Role of zinc in chronic telogen effluvium in serum and hair of patients with alopecia

Objectives

To determine the levels of zinc in hair and serum samples of chronic telogen effluvium patients.

METHODS

The case-control study was conducted at the Dow University of Health Sciences, Karachi, from April 2017 to May 2018, and comprised diagnosed cases of chronic telogen effluvium in group A, and healthy controls matched for age and gender in group B. Hair pull test was done, and level of zinc in hair and serum samples was determined using atomic absorption spectrophotometer. Data was analysed using SPSS 21.

RESULTS

Of the 100 subjects, 50(50%) were in group A; 28(56%) females ad 22(44%) males with mean age 27.46±4.98 years. There were 50(50%) subejcts in group B; 26(52%) males ad 24(48%) females with mean age 28.34±4.92 years (p>0.05). Significantly low levels of zinc were observed in serum as well as hair samples in group A compared to group B (p<0.05). A positive significant association was observed in the level of zinc in hair with their concentration in the serum of subjects in both the groups (r=0.310, p<0.05).

CONCLUSIONS

Low levels of zinc in hair and serum were found to be associated with chronic telogen effluvium.

Genetic variant in TNF-α gene and its plasma level in relation to obstructive sleep apnoea in the Pakistani population

OBJECTIVE

To assess the link between tumour necrosis factor-alpha -308 guanine/adenine polymorphism and tumour necrosis factor-alpha plasma levels in relation to obstructive sleep apnoea.

METHODS

The cross-sectional study was conducted from December 2018 to March 2021 at the sleep clinic of Dow University Hospital, Karachi, on obstructive sleep apnoea patients and healthy controls. Epworth Sleep Scale score was used to determine daytime sleepiness, while full-night polysomnography was carried out for obstructive sleep apnoea confirmation and categorisation according to severity. Blood sample collection was followed by deoxyribonucleic acid extraction and plasma tumour necrosis factor-alpha measurement using enzyme-linked immunosorbent assay. Genotype distribution and allelic frequency were assessed. Data was analysed using SPSS 20.

RESULTS

Out of the 225 subjects, with a mean age of 47.68±9.88 years, 132 (58.7%) were males, and 93 (41.3%) were females. Among them, 150 (66.7%) were patients, and 75 (33.3%) were controls. Heterozygous tumour necrosis factor-alpha -308 guanine/adenine genotypes were significantly higher among the patients (p<0.05). Minor allele - 308 adenine showed an association with obstructive sleep apnoea, its severity, higher tumour necrosis factor-alpha levels, neck circumference, excessive daytime sleepiness and the presence of hypertension (p<0.05).

CONCLUSIONS

Tumour necrosis factor-alpha -308 adenine allele and higher tumour necrosis factor-alpha levels were found to be linked with obstructive sleep apnoea. The polymorphism also showed an association with hypertension in obstructive sleep apnoea patients.

Oxidative stress in polycystic ovary syndrome: a case-control study

OBJECTIVE

To compare the serum levels of biochemical and oxidative stress markers i.e., malondialdehyde (MDA) and paraoxonase-1(PON1) in polycystic ovary syndrome (PCOS) patients and healthy female individuals of reproductive age group (18-40 years).

METHODS

This case-control study was conducted in Dow University of Health Sciences (DUHS), Karachi from June 2019 to October 2020. Seventy Subjects including 35 PCOS patients that have primary subfertility problem (cases) and 35 healthy and fertile females (controls) were recruited. Serum samples were collected for analysis of insulin, sex hormone-binding globulin, testosterone, fasting blood glucose and lipid profile. PON 1 and MDA levels were estimated by ELISA. Comparison between the two groups was done using independent t-test.

RESULTS

The patients had significantly increased mean body mass index (28.5+4.6 kg/m2 vs 25.7+4.5 kg/m2, p=0.014), systolic (129.6±13.9 mm of Hg vs 113±7.7 mm of Hg, p<0.001) and diastolic (78.7±8.8 mm of Hg vs 74.6±6.7 mm of Hg, p=0.032) blood pressures compared to controls. The high-density lipoprotein cholesterol levels were significantly lower in PCOS (42.2±8.6mg/dl) than controls (48.8±11.8mg/dl, p=0.009, p=0.009). Serum insulin (14.3±5.8 uIU/mL) vs (10.0±5.2 uIU/mL), p=0.002 and testosterone levels (1.3±0.9 nmol/L) vs (0.82±0.3 nmol/L), p<0.001 were significantly higher whereas sex hormone binding globulin (SHBG) levels (35.2±19.7nmol/L vs 58.8±31.0 nmol/L) were significantly lower in patients than healthy controls (p<0.001). Both oxidative stress markers, paraoxonase 1 (7.7±2.4 vs 6.4±2.6 μg/mL, p=0.04) and malondialdehyde (2.5±1.0 vs 1.9+0.51μg/mL, p=0.034) levels were significantly elevated in PCOS patients than controls. No significant correlation was found between dietary habits and life style between cases and controls.

CONCLUSIONS

The study reported significantly elevated levels of oxidative stress markers in PCOS patients.

AI in biomedical research: unleashing the potential of a transformative partnership

Biomedical Science research, by its very nature, generates colossal volumes of data ranging from genomics to medical imaging, that is both complex and diverse. It demands a lot of time and expertise to translate that data into meaningful interpretations to be applied on the bedside. AI algorithms on the other hand, possess the exceptional ability to examine this wealth of information, uncovering patterns and relationships. It has been claimed that it may elude even the most astute human minds1 in some areas of social sciences. The interpretation of data in the field of Biomedical research, however, remains debatable2. Nonetheless, it can accelerate the pace of scientific discovery, enabling researchers to identify novel therapeutic targets, understand disease mechanisms, and develop innovative treatments. Moreover, the resounding question that echoes across laboratories and research institutions globally is not whether AI can be employed in biomedical research, but instead, how extensively we can tap into its complete potential. The integration of AI into Biomedical Sciences is yet not free from its set of challenges. Privacy concerns and ethical considerations related to data usage must be diligently addressed. Additionally, robust validation and transparency in AI models are essential to ensure their reliability and safety3. continue...

Serum Leptin levels in newly diagnosed Epileptic Patients

Objectives

To compare leptin levels in newly-diagnosed treatment-naive epileptic patients and healthy controls.

METHODS

This case-control study was conducted from January 10 to September 15, 2022, at the Dow University of Health Sciences, Karachi, and comprised newly-diagnosed epileptic patients age 12-35years who had no comorbidity. The subjects were enrolled from the Neurology out-patient department of Civil Hospital, Karachi. Healthy individuals matched for age, gender and body mass index were also enrolled as controls. Blood samples were collected between 8am and 10am for the evaluation of serum leptin levels using enzyme-linked immunosorbent assay. Data was analysed using SPSS 26.

