Multifocal atypical teratoid/rhabdoid tumour in an infant-a rare case report

BACKGROUND

Atypical teratoid/rhabdoid tumours (AT/RT) are uncommon but aggressive, malignant tumours in the paediatric age group. Presentation of concomitant supratentorial and infratentorial lesions in an infant is extremely rare. We discuss an infant diagnosed with such lesions. Systematic PubMed search was conducted using keywords 'atypical teratoid /rhabdoid tumor', 'paediatric' and 'multifocal'. Reports were included for patients younger than 18 years with two or more lesions. The search yielded additional five cases and were tabulated. Age, sex, location, treatment given and survival/outcome were noted.

CASE REPORT

A 10-month-old child presented with complaints of drowsiness and intractable vomiting. Imaging showed multifocal supra- and infratentorial lesions with obstructive hydrocephalus. The child underwent ventriculoperitoneal shunt followed by surgical removal of the posterior fossa lesion. Histopathological features were consistent with AT/RT.

CONCLUSIONS

Multifocal AT/RT are very rare. The impact of multifocality in the outcome is not known as very few reports are available. Newer targeted therapies may offer insight in improving outcomes in the future.

Preferences and experiences of parents/guardians of youth with epilepsy and intellectual disability on reproductive health counseling

OBJECTIVE

To explore the experiences and preferences of parents/guardians of adolescents and young adults (AYA) of childbearing potential with co-occurring epilepsy and intellectual disability (ID) regarding counseling by neurologists on sexual and reproductive health (SRH) topics such as pregnancy, contraception, menstruation, and folic acid supplementation.

METHODS

We conducted semi-structured interviews with parents/guardians of AYAs (12-28 years old) of childbearing potential with co-occurring epilepsy and ID, recruited from a tertiary-care children's hospital. We confirmed the diagnoses of epilepsy and ID with the patient's neurologist and parent/guardian. All degrees of ID (e.g. mild/moderate/severe) were eligible. We audio-recorded and transcribed interviews. Two coders performed qualitative thematic analysis.

RESULTS

Twenty-five parents/guardians completed interviews. Themes included: (1) Parents/guardians believe their child to be immune from sexual abuse due to their supervision, yet desire counseling about abuse recognition and prevention, which they also report not occurring (2) A common opinion was that counseling on menstruation was more relevant to their child's life than counseling about pregnancy-related topics (3) Parents/guardians reported a lack of counseling on pregnancy-related topics such as folic acid supplementation and teratogenesis and generally also reported some degree of interest in hearing about these topics from neurologists (4) Parents/guardians also reported a lack of counseling on drug interactions between contraception and ASMs, and were highly interested in learning more about this topic (5) Parents/guardians want neurologists to initiate annual comprehensive SRH counseling at puberty about most topics, but report that they often initiate SRH discussions themselves.

CONCLUSION

Parents/guardians of AYAs with epilepsy and ID prefer more frequent, neurologist-initiated, comprehensive conversations surrounding SRH particularly emphasizing menstruation and sexual abuse recognition/prevention. Findings may inform professional and patient education and health systems interventions including development of discussion guides and/or decision aides to improve SRH care for AYAs with epilepsy and ID.

SMARCB1 (INI-1) - Deficient sinonasal carcinoma: Report of two cases

SMARCB1 (INI-1)-deficient sinonasal carcinoma is a rare, poorly differentiated carcinoma defined by complete loss of tumor suppressor gene SMARCB1 (INI-1) within the neoplastic cell nuclei demonstrated by the immunohistochemical stain. SMARCB1 (INI-1) gene inactivation has been implicated in the pathogenesis of a diverse group of malignant neoplasms that tend to share "rhabdoid" morphology. SMARCB1 (INI-1)-deficient sinonasal carcinoma was first reported by Agaimy et al. in 2014. These tumors are often basaloid with focal rhabdoid differentiation, prominent necrosis, increased mitotic activity, and aggressive behavior. Other than being INI-1 and NUT negative, they are positive for pancytokeratin and express variable immunoreactivity for squamous markers like p63 and neuroendocrine markers like synaptophysin. Most patients present with locally advanced disease and hence a combination of chemotherapy, radiotherapy, and surgery is usually recommended.

