Functional Pyromellitic Diimide as a Corrosion Inhibitor for Galvanized Steel: An Atomic-Scale Engineering

Corrosion of metal/steel is a major concern in terms of safety, durability, cost, and environment. We have studied a cost-effective, nontoxic, and environmentally friendly pyromellitic diimide (PMDI) compound as a corrosion inhibitor for galvanized steel through density functional theory. An atomic-scale engineering through the functionalization of PMDI is performed to showcase the enhancement in corrosion inhibition and strengthen the interaction between functionalized PMDI (F-PMDI) and zinc oxide (naturally existing on galvanized steel). PMDI is functionalized with methyl/diamine groups (inh1 (R = -CH₃, R' = -CH₃), inh2 (R = -CH₃, R' = -CH₂CH₂NH₂), and inh3 (R = -C₆H₃(NH₂)₂, R' = -CH₂CH₂NH₂). The corrosion inhibition parameters (e.g., orbital energies, electronegativity, dipole moment, global hardness, and electron transfer) indicate the superior corrosion inhibition performance of inh3 (inh3 > inh2 > inh1). Inh3 (∼182.38 kJ/mol) strongly interacts with ZnO(101̅0) compared to inh2 (∼122.56 kJ/mol) and inh1 (∼119.66 kJ/mol). The superior performance of inh3 has been probed through charge density and density of states. Larger available states of N and H (of inh3) interact strongly with Zn and O_surf (of the surface), respectively, creating N-Zn and H-O_surf bonds. Interestingly, these bonds only appear in inh3. The charge accumulation on O_surf, and depletion on H(s), further strengthens the bonding between inh3 and ZnO(101̅0). The microscopic understanding obtained in this study will be useful to develop low-cost and efficient corrosion inhibitors for galvanized steel.

Chlorophyll(a)/Carbon Quantum Dot Bio-Nanocomposite Activated Nano-Structured Silicon as an Efficient Photocathode for Photoelectrochemical Water Splitting

Solar-driven water splitting is considered as a futuristic sustainable way to generate hydrogen and chemical storage of solar energy. Further, considering the technological competence, silicon is one of the potential materials for developing large-scale and cost-effective photocathodes (PCs), but it lacks efficacy and stability. Here, we show that chlorophyll(a)/carbon quantum dots (Chl/CQDs) bio-nanocomposite (b-NC)-decorated Si-nanowires (SiNWs) as PC can surpass the reported efficiency for photoelectrochemical (PEC) hydrogen generation along with stability. The optimized heterojunction (Chl/CQDs_SiNW) significantly enhances broad-band solar absorption and protects Si surface from corrosion. Further, the appropriate band alignment enforces efficient photogenerated charge separation and possesses directional exciton transport property via the Förster resonance energy transfer (FRET) mechanism. This synergic effect demonstrates an ∼18 times increase in photocurrent density (26.36 mA/cm²) compared to pristine SiNW PC at 1.07 V vs reversible hydrogen electrode (RHE). The efficiency reaches ∼7.86%, which is comparably the highest reported for hybrid Si-based photocathodes. Hydrogen evaluation rate was measured to be ∼113 μmol/h at 0.8 V vs RHE under 1 sun illumination. With Si-process line compatibility, this new finding opens a new direction toward the development of Si-based efficient and stable PCs at a large scale for commercial applications.

Surface Plasmon-Enhanced Carbon Dot-Embellished Multifaceted Si(111) Nanoheterostructure for Photoelectrochemical Water Splitting

Because of the excellent electronic properties, Si is a well-established semiconducting material for PV technology. However, slow kinetics and a fast corroding nature make Si inefficient for the hydrogen evolution reaction (HER) in photoelectrochemical (PEC) applications. Herein, we demonstrate a multifacet Si nanowire (SiNW) decorated with surface plasmon-enhanced carbon quantum dots (AuCQDs) as efficient, stable, economical, and scalable photocathodes (PCs) for HER. The PEC performance of SiNW_AuCQDs has more than a fourfold efficiency enhancement than the pristine SiNW, which we have attributed to the combined effect of enhanced solar absorption and efficient carrier transport. The optimized PC SiNW_AuCQDs results in the highest photocurrent ∼1.7 mA/cm², an applied bias photon-to-current conversion efficiency of ∼0.8%, and H₂ gas evolution rate of ∼182.93 μmol·h^-1. Furthermore, these SiNW_AuCQDs PCs provide extraordinary stability under continuous operating conditions with 1 sun illumination (100 mW/cm²). The process-line compatible fabrication process of these PCs will open a new direction at the wafer-level designing of a heterostructure for large-scale solar-fuel conversion.

