A Case Report on an Unusual Presentation of Pernicious Anemia.

Pernicious anemia is an autoimmune disease leading to impaired absorption of dietary cobalamin. Patients with pernicious anemia can present with multiple hematological, neurological and gastrointestinal complaints. Herein, we have a case of pernicious anemia presenting with alternating bowel habit. This was challenging and unique as the patient didn't have any usual condition responsible for alternating bowel habit and it is not reported in cases of pernicious anemia either. The case is a 46-year-old male who was admitted with alternating bowel habit, paresthesia and fever for the last 6 months. Patient was found to be severely anemic. After full workup, he was diagnosed with pernicious anemia. The patient was treated with IM Injections of Vitamin B12. After 3 months of discharge, the patient was free of all the symptoms. This case emphasizes the importance of investigating anemic patients with alternating bowel habit for pernicious anemia and also the need to exclude other causes of this symptom before labeling it as pernicious anemia only.

Current Trends of Using Antimicrobials at Obstetrics and Gynaecology Department in a Tertiary Care Hospital.

This cross-sectional descriptive study was done to analyse the current trends of using antimicrobials in various surgical procedures at Obstetrics and Gynaecology department in Mymensingh Medical College Hospital, Mymensingh from July 2014 to June 2015. Among 300 postoperative obstetrics and gynaecological surgery cases, samples were selected as non-random purposive selection method where pattern of using antimicrobials were analysed by SPSS method 20.1 versions. The incidence of antimicrobial resistance is on continued rise with a threat to return to the pre-antibiotic era. This has led to emergence of such bacterial infections which are essentially untreatable by the current armamentarium of available treatment options. Now-a-days variation of choosing antibiotic are quietly accepted in Obstetrics and Gynaecology department as prophylaxis purpose to control life threatening conditions such as postoperative wound infection, septicaemia, urinary tract infection etc. The data analysis revealed that among 300 obstetrical and gynaecological surgeries, Nitroimidazoles (93.33%), Cephalosporins (91%) and Aminoglycosides (59%) group were most commonly used antimicrobials in both obstetrics and gynaecological surgeries. Metronidazole (93.33%), Ceftriaxone (68.66%), Gentamicin (60.33%), Cefuroxime (48%), Flucloxacillin (42%), Cefixime (27%) were the most commonly used antimicrobials at obstetrics and gynaecology department. Combination of Ceftriaxone, Metronidazole and Gentamicin (37.66%), Ceftriaxone and Metronidazole (25.33%), Cefuroxime, Metronidazole and Gentamicin (16%), Ciprofloxacin, Metronidazole and Gentamicin (5.33%) were most commonly used antimicrobials postoperatively. Total mean duration of antimicrobial therapy was 10.45 days. Antibiotics are useful in prevention of infection. But indiscriminately use of antibiotics without any guideline may lead to antimicrobial resistance. So, antimicrobial surveillance committee should be formed by hospital authority to know the local using pattern of antibiotics.

Psychiatric Disorders in Drop out from Educational Attainment Attending Mental Health Facilities: A Descriptive Cross Sectional Study.