RESULTS

Of the 100 subjects, 64(64%) were males and 36(36%) were females. There were 50(50%) cases with mean age 19.34±5.65 years, and 50(50%) controls with mean age 19.76±5.67 (p=0.614). 100% of 50 individuals in control group did not have any family history of epilepsy,while 18% of cases (9) reported a positive family history. Mean leptin level in cases was 31.03±19.37 compared to 5.25±4.03 in the controls (p<0.05).

CONCLUSIONS

Serum leptin levels were elevated in newly-diagnosed epileptic patients compared to healthy controls.

1st International Conference on Biomedical Sciences, Dow University of Health Sciences, Karachi Pakistan

Institute of Biomedical Sciences (IBMS) at Dow University of Health Sciences (DUHS), organised a two day's conference on Biomedical Sciences. IBMS being the part of one of the largest public sector health universities of Pakistan, is now transforming the research trends to be effectively translated at the community level. Currently with a strong PhD faculty line in basic and clinical sciences, DUHS has a significant contribution in research output of the country. The scientific data however represents a small population per scientific study and the generalization of results may not be inferred. It must be extended through translational research for effectiveness. The conference was planned with a theme to bridge the gap between basic and translational research. The two day's conference conducted in second week of March 2023 at Dow International Medical College Ojha Campus DUHS was able to attract more than 300 participants. The scientific sessions encompassed a vast variety of health issues and their proposed solutions including neurosciences, virtual biopsies, metabolomics, medical writings and incorporation of engineering and artificial intelligence to facilitate detection and prognosis of disease. The conference was able to conclude that the multidisciplinary research studies with collaboration of two or more institutes/organizations are the need of time. Young researchers need an effective platform to showcase their research and make collaborations. Moreover, the incorporation of artificial intelligence would enhance patient care within health systems.

Comparison of Quality of Life of Medical Students in Annual and Modular System in Public Sector Medical Colleges in Karachi, Pakistan

Background: The annual system is regarded as the oldest but foundational trends of teaching, with its curriculum based on subject wise learning and clinical rotations accordingly. The modular system has a curriculum that encompasses modules based on different organ systems and processes, with the basic and clinical sciences taught cohesively. Methods: A cross-sectional study was carried out, including 404 students of three different public sector medical colleges in Karachi. QoL was measured using the WHOQOL-BREF questionnaire, which comprised of 26 items. Data analysis was done via SPSS v.20. Kruskal Wallis test and Mann-Whitney U test was used to compare scores among different years of medical study and between different curricular systems, respectively. Results: Out of 404 students, 81.3% were females, 18.3% were males. The mean age of the sample was 21.23±1.29 years. According to the year of study, significant differences were observed in physical health and overall QoL domain (p<0.05), with 3rd-year students having the highest scores. When comparing annual and modular systems, the modular system yielded a better QoL with a mean score of 83.34. The overall QoL of students in clinical years was found to be significantly better (p<0.05) than the students present in preclinical years. Conclusion: Overall QoL score in the modular system was slightly higher than the annual system, but a significant difference was noted only in the environmental domain between the two systems. It was also noted that the QoL of students in clinical years was better than preclinical years.

Obstructive sleep apnoea: Potential role of tumour necrosis factor alpha as a circulating biomarker

Objective: To assess the relationship of tumour necrosis factor-alpha with obstructive sleep apnoea and its severity in Pakistani population. Method: The cross-sectional study was conducted at the Sleep Laboratory of Dow University Hospital, Karachi, from December, 2018, to March, 2020, and comprised patients of either gender having symptoms of snoring, witnessed apnoea or daytime sleepiness. They were divided into four groups on the basis of obstructive sleep apnoea status. Those without obstructive sleep apnoea were in Group A, mild status in Group B, moderate in Group C and severe obstructive sleep apnoea in Group D. Polysomnography was done to confirm obstructive sleep apnoea status and to categorise the subjects using apnoea-hypopnea index, while enzyme-linked immunosorbent assay was used to assess their tumour necrosis factor alpha levels.. Data was analysed using SPSS 20. Results: Of the 150 subjects, 94(63%) were males. The overall mean age was 49.68±12.14 years. There were 50(33.33%) subjects in Group A, 19(12.66%) Group B, 23(15.33%) Group C and 58(38.66%) in Group D. Mean tumour necrosis factor-alpha level was 3.88±1.65pg/mL in Group A, 9.97±4.33pg/mL in Group B, 12.65±4.46pg/mL in Group C and 12.83±4.33pg/mL in Group D. Mean tumour necrosis factor-alpha levels had significant association with the severity of obstructive sleep apnoea (p<0.001). Conclusion: Higher levels of tumour necrosis factor-alpha were found to be associated with obstructive sleep apnoea, and can be considered a potential biomarker for early diagnosis. Key Words: Sleep, Obstructive sleep apnoea, Biomarker, TNF-alpha, Inflammation, Sleep-related breathing disorder.

Effects of Metronidazole as an Adjunct to Non-Surgical Periodontal Therapy on Insulin Resistance in Type 2 Diabetics

Treating periodontitis with metronidazole (MET) as an adjunct to scaling root planing (SRP) is suggested to have inconsistent effects on insulin resistance (IR) in type 2 diabetes mellitus (T2DM). This paper will present the effects of MET, in addition to SRP, on the homeostatis model assessment of IR (HOMA-IR). A three-arm clinical trial was conducted and analyses were performed on T2DM participants with periodontitis (n = 74) who completed follow-up visits at 3 and 6 months after the intervention. The observed between-group and within-group mean changes in IR were found using ANOVA with repeated measures, followed by a post-hoc analysis, and a p-value of ≤0.05 was considered significant. Between-group analyses showed no difference in the HOMA-IR at 3 months, but at 6 months the difference was significant (p = 0.046). Within-group analyses showed that the HOMA-IR was significantly reduced in both test groups (p ≤ 0.05) over the period of time. Adjunct use of MET may result in a sudden short-term lowering of the HOMA-IR level within 3 months that may not be retained over 6 months when compared to the sustained lowering of the HOMA-IR levels in T2DM when intervened with SRP without MET.

Evaluation of HbA1c in type-2 diabetes mellitus patients with periodontitis: preliminary findings of three-arm clinical trial

OBJECTIVE

To assess a relationship and predict changes in glycaemic control due to chronic periodontitis in type-2 diabetic patients.