Fluorescence enhancement via aggregation effect due to microenvironmental alterations in human hemoglobin protein in presence of carbon quantum dots (CQD): Comparative spectroscopic approach

CQDs have emerged with outstanding properties as a star member of carbon nanomaterial family and in order to reveal its wide-range of application in biological microenvironment the interactions between human hemoglobin (HHb) and CQD and also with ethylenediamine-functionalized CQD (NCQD) are assessed using several techniques. Firstly, UV-vis absorption spectra of HHb reveal hyperchromic effect in the region of absorbance of tryptophan and tyrosine residues and also hypochromicity of Soret band in presence of CQD and NCQD. Interestingly, steady-state fluorescence spectroscopy reveal distinct fluorescence enhancement of HHb with significant red shift thereby indicating exposures of tryptophan and tyrosine residues to a more hydrophilic environment. However synchronous fluorescence spectra reveal that the microenvironment of tryptophan and tyrosine residues is altered in opposite manner, i.e. exposure of tryptophan residues to a more hydrophilic environment and the tyrosine residues to a more hydrophobic environment. Moreover the fluorescence enhancement is observed to be accompanied by increase in average fluorescence-lifetime and decrease in steady-state anisotropy thus signifying a decrease in restriction of rotational motion. Furthermore tryptophan residues within HHb appear to interact more with CQD compared to NCQD. Thermodynamic parameters as revealed by Isothermal Titration Calorimetry (ITC) demonstrate that electrostatic, hydrogen bonding and hydrophobic interactions are the predominant modes of interactions in presence of CQD. Whereas hydrophobic and hydrogen bonding interactions are the major interacting forces in presence of NCQD with five-site sequential binding as best-fit model in both the cases. Such interactions also appear to be associated with an increase in aggregation of HHb as evident from the measurements by atomic force microscopy (AFM) and dynamic light scattering (DLS) study. Although FT-IR spectra display alteration of amide I band, but the overall secondary structure of HHb seems to be nearly retained even in presence of CQDs, as evident in the CD spectra. These observations thus highlight the potential biomedical application of CQDs in biological microenvironment of human especially as drug-delivery system. Also bimolecular interaction of HHb as a model protein with other nanoparticles at the nano bio-interface has been outlined.

Graphene-based anticorrosive coatings for copper

The present study was focused on the development of environmentally friendly graphene-based anti-corrosive coatings and understanding the effect of these coatings on the electrochemical corrosion behavior of copper.

Single In x Ga1-x As nanowire/p-Si heterojunction based nano-rectifier diode

Nanoscale power supply units will be indispensable for fabricating next generation smart nanoelectronic integrated circuits. Fabrication of nanoscale rectifier circuits on a Si platform is required for integrating nanoelectronic devices with on-chip power supply units. In the present study, a nanorectifier diode based on a single standalone In _x Ga_1-x As nanowire/p-Si (111) heterojunction fabricated by metal organic chemical vapor deposition technique has been studied. The nanoheterojunction diodes have shown good rectification and fast switching characteristics. The rectification characteristics of the nanoheterojunction have been demonstrated by different standard waveforms of sinusoidal, square, sawtooth and triangular for two different frequencies of 1 and 0.1 Hz. Reverse recovery time of around 150 ms has been observed in all wave response. A half wave rectifier circuit with a simple capacitor filter has been assembled with this nanoheterojunction diode which provides 12% output efficiency. The transport of carriers through the heterojunction is investigated. The interface states density of the nanoheterojunction has also been determined. Occurrence of output waveforms incommensurate with the input is attributed to higher series resistance of the diode which is further explained considering the dimension of p-side and n-side of the junction. The sudden change of ideality factor after 1.7 V bias is attributed to recombination through interface states in space charge region. Low interface states density as well as high rectification ratio makes this heterojunction diode a promising candidate for future nanoscale electronics.