Ectopic Cervical Thymoma: An Uncommon Entity

Thymomas originates from the epithelial cells of thymic tissue. These tumors commonly occur in the anterior mediastinum. However, thymomas can arise anywhere from the aberrant or remnant thymus in the neck or mediastinum. Ectopic cervical thymoma is a rare disease. It is important to be aware that cervical masses can also be thymomas rather than thyroid or parathyroid masses. Here, we present a case of a 62-year-old female who presented with swelling in the neck and was diagnosed with cervical thymoma type AB.

Ovarian borderline mucinous tumor with squamous overgrowth: An unusual finding with review of literature

Borderline mucinous tumor (BMT) is often associated with other entities such as dermoid cyst, Brenner tumor, and endometriosis. Squamous areas are often associated which may be a part of BMT or its associated conditions. Here, we describe squamous overgrowth in a case of intestinal type of mucinous borderline tumor in a 29-year-old uniparous female and discuss the diagnostic difficulties.

Infectious dose-dependent accumulation of live highly pathogenic avian influenza H5N1 virus in chicken skeletal muscle-implications for public health

Highly pathogenic avian influenza viruses (HPAIV) of H5N1 subtype are a major global threat to poultry and public health. Export of poultry products, such as chicken and duck meat, is a known source for the cross-boundary spread of HPAI H5N1 viruses. Humans get infected with HPAI H5N1 viruses either by close contact with infected poultry or through consumption of fresh/undercooked poultry meat. Skeletal muscle is the largest soft tissue in chicken that has been shown to contain virus during systemic HPAIV infection and supports productive virus infection. However, the time between infection of a chicken with H5N1 virus and presence of virus in muscle tissue is not yet known. Further, it is also not clear whether chicken infected with low doses of H5N1 virus that cause non-fatal subclinical infections continue to accumulate virus in skeletal muscle. We investigated the amount and duration of virus detection in skeletal muscle of chicken experimentally infected with different doses (10² , 10³ and 10⁴ EID₅₀ ) of a HPAI H5N1 virus. Influenza viral antigen could be detected as early as 6 hr after infection and live virus was recovered from 48 hr after infection. Notably, chicken infected with lower levels of HPAI H5N1 virus (i.e., 10² EID₅₀ ) did not die acutely, but continued to accumulate high levels of H5N1 virus in skeletal muscle until 6 days post-infection. Our data suggest that there is a potential risk of human exposure to H5N1 virus through meat from clinically healthy chicken infected with a low dose of virus. Our results highlight the need to implement rigorous monitoring systems to screen poultry meat from H5N1 endemic countries to limit the global spread of H5N1 viruses.

Bladder Adenocarcinoma: A Persisting Diagnostic Dilemma

Primary urinary Bladder Adenocarcinoma (PBA) is an uncommon neoplasm and can cause diagnostic difficulties due to histologic similarities with adenocarcinomas of adjacent structures like Gastrointestinal Tract (GIT) and prostate, since involvement of the bladder by metastasis or direct spread can occur. Seven cases of bladder adenocarcinomas were diagnosed during a period of four years in a tertiary care hospital. Patient's age ranged from 26-78 years with a male predilection. Three cases were signet ring type adenocarcinomas, two cases were subtyped as enteric variant, one as mucinous variant and one as adenocarcinoma Not Otherwise Specified (NOS) variant. One case showed urachal involvement. Common site of involvement was the base and posterior wall of the bladder. Three cases had prior history of GIT malignancy. No morphologic difference was identified to differentiate primary from secondary adenocarcinomas. Bladder adenocarcinoma is rare tumours. Primary and secondary adenocarcinomas cannot be distinguished from each other on morphologic grounds. Ancillary studies may have limited role in distinguishing between the two. Hence, clinical correlation has a major role in their evaluation.