METHODS

Chronic periodontitis (CP) of a cross-section of 118 patients (age ?32 years) was determined using bleeding on probing (BOP), periodontal pocket depth (PPD) and clinical attachment loss (CAL). Their HbA1c, fasting blood glucose (FBG), fasting serum insulin (FSI) and homeostasis assessment model of insulin resistance (HOMA-IR) levels were also tested. Stata 11.0 was used to assess correlation between periodontal and glycaemic measures. Univariate analysis followed by multiple regression analysis through stepwise forward selection process was used to explore significant variables that may predict change in HbA1c. Multi-collinearity and heteroskedasticity were assessed at p-value > 0.05.

RESULTS

Results of participants (n=95) showed significantly positive correlations (r) between HbA1c and BOP [r = 0.34, p-value = 0.002], PPD [r = 0.36, p-value = 0.003] and CAL [r=0.42, p-value = 0.002]. However, FBG and HOMA-IR were not found correlated with any of the periodontal measures; except CAL with FBG [r=0.27, p-value=0.02]. In addition to healthy controlled diet, cultural background, education and FBG, CAL was found significant [coef. = 0.746, p-value = 0.001, CI = 0.339, 1.153] to predict change in HbA1c in the final model [R2 = 0.549, p-value < 0.001] with no multicollinearity [mean VIF =1.30] and heteroskedasticity [chi 2 =0.02, p-value= 0.878] in fi n al model.

CONCLUSIONS

Increased CAL is estimated to increase HbA1c level by 0.75% in T2DM patients after controlling other factors. It is suggested that periodontal prophylactic management may be planned with an aim to reduce HbA1c.

Clinical Trial Registration No

NCT03343366.

Clinical efficacy of scaling and root planing with and without metronidazole on glycemic control: three-arm randomized controlled trial

Background

Treating periodontitis through non-surgical periodontal therapy (NSPT) may improve glycemic control in type-2 Diabetes Mellitus (T2DM) patients. However, the evidence to maintain this improvement beyond four months is insufficient. Hence, this trial was conducted to assess clinical efficacy of NSPT on glycemic control in T2DM patients.

Methods

This three-arm randomized controlled trial recruited 150 known T2DM participants (35–65 years), suffering from moderate to severe periodontitis, having HbA1c level ≥ 6.5% at baseline. Participants were followed up at 3 and 6 months. Intervention for test group-1 included scaling and root planing (SRP) with metronidazole (MET) and oral hygiene instructions (OHI). Test group-2 was intervened with SRP + OHI and control group with OHI only. Stata v. 14 was used to observe inter and intragroup mean changes in glycemic [glycated hemoglobin (HbA1c), fasting blood glucose (FBG)] and periodontal variables [bleeding on probing (BOP), periodontal pocket depth (PPD), clinical attachment loss (CAL)] using ANOVA and RMANOVA. Proportion of change in outcome variable (HbA1c) was assessed between treatment groups using chi-square test. Change was considered significant at p-value ≤ 0.05.

Results

A significant reduction was observed in BOP, PPD, CAL, HbA1c and FBG over time [p < 0.05]. Significant reductions were observed in same variables in both test groups in comparison to control arm [p < 0.05]. No change between the two test groups was observed [p > 0.05].

Conclusion

Scaling and root planing improves glycemic control of T2DM patients independently of the use of MET. Therefore, SRP after every 6 months may be suggested and included as a part of overall diabetes management for patients suffering from T2DM.

Clinical trial registration NCT 03,343,366 [Date of Registration: 17/11/2017]

HbA1C as a Biomarker of Non-alcoholic Fatty Liver Disease: Comparison with Anthropometric Parameters

BACKGROUND AND AIMS

Multiple non-invasive methods including radiological, anthropometric and biochemical markers have been reported with variable performance. The present study assessed glycosylated hemoglobin (HbA_1C) as a biomarker to predict non-alcoholic fatty liver disease (NAFLD) and its severity, compared with body mass index (BMI), waist to hip ratio (WHR) and waist circumference (WC).

METHODS

This case control study included 450 individuals, including 150 cases and 300 age- and gender-matched controls recruited from the Dow Radiology Institute on the basis of radiological findings of fatty infiltration on abdominal ultrasound through convenient sampling. BMI, WHR and WC were measured according to standard protocols. HbA_1C was determined by turbidimetric inhibition immunoassay.

RESULTS

Among the cases and controls, 66% and 32% had HbA_1C levels higher than 5.7% respectively. HbA_1C and BMI were significantly associated with NAFLD [crude odds ratio (cOR)=4.12, 2.88, 2.25 (overweight) and 4.32 (obese)]. WC was found to be significantly associated with NAFLD for both genders (cOR in males=5.50 and females=5.79, p<0.01). After adjustment for other parameters, HbA_1C and WC were found to be significantly associated with NAFLD (aOR=3.40, p<0.001) along with WC in males (aOR=2.91, p<0.05) and in females (aOR=4.28, p<0.05). A significant rise in severity of hepatic steatosis was noted with increases in HbA_1C, BMI and WC. HbA_1C possessed a positive predictive value of 76% for the study population [0.76, confidence interval (CI): 0.715-0.809], 70.6% for males (0.706, CI: 0.629-0.783) and 80% for females (0.80, CI: 0.741-0.858).

CONCLUSIONS

Higher than normal HbA_1C and WC measurements possess a more than 70% potential to predict NAFLD. It is the single risk factor that is strongly associated with NAFLD after adjustment for indices of body measurements. HbA_1C may be presented as a potential biomarker for NAFLD in examination with other anthropometric measures in the adult population.

A Novel Variant in Dopamine Receptor Type 2 Gene is Associated with Schizophrenia

BACKGROUND

Being the primary target of antipsychotic therapy, dopamine receptor type 2 (DRD2) remains a point of interest in schizophrenia pathology. Polymorphisms in DRD2 have been shown to alter patients' response to antipsychotics. DRD2 SNP rs6275 (C>T) have found to be associated with schizophrenia in different populations; however, data remains inconsistent.

AIM OF THE STUDY

Keeping in view the genetic diversity the present study was aimed to explore association of rs6275 with schizophrenia in population from Pakistan.

METHOD

Using Diagnostic and statistical Manual 5 (DSM 5) criteria, 100 schizophrenia cases and 100 controls (individuals without any psychiatric illness) were enrolled in the study. Severity of illness was determined using PANSS score. Genotyping was done via Sanger sequencing. MEGA-X was used to align the sequences, Expasy translate tool was used to translate nucleotide sequences. Difference in genotype and allele frequencies between cases and controls was determined using χ² test.

RESULT

No significant difference in genotype or allele frequencies of rs6275 (p >0.0.5) was found between cases and controls. Interestingly, a novel SNP (C>A, Pro297Thr) was spotted during electropherogram analysis at position chr11:113412805. Significant difference was found in genotype and allele frequency of this novel SNP among schizophrenia cases and controls (p = 0.003).