Studies of the impact of mental disorders on educational attainment are rare. Mental disorders, those beginning in childhood or adolescence may increase the risk of early drop out from education. The latter has been shown to have adverse life-course consequences on individuals such as greater demand on social welfare entitlements. A descriptive cross sectional study was carried out at the department of Psychiatry, Comilla Medical College, Comilla, Bangladesh. All cases were selected from patients attending at Comilla Medical College Hospital and Private Mental Health Facilities in Comilla City from March 2015 to February 2016. We found out the psychiatric disorders and socio-demographic status of patients with educational drop out over the early life course. A total of 50 dropout patients aged 10 to 30 years who fullfiled the enrolment criteria included in the study. Sociodemographic questionnaires, diagnostic information (DSM-5 and ICD-10) as well as an account of a various level of education were used as research instruments. The Frequency tables, summary tables and appropriate graphs were prepared to describe the population characteristics and study finding. The most of the psychiatric morbidity presents in male (62%) and age group of 18-24 years (54%). In this study, anxiety disorders was 8%, behaviour/ impulse control disorders was 8%, mood disorders was 16%, substance use disorders was 24%, schizophrenia spectrum disorders was 12% and composite psychiatric disorders was 32%. Among drop out patient's non- completion of primary education was 14%, non-completion of secondary education was 20%, non- completion of higher secondary education was 24%, not entry to tertiary education was 12% and non-completion of tertiary education was 30%. Among behaviour/impulse control disorders non-completion of primary education was 6%, substance use disorders non-completion of higher secondary education was 10%, mood disorder both non-completion of higher secondary education and non-completion of tertiary education were 6%. Among composite psychiatric disorders non-completion of secondary education, non-completion of higher secondary education and non-completion of tertiary education were 8%, 6% and 12% respectively. Onset of mental disorders and subsequent drop out from education was found in this study. Further multi-centered prospective and population-based studies should be designed to find out the exact situation.

Menstrual pattern among adolescent girls of Pokhara Valley: a cross sectional study.

BACKGROUND: Menstruation is a normal physiological process occurring every month throughout the reproductive age of the females. However, significant variation in menstrual pattern is observed among adolescents. The objective of this study was to determine menstrual pattern among adolescent girls of Pokhara Valley. METHOD: A cross sectional study was conducted in seven schools of Pokhara Valley. A total of 260 adolescent girls were included in the study. Girls were requested to complete questionnaire containing 19 items. Selected girls voluntarily agreed to answer questionnaire under the supervision of the researcher and then the data was analyzed. RESULTS: Mean age of the girls was 14.0 ± 1.3 years. Mean age at menarche was 12.2 ± 0.9 years. The mean cycle length of the subjects was 34.8 ± 11.8 days. It was observed that as many as 167(64.2%) girls had irregular menstrual cycle and significant association was found between regularity of menstruation and ethnicity. Seven (2.7%) girls had a menstrual cycle length shorter than 21 days, 60(23.1%) had cycle longer than 35 days and 193(74.2%) had a normal cycle length between 21 and 35 days. Majority 231(88.8%) had normal duration of menstruation. Dysmenorrhoea was reported by more than half of the girls and significant association was found between severity of dysmenorrhoea with school absenteeism and treatment needed. CONCLUSION: Dysmenorrhoea was the most common menstrual problem among adolescent girls. Girls' school attendance was affected due to menstrual pain. Girls with severe dysmenorrhea needed medical treatment. Irregular menstruation was reported by more than half of the girls and significant association was found with the ethnicity.

A consortium of non-rhizobial endophytic microbes from Typha angustifolia functions as probiotic in rice and improves nitrogen metabolism.

Endophytic microbes isolated from plants growing in nutrient-deficient environments often possess properties that improve nutrition of agriculturally important plants. A consortium of non-rhizobial endophytic microbes isolated from a macrophyte Typha angustifolia growing in the marginal wetlands associated with a Uranium mine was characterized for their beneficial effect on rice and the mechanisms of growth promotion were investigated. The microbes were identified and characterized for their potential plant growth promoting (PGP) properties. Effect of these microbes on nitrogen (N)-metabolism of rice was tested as Typha endophytes were predominantly (N)-fixing. Relative N-use efficiency and expression of genes involved in N-uptake and assimilation were investigated in treated plants. Evidence of horizontal gene transfer (HGT) of dinitrogen reductase gene was observed within the consortium from a Pseudomonas stutzeri strain. The consortium behaved as plant probiotic and showed substantial growth benefits to Typha, their natural host as well as to rice. Typha endophytes colonized rice endosphere significantly increasing biomass, shoot length and chlorophyll content in rice plants both under N-sufficient and N-deficient conditions. N-uptake and assimilation genes were upregulated in plants treated with the endophytes even after three weeks post infection. Our results suggested, HGT of nitrogen-fixation trait to be highly prevalent among endophytes isolated from nutrient-poor habitats of the uranium mine. A long-term nitrogen deficiency response in the treated plants was elicited by the consortium improving N-uptake, assimilation and relative N-use efficiency of rice plants. This appeared to be at least one of the main strategies of plant growth promotion.