Mucoepidermoid Carcinoma of Salivary Gland: Limitations and Pitfalls on FNA

Mucoepidermoid Carcinoma (MEC) is the most common malignant neoplasm of salivary gland origin. However, its morphologic heterogeneity poses difficulty in interpretation. In the present series we discuss the morphologic features of MEC, limitations and pitfalls in its diagnosis on Fine Needle Aspiration Cytology (FNAC). Fourteen cases of suspected MEC were evaluated cytologically followed by histopathological examination for confirmation. A definite cytological diagnosis was rendered in nine cases; three of the remaining five were underdiagnosed as abscess, pleomorphic adenoma and mucus cyst. Of the remaining two cases, one case each of sebaceous carcinoma and sialadenitis was mislabeled as MEC on cytology. A satisfactory aspirate composed of intermediate cells, mucin secreting cells and squamous cells in a mucinous background may not be obtained in all cases of low grade MEC. High grade MEC can be classified as squamous cell carcinoma. Hence, awareness of confounding factors with clinicopathologic correlation and judicious use of frozen section can help in minimizing errors.

Primary Small Cell Carcinoma of The Esophagus - An Eight Year Retrospective Study

INTRODUCTION

Primary small cell carcinoma of the esophagus is a rare and aggressive tumor. Patients present with metastatic disease and have a poor clinical outcome. The objective of the study was to correlate clinical and histopathological features of primary small cell carcinoma of the esophagus diagnosed and treated at our hospital.

MATERIALS AND METHODS

A retrospective study of 11 patients diagnosed with primary small cell carcinoma of the esophagus in Kasturba Hospital, Manipal between 2006 and 2014 was done. The histopathological and immunohistochemical features were correlated with clinical and endoscopic findings.

RESULTS

Eleven patients were diagnosed to have small cell carcinoma of esophagus with a male preponderance. Common presenting symptoms were dysphagia and weight loss. Majority of the patients showed mid esophageal ulceroproliferative growth. Biopsy findings were consistent with the characteristic morphology of small cell carcinoma and demonstrated immunoreactivity to neuroendocrine markers. In addition, few cases also showed adjacent squamous dysplasia/carcinoma. Most of the patients presented with metastatic disease, liver being the most common site. These patients were treated by chemotherapy and radiotherapy.

CONCLUSION

Esophageal small cell carcinomas are aggressive tumors with high rates of distant metastasis. Presence of squamous dysplasia /squamous cell carcinoma in the adjacent mucosa supports the hypothesis that this neoplasm arise from pleuripotent stem cells. Presence of the latter is also useful to rule out spread from lung primary.

Hepatic Epithelioid Hemangioendothelioma in an Eight Year old - A Case Report

Hepatic epithelioid haemangio-endothelioma (HEHE) is a rare vascular tumour of endothelial origin. The etiology of this tumour is unknown and has a variable clinical outcome. It usually affects adults and is extremely rare in children. Histologically, HEHE is characterized by epithelioid to dendritic tumour cells with intracytoplasmic lumina containing RBCs and a myxoid to sclerotic stroma. Being a rare entity, awareness and a high degree of suspicion is required to correctly identify this tumour. We report a case of hepatic hemangioendothelioma in an 8-year-old child.

MDX-1100, a fully human anti-CXCL10 (IP-10) antibody, is a high affinity, neutralizing antibody that has entered Phase I clinical trials for the treatment of Ulcerative Colitis (UC). (131.20)

The chemokine, CXCL10 or interferon γ inducible protein-10 (IP-10) is a chemotactic cytokine for activated T cells and monocytes and plays an important role in migration of cells into sites of inflammation. The receptor for CXCL10, CXCR3, is expressed by activated T cells, eosinophils, NK, and endothelial cells. CXCL10 levels are elevated in ulcerative colitis (UC) amongst other inflammatory diseases. In preclinical animal models of UC, antibodies against CXCL10 have been shown to modify disease progression. Medarex, Inc. has developed a fully human monoclonal antibody (MDX-1100) that binds selectively to CXCL10. This antibody binds to the ligand with high affinity and effectively competes for ligand binding to CXCR3 expressing cells. MDX-1100 blocks CXCL10 induced calcium flux and cell migration with an estimated IC50 in the low nM range. In order to identify potential pharmacodynamic markers for CXCL10 activity, gene chip analysis was performed with RNA purified from CXCL10-stimulated human PBMCs. We identified cell surface receptors, intracellular and soluble markers that are CXCL10 responsive and confirmed the induction of a subset of these genes using quantitative RT-PCR. In summary, MDX-1100, an antibody that binds and neutralizes the activity of CXCL10 is predicted to reduce disease severity in patients with UC and thus a Phase I clinical trial has been initiated.