CONCLUSION

No association of rs6275 was observed with schizophrenia in Pakistani population. However, the study found significant association of a novel missense SNP of DRD2 at chr11:113412805 (C>T) with schizophrenia in Pakistani population. A large-scale multicenter study will be required to confirm the association of this novel SNP with schizophrenia.

Biomanagement of rice root-knot nematode Meloidogyne graminicola using five indigenous microbial isolates under pot and field trials

AIMS

To ascertain the effectiveness of Aspergillus niger, Trichoderma harzianum, Pochonia chlamydosporia, Bacillus subtilis and Pseudomonas fluorescens against rice root-knot nematode, Meloidogyne graminicola, and to optimize their application methods.

METHODS AND RESULTS

The relative effectiveness of five indigenous biocontrol agents (BCA) against M. graminicola on rice cv. PS-5 was tested initially in pot culture. The BCAs, A. niger, P. chlamydosporia and P. fluorescens proved more effective, and significantly reduced the nematode disease. It is hypothesized that success of a biocontrol module may vary with the BCA and application methods. Hence, the effectiveness of the above three BCAs as well as seven different treatment schemes were evaluated in naturally infested farmer's fields during 2 consecutive years. In nematode-infested plots without any BCA treatments, terminal galls formed on the roots, and plants suffered a 19-31% decrease in the growth and yield. The treatments with P. chlamydosporia or A. niger through root-dip (RD) plus one soil application (SA) at 15 days after planting were found to be highly effective against the nematode.

CONCLUSIONS

Relatively greater nematode control was achieved with RD plus two SAs (15 + 30 DAP) but statistically the effect was on par with RD + one SA at 15 DAP. These treatments significantly reduced galling (22-25%), egg mass production (21-29%) and reproduction factor (63-70%) of M. graminicola, and subsequently increased the grain yield (11-21%).

SIGNIFICANCE AND IMPACT OF THE STUDY

Application methods enhanced the effectiveness of BCAs against M. graminicola. The RD plus one SA at 15 DAP proved to be most effective treatment to control root-knot disease in rice. Use of multiple treatments (root dip and SA) appears cumbersome, but in view of effectiveness and limitation of chemical control in rice paddies, farmers may adopt the above module that may lead to 11-21% yield improvement.

Gender Differences and Prevalence of Mental Health Problems in Students of Healthcare Units

The aim of the present was to assess and compare the mental health of male and female healthcare students in a Health University of Karachi, Pakistan. A cross-sectional study was conducted for which questionnaire was designed along the standard scoring scales of depression (PHQ-9), anxiety (GAD-7) and phobia (IAPT) completed by 300 enrolled students. Females (52%) of the medical institute suffered from mild to moderately-severe depression in contrast to the males (33%). Females were found to be affected by mild anxiety and phobia (42.7 and 26% respectively) exceeding the male population (27.3 and 15.3% respectively). However, severe depression or anxiety was not observed in either gender groups significantly, suggesting a healthy mental picture of these medical students. It can be concluded that health care students in modern upgraded education systems, in contrast to evidence from literature, have been able to adopt better coping mechanisms for maintaining their mental health.

Correction to: Gender Differences and Prevalence of Mental Health Problems in Students of Healthcare Units

The original version of this article unfortunately contained a typo in the author name. The co-author name should be Ahsan Ehtesham instead it was published as Ahsan Ehtisham.

Valence State of Eu and Superconductivity in Se-Substituted EuSr2Bi2S4F4 and Eu2SrBi2S4F4

Recently, we reported the synthesis and investigations of EuSr₂Bi₂S₄F₄ and Eu₂SrBi₂S₄F₄. We have now been able to induce superconductivity in EuSr₂Bi₂S₄F₄ by Se substitution at the S site (isovalent substitution) with T_c = 2.9 K in EuSr₂Bi₂S₂Se₂F₄. The other compound, Eu₂SrBi₂S₄F₄, shows a significant enhancement of T_c. In Se-substituted Eu₂SrBi₂S_4-xSe_xF₄, we find T_c = 2.6 K for x = 1.5 and T_c = 2.8 K for x = 2, whereas T_c = 0.4 K in the Se-free sample. In addition to superconductivity, an important effect associated with Se substitution is that it gives rise to remarkable changes in the Eu valence. Our ¹⁵¹Eu Mössbauer and X-ray photoemission spectroscopic measurements show that Se substitution in both of the compounds Eu₂SrBi₂S₄F₄ and EuSr₂Bi₂S₄F₄ gives rise to an increase in the Eu²⁺ component in the mixed-valence state of Eu.

Unusual Mixed Valence of Eu in Two Materials-EuSr2Bi2S4F4 and Eu2SrBi2S4F4: Mössbauer and X-ray Photoemission Spectroscopy Investigations

We have synthesized two new Eu-based compounds, EuSr₂Bi₂S₄F₄ and Eu₂SrBi₂S₄F₄, which are derivatives of Eu₃Bi₂S₄F₄, an intrinsic superconductor with T_c = 1.5 K. They belong to a tetragonal structure (SG: I4/mmm, Z = 2), similar to the parent compound Eu₃Bi₂S₄F₄. Our structural and ¹⁵¹Eu Mössbauer spectroscopy studies show that, in EuSr₂Bi₂S₄F₄, Eu-atoms exclusively occupy the crystallographic 2a-sites. In Eu₂SrBi₂S₄F₄, 2a-sites are fully occupied by Eu-atoms and the other half of Eu-atoms and Sr-atoms together fully occupy 4e-sites in a statistical distribution. In both compounds Eu atoms occupying the crystallographic 2a-sites are in a homogeneous mixed valent state ∼2.6-2.7. From our magnetization studies in an applied H ≤ 9 T, we infer that the valence of Eu-atoms in Eu₂SrBi₂S₄F₄ at the 2a-sites exhibits a shift toward 2+. Our XPS studies corroborate the occurrence of valence fluctuations of Eu and after Ar-ion sputtering show evidence of enhanced population of Eu²⁺-states. Resistivity measurements, down to 2 K, suggest a semimetallic nature for both compounds.