Computer Decision Support Changes Physician Practice But Not Knowledge Regarding Autism Spectrum Disorders.

OBJECTIVE: To examine whether adding an autism module promoting adherence to clinical guidelines to an existing computer decision support system (CDSS) changed physician knowledge and self-reported clinical practice. METHODS: The CHICA (Child Health Improvement through Computer Automation) system, a CDSS, was enhanced with a module to improve management of autism in 2 of the 4 community pediatric clinics using the system. We examined the knowledge and beliefs of pediatric users using cross-sectional surveys administered at 3 time points (baseline, 12 months and 24 months post-implementation) between November 2010 and January 2013. Surveys measured knowledge, beliefs and self-reported practice patterns related to autism. RESULTS: A total of 45, 39, and 42 pediatricians responded at each time point, respectively, a 95-100% response rate. Respondents' knowledge of autism and perception of role for diagnosis did not vary between control and intervention groups either at baseline or any of the two post-intervention time points. At baseline, there was no difference between these groups in rates in the routine use of parent-rated screening instruments for autism. However, by 12 and 24 months post-implementation there was a significant difference between intervention and control clinics in terms of the intervention clinics consistently screening eligible patients with a validated autism tool. Physicians at all clinics reported ongoing challenges to community resources for further work-up and treatment related to autism. CONCLUSIONS: A CDSS module to improve primary care management of ASD in pediatric practice led to significant improvements in physician-reported use of validated screening tools to screen for ASDs. However it did not lead to corresponding changes in physician knowledge or attitudes.

Role of folic Acid on symptoms of chronic arsenic toxicity.

BACKGROUND: Chronic arsenic toxicity (Arsenicosis) due to drinking of arsenic contaminated ground water is a global problem. However, its treatment is unsatisfactory. Methylation of arsenic facilitates its urinary excretion. Persons with relatively lower proportion of urinary dimethyl arsenic acid (DMA) are found to have at greater risk of developing symptoms of arsenicosis including its complications. The biochemical pathway responsible for methylation of arsenic is a folate-dependent pathway. Studies in rodents and humans suggest that folate nutritional status influences the metabolism of arsenic. METHODS: The present study compares the effect of giving folic acid on 32 arsenicosis patients during a 6-month period and comparing the results with clinical effect of taking only arsenic-free safe water on 45 age and sex-matched arsenic-affected people for the same period. RESULTS: There was significant improvement of arsenical skin lesion score of both patients treated with folic acid (2.96 ± 1.46 to 1.90 ± 0.90, P < 0.001) and arsenic free safe water (2.91 ± 1.26 to 1.62 ± 1.05, P < 0.001) for a period of 6 months. Significant improvement in systemic disease score was also observed from the baseline systemic score in folic acid treated group (4.78 ± 3.43 to 1.00 ± 1.56, P < 0.001) and the group treated with arsenic-free water (1.87 ± 2.11 to 0.82 ± 1.62, P < 0.001). However, there was a significant increased improvement of systematic disease score in the folic acid treated group compared to the control group taking arsenic free water (P < 0.001). CONCLUSIONS: This study provides evidence that folic acid treatment in arsenicosis cases could help in reducing clinical symptoms of arsenicosis.

Seasonal and diel variations of ammonia and methane emissions from a naturally ventilated dairy building and the associated factors influencing emissions.