Computer simulation of protein-ligand interactions: challenges and applications

The accurate modeling of protein-ligand interactions, like any prediction of macromolecular structure, requires an energy function of sufficient detail to account for all relevant interactions and a conformational search method that can reliably find the energetically favorable conformations of a heterogeneous system. Both of these prerequisites represent daunting challenges. Consequently, the routine docking of small molecules or peptides to proteins in their correct binding modes, and the reliable ranking of binding affinities remain unsolved problems. Nonetheless, computational techniques are continually evolving so as to broaden the range of feasible applications, and the accuracy of predictions and theoretical approaches can often be of great help in guiding and interpreting experiments. We discuss the energetics of protein-ligand systems and survey conformational searching techniques. We illustrate how molecular modeling of a protein-ligand complex sheds light on the observed resistance of a mutant dihydrofolate reductase to the antibiotic trimethoprim. In another example, we show that relaxation of side chains in different crystal structures of the same complex, benzamidine bound to trypsin, is needed to draw sensible conclusions from the calculations. The results of these relatively simple conformational searches underscore the importance of incorporating protein flexibility in simulations of protein-ligand interactions, even in the context of relatively rigid binding pockets.

Consequence of beta 16 and beta 112 replacements on the kinetics of hemoglobin assembly

The rates of alpha/beta monomer combination of four beta(A) variants (beta 112C --> S, beta 112C --> D, beta 112C --> T, and beta 112C --> V) in the presence and absence of beta 16G --> D (beta(J)) were measured in an attempt to assess the consequences of amino acid substitution at both a surface (beta 16) and an alpha(1)beta(1) interface (beta 112) residue on oxyhemoglobin assembly. Rates of alpha/beta monomer combination determined spectrally in 0.1 M Tris-HCl, 0.1 M NaCl, 1 mM EDTA, pH 7.4, at 21.5 degrees C differed by over 40-fold (22 +/- 2.0 to 0.49 +/- 0.1 x 10(5) M(-1) s(-1)), and were in the order: HbA beta 112S = HbJ beta 16D, beta 112S > HbA beta 112D = HbJ beta 16D, beta 112D > HbA > Hb J > HbA beta 112T = HbJ beta 16D, beta 112T > HbJ beta 16D, beta 112V > HbA beta 112V. This extensive kinetic investigation of single/double amino acid-substituted recombinant hemoglobin molecules, in conjunction with molecular modeling studies, has allowed examination of an array of unique alpha/beta subunit interactions and assembly processes.

Point mutations in a nucleoside transporter gene from Leishmania donovani confer drug resistance and alter substrate selectivity

Leishmania parasites lack a purine biosynthetic pathway and depend on surface nucleoside and nucleobase transporters to provide them with host purines. Leishmania donovani possess two closely related genes that encode high affinity adenosine-pyrimidine nucleoside transporters LdNT1.1 and LdNT1.2 and that transport the toxic adenosine analog tubercidin in addition to the natural substrates. In this study, we have characterized a drug-resistant clonal mutant of L. donovani (TUBA5) that is deficient in LdNT1 transport and consequently resistant to tubercidin. In TUBA5 cells, the LdNT1.2 genes had the same sequence as wild-type cells. However, because LdNT1.2 mRNA is not detectable in either wild-type or TUBA5 promastigotes, LdNT1.2 does not contribute to nucleoside transport in this stage of the life cycle. In contrast, the TUBA5 cells were compound heterozygotes at the LdNT1.1 locus containing two mutant alleles that encompassed distinct point mutations, each of which impaired transport function. One of the mutant LdNT1.1 alleles encoded a G183D substitution in predicted TM 5, and the other allele contained a C337Y change in predicted TM 7. Whereas G183D and C337Y mutants had only slightly elevated adenosine K(m) values, the severe impairment in transport resulted from drastically ( approximately 20-fold) reduced V(max) values. Because these transporters were correctly targeted to the plasma membrane, the reduction in V(max) apparently resulted from a defect in translocation. Strikingly, G183 was essential for pyrimidine nucleoside but not adenosine transport. A mutant transporter with a G183A substitution had an altered substrate specificity, exhibiting robust adenosine transport but undetectable uridine uptake. These results suggest that TM 5 is likely to form part of the nucleoside translocation pathway in LdNT1.1