Coexistence of superconductivity and ferromagnetism in Sr0.5Ce0.5FBiS2-xSex (x = 0.5 and 1.0), a non-U material with Tc < TFM

We have carried out detailed magnetic and transport studies of the new Sr_0.5Ce_0.5FBiS_2-xSe_x (0.0 ≤ x ≤ 1.0) superconductors derived by doping Se in Sr_0.5Ce_0.5FBiS₂. Se–doping produces several effects: it suppresses semiconducting–like behavior observed in the undoped Sr_0.5Ce_0.5FBiS₂, the ferromagnetic ordering temperature, T_FM, decreases considerably from 7.5 K (in Sr_0.5Ce_0.5FBiS₂) to 3.5 K and the superconducting transition temperature, T_c, gets enhanced slightly to 2.9–3.3 K. Thus in these Se–doped materials, T_FM is marginally higher than T_c. Magnetization studies provide evidence of bulk superconductivity in Sr_0.5Ce_0.5FBiS_2-xSe_x at x ≥ 0.5 in contrast to the undoped Sr_0.5Ce_0.5FBiS₂ (x = 0) where magnetization measurements indicate a small superconducting volume fraction. Quite remarkably, as compared with the effective paramagnetic Ce–moment (~2.2 μ_B), the ferromagnetically ordered Ce–moment in the superconducting state is rather small (~0.1 μ_B) suggesting itinerant ferromagnetism. To the best of our knowledge, Sr_0.5Ce_0.5FBiS_2-x Se_x (_x = 0.5 and 1.0) are distinctive Ce–based bulk superconducting itinerant ferromagnetic materials with T_c < T_FM. Furthermore, a novel feature of these materials is that they exhibit a dual and quite unusual hysteresis loop corresponding to both the ferromagnetism and the coexisting bulk superconductivity.

Unconventional superconductivity at mesoscopic point contacts on the 3D Dirac semimetal Cd3As2

Three-dimensional (3D) Dirac semimetals exist close to topological phase boundaries which, in principle, should make it possible to drive them into exotic new phases, such as topological superconductivity, by breaking certain symmetries. A practical realization of this idea has, however, hitherto been lacking. Here we show that the mesoscopic point contacts between pure silver (Ag) and the 3D Dirac semimetal Cd3As2 (ref. ) exhibit unconventional superconductivity with a critical temperature (onset) greater than 6 K whereas neither Cd3As2 nor Ag are superconductors. A gap amplitude of 6.5 meV is measured spectroscopically in this phase that varies weakly with temperature and survives up to a remarkably high temperature of 13 K, indicating the presence of a robust normal-state pseudogap. The observations indicate the emergence of a new unconventional superconducting phase that exists in a quantum mechanically confined region under a point contact between a Dirac semimetal and a normal metal.

Behavioral, hormonal and central serotonin modulating effects of injected leptin

Leptin is viewed as an important target for developing novel therapeutics for obesity, depression/anxiety and cognitive dysfunctions. The present study therefore concerns behavioral, hormonal and central serotonin modulating effects of systemically injected leptin. Pharmacological doses (100 and 500 μg/kg) of leptin injected systemically decreased 24h cumulative food intake and body weight in freely feeding rats and improved acquisition and retention of memory in Morris water maze test. Potential anxiety reducing, hormonal and serotonin modulating effects of the peptide hormone were determined in a separate experiment. Animals injected with 100 or 500 μg/kg leptin were tested for anxiety in an elevated plus maze test 1h later. A significant increase in the number of entries and time passed in open arm of the elevated plus maze in leptin injected animals suggested pronounced anxiety reducing effect. Moreover, circulating levels of leptin correlated significantly with anxiety reducing effects of the peptide hormone. Serum serotonin increased and ghrelin decreased in leptin injected animals and correlated, positively and negatively respectively, with circulating leptin. Corticosterone increased at low dose and levels were normal at higher dose. Serotonin metabolism in the hypothalamus and hippocampus decreased only at higher dose of leptin. The results support a role of leptin in the treatment of obesity, anxiety and cognitive dysfunctions. It is suggested that hormonal and serotonin modulating effects of leptin can alter treatment efficacy in particularly comorbid conditions.

Immobilization-induced increases of systolic blood pressure and dysregulation of electrolyte balance in ethanol-treated rats

Clinical and experimental studies revealed that alcohol drinking and life event stresses are predisposing factors to hypertension. Intra and extra cellular levels of electrolytes may play important role in the pathogenesis and treatment of hypertension. Dietary intake of sodium, potassium, calcium and magnesium is suggested to have a role in the regulation of blood pressure. The present study was designed to monitor the effects of acute exposure to 2h immobilization stress and ethanol administration at a dose of 2.5 g/kg body weight (i.p.) and combined effect of acute administration of ethanol and immobilization stress on systolic blood pressure (SBP), intraerythrocyte, serum and tissue electrolytes in rats. Results showed that acute exposure to 2h immobilization increased SBP, intraerythrocyte sodium and decreased intraerythrocyte potassium in water as well as in ethanol injected rats. The concentration of Na⁺ and Ca²⁺ increased while that of K⁺ and Mg²⁺ decreased in the heart and kidney tissue. Ethanol administration also increased Na⁺ and Ca²⁺ levels and decreased K⁺ and Mg²⁺ levels in the heart and kidney tissue. Restraint stress decreased serum levels of Na⁺, K⁺, Ca²⁺, P, and Cl⁻ and increased serum Mg²⁺, glucose and haematocrit. Ethanol administration also decreased serum levels of Na⁺, K⁺, Ca²⁺, P, and Cl⁻ and increased serum Mg²⁺, glucose and haematocrit. The effects of ethanol and stress on the changes of blood and tissues electrolytes were additive and may be involved in the greater occurrence of hypertension in alcoholics. Our results suggested an important role of intra and extra cellular electrolytes in both stress and ethanol-induced hypertension. The findings may help to develop strategies for the treatment of hypertension in alcoholics.

Gender and stress perception based differences in BMI, hormonal response and appetite in adult Pakistani population

OBJECTIVE

To evaluate and compare the gender based variations in stress perception induced changes in leptin, cortisol and serotonin (5-HT) trends, appetite and Body Mass Index (BMI).

STUDY DESIGN

An analytical comparative study.

PLACE AND DURATION OF STUDY

Neurochemistry Laboratory, University of Karachi, from January to August 2013.

METHODOLOGY

Appetite, BMI and serum leptin, cortisol, and 5-HT were measured in 100 men and women of aged 30-60 years, working in teaching institutes of Karachi, to evaluate gender based, stress perception induced variations. The samples were identified by stratified random technique. The chemical variables were estimated through ELISA. RESULTS were analysed using one-way ANOVA and multivariate general linear model using SPSS version 17.

RESULTS

Mean stress perception, BMI and serum leptin levels were significantly more in women (p<0.05). Serum cortisol and 5-HT were found significantly reduced in women (p<0.05). BMI, serum cortisol and leptin were found to be increased with increasing level of stress perception (p<0.05). VAS for hunger and desire to eat as the measure of appetite was significantly higher in men (p<0.05).

