruit at least 4 days a week) shows 20.5% cases and 33% of controls (OR 0.524, 95%CI 0.333-0.823) and p value was 0.005. Around 23.5% of the cases were diabetic compared with 4.5% of controls. We found 5% cases and 1.5% controls having known dyslipidemia. Although the body-mass index of cases was 24.68±3.06 Kg/M² and controls 20.54±4.37 Kg/M². The WHR was also significantly greater in cases 0.98±0.05M vs. controls 0.93±0.102M (p<0.001). About 31% of cases and 2% of controls had past history of myocardial infarction. The most predictive independent variables were previous smoking (p<0.001), WHR (p<0.001), history of hypertension (p<0.001), and income (p<0.001). Smoking and WHR were associated with the highest risks. The variables revealed to be significantly associated with acute coronary syndrome by bivariate analyses were all entered into the model directly. Eleven variables entered into the model. Of them Age, occupation, family income (yearly), fruit consumption, known hypertension, known DM, known dyslipidemia, previous MI, previous smoking, BMI and Waist and hip ratio were found to be the independent predictors of acute coronary syndrome. The study found that smoking tobacco, diabetes mellitus, hypertension, visceral obesity and less fruit intake are the important factors of acute coronary syndrome in Bangladesh.

High-dose thiamine therapy for patients with type 2 diabetes and microalbuminuria: a randomised, double-blind placebo-controlled pilot study

AIMS/HYPOTHESIS

High-dose supplements of thiamine prevent the development of microalbuminuria in experimental diabetes. The aim of this pilot study was to assess whether oral supplements of thiamine could reverse microalbuminuria in patients with type 2 diabetes.

METHODS

Type 2 diabetic patients (21 male, 19 female) with microalbuminuria were recruited at the Diabetes Clinic, Sheikh Zayed Hospital, Lahore, Pakistan, and randomised to placebo and treatment arms. Randomisation was by central office in sequentially numbered opaque, sealed envelopes. Participants, caregivers and those assessing the outcomes were blinded to group assignment. Patients were given 3 x 100 mg capsules of thiamine or placebo per day for 3 months with a 2 month follow-up washout period. The primary endpoint was change in urinary albumin excretion (UAE). Other markers of renal and vascular dysfunction and plasma concentrations of thiamine were determined.

RESULTS

UAE was decreased in patients receiving thiamine therapy for 3 months with respect to baseline (median -17.7 mg/24 h; p < 0.001, n = 20). There was no significant decrease in UAE in patients receiving placebo after 3 months of therapy (n = 20). UAE was significantly lower in patients who had received thiamine therapy compared with those who had received placebo (30.1 vs 35.5 mg/24 h, p < 0.01) but not at baseline. UAE continued to decrease in the 2 month washout period in both groups, but not significantly. There was no effect of thiamine treatment on glycaemic control, dyslipidaemia or BP. There were no adverse effects of therapy.

CONCLUSIONS/INTERPRETATION

In this pilot study, high-dose thiamine therapy produced a regression of UAE in type 2 diabetic patients with microalbuminuria. Thiamine supplements at high dose may provide improved therapy for early-stage diabetic nephropathy.

TRIAL REGISTRATION

CTRI (India) CTRI/2008/091/000112.

FUNDING

Pakistan Higher Education Commission.

Congenital heart disease and associated malformations in children with cleft lip and palate in Pakistan

Children with cleft lip and palate often have other associated malformations. The reported incidence and types of associated malformations vary between different studies. There is a great paucity of literature on the subject from the region in general and none from Pakistan at all. The purpose of this study was to assess the frequency of associated malformations, particularly congenital heart disease, in children with cleft lip and palate presenting to the Aga Khan University (AKU) and Murshid Hospital (MH). From 1st October 1999 to 31st March 2002, all children with cleft lip and palate who presented to AKU and MH were prospectively enrolled in the study group. Socio-demographic characteristics and a number of other variables were documented. All children underwent a thorough clinical examination and an echocardiogram as part of the study protocol. 123 children formed the study group. Thirty-five (29%) of these children were found to have associated malformations. The most common of these was congenital heart disease, which accounted for 51% of all associated malformations. Thirty percent of cleft palate children had associated anomalies while 27% of cleft lip, with or without cleft palate, children had associated anomalies. There was a significant association between children born of a consanguineous marriage and the risk of associated malformations (p-value: 0.001). Consanguinity was present in 74% of children with associated anomalies as compared to 40% of children with no associated anomaly. Dysmorphic features and the presence of associated anomalies were also significantly associated (p-value: 0.009). Dysmorphic features were present in 46% of children with anomalies as compared to 21% of children with no associated anomaly. Fifty percent of children with associated anomalies had a low birth weight compared to 34% of children with no anomalies, but the difference was not statistically significant. The presence of consanguinity in a child with dysmorphic features should raise the suspicion of an associated anomaly. The likelihood of this being a cardiac defect is high and should be ruled out with a thorough clinical examination, supplemented with an echocardiogram in certain cases.