Wavelength-dependent spectral changes accompany CN-hemin binding to human apohemoglobin

The interaction of apohemoglobin with two heme derivatives, CN-protohemin and CN-deutero-hemin, was monitored at multiple Soret wavelengths (417-423 and 406-412 nm, respectively) in 0.05 M potassium phosphate buffer, pH 7.0, at 10 degrees C and revealed, as previously reported, a multiphasic kinetic reaction. Wavelength-dependent reactions were observed for both CN-protohemin and CN-deuterohemin derivatives with the alpha chain (bathochromic entity) displaying faster (4- to 7-fold) rates throughout the courses of both heme-binding reactions. The basis of this spectrally heterogeneous kinetic phenomenon could be deduced from molecular modeling studies of alpha- and beta-chain structures. Key differences in the number of stabilizing contacts of the two chains with the peripheral alpha propionyl 45(CE3); 58(E7); 61(E10) as well as the beta vinyl 38(C4); 71(E15); 106(G8) groups were found. Furthermore, RMS plots comparing apo- and heme-containing subunits reveal substantial structural disparities in the C-CD-F-FG helical regions of the alphabeta dimer interface.

Cloning of a novel inosine-guanosine transporter gene from Leishmania donovani by functional rescue of a transport-deficient mutant

Purine transport is an indispensable nutritional function for protozoan parasites, since they are incapable of purine biosynthesis and must, therefore, acquire purines from the host milieu. Exploiting a mutant cell line (FBD5) of Leishmania donovani deficient in inosine and guanosine transport activity, the gene encoding this transporter (LdNT2) has been cloned by functional rescue of the mutant phenotype. LdNT2 encodes a polypeptide of 499 amino acids that shows substantial homology to other members of the equilibrative nucleoside transporter family. Molecular analysis revealed that LdNT2 is present as a single gene copy within the leishmanial genome and encodes a single transcript of 3 kilobase pairs. Transfection of FBD5 parasites with LdNT2 re-established their ability to take up inosine and guanosine with a concurrent restoration of sensitivity to the inosine analog formycin B. Kinetic analyses reveal that LdNT2 is highly specific for inosine (K(m) = 0.3 micrometer) and guanosine (K(m) = 1.7 micrometer) and does not recognize other naturally occurring nucleosides. Expression of LdNT2 cRNA in Xenopus oocytes significantly augmented their ability to take up inosine and guanosine, establishing that LdNT2 by itself suffices to mediate nucleoside transport. These results authenticate genetically and biochemically that LdNT2 is a novel nucleoside transporter with an unusual and strict specificity for inosine and guanosine.

Soret spectroscopic and molecular graphic analysis of human semi-beta-hemoglobin formation

The interaction of heme-free alpha (alpha(o)) and heme-containing beta (beta(h)) chains of human hemoglobin has been monitored in 0.1 M potassium phosphate buffer, pH 7 or 8, at 5 degrees C. Soret zero and first-derivative spectra were consistent with a uniform association reaction. Stopped-flow investigations demonstrated association rates on the order of 10(7) M(-1) s(-1). This was 100-fold more rapid than the reported rate of combination of alpha(h) and beta(h) proteins. This encounter-like rate of semi-beta-hemoglobin (alpha(o)beta(h)) formation was increased by raising the pH from 7 to 8. pH change is known to affect the spatial arrangement of AB-GH helical entities. Molecular graphic analysis of modeled alpha(o) protein superimposed over native alpha(h) protein revealed an apo Mb-like structure with well-defined AB-GH segments. Repositioning of these core helical segments, resulting in increased conformational freedom of the alpha1beta1 interface, was apparently responsible for the enhanced association properties of the alpha(o) protein.