CONCLUSION

Stress perception attenuates the positive effect of cortisol and negative effects of leptin and 5-HT on appetite through changes in their circulatory levels. Women perceive more stress and exhibit significantly attenuated changes in hormonal levels and appetite which may be the contributing factor towards obesity. Increased BMI in women despite decreased appetite merits more studies.

Inhibition of immobilization stress-induced anorexia, behavioral deficits, and plasma corticosterone secretion by injected leptin in rats

Leptin, originally identified as an anti-obesity hormone, also has an important role in the regulation of mood and emotion. The present study was designed to monitor effects of injected leptin on immobilization stress-induced anorexia, behavioral deficits, and plasma corticosterone secretion in rats. Exposure to 2 h immobilization stress decreased food intake and body weight in saline-injected animals. Animals exposed to open field, elevated plus maze, and light-dark transition tests the day following immobilization exhibited anxiety-like behavior. Leptin injected at doses of 0.1 and 0.5 mg/kg also decreased food intake and body weight in unstressed animals and elicited anxiolytic effects at dose of 0.5 mg/kg, monitored on the following day. Immobilization-induced decreases in food intake, body weight, as well as stress-induced behavioral deficits in the open field, elevated plus maze, and light-dark transition test were reversed by exogenous leptin in a dose-dependent (0.1-0.5 mg/kg) manner. Acute exposure to 2 h immobilization produced a fourfold rise in plasma levels of corticosterone. Animals injected with leptin at a dose of 0.1 mg/kg, but not at dose of 0.5 mg/kg, exhibited a marginal increase in plasma corticosterone. Immobilization-induced increases of plasma corticosterone were reversed by leptin injected at doses of 0.1 or 0.5 mg/kg. The data suggest that exogenous leptin can reduce stress perception, resulting in an inhibition of stress effects on the activity of hypothalamic-pituitary-adrenal axis and behavior. The reported pharmacological effects of leptin represent an innovative approach for the treatment of stress-related disorders.

Occipital somites guide motor axons of the accessory nerve in the avian embryo

The accessory nerve (nervus accessorius) displays a unique organization in that its axons ascend along the rostrocaudal axis after exiting the cervical spinal cord and medulla oblongata and thereafter project ventrally into the periphery at the first somite level. Little is known about how this organization is achieved. We have investigated the role of somites in the guidance of motor axons of the accessory nerve using heterotopic transplantations of somites in avian embryos. The formation of not only accessory nerve but also the vagal nerve was affected, when a more caudal occipital somite (somites 2-4) was grafted to the position of the first occipital somite. Our study reveals that only the first occipital somite permits the development of ventral projection of accessory axons, a process that is inhibited by more caudal occipital somites.

Drinking water: a major source of lead exposure in Karachi, Pakistan

Excess lead in drinking water is a neglected source of lead toxicity in Pakistan. A cross-sectional survey in 2007/08 was made of water samples from drinking water sources in Karachi, a large industrial city. This study aimed to compare lead levels between untreated ground water and treated surface (tap) water in 18 different districts. Of 216 ground and surface water samples collected, 86% had lead levels higher than the World Health Organization maximum acceptable concentration of l0 ppb. Mean lead concentration in ground water [146 (SD 119) ppb] was significantly higher than in surface water [77.1 (SD 54) ppb]. None of the 18 districts had a mean lead level of ground or surface water below the WHO cut-off and ground water sources in 9 districts had a severe level of contamination (>150 ppb). Urgent action is needed to eliminate sources of contamination.

Wilms tumor in adult

Wilms Tumor (WT) is a very rare malignancy in adults representing 1% of all renal neoplasms. It is however the most common renal tumor of children and adult patients are treated like pediatric cases. Bilateral tumors occur in 5% of adult cases. The typical presenting features are asymptomatic abdominal mass (most common), hematuria, pain, fever, and hypertension. As clinical presentation of WT is similar to that of renal cell carcinoma (RCC), it tends to be an unsuspected pathological diagnosis in most cases. The diagnosis of the tumor needs positive sonographic and computed tomography (CT) findings with histopathological confirmation. Prognosis of adult WT is relatively poor and resistant to chemotherapy. We present a case of wilms tumor in a 68 years old male patient with right sided non tender abdominal mass and occasional flank pain. The patient was normotensive but hematuric and radiological findings suggested right renal mass with enlarged lymph node and histopathological analysis revealed nephroblastoma associated with lymph node metastases.

Drinking water contamination by chromium and lead in industrial lands of Karachi

OBJECTIVES

To identify and quantify chromium and lead as contaminant in water sources of Karachi.

METHODS

This water assessment survey was conducted from June 2007 to February 2008 in all the 18 towns of Karachi. In total 216 water samples were collected from ground (n=108) and surface water sources (n = 108). Water samples were collected in a liter polyethylene acid resistant bottle with extreme care to prevent contamination and concentrations of heavy metals (chromium and lead). Metallic ion contents were estimated by Atomic Absorption Spectrophotometer. Statistical analysis was done by applying T-test and chi-square for continuous and categorical variables respectively at 95% confidence level; Pearson correlation was also determined between chromium and lead concentrations.

RESULTS

A total of 187 water samples had lead concentration higher than the maximum acceptable concentration (MAC) in drinking water, established by WHO (10 PPB) and lead contaminated sources were in significantly higher proportion than chromium contaminated water samples (n = 49) [chi2 = 128; P- < 0.001]. Mean chromium concentration in ground water was (micro = 49; SE = 3.8) was significantly higher than mean chromium concentration (micro = 33, SE = 3.5) in surface water (P = 0.003). There was a significant and positive correlation between chromium and lead concentrations in ground water (P = 0.04) however Pearson correlation was not significant for surface water (P = 0.6). Industrial towns (Korangi, Landhi and SITE) had significantly higher concentration of chromium (micro = 82.4; SE = 8.9) in their ground and tap water as compared to the mean chromium concentration (micro = 33; SE = 2.2) in the water samples of rest of the towns of Karachi (P < 0.001).

CONCLUSION

Chromium and Lead levels are high in almost all ground water sources, however extremely high concentrations were found in industrial areas. Presence of any one of the heavy metal contamination necessitate the need for the estimation of other heavy metals as significant positive correlation was found between chromium and lead concentration, indicating the possibility of similar contamination sources in Karachi.

Awareness about BLS (CPR) among medical students: status and requirements

OBJECTIVES

To study the awareness on Basic Life Support (BLS) (CPR) in undergraduate medical students.

METHODS

A cross sectional studywas conducted by using responses to a questionnaire regarding BLS by 61 students. The results were analyzed with SPSS version 11.101.