Synthesis of graphene oxide–silver nanocomposite with photochemically grown silver nanoparticles to use as a channel material in thin film field effect transistors

The transport of charge carriers in a graphene oxide–silver nanoparticle composite is found to be controlled by nanoparticle dose.

Leakage current characteristics in MOCVD grown InAs quantum dot embedded GaAs metal-oxide-semiconductor capacitor

Carrier transport vis-a-vis leakage current in GaAs MOS capacitors with various structures; quantum dot embedded devices show the lowest leakage.

Epidemiology of HIV infection among brothel-based sex workers in Kolkata, India

A cross-sectional study was carried out during January-June 2004 to assess the status of HIV infection among brothel-based sex workers in Kolkata city, India. Six hundred and twenty-two sex workers, selected from six brothels, were included in the study to assess their HIV status, and 362 sex workers, a subset of the above population, were interviewed to study their risk behaviour and practices. Blood samples were collected from each sex worker for testing HIV by an unlinked anonymous method. The prevalence of HIV infection was 9.6%, but was much higher among younger sex workers aged 20 years or less (27.7%) compared to the older age group (8.4%). This difference was statistically significant, indicating an association of younger ages with HIV infection [p = 0.006 and odds ratio (OR) = 4.18; (95% confidence interval (CI) 1.2-13.8)]. HIV was not associated with duration of sex work, average number of clients entertained per day, condom use, practice of sex during menstruation, pre-coital examination of penis for visible ulcer/discharge, suffering from sexually transmitted infections, and entertaining clients outside the brothel. There was a big gap between the reported and the evaluated condom use by sex workers. The results suggest that there is a need to develop suitable HIV intervention strategies, considering the socioeconomic and cultural aspects of city sex workers, with a provision for continuous monitoring and evaluation.

Biomonitoring insecticide pollution using non-target soil microarthropods

The scope of biomonitoring insecticide pollution in soil is discussed with the help of field and laboratory findings on the density, prey-predator ratio and fecundity of non-target microarthropod fauna. Field experiments were conducted in small plots with mustard, wheat and lady's finger crops and insecticides namely heptachlor 20EC (3.25 kg ai/ha = 16.25 lit/ha) and endosulfan 35EC (0.875 kg ai/ha = 2.5 lit/ha) applied at the seedling stages. Soil microarthropod population estimated at fortnightly intervals in the treated and untreated control plots revealed a general trend of adverse effect of the insecticides, prominently on the density and relative abundance of major prey groups like Collembola and Acari leading to notable decline in prey-predator ratio. Comparison of the percentage reductions of major taxonomic and trophic groups between pre-treatment and post-treatment intervals also demonstrated the ill effect of both heptachlor and endosulfan, notably on Collembola and the prey category. In the laboratory the survival success and fecundity of Cyphoderus javanus (Collembola) and Archegozetes longisetosus (Acari) were compared by exposing freshly emerged adults to sub-lethal concentrations of heptachlor and endosulfan for varying durations. The untreated control sets recorded high fecundity for both C. javanus and A. longisetosus, but chronic toxicity of the insecticides on adults confined to the treated soil resulted into very low fecundity. Even short duration exposure to heptachlor and endosulfan treated soil for 24 or 72 hours only was found to delay the egg-laying and decrease the fecundity of both the species. It is concluded that population responses and reproductive sensitivity in non-target soil microarthropods are potential eco-toxicological parameters for detecting pesticide pollution in soil and for ecological health assessment since the results are based on the bioactivity of toxicants.