Prospective evaluation of unexplained chronic liver transaminase abnormalities in asymptomatic and symptomatic patients

OBJECTIVES

It is currently recommend to perform a liver biopsy for patients with chronically elevated liver function tests (LFT) of unknown etiology (marker negative). The necessity and benefits of these recommendations are unknown. The aims of this study were to determine the prevalence of marker-negative LFT in patients referred for evaluation of chronically elevated LFT; to determine the prevalence of diseases that may be associated with marker-negative abnormal LFT; and to assess whether a liver biopsy alters the management of such patients.

METHODS

We conducted a prospective observational study of 1124 adults referred for evaluation of chronically elevated LFT. Patients who consented to a liver biopsy were eligible. Marker-negative abnormal LFT was defined as the absence of accepted serum markers for infectious, metabolic, autoimmune, or hereditary liver disease, the absence of a history of alcohol or hepatotoxic drug use, and the absence of signs of chronic liver disease.

RESULTS

Eighty-one of 1124 eligible patients were marker-negative. Liver biopsies in the 81 marker-negative patients revealed: normal histology (eight), steatosis (41), steatohepatitis (26), fibrosis (four), and cirrhosis (two). All 73 abnormal liver biopsies had some degree of steatosis. There were no significant associations between histological findings and the presence of obesity (p = 0.13), hyperlipidemia (p = 0.4), or diabetes (p = 0.9). There were no significant associations when classifying patients by gender or by symptoms.

CONCLUSION

In the setting of marker-negative elevated LFT, the most likely histological diagnosis is fatty metamorphosis of the liver with occasional associated fibrosis.

Cloning of Leishmania nucleoside transporter genes by rescue of a transport-deficient mutant

All parasitic protozoa studied to date are incapable of purine biosynthesis and must therefore salvage purine nucleobases or nucleosides from their hosts. This salvage process is initiated by purine transporters on the parasite cell surface. We have used a mutant line (TUBA5) of Leishmania donovani that is deficient in adenosine/pyrimidine nucleoside transport activity (LdNT1) to clone genes encoding these nucleoside transporters by functional rescue. Two such genes, LdNT1.1 and LdNT1.2, have been sequenced and shown to encode deduced polypeptides with significant sequence identity to the human facilitative nucleoside transporter hENT1. Hydrophobicity analysis of the LdNT1.1 and LdNT1.2 proteins predicted 11 transmembrane domains. Transfection of the adenosine/pyrimidine nucleoside transport-deficient TUBA5 parasites with vectors containing the LdNT1.1 and LdNT1.2 genes confers sensitivity to the cytotoxic adenosine analog tubercidin and concurrently restores the ability of this mutant line to take up [3H]adenosine and [3H]uridine. Moreover, expression of the LdNT1.2 ORF in Xenopus oocytes significantly increases their ability to take up [3H]adenosine, confirming that this single protein is sufficient to mediate nucleoside transport. These results establish genetically and biochemically that both LdNT1 genes encode functional adenosine/pyrimidine nucleoside transporters.

Analysis of the global architecture of hemoglobin A2 by heme binding studies and molecular modeling

The kinetics of CNProto- and CNDeutero-hemin binding to apohemoglobin A2 was investigated in a stopped-flow device in 0.05 M potassium phosphate buffer, pH 7, at 10 degrees C. The overall kinetic profile exhibited multiple phases: Phases I-IV corresponding with heme insertion (8.5-13 x 10(7) M(-1) s(-1)), local structural rearrangement (0.21-0.23 s(-1)), global alphadelta structural event (0.071-0.098 s(-1)), and formation of the Fe-His bond (0.009-0.012 s(-1)), respectively. Kinetic differences observed between apohemoglobin A2 and apohemoglobin A (previously studied) prompted an analysis of the structures of beta and delta chains through molecular modeling. This revealed a structural repositioning of the residues not only at, but also distant from the site of the amino acid substitutions, specifically those involved in the heme contact and subunit interface. A significant global change was observed in the structure of the exon-coded 3 region and provided additional evidence for the designation of this as the subunit assembly domain.