RESULTS

Out of 61 students only 9 (14.7%) had taken a BLS (CPR) course while 52 (85.3%) students had not attended any such course. Significantly more number of students had the theoretical knowledge about BLS (76.07% vs 49.18%, p<0.00). Practical knowledge about BLS was scored as having no, some and complete knowledge of the course. Of all the students, 57.3% had no knowledge, among those 34% had heard BLS from somewhere, 22.9% had some knowledge out of which 50% had heard about it. Significantly less number of students had complete knowledge about BLS (4% p<0.05). Among the students who had taken the course, 22% had complete knowledge (p<0.05). Significantly less number of students knew about the skills for BLS (21% p<0.05).

CONCLUSION

Most of the medical students although had not attended the course, still they had some knowledge about BLS. Inclusion of this course in the undergraduate curriculum will increase awareness and application of this valuable life saving maneuver.

Immunoglobulin (Ig)-containing plasma cells in the Harderian gland in broiler and native chickens of Bangladesh

The distribution and frequency of immunoglobulin (Ig)-containing plasma cells, their variations due to sex, and the mode of secretion of Ig cells into the duct system of the Harderian gland was investigated in broiler and native chickens of both sexes in Bangladesh. The Harderian gland is covered by a capsule, and the connective tissue septa divide the gland into numerous unequal-sized numerous lobes and lobules. The Ig-containing plasma cells were located in the interstitial space, interacinar space, apical part of the lobule, and lumina of the lobules of the Harderian gland in both broiler and native chickens. The population of these Ig-containing plasma cells varied in between broiler and native chickens, and also between male and female broiler and native chickens. In the broiler, the number of IgM-containing plasma cells was higher; in contrast, in the native chickens, the population of IgA-containing plasma cells was larger. In the broiler, there were more IgA- and IgG-containing plasma cells in the male; in contrast, there were more IgM-containing plasma cells in female. In native chickens the frequency of IgA-containing plasma cells was greater in the female than male. When the data for broiler and native birds were compared, it was found that there were significantly more IgA- and IgG-containing plasma cells in the native male and female chickens than in the broiler males and females. The secretory Igs were located in the lumina of acini and the duct system of the Harderian gland. In the present study Ig-containing plasma cells were observed to be released in the lumina of the lobules of Harderian gland by the breakdown of acinar tissues in broilers, and by holocrine mode of secretion in the native chicken. These results suggested that the Harderian gland, even though it is not a lymphoid organ as a whole, but acts as an immunopotent organ in chickens, and that the gland in native chicken contains more Ig-containing plasma cells due to their scavenging.

Serum leptin levels correlation with high blood pressure in adult females

OBJECTIVE

To measure serum leptin levels and compare them in lean and obese subjects and to identify correlation between serum leptin levels, heart rate and hypertension in lean and obese subjects among adult females.

DESIGN

A case control study.

PLACE AND DURATION

Jinnah Medical and Dental College Hospital's Outpatient Department (OPD) during the calender year 2003.

PATIENTS AND METHODS

Seventy female subjects with different body mass indices were selected from OPD of Jinnah Medical and Dental College Hospital (OPD), Karachi. Heart rate was counted manually; blood pressure was measured by mercury sphygmomanometer while serum leptin was measured using enzyme-linked immunoassay. The outcomes hypertension and heart rate were correlated to risk factor leptin.

RESULT

Mean heart rate, systolic and diastolic blood pressure and serum leptin levels of obese people were 90 +/- 1, 142 +/- 2, 89 +/- 1 and 24.13 +/- 1.7 respectively, which were significantly higher as compared to lean subjects (p<0.05). All the parameters correlated positively and significantly with increasing BMI.

CONCLUSION

There was a relationship of tachycardia and hypertension with high serum leptin levels in obesity. Serum leptin levels increase with the level of obesity. Hyper-leptinemia is associated with tachycardia and increases in both systolic and diastolic blood pressure in obesity via complex mechanisms.

The prevalence of glaucoma in Bangladesh: a population based survey in Dhaka division

BACKGROUND/AIM

Few studies have reported on the epidemiology and clinical characteristics of glaucoma in south Asia. This project aimed to determine the prevalence of glaucoma of Dhaka, Bangladesh.

METHOD

A multistage, stratified, clustered sample was drawn from Dhaka Division, Bangladesh, using systematic sampling to identify individual subjects aged 35 years and older. Examination of all subjects included Snellen visual acuity, slit lamp examination (including gonioscopy and applanation tonometry) and a stereoscopic assessment of the vertical cup:disc ratio (CDR). In selected subjects, a threshold visual field examination was performed. Glaucoma was diagnosed on the basis of statistical abnormality of the vertical CDR combined with an abnormal visual field test, or in subjects with advanced glaucoma who could not complete field testing, a grossly abnormal CDR. If it was not possible to examine the optic discs and the subject was blind, glaucoma was diagnosed on the basis of a raised intraocular pressure.

RESULTS

Of 3562 eligible subjects, 2347 were examined (66%). Among people aged 40 years and older, the prevalence of definite glaucoma was 2.1% (95% confidence interval: 1.5 to 2.9; 39 people). The prevalence of definite and probable glaucoma was 3.1% (95% CI: 2.4 to 4.0; 58 people) in subjects of the same age. Primary open angle glaucoma was the most common form of glaucoma, accounting for 75% of the total. Among cases of blindness not attributable to refractive error, 5% were caused by glaucoma. Glaucoma prevalence was higher in men than women, but did not show the typical increase with age.

CONCLUSION

Glaucoma prevalence is relatively high in Bangladesh, although it accounts for only a small proportion of blindness in the community. It is estimated that there are approximately 586 000 people 40 years and older with definite or probable glaucoma in Bangladesh.

Metabolic and stress responses of the body to trauma: produced by the laparoscopic and open cholecystectomy

Laparoscopic cholecystectomy is regarded as gold standard therapy for symptomatic gall stone disease. This study was done to compare the metabolic and stress responses between open and lapraroscopic cholecystectomy and to evaluate their significance in postoperative recovery. Thirty patients with symptomatic gall stone disease were treated with open and laparoscopic cholecystectomy on elective basis (14 versus 16). Three samples of blood were collected from each patient to investigate serum cortisol, adrenaline, nor-adrenaline, C-reactive protein and blood glucose level. The mean age of patients was 41.86+/-10.13 blood glucose and stress hormones (cortisol, adrenaline, nor adrenaline) and C-reactive protein all were found significantly raised in the postoperative period in open cholecystectomy than laparoscopic cholecystectomy group. The postoperative recovery was also prolonged in the open group. The obvious clinical advantages of laparoscopic cholecystectomy over open cholecystectomy is mainly because of less metabolic and stress response.