Polymorphism of HIV-1 gag (p17) gene from female sex workers in Calcutta, India

HIV-1 subtype C is the major subtype in India as evidenced from the analysis of specific regions within envelope and gag gene. The matrix protein (p17) of HIV-1 which is involved in several functions like the viral RNA transport, nuclear localization, assembly of pre-integration complex into host nucleus has been used to study the strain diversity among female sexworkers in Calcutta. The gene encoding for the HIV-1 matrix protein, p17 was amplified by nested polymerase chain reaction (PCR) from blood samples of HIV-1 seropositive female sex workers (FSW) in Calcutta, India. Genes of twenty-two samples were sequenced and the phylogenetic analysis with different global strains showed that the majority (seventeen) was clustered with Indian type C. A few samples were found to be close to other C subtypes isolated from South Africa, China and Myanmar. The comparison of Calcutta samples with the samples from other regions of India along with other non-asian subtype C sequences clearly revealed a different cluster of Indian sequences. The two samples, cal 242 and cal 709 was found to be the most divergent type and showed close relatedness with African C subtypes.

A new method for isolation of leukocytes from the peripheral blood of amphibians [Bufo himalayanus, (Gunther)] and study of their surface morphology by scanning electron microscopy

Using percoll as the density gradient, a new single step method to isolate leukocytes from the peripheral blood of amphibians (B. himalayanus) has been described. Isolated leukocytes were photographed under the scanning electron microscope and an attempt has been made to characterize the leukocyte population on the basis of surface morphology. Apart from regular blood cell types, B. himalayanus have slender, elongated and slightly curved leukocyte type cells in their peripheral blood. Such slender elongated cells were absent in the blood of a related species B. stomnaticus and hence could not be categorized under the known blood cell types.

Estimation of tear glucose level and its role as a prompt indicator of blood sugar level

Tear glucose level was measured by glucose oxidase method to determine the relationship between tear glucose and corresponding blood glucose levels in 200 patients. It was observed that this test had a definite value in finding the hyperglycaemics semiquantitatively.

An unusual case of a retained metallic arrowhead in the orbit and sphenoidal sinus

A case of retained metallic arrowhead in orbit and sphenoidal sinus through an unusual route is reported. The eyeball was removed because of a possible risk of sympathetic ophthalmia.

Revolutions in ophthalmology

Cataract is the major cause of blindness worldwide. The transition of couching of cataract to most modem phaco-emulsification gained popularity with more scientific capsulorhexis. Ongoing research is taking place with laser technologies for removal of cataract. Surgery has an important role in advanced corneal diseases. Corneal transplantation is the most successful form. The refractive errors can be corrected by laser-assisted in-situ keratomileusis, intrastromal corneal rings and phacic intra-ocular lenses. Current research is going on to identify the gene responsible for glaucoma and once this is identified, medical therapy can be developed to control the disease. Thermocautery or photocoagulation and indenting the globe so as to bring the choroid nearer the break by scleral buckling forms the basis of modern surgery of retinal detachment. Vitreoretinal diseases, macular degeneration, diabetic retinopathy are no longer considered problematic. We are optimistic that more clinical breakthroughs are expected in the 21st century with new advances of ophthalmic researches.

Estimation of total collagen and types I and III collagen in canine rotator cuff tendons

The collagen composition of the supraspinatus, infraspinatus, and subscapularis tendons, which form part of the rotator cuff of the shoulder, was determined. Tendons were obtained from adult, male beagle dogs and total collagen was estimated by measurement of hydroxyproline. There was little variation in collagen content among the three major cuff tendons and the quantity approximated that cited in the literature for other tendons. However, the collagen content in the insertion zone of the supraspinatus tendon was significantly higher than in the tendon proper. NaCl fractionation of supraspinatus collagen indicated that type I was the predominant collagen but significant amounts of type III and possibly some type II and type V were also present. Interestingly, there appeared to be more type III collagen in the insertion zone than in the tendon proper, cyanogen bromide digestion and peptide mapping confirmed this finding. The differential collagen composition of the supraspinatus tendon may contribute to the high incidence of tear that is associated with this rotator cuff tendon.