Fluorescence studies of human semi-beta-hemoglobin assembly

The intrinsic fluorescence properties of human alpha apohemoglobin at protein concentrations from 1 to 5 microM in 0.1 M potassium phosphate buffer, pH 7 or 8 at 5 degrees C were monitored in the absence and presence of a fixed concentration (5 microM) of a fluorescence quenching heme-containing native or Des (146-His, 145-Tyr) beta chain partner. These "reverse quenching" studies revealed that the emission intensity changes observed correlated well with protein concentration and theoretical extent of semi-beta-hemoglobin assembly. Furthermore, the relative quenching efficiencies were calculated to be 0.32, 0.25 and 0.61 for beta (pH 7), beta (pH 8) and Des beta (pH 7) chains, respectively. Thus, heme-mediated quenching was sensitive to the expected pH induced alpha apohemoglobin conformational change and to alteration in beta chain structure. Intramolecular changes induced by carboxylterminal modification (decreased "beta chain self-quenching") appeared to enhance the intermolecular rearrangements (increased "alpha chain partner quenching") seen upon subunit assembly.

Spectral demonstration of semihemoglobin formation during CN-hemin incorporation into human apohemoglobins

The incorporation of CN-hemin into three human adult apohemoglobin species (apohemoglobin, alpha-apohemoglobin, and apohemoglobin modified at its beta93 sulfhydryl with p-hydroxymercuribenzoate) has been monitored at micromolar concentrations in 0.05 M potassium phosphate buffer, pH 7.0, at 10 degrees C. In all cases, Soret spectral blue shifts accompanied CN-protohemoglobin but not CN-deuterohemoglobin formation. This finding in conjunction with isofocusing studies provided evidence of a CN-protosemi-alpha-hemoglobin intermediate, the formation of which appeared to be a direct consequence of CN-protohemin-alpha heme pocket interactions. The kinetics of full reconstitution of CN-protohemoglobin and CN-deuterohemoglobin revealed four distinct phases that apparently correlated with heme insertion (Phase I), local structural rearrangement (Phase II), global conformational response (Phase III), and irreversible histidine iron bond formation (Phase IV). These phases exhibited rates of 7.8-22 x 10(7) M(-1) s(-1), 0.19-0.23 s(-1), 0.085-0.12 s(-1), and 0.008-0.012 s(-1), respectively. Partial (50%) reconstitution with CN-protohemin, in contrast, revealed only three kinetic phases (with Phase III missing) of heme incorporation into native and p-hydroxymercuribenzoate-modified apohemoglobin. Furthermore, the absence of Phase III slowed the rate of proximal bond formation. These findings support the premise that irreversible assembly of CN-protosemi-alpha-hemoglobin is deterred by the presence of a heme-free beta partner, the consequence of which may be that intermolecular heme transfer is encouraged under conditions of heme deficiency in vivo.

Carboxyl-terminal modification influences subunit assembly of sickle hemoglobin beta chains

The subunit assembly properties of isolated beta and Des(His-146,Tyr-145) beta chains of sickle hemoglobin were investigated by isoelectric focusing over a protein concentration range from 500-125 microM in heme. Two components (presumably tetramer and monomer) and three components (designated tetramer, dimer and monomer) were visualized for beta s and Des(His-146,Tyr-145) beta s chains, respectively. Intensitometric quantitation of Des(His-146,Tyr-145) beta s chains demonstrated a similar distribution of all three structural components before and after the addition of their heteropartner alpha chains. This is in direct contrast to the reported preferential loss of Des(His-146,Tyr-145) beta A monomer species upon assembly and points to a major role of the beta 6 residue in the overall structural homeostasis of carboxylterminal modified human beta chains.

Use of serum bactericidal activity in assessing previous antibiotic therapy in acute lower respiratory tract infection in children

Bactericidal activity in sera of children with acute lower respiratory tract infection was assayed to determine its effect on the outcome of blood culture. Parental reporting of prior antibiotic therapy was also determined. 14.4% of samples without serum bactericidal activity yielded pathogens from blood culture, whereas only 2.4% of samples with serum bactericidal activity yielded pathogens. A statistically significant correlation was found between isolation of pathogens by blood culture and serum bactericidal activity. Parental reporting could not be relied upon as there was no positive correlation.