Understanding seasonal and diel variations of ammonia (NH3) and methane (CH4) emissions from a naturally ventilated dairy (NVD) building may lead to develop successful control strategies for reducing emissions throughout the year. The main objective of this study was to quantify seasonal and diel variations of NH3 and CH4 emissions together with associated factors influencing emissions. Measurements were carried out with identical experimental set-up to cover three winter, spring and summer seasons, and two autumn seasons in the years 2010, 2011, and 2012. The data from 2010 and 2011 were used for developing emission prediction models and the data from 2012 were used for model validation. The results showed that NH3 emission varied seasonally following outside temperature whereas CH4 emission did not show clear seasonal trend. Diel variation of CH4 emission was less pronounced than NH3. The average NH3 and CH4 emissions between 6a.m. and 6p.m. were 66% and 33% higher than the average NH3 and CH4 emissions between 6p.m. and 6a.m., respectively for all seasons. The significant relationships (P<0.0001) between NH3 and influencing factors were found including outside temperature, humidity, wind speed and direction, hour of the day and day of the year. The significant effect (P<0.0001) of climate factors, hours of the day and days of the year on CH4 emission might be directly related to activities of the cows.

Encoding a superantigen by Staphylococcus aureus does not affect clinical characteristics of infected atopic dermatitis lesions.

BACKGROUND: Bacterial infection with Staphylococcus aureus is a known trigger for the worsening of atopic dermatitis (AD). Staphylococcal superantigens have been theorized to make a potential contribution to this worsening of AD seen with infection. OBJECTIVES: We sought to assess whether encoding a superantigen by S. aureus affects the inflammatory characteristics of impetiginized AD skin lesions. METHODS: Fifty-two children with clinically impetiginized lesions of AD which were positive for S. aureus were enrolled in this study. A lesion was graded clinically using the Eczema Area and Severity Index (EASI), and then wash fluid was obtained from the lesion for quantitative bacterial culture, and measurement of bacterial products lipoteichoic acid and staphylococcal protein A and cytokines. The staphylococcal isolate was tested for antibiotic susceptibilities and the presence of a superantigen. RESULTS: Fifty-four per cent (28 of 52) of the staphylococcal isolates encoded a superantigen. The presence of a superantigen had no significant effect on EASI score, amounts of bacterial products or inflammatory cytokines in the AD lesion. CONCLUSIONS: These studies suggest that the expression of a superantigen by S. aureus alone does not play an important role in the increased skin inflammation associated with staphylococcal infection in childhood AD.

The incidence of color blindness among some school children of Pokhara, Western Nepal.

The incidence of color blindness varies from race to race and different in different geographical area. Since, there is no such report about the prevalence of color blindness in the western part of Nepal, the present study had been conducted to find out the incidence of color blindness among school children of Pokhara city, western Nepal. Participant's (n=964, 474 boys, 490 girls, age group 10 to 19 years) color vision was tested by using Ishihara chart (38 plates). Among 474 boys, 18 boys were color blind with the prevalence of 3.8%. None of girls were found to be color blind. Out of 18 color blind boys, nine, six and three boys were the victims of deuteranopia, deuteranomaly and protanomaly respectively. The incidence of color blindness were more amongst the Darji (14.3%) and Newar (9.1%) ethnic groups.

An unusual case of obstructive jaundice.

Tuberculosis of the pancreas is a rarity, reported in a handful of literature. We enumerate the case of a young girl with high fever, jaundice, and right hypochondrial pain, whose investigations revealed a mass at the head of the pancreas. FNAC from the mass astoundingly proclaimed tuberculosis.

Age at menarche of subpopulation of Nepalese girls.

The present study was carried out to explore the mean age at menarche of school going girls of Western Nepal, Pokhara and to determine the factors influencing age at menarche. The data was collected from five schools located within the Pokhara Valley of Western Nepal. Only the students who had experienced menarche were included in the study. Verbal consent was obtained after explaining the objectives of the study; the students were interviewed for personal and family details and information obtained was recorded. The age at menarche was found to be 12.69 +/- 0.95 years. The mean age at menarche of those attending community schools was significantly higher than that of those attending private schools (12.85 +/- 0.87 vs 12.41 +/- 0.99 years). The mean age at menarche was found to be delayed with increase in number of family members and more siblings. The mean age at menarche of the vegetarians was higher than that of non-vegetarians (12.82. +/- 0.81 vs 12.68 +/- 0.95 years).