Protective effect of neoglycoprotein-conjugated muramyl dipeptide against Leishmania donovani infection: the role of cytokines

Active targeting of muramyl dipeptide (MDP) to macrophages was studied by conjugation with the neoglycoprotein, mannosyl human serum albumin (mannose-HSA) using visceral leishmaniasis as the model macrophage disease. Conjugation did not decrease the affinity of the neoglycoprotein for macrophage mannose receptor. Mannose-HSA-MDP was 50 times more efficient than free MDP in inhibiting the growth of Leishmania donovani inside peritoneal macrophages. Moreover, in a 60-day murine model of visceral leishmaniasis, 95% of the spleen parasite burden was reduced by mannose-HSA-MDP at a dose of 0.5 mg/kg/day given for 4 days. Free MDP at a similar dose had very little effect. In vitro exposure of MDP caused enhanced generation of O2- by macrophages, whereas generation of nitric oxide (NO) was not induced. The elevated antileishmanial activity of MDP-treated macrophages in culture was abrogated by O2- scavengers. In contrast, considerably enhanced amounts of NO and O2- were generated from macrophages of mannose-HSA-MDP-treated animals, and their splenocytes secreted soluble factors providing all the signals required for the induction of NO biosynthesis. The increase in NO production was paralleled by a concomitant increase in antileishmanial activity, which was reversed by NO synthesis inhibitors. Splenocyte supernatants treated with anti-IFN-gamma or anti-TNF-alpha Abs suppressed inducible NO generation by macrophages. Moreover, i.v. administration of anti-IFN-gamma and anti-TNF-alpha along with mannose-HSA-MDP greatly reduced protection against L. donovani infection. Neoglycoprotein-conjugated MDP, therefore, activated mouse macrophages in vivo to kill L. donovani, and this may depend on the physiologic generation of NO induced by IFN-gamma and TNF-alpha.

Protective effect of neoglycoprotein-conjugated muramyl dipeptide against Leishmania donovani infection: the role of cytokines

Active targeting of muramyl dipeptide (MDP) to macrophages was studied by conjugation with the neoglycoprotein, mannosyl human serum albumin (mannose-HSA) using visceral leishmaniasis as the model macrophage disease. Conjugation did not decrease the affinity of the neoglycoprotein for macrophage mannose receptor. Mannose-HSA-MDP was 50 times more efficient than free MDP in inhibiting the growth of Leishmania donovani inside peritoneal macrophages. Moreover, in a 60-day murine model of visceral leishmaniasis, 95% of the spleen parasite burden was reduced by mannose-HSA-MDP at a dose of 0.5 mg/kg/day given for 4 days. Free MDP at a similar dose had very little effect. In vitro exposure of MDP caused enhanced generation of O2- by macrophages, whereas generation of nitric oxide (NO) was not induced. The elevated antileishmanial activity of MDP-treated macrophages in culture was abrogated by O2- scavengers. In contrast, considerably enhanced amounts of NO and O2- were generated from macrophages of mannose-HSA-MDP-treated animals, and their splenocytes secreted soluble factors providing all the signals required for the induction of NO biosynthesis. The increase in NO production was paralleled by a concomitant increase in antileishmanial activity, which was reversed by NO synthesis inhibitors. Splenocyte supernatants treated with anti-IFN-gamma or anti-TNF-alpha Abs suppressed inducible NO generation by macrophages. Moreover, i.v. administration of anti-IFN-gamma and anti-TNF-alpha along with mannose-HSA-MDP greatly reduced protection against L. donovani infection. Neoglycoprotein-conjugated MDP, therefore, activated mouse macrophages in vivo to kill L. donovani, and this may depend on the physiologic generation of NO induced by IFN-gamma and TNF-alpha.

Relationship of national highway with injecting drug abuse and HIV in rural Manipur, India

Earlier study reported that about 1% of general population or urban Manipur was injecting drug users (IDUs). A study was conducted to observe the IDU prevalence in rural Manipur and the role of national highway (NH) in determining the IDU prevalence if any. It was also aimed to study the HIV prevalence among IDUs of different villages. Villages were startified in to 3 categories based on distance and communication facilities from the national highway, which cuts across the villages to the neighboring state, Nagaland. Villages close to NH had the highest IDU prevalence of 1.3% and remote villages had the least prevalence of 0.2% whereas villages in between the above mentioned two groups had a prevalence of 0.9%. It was surprisingly observed that HIV was uniformly distributed among the IDUs of all villages and ranged from 50-51%. This indicates that IDU prevalence at distance is predominantly determined by the presence of drug trafficking route/s like national highway whereas HIV prevalence is mainly determined by the needle sharing behaviour of IDUs.