Effect of the administration of recombinant activated factor VII (rFVIIa; NovoSeven) in the management of severe uncontrolled bleeding in patients undergoing heart valve replacement surgery

Recombinant activated factor VII (rFVIIa; NovoSeven, Novo Nordisk A/S, Bagsvaerd, Denmark) is being increasingly used to secure haemostasis in difficult clinical situations. The role of rFVIIa in the treatment of patients undergoing open-heart surgery for valvular heart disease was evaluated in an open pilot study. Study objectives included evaluation of blood loss, haemostatic effect and safety and laboratory parameters following rFVIIa administration. To date, we have treated five patients (one child aged 2.5 years and four adults) undergoing surgical procedures including arterial switch, closure of atrial septal defect and De Vega's procedure (mitral valve replacement with tricuspid valve repair). Four patients received rFVIIa intraoperatively, while the fifth received it postoperatively. Satisfactory haemostasis was achieved with a single dose (30 microg/kg) of rFVIIa. Four hours after treatment mean blood loss was 262.5 ml for adults (220-334 ml) and 85 ml for the child. No significant adverse events were reported. Laboratory parameters indicated a mean 18.5-fold (range 3.7-42) increase in FVII levels at 30 min postinjection and a mean reduction of 12 s (range 3-39 s) in prothrombin time. In conclusion, rFVIIa represents an effective and well-tolerated treatment for serious bleeding episodes both during cardiac surgery and postoperatively.

Fulminant septicaemic syndrome of Bacillus cereus: three case reports

Three patients with acute leukaemia, who were severely neutropenic and iatrogenically immunosuppressed post-chemotherapy, developed rapidly fatal septicaemic shock and coma caused by Bacillus cereus (B. cereus). The illness was marked by two phases: a mild febrile illness lasting 6-14 h and accompanied by subtle symptoms of autonomic sympathetic nervous system overactivity, and a second short fulminant one, marked by high fever of 40-41 degrees C accompanied by major central nervous system disturbances, and ending with deep coma and brain stem dysfunction. One patient developed the sepsis in spite of 4 days of coverage with amikacin. In the other two patients, amikacin was commenced at the earliest phase of the infection, but failed to influence the outcome. This form of B. cereus sepsis in neutropenic patients seems to be caused by strains capable of causing bacteraemia and meningitis and has the ability to produce a substance that causes leptomeningeal and neuronal necrosis. Lack of early clinical and laboratory markers inevitably leads to death. Use of antibiotics effective against B. cereus and capable of achieving high concentrations in the cerebrospinal fluid. and identification and neutralization of the necrotizing substance may hopefully help to reverse this fatal illness.

Randomised prospective masked study comparing patient comfort following the instillation of topical proxymetacaine and amethocaine

AIMS

To evaluate the claim that topical proxymetacaine produces little or no discomfort on instillation by comparing it against topical amethocaine.

METHODS

This randomised, masked, double blind, prospective study involved 53 consecutive patients. Each patient received one drop of amethocaine 0.5% in one eye and one drop of proxymetacaine 0.5% in the other. The duration of the stinging sensation and degree of discomfort (using descriptive and a linear analogue method) for each topical anaesthetic was assessed.

RESULTS

The mean duration of stinging was 3.2 seconds for proxymetacaine and 22.1 seconds for amethocaine the difference being statistical significant (p < 0.001). The mean descriptive discomfort score was 2.6 for proxymetacaine and 14.2 for amethocaine (p = 0.01). The mean linear analogue score was 5.8 for proxymetacaine and 35.6 for amethocaine (p < 0.001). Proxymetacaine had a successful tonometry rate of 93% and amethocaine 98%.

CONCLUSION

This clinical study confirms that proxymetacaine is more comfortable on instillation than amethocaine. Minimising unnecessary patient discomfort is not only ideal, but encourages cooperation in apprehensive patients especially in children.

Effect of dialysis on bleeding time in chronic renal failure

Renal failure is associated with severe haemorrhagic complications. Platelets play an important role in coagulation and their dysfunction may be responsible for the bleeding tendency in these patients. Sixty patients with advanced renal failure were investigated for bleeding tendency due to platelet dysfunction. The pre-dialysis platelet count was 46 to 325 x 10(9)/L) (mean 166 x 10(9)/L). Post-dialysis platelet count was 60 to 310 x 10(9)/L, (mean 172 x 10(9)/L) Pre-dialysis mean bleeding time (BT) was 4.95 +/- 0.27 minutes (range 1.30 to 20 minutes). Thirty-three patients (55%) had prolonged BT before dialysis. Mean BT in all patients after dialysis was 2.46 +/- 0.24 minutes (range 1.15 to 10 minutes). BT was corrected in 27 (81.8%) out of 33 patients with prolonged BT before dialysis. In 6 patients (10%) it remained prolonged. This improvement in BT after dialysis was statistically significant (p value < 0.001). Both peritoneal and hemodialysis resulted in significant improvement in bleeding time.