Study on the refractive errors of school going children of Pokhara city in Nepal.

OBJECTIVES: Refractive errors are the one of the most common visual disorders found worldwide in school going children and also it is one of the causes of blindness. It can easily be prevented, if timely proper measures are taken. In Kathmandu valley and Mechi Zone of Nepal, the distribution of refractive errors was found to be very high. No records are available from the Western part of Nepal. Considering the importance of the refractive errors the present study had been undertaken in Pokhara city. MATERIALS AND METHODS: 964 subjects (474 boys, 490 girls) were selected between age groups 10 to 19 years from 6 schools representing different region of Pokhara. After Preliminary examination: on acuity of vision with Snellen's and Jaeger's charts, the subjects were referred to the Manipal Teaching Hospital, Pokhara for confirmation of the refractive errors. RESULTS: Sixty two schools children (6.43%), out of 964 had refractive errors. The myopia was found to be most common (4.05%). The refractive errors were found more in Private school children (9.29%) than Government school children (4.23%), which is statistically significant (P < 0.05). More boys (7.59%) were found to have suffered from refractive errors than girls (5.31%). Further, children with vegetarian diet (10.52%) had greater number of refractive errors than non-vegetarian diet children (6.17%). CONCLUSION: In the present study, percentage distribution of myopia was found to be higher (4.05%) than the hyperopia (1.24%) and astigmatism (1.14%). Interestingly, in the present study the refractive errors were found significantly higher in Private schools children than Government schools because the children who read in Private schools have higher socioeconomic status; spend more time in home work, watching Television and Computer as compared to government schools children. These near activities of the eyes causes stress on eyes of the children and might be one of the causes of developing myopia.

A comparative study of the peak expiratory flow rate of Indian and Nepalese young adults in a teaching institute.

Peak expiratory flow rate (PEFR) measurement is the easiest and cheapest method to evaluate respiratory functions. So, the study was carried out to evaluate PEFR of healthy Nepalese adults and compare their values with healthy Indian counterparts to know whether Indian prediction equations for PEFR can be used for Nepalese adult population or not. One hundred twenty-three healthy, young, non smoker adult Indian (64: 28 Males, 36 Females) and Nepalese (59: 32 Males, 27 Females) medical students of 18 to 20 years of age participated in the study. The mean PEFR of Indian (male: 490.4 liter/min, female: 386.0 liter/min) and Nepalese (male: 485.9 liter/min, Female: 365.2 liter/min) young adults were found to have no significant differences. As there is no significant difference in the mean PEFR of Indian and Nepalese young adults, prediction equations made for Indian adults can be used to predict PEFR of Nepalese subjects. Therefore, an attempt has been made to formulate a regression equation from the combined Indian and Nepalese subjects. A stepwise, multiple, linear, regression analysis was performed for this purpose. The analysis showed that height is the best predictor for PEFR in the present study. The regression equation based on height for the combined Indian and Nepalese young adults is calculated as: PEFR = 5.687 x Height (cm) - 495.787. However, a stepwise, multiple, linear, regression equation with residual analysis for the best fit model was performed to formulate prediction equation for PEFR and this showed a change of the earlier regression equation to PEFR = 5.930 x Height (cm) - 536.131.

Home blood pressure monitoring improves the diagnosis of hypertension in hemodialysis patients.