Evidence of a laminin binding protein on the surface of Leishmania donovani

Both the promastigote and amastigote forms of the intracellular parasite, Leishmania donovani bind the basement membrane glycoprotein laminin with high affinity (Kd = 3.56 x 10(-9) M and 3.98 x 10(-9) M respectively) with approximately 9000 and approximately 800 sites per cell. Bound laminin was identified by direct autoradiography and the binding protein through analysis of the parasite extract by SDS-PAGE and immunoblotting. A major component of 67 kDa was detected. The same protein was obtained when parasite outer membrane proteins were adsorbed to laminin-sepharose affinity matrix and subsequently eluted with SDS. The binding affinity of the isolated receptor was similar to that of the whole cells. Such a receptor isolated in Leishmania for the first time, may function as one of the bridging molecules for extracellular matrix recognition.

Receptor-mediated endocytosis of fucosylated neoglycoprotein by macrophages

The characteristics of the recognition system involved in the receptor mediated endocytosis of the neoglycoprotein, fucose-human serum albumin (HSA) were studied. It was found that (i) fucose-HSA showed strong affinity binding and uptake by various macrophages; (ii) binding was specific for L-fucose and D-mannose; (iii) binding was found to be inhibited by oxidant like H2O2 and swainsonine whereas it was elevated by dexamethasone; (iv) clearance of 125I-fucose-HSA was rapid and strongly inhibited by unlabelled fucose-HSA. Greater than 70% of fucose-HSA was found in liver and more than 60% of this was found in liver lysosomes; (v) uptake of fucose-HSA was thirty-fold more efficient in liver macrophages (Kupffer cells) than in hepatocytes; (vi) moreover, mannose-HSA and ovalbumin which are potent inhibitors of mannose/N-acetylglucosamine receptors inhibited clearance and uptake of fucose-HSA by liver as well as by isolated Kupffer cells suggesting the involvement of both fucose and mannose receptors or a single type of receptor having greater affinity for fucose-HSA than for mannose-HSA. These results emphasize the important role of fucose-terminated glycoproteins in site-specific drug targeting.

Structural and functional changes in the canine shoulder after cessation of immobilization

The functional and structural consequences of remobilization of the glenohumeral joint after 12 weeks of immobilization were studied in 10 beagle dogs. The dogs were grouped in pairs: 2 were used as controls, and in 8 others 1 forelimb was immobilized. At the end of 12 weeks, 2 dogs in the experimental group were euthanized, as were the 2 dogs used as controls. The cast was removed from the other 6 dogs, and the remobilized animals were euthanized in pairs at the end of 4, 8, and 12 weeks. It was found that after 12 weeks of immobilization, the passive range of motion was markedly impaired, intraarticular pressure was raised during movements, and the filling volume of the joint cavity was reduced. Histologically, the capsule showed synovial lining hyperplasia and vascular proliferation in the wall. Immunohistochemical labeling for collagen Types I and III failed to show an increase of fibrous collagens in the capsular wall. Both the functional and structural changes were unaltered after 4 weeks of remobilization, but after 8 weeks they began to reverse, and they returned to normal levels after 12 weeks. Both functional and structural changes after 12 weeks of immobilization of the uninjured glenohumeral joint are reversible by remobilization. The collagen composition of the capsule seems unrelated to the degree of capsular contraction that occurs during 12 weeks of immobilization and subsequent remobilization.

[Anatomy and pathology of the rotator cuff]

In this contribution we stress the fact that not all rotator cuff tendinopathies are degenerative in nature. Moreover, we insist on a clear distinction between intrinsic and extrinsic tendinopathies. In a final note we point out that the impingement syndrome is not always due to a developmental or acquired spur of the anterior part of the acromion.