Genital standards for south Indian male newborns

One hundred and thirty-five male newborns in JIPMER hospital were studied. The penile length (stretched and unstretched), width as well as testicular length and breadth were measured. The influence of the gestational age and intrauterine growth on these measurements were studied. The mean stretched penile length for term babies was 3.57 cms (+/- 0.46), the unstretched length 3.26 cms (+/- 0.41), and the width was 1.04 cms (+/- 0.15). There was a linear increase in the above measurements with increasing gestational age. The right testicular length was 1.39 cms (+/- 0.28) and breadth was 0.98 cm (+/- 0.15) while the length and breadth for left testis were 1.32 cms (+/- 0.24) and 0.95 cm (+/- 0.14) respectively for term babies. The prepucial type was tubular in 103 (76.3%) babies and of ring type in 32 (23.7%). In 72 (53.3%) babies the prepuce could be retracted enough to visualise external urinary meatus.

Echographic-quantified severity of mitral anulus calcification: prognostic correlation to related hemodynamic, valvular, rhythm, and conduction abnormalities

Clinical and echocardiographic findings in 123 patients with mitral anulus calcification (MAC) were analyzed. In all patients M-mode echocardiography demonstrated a dense band of echoes posterior to the mitral valve, moving parallel and anterior to the left ventricular endocardium. Thirty-three per cent of patients were classified as having minimal to mild MAC (< 5 mm) and 67% had moderate to severe MAC (greater than or equal to 5 mm). There was a significant correlation between the degree of MAC to left atrial enlargement, congestive heart failure, aortic valve sclerosis, mitral regurgitation, atrial fibrillation, and AV-fascicular conduction defects. ECG evidence of conduction disturbances was significantly associated with MAC greater than or equal to t mm in width. The echocardiographic demonstration of MAC greater than or equal to 5 mm was significantly associated with the clinical implications known to occur with MAC; this echographic finding has important prognostic value in the evaluation of patients with mitral anulus calcification.

Alternating Wenckebach periods with acute myocardial infarction. Report of two cases

This report describes two patients with the spontaneous occurrence of alternating Wenckebach periods during the course of acute myocardial infarction. Both patients demonstrated alternating Wenckebach periods which terminated in a sequence of two blocked P waves. In one patient, His bundle electrocardiographic study documented the site of block to be proximal to the His bundle. Alternating Wenckebach periods with the block proximal to the His bundle may be compatible with a benign prognosis.

Lactic dehydrogenase isoenzyme determination in the diagnosis of acute myocardial infarction

Lactic dehydrogenase (LD) isoenzymes were determined by a rapid, simple technique and their utility in the diagnosis of acute myocardial infarction (AMI) was evaluated. LD isoenzymes were separated by ion-exchange column chromatography using DEAE-Sephadex. The cardiac fractions (LD-1 and LD-2) were measured separately on an Abbott ABA-100 analyzer and ratio of LD isoenzyme 1 to LD isoenzyme 2 (LD1:2) calculated. Daily serum samples were obtained from 100 patients selected only for a history of chest pain of abrupt onset. In 47 patients whose diagnosis was acute myocardial infarction (AMI), confirmed by typical clinical presentation and typical rise in cardiac-specific creatine kinase isoenzyme (MB(, peak LD1:2 ranged from 0.77 to 2.26. In 44 patients without AMI, peak LD1:2 ranged from 0.25 to 0.76. In two patients with electrocardiographic changes chest pain occurred two and five days previously; there was no rise in MB, but LD1:2 was elevated. Four patients with small AMI had no rise in LD1:2. Three more patients (one with active hemolysis) had false positive results. Thus, there was a sensitivity of 96% and a specificity of 97% when the cut-off point was LD1:2 = 0.76. LD1:2 is not quite as sensitive or specific as MD, but the ratio allows for the diagnosis of infarction in cases where MB has already returned to normal.