Severe aquired haemophilia A treated with recombinant factor VIIa

Acquired haemophilia can be associated with various conditions including pregnancy, autoimmune diseases and lymphoproliferative disorders, though often no underlying cause is found. It often presents with a rapid onset of muscle bleeding and involves the IgG antibody. It may be treated with human or porcine factor VIII (FVIII), prothrombin complex concentrates, factor IX (FIX) complex concentrates, factor VIIa (FVIIa) or by immunosuppression. We report a case of acquired haemophilia in a 40-year-old woman diagnosed following laparotomy. She was treated unsuccessfully using human FVIII and cryoprecipitate, porcine FVIII and FIX complex concentrate, before being treated with recombinant FVIIa (NovoSeven, Novo Nordisk). On treatment with recombinant FVIIa, bleeding stopped rapidly with no side-effects and the abdominal haematoma was evacuated with minimal post-operative bleeding.

The experience of bone marrow transplantation at riyadh armed forces hospital

This is a report about the program of bone marrow transplantation (BMT), which was established in 1989 at the Armed Forces Hospital in Riyadh, Saudi Arabia. We follow the strict international protocol of pre transplant assessment of the donor and the recipient, BMT conditioning by Cyclosphosphamide and Basulphan or body irradiation, BM harvest and processing, graft versus host disease prophylaxis by cyclosporin and methotrexate, and post-transplant care. Since the start of the BMT programme at the Armed Forces Hospitals in Riyadh in May 1989 and until the end of March 1996, fifty nine allogeneic and one autologous transplants have been performed. Chronic myelocytic and acute myeloid leukemia were the principal indications for BMT in our institute. The acturial five years survival of BMT in these two conditions was 67% and 47% respectively. Besides allografting, we finished the preparations for autologus BMT and peripheral blood stem cells transplantation, which may be used for treating patients with solid tumors and leukemias who are not suitable for allogenic transplantation due to older age or donor unavailability.

Haemolytic uraemic syndrome in children

Of the 4070 children admitted in the department of paediatrics, 830 (24%) presented with diarrhoea. Eleven of these had haemolytic ureamic syndrome (HUS) characterised by microangiopathic haemolytic anaemia, thrombocytopenia and acute renal failure. Only 3 had positive stool cultures (E. Coli 2, shigella dysenteriae 1). Two children expired while the rest recovered with conservative management and peritoneal dialysis. Thus HUS should be remembered as a complication of diarrhoea and a cause of acute renal failure in children.

Infusion intravenous pyelography and renal function. Effects in patients with chronic renal insufficiency

Acute renal failure (ARF) following infusion intravenous pyelography (IVP) has been reported in patients with chronic renal insufficiency, particularly diabetics. Renal function was evaluated before and after infusion IVP in 40 patients with chronic renal insufficiency. In 11 of 12 (92%) diabetics and 17 of 28 (61%) nondiabetics, a 25% or greater increase in serum creatinine values and/or decrease in creatinine clearance was noted after IVP despite adequate hydration in all patients. The maximum decrease in kidney function occurred within three days and usually returned to or near pre-IVP levels in seven to ten days. At least 70% of the patients had hypertension and/or evidence of vascular disease. The data suggest that preexisting vascular disease in the kidney, possibly associated with the known vasoconstricting effects of contrast media, may be an important factor in the ARF following infusion IVP.

Effects of acetazolamide on proximal tubule C1, Na, and HCO3 transport in normal and acidotic dogs during distal blockade

It has been suggested that the establishment of a tubular fluid to plasma chloride gradient in the late proximal tubule by the reabsorption of bicarbonate (and other anions) in the early proximal tubule is responsible for a significant part of sodium chloride and water reabsorption in the proximal tubule. In the present study the effects of acetazolamide on proximal tubule water and electrolyte excretion were examined in 6 normal dogs and 10 chronic ammonium chloride-loaded dogs during distal blockade produced by ethacrynic acid and chlorothiazide administration. During distal blockade control urine/plasma osmolality and urine/plasma sodium were close to unity in all experiments. Urine/plasma chloride and urine/plasma bicarbonate were 1.21+/-0.02 and 0.75+/-0.07 in normal and 1.24+/-0.01 and 0.04+/-0.01 in acidotic dogs, respectively. After the administration of acetazolamide (20 mg/kg i.v.), there was a significant increase in urine flow, absolute and fractional excretion of sodium, bicarbonate, and chloride in all animals. Associated with these effects, urine/plasma osmolality and urine/plasma sodium remained unchanged but urine/plasma chloride decreased significantly to 1.15+/-0.01 in normal and to 1.19+/-0.01 in acidotic dogs. In acidotic dogs there was a significant correlation between the increase in bicarbonate, sodium, or chloride excretion after acetazolamide and the plasma bicarbonate level (range 6.8-12.5 meq/liter). These data demonstrate a significant effect of acetazolamide on bicarbonate, sodium, and chloride reabsorption in the proximal tubule even in the face of severe acidosis. Moreover, the data suggest that the decrease in chloride reabsorption (and accompanying sodium) after acetazolamide is related to the decrease in bicarbonate reabsorption and the associated decrease in the transtubular chloride gradient.