A cross-sectional study on factors including HIV testing and counselling determining unsafe injecting practices among injecting drug users of Manipur

In India, a steep increase in the prevalence of HIV (0% to 50% within six months) among the IDUs has been reported in Manipur, a north eastern state in 1990. In spite of large scale intervention program like educational campaign and widespread voluntary HIV testing in this state, the infection has quickly spread to the heterosexual population at large. The determinants of risk taking behaviors like sharing of unclean needle among the IDU population has been explored in this paper. A cross sectional study has been carried out among all of the 488 IDUs who attended any detoxification centers and prison during last two years at Imphal, the capital city of this state. Self reported behaviors based on the pre-scheduled interview were recorded and participation rate was satisfactory. The data was compared to a similar survey carried out by us in 1990. Although there has been decline in risk behavior among the IDUs, a logistic regression analysis reveals that unsafe needle sharing behavior is not influenced by the knowledge on HIV transmission, educational status or history of HIV testing or serostatus of the individual. The limitation of cross sectional nature of the study, bias due to collection of data in prison, self reported behavior, possible differences with street samples of the addict are discussed.

Clinical features of HIV infection in drug users of Manipur

BACKGROUND

The human immunodeficiency virus was first detected in young intravenous drug users in Manipur in 1989 and it quickly reached a high prevalence in this group. Diagnostic facilities are scarce and it is thus important to suspect the presence of the infection by its clinical features.

METHODS

We did a cross-sectional survey for 13 months among residents of different detoxification centres of Imphal, Manipur, to study the sensitivity, specificity and positive predictive values of different signs and symptoms occurring at the early phase of the infection.

RESULTS

Most of the young injectors in this survey were found to be in the early phases (stage I 43%; stage II 32%; stage III 15% and stage IV 9.9%) of the World Health Organization clinical staging of human immunodeficiency virus infection and disease. Herpes zoster, oral candidiasis, pruritic papular eruptions, jaundice and lymphadenopathy had positive predictive values of 100%, 100%, 93%, 93% and 88% respectively. Cryptosporidial diarrhoea and tuberculosis (pulmonary and extrapulmonary) were also encountered.

CONCLUSION

Intravenous drug users in Manipur who have human immunodeficiency virus infection suffer from different opportunistic infections which give rise to clinical features that are easily recognizable. It is important to be aware of these in areas which lack diagnostic facilities for confirming the infection.

The collagen types in the attachment zone of rotator cuff tendons in the elderly: an immunohistochemical study

OBJECTIVE

The attachment zone of the rotator cuff tendons in the elderly was studied immunohistochemically in order to determine how degenerative changes affected the pattern of collagen fiber distribution.

METHODS

Twenty-seven cuffs with their bony insertion were obtained from 22 postmortem cases of both sexes ranging in age from 52 to 90 years and without a history of shoulder ailments. In addition, 3 cuff specimens from cadavers in the 3rd and 4th decades were examined for comparison. Sections of formalin fixed tissues were stained by peroxidase antiperoxidase (PAP) technique using monoclonal antibodies against types I, II and III collagen.

RESULTS

Degenerative changes affecting the fibrocartilage primarily were characterized by calcification, fibrovascular proliferation and microtears. In addition, they were found in all the cuff tendons of elderly individuals but not in those from younger subjects. Immunohistochemically, the attachment zone in areas without degenerative lesions showed collagen type I labelling strongly in bone but only moderately in the fibrocartilage. The predominant labelling in the fibrocartilage was for collagen type II, and collagen type III labelled principally in perichondrocytic areas. The tide-mark showed inconsistent labelling for any of the collagen types. In the presence of degenerative lesions, the disposition of fiber types was interrupted by calcification and microtears. Collagen type II composition of the fibrocartilage was markedly altered by the presence of fibrovascular tissue which labelled only for collagen type III.

CONCLUSION

We conclude that severe degenerative changes in the cuff tendons of elderly individuals, alter the collagen characteristic of the rotator cuff and that the changes could be associated with impairment of biomechanical properties of the attachment zone, and may give rise to the clinical syndrome of enthesopathy.