Serum leptin levels in female patients with NIDDM

OBJECTIVE

To compare serum leptin levels of diabetic and non-diabetic female subjects and also assess the relationship of hyperglycemia with serum insulin, C-peptide and leptin levels.

DESIGN

It is a case control study.

PLACE AND DURATION OF STUDY

The study was conducted at Medicare Hospital, Family Care Clinic and Baqai Institute of Diabetes and Endocrinology between December 1997 to September 1999.

SUBJECT AND METHODS

One hundred and forty female subjects with different body mass indices and fasting blood sugar levels were selected from three different diabetic centers. A venous sample was drawn after an overnight fast (12 hours) for determination of blood parameters in all groups. Glycosylated hemoglobin, hexosamine, fructosamine, insulin and C-peptide were determined only in diabetic patients. Blood glucose, triacylglycerol (TAG), total cholesterol, HDL cholesterol, HbA1C, hexosamine and fructosamine were determined enzymatically. Serum leptin, C-peptide and insulin were measured using enzyme-linked immunoassay.

RESULTS

Serum leptin levels of obese diabetic and non-diabetic subjects were significantly higher as compared with lean diabetic patients and non-diabetic subjects (P< 0.05). Leptin levels were positively correlated with serum insulin and C-peptide levels. Serum leptin increased with increase in body mass index and waist hip ratio was strongly related with insulin resistance in NIDDM.

CONCLUSION

Leptin levels are increased in obesity and may play a role in development of insulin resistance and NIDDM.

Hypoxia-induced respiratory patterned activity in Lymnaea originates at the periphery

Respiration in Lymnaea is a hypoxia-driven rhythmic behavior, which is controlled by an identified network of central pattern generating (CPG) neurons. However, the precise site(s) (i.e., central or peripheral) at which hypoxia acts and the cellular mechanisms by which the respiratory chemosensory drive is conveyed to the CPG were previously unknown. Using semi-intact and isolated ganglionic preparations, we provide the first direct evidence that the hypoxia-induced respiratory drive originates at the periphery (not within the central ring ganglia) and that it is conveyed to the CPG neurons via the right pedal dorsal neuron 1 (RPeD1). The respiratory discharge frequency increased when the periphery, but not the CNS, was made hypoxic. We found that in the semi-intact preparations, the frequency of spontaneously occurring respiratory bursts was significantly lower than in isolated ganglionic preparations. Thus the periphery exerts a suppressive regulatory control on respiratory discharges in the intact animal. Moreover, both anoxia (0% O(2)) and hypercapnia (10% CO(2)) produce a reduction in respiratory discharges in semi-intact, but not isolated preparations. However, the effects of CO(2) may be mediated through pH changes of the perfusate. Finally, we demonstrate that chronic exposure of the animals to hypoxia (90% N(2)), prior to intracellular recordings, significantly enhanced the rate of spontaneously occurring respiratory discharges in semi-intact preparations, even if they were maintained in normoxic saline for several hours. Moreover, we demonstrate that the peripherally originated hypoxia signal is likely conveyed to the CPG neurons via RPeD1. In summary, the data presented in this study demonstrate the important role played by the periphery and the RPeD1 neuron in regulating respiration in response to hypoxia in Lymnaea.

CREB-binding protein is a nuclear integrator of nuclear factor-kappaB and p53 signaling

Transcriptional coactivators may function as nuclear integrators by coordinating diverse signaling events. Here we show that the p65 (RelA) component of nuclear factor-kappaB (NF-kappaB) and p53 mutually repress each other's ability to activate transcription. Additionally, tumor necrosis factor-activated NF-kappaB is inhibited by UV light-induced p53. Both p65 and p53 depend upon the coactivator CREB-binding protein (CBP) for maximal activity. Increased levels of the coactivator relieve p53-mediated repression of NF-kappaB activity and p65-mediated repression of p53-dependent gene expression. Nuclear competition for limiting amounts of CBP provides a novel mechanism for altering the balance between the expression of NF-kappaB-dependent proliferation or survival genes and p53-dependent genes involved in cell cycle arrest and apoptosis.

Collagen cross-linking in sun-exposed and unexposed sites of aged human skin

A recently described nonreducible, acid-heat stable compound, histidinohydroxylysinonorleucine (HHL), is a collagen cross-link isolated from mature skin tissue. Its abundance is related to chronologic aging of skin. The present communication describes the quantity of HHL from aged human skin of the same individuals in sun-exposed (wrist) and unexposed (buttock) sites. Punch biopsies were obtained from these sites from nine people of age 60 or older. HHL contents (moles/mole of collagen) at these sites were for wrist 0.13 +/- 0.07 and for buttock 0.69 +/- 0.17 (mean +/- SD, p less than 0.001). In addition, it was found that acute irradiation of the cross-linked peptides with UVA (up to 250 J/cm2) and UVB (up to 1 J/cm2) had no effect on HHL structure. The same treatment significantly degraded another nonreducible, stable collagen cross-link, pyridinoline. The results suggest that chronic sunlight exposure may be associated with an impediment to normal maturation of human dermal collagen resulting in tenuous amount of HHL. Thus, the process of photoaging in dermal collagen is different from that of chronologic aging in human skin.

Effect of malnutrition and subsequent rehabilitation on the development of mouse brain myelin

Malnutrition in mice from birth resulted in myelin of brain having higher than normal molar proportions of cholesterol and phospholipids relative to a molar unit of cerebroside + sulphatide. This was found at all ages between 20 and 60 days, and the molar ratio of these lipids in older animals was comparable to that in the younger controls. The phospholipid and the ganglioside patterns were also immature for age. The phospholipid composition was characterized by lower molar proportions of ethanolamine phosphoglyceride (EPG) and sphingomyelin (SPh) and higher proportion of choline phosphoglyceride (CPG), and the ganglioside pattern was characterized by higher molar proportions of the disialogangliosides GD1a and GD1b and markedly lower proportion of the monosialoganglioside GM1. Malnutrition imposed from 30 days of age did not affect the contents of the major lipids (and so their molar ratio), but within the phospholipids there was a small but significant deficit of SPh, which was compensated by a higher content of CPG. The ganglioside pattern was as if the animals were malnourished from birth. Nutritional rehabilitation up to 60 days of age subsequent to malnutrition for the first 30 days fully corrected the ganglioside pattern, but not the molar ratio, of the major lipids (because of persistent deficit in cerebroside + sulphatide) and the composition of the phospholipids (because of small but significant deficit of SPh). The results indicate that malnutrition instituted at any time during the entire programme of myelination can affect one or other aspect of myelin development, and nutritional rehabilitation of animals malnourished in early life cannot fully correct this developmental gap.