Using interdialytic ambulatory blood pressure (BP) recordings as the reference standard, we compared the performance of routine, standardized and home BP monitoring in 104 predominantly black patients on chronic hemodialysis for at least 3 months. Dialysis unit BP recordings were averaged over 2 weeks and home BP over 1 week. Awake ambulatory BP of > or =135 mmHg systolic or > or =85 mmHg diastolic was taken as evidence of hypertension. Average awake ambulatory BP was 128.1+/-21.6/73.5+/-13.5 mmHg, home BP 141.3+/-21.9/78.7+/-11.9 mmHg, standardized pre-dialysis BP 141.7+/-22.6/74.2+/-13.5 mmHg and post-dialysis 119.9+/-20.5/69.1+/-13.1 mmHg, routine pre-dialysis 145.4+/-21.8/79.0+/-13.1 mmHg and post-dialysis 131.5+/-19.2/72.5+/-11.4 mmHg. Sixty-three percent of the patients had well-controlled BP by ambulatory BP monitoring and isolated diastolic hypertension was rare (3%). The standard deviation of the differences between ambulatory and routine pre-dialysis BP was 17.6 mmHg, routine post-dialysis was 16.1 mmHg, standardized pre-dialysis was 16.4 mmHg, standardized post-dialysis was 14.1 mmHg, and home BP was 14.2 mmHg. The area under receiver operating characteristic curves was similar for home and standardized BP but lower for routine BP. Home systolic BP of > or =150 mmHg averaged over 1 week had the best combination of sensitivity (80%) and specificity (84.1%) in diagnosing systolic hypertension--present in 94% of the hypertensive dialysis patients. Home BP monitoring is similar to standardized recording of BP in hemodialysis patients. A systolic BP threshold of 150 mmHg at home averaged over 1 week serves as a useful predictor of hypertension diagnosed by ambulatory BP monitoring.

A comparative study of body mass index (BMI) in diabetic and non-diabetic individuals in Nepalese population.

INTRODUCTION AND OBJECTIVES: Diabetes Mellitus (DM) is the most common endocrine disorder world-wide. The prevalence of diabetes mellitus is increasing. In the present study an attempt has been made (i) to examine the relation between obesity and diabetes mellitus in Nepalese people, (ii) to find out whether BMI cut-off points for determining over weight and obesity as per WHO criteria are applicable in Nepalese study population. MATERIALS AND METHODS: The present study was carried out in Manipal College of Medical Sciences (MCOMS) and Manipal Teaching Hospital (MTH), Pokhara. The Diabetic patients of Pokhara and surroundings who attended the 'Diabetic Clinic' and Out Patient Department (OPD) during August 2004 to November 2004 at Manipal Teaching Hospital were included in the present study. The number of diabetic patients was two hundred (200), out of which, one hundred and fourteen (114) were male and eighty six (86) were female. In addition one hundred (100) non-diabetic subjects who attended the OPD at MTH were taken for comparison with the diabetic patients, of which, forty seven (47) were male and fifty three (53) were female. Age, height and weight were recorded for every subject. BMI was calculated by the standard formula. In the present study, body mass index (BMI) of the diabetic subjects was found to be more than that of non-diabetic subjects. BMI of non-diabetic males and females were found to be around 22 kg/m2 which is within normal range as per WHO recommendations. On the other hand, diabetic subjects' BMI were found to be around 25 kg/m2, which denotes borderline obesity. It is clear from the present study that 51.5% of the diabetic subjects were within the normal range (BMI 18.5-24.9 kg/m2). More diabetic subjects were found in over-weight (25-29.9) category than non-diabetic subjects. As per WHO criteria 56% of the non-diabetic subjects were within the normal BMI range (BMI 18.5-24.9 kg/m2). It is also evident that when BMI in the range of 25.0-29.9 kg/m2 is considered as over-weight, only 33% were found to be over-weight in diabetic subjects. But when BMI > or =23 kg/m2 (as recommended for Asians) is taken as the determining factor for overweight, 64% of overweight male subjects and 72.09% of overweight female subjects were found to be diabetic. CONCLUSION: According to the observations of the present study on Nepalese it can be concluded that BMI cut-off points for determining over-weight and obesity should be lowered to 23 kg/m2 or less which can provide an adequate basis of taking action on risks related to overweight and obesity in Nepal.

Expanding role of G proteins in tight junction regulation: Galpha(s) stimulates TJ assembly.

Multiple signaling mechanisms regulate epithelial cell tight junction (TJ) assembly and maintenance. Several G proteins are likely to regulate these processes, but only G(i/o) have been specifically tested. Treatment of MDCK cells with cholera toxin, a Galpha(s) activator, accelerated TJ development in the calcium switch as measured by the time to half-maximal [T(50) (H)] transepithelial resistance (TER). Galpha(s) was predominantly localized in the lateral membrane, but a fraction colocalizes with ZO-1 in the TJ. MDCK cell lines expressing epitope-tagged Galpha(s) and constitutively active (R201Calpha(s)) showed a similar localization. TJ assembly was significantly faster in R201Calpha(s)-MDCK cell lines (T(50) (H) of 1.7 versus 3.3 h for controls) without detectable differences in cAMP levels. Confocal studies showed R201Calpha(s)-MDCK cells more rapidly localized ZO-1 and occludin into the developing TJ without affecting E-cadherin or Na(+)/K(+) ATPase localization. Endogenous Galpha(s) and R201Calpha(s) were immunoprecipitated with ZO-1 at baseline and during TJ assembly. The data supports a model of multiple Galpha subunits interacting with TJ proteins to regulate the assembly and maintenance of the TJ.

Serum ferritin level as a marker of preterm labor.

OBJECTIVE: To compare the serum ferritin levels in women with preterm labor (PTL) or preterm premature rupture of membranes with those in normal gravid women. METHOD: The study group consisted of 50 consecutive subjects with preterm labor and 49 subjects with preterm premature rupture of membranes (PROM). The control group consisted of 50 subjects matched with the study group for hemoglobin (Hb) and gestation who did not have PTL or preterm PROM. Serum ferritin levels were assayed in both the groups. RESULTS: Mean serum ferritin levels in patients with preterm labor and preterm premature rupture of membranes were 23.24+/-12.13 ng/ml and 29.44+/-28.41 ng/ml, respectively. The mean serum ferritin in control subjects was 8.69+/-3.7 ng/ml. The difference was evaluated by Student's t-test and was found to be statistically significant. CONCLUSION: The serum ferritin level is significantly raised in pregnant women with preterm labor and preterm PROM.

Generation of the O630 photointermediate of bacteriorhodopsin is controlled by the state of protonation of several protein residues.

The last stages of the photocycle of the photosynthetic pigment all-trans bacteriorhodopsin (bR570), as well as its proton pump mechanism, are markedly pH dependent. We have measured the relative amount of the accumulated O630 intermediate (Phir), as well as its rise and decay rate constants (kr and kd, respectively), over a wide pH range. The experiments were carried out in deionized membrane suspensions to which varying concentrations of metal cations and of large organic cations were added. The observed pH dependencies, s-shaped curves in the case of Phir and bell-shaped curves for kr and kd, are interpreted in terms of the titration of three protein residues denoted as R1, R2, and R3. The R1 titration is responsible for the increase in Phir, kr, and kd upon lowering the pH from pH approximately 9.5 to 7. At low pH Phir exhibits a secondary rise which is attributed to the titration of a low pKa group, R2. After reaching a maximum at pH approximately 7, kr and kd undergo a decrease upon decreasing the pH, which is attributed to the titration of R3. All three titrations exhibit pKa values which decrease upon increasing the salt concentration. As in the case of the Purple (bR570) if Blue (bR605) equilibrium, divalent cations are substantially more effective than monovalent cations in shifting the pKa values. Moreover, bulky organic cations are as effective as small metal cations. It is concluded that analogously to the Purple if Blue equilibrium, the salt binding sites which control the pKa values of R1, R2, and R3 are located on, or close to, the membrane surface. Possible identifications of the three protein residues are considered. Experiments with the E204Q mutant show that the mutation has markedly affected the R2 (Phir) titration, suggesting that R2 should be identified with Glu-204 or with a group whose pKa is affected by Glu-204. The relation between the R1, R2 and R3 titrations and the proton pump mechanism is discussed. It is evident that the pH dependence of Phir is unrelated to the measured pKa of the group (XH) which releases the proton to the extracellular medium during the photocycle. However, since the same residue may exhibit different pKa values at different stages of the photocycle, it cannot be excluded that R2 or R3 may be identified with XH.