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Biomedical subjects

D Singh

Publications and source records attributed to D Singh.

At least 55 records · Page 3Linked to original sources

The peroneus quartus muscle. Anatomy and clinical relevance.

Whilst a few studies have associated various symptoms with the presence of a peroneus quartus muscle in the peroneal compartment of the leg, little is known of the clinical relevance of this muscle. We dissected 102 cadaver legs and reviewed the magnetic resonance images of 80 patients with symptoms from the ankle. The peroneus quartus, with a number of different attachments, was present in 6.6% of the legs. It most commonly arose from the peroneus brevis muscle and inserted into the retrotrochlear eminence of the calcaneum. Associated pathology included a longitudinal tear in the tendon of peroneus brevis, possible peroneal tendon subluxation or dislocation, and a prominent retrotrochlear eminence. On the MR scans its presence was associated with pain and weakness of the ankle. Orthopaedic surgeons and radiologists should be aware of the possible presence of the peroneus quartus muscle, not only because of possible associated pathology, but also for its potential use for surgical reconstruction.

Adolescent↗

Endoscopic third ventriculostomy in obstructed hydrocephalus.

Forty-three ETV were performed in 46 patients of obstructive hydrocephalus. Study was divided into two groups. Group 1 was with 29 children of less than two years age. Group 2 had seventeen patients of more than 2 years, adolescent and adults. Group 1 had 70% clinical and 63% radiological improvement whereas Group 2 showed 100% clinical and 73% radiological improvement. ETV failed in relieving the symptoms of hydrocephalus in eight patients. They were eventually benefited with VP Shunt. There was one postoperative death, which was not related to the procedure. ETV is an important alternative to VP Shunt in relieving hydrocephalus due to obstruction in CSF pathway.

Adolescent↗

Glioblastoma of the cerebellum. A report of 3 cases.

Glioblastoma (GBM) is one of the commonest intra cranial tumors. Infratentorial GBM is, however, a rare entity. We report 3 cases of histologically proven posterior fossa GBM. The clinical presentation was of a rapidly growing posterior fossa mass. The diagnosis was made only on histological examination. The radiological features are non-specific and the clinical course same as GBM elsewhere. We describe their clinical presentation, radiological and pathological features and a review of describe the literature.

Adolescent↗

Subdural hemorrhage associated with falcine meningioma.

A case of falcine meningioma associated with acute subdural hemorrhage is reported. The possible mechanisms of hemorrhage in the case are discussed. We believe that an early recognition and surgery can prevent neurological deterioration.

Aged↗

Catheter associated urinary tract infections in neurology and neurosurgical units.

OBJECTIVE: Catheter associated bacteriuria is the most common infection acquired in hospitals. The objective of the study was (1) to study the incidence of bacteriuria following indwelling urethral catheterization in patients with short-term vs long-term catheterization (2) to define the antibiotic resistance pattern among these isolates so that the study can provide guidelines for choosing an effective antibiotic against infections in catheterized patients. METHODS: This is a prospective study carried out over a period of 18 months in Neurology/Neurosurgical patients who had indwelling catheters for > or =48 h. RESULTS: In this study, 68 out of 800 (8.5%) adult inpatients acquired urinary tract infection following indwelling bladder catheterizations. The risk was significantly higher for female, elderly patients, critically ill and patients on prolonged catheterization. Among the bacterial pathogens, Escherichia coli was the commonest organism isolated (32.9%) followed by Pseudomonas sp. (15.1%) and Staphylococcus aureus (12.3%). Candida sp. comprised 13.7% of all isolates. Among Gram negative bacterial pathogens maximum number of isolates were sensitive to Amikacin (sensitivity of 42%). All Gram positive organisms were however sensitive to Vancomycin. CONCLUSIONS: Our results provide guidelines for choosing salvage therapy against hospital resistant strains causing infection in catheterized patients. However, antibiotics seem to prevent urinary tract infections but primarily in patients catherized for short duration, i.e. 3-14 days and not in patients with long-term catheterization.

Aged↗

Suprasellar cystic meningioma: unusual presentation and review of the literature.

We report on a case of suprasellar cystic meningioma. The magnetic resonance imaging of this tumor resembled that of a craniopharyngioma. The definitive diagnosis of meningioma was made only after histopathological confirmation. We conclude that preoperative studies are often equivocal. The possibility of meningioma should be considered in the diagnosis of any intracranial neoplasms with radiological and surgical evidence of a cystic lesion.

Central Nervous System Cysts↗

rCBF/SPECT in the evaluation of inner-city minority patients with a history of impaired memory: a pilot blind read pre- and poststudy.

Eight patients (seven women), mean +/- SD T1 age 68.57 +/- 12.43 years, average educational level 5.83 +/- 3.70 years, had two Tc-99m ECD SPECT examinations separated by an average 8.49 +/- 5.59 months. Patients were imaged using standard Harlem Hospital acquisition and processing protocols with approximately 30 mCi of ECD on a Prism 3000 triple head gamma camera. Images were interpreted by an independent reader blinded to the patients' clinical history and imaging date. T1 psychiatric diagnosis was seven Alzheimer's dementia (AD) and one depression. Eight T1 images were interpreted as abnormal, six indicative of AD. Binomial 95% two-tail confidence interval for T1 agreement between diagnosis and interpretation was 0.25 0.63 0.92. T2 diagnosis was seven AD and one none. Seven T2 images were abnormal and indicative of AD, and one was normal. T2 confidence interval was 0.34 0.75 0.97. These findings suggest SPECT's value in assessing AD in uneducated socioeconomically disadvantaged geriatric patients.

Aged↗

Serine 85 in transmembrane helix 2 of short-wavelength visual pigments interacts with the retinylidene Schiff base counterion.

Short-wavelength cone visual pigments (SWS1) are responsible for detecting light from 350 to 430 nm. Models of this class of pigment suggest that TM2 has extensive contacts with the retinal binding pocket and stabilizes interhelical interactions. The role of TM2 in the structure-function of the Xenopus SWS1 (VCOP, lambda(max) = 427 nm) pigment was studied by replacement of the helix with that of bovine rhodopsin and also by mutagenesis of highly conserved residues. The TM2 chimera and G78D, F79L, M81E, P88T, V89S, and F90V mutants did not produce any significant spectral shift of the dark state or their primary photointermediate formed upon illumination at cryogenic temperatures. The mutant G77R (responsible for human tritanopia) was completely defective in folding, while C82A and F87T bound retinal at reduced levels. The position S85 was crucial for obtaining the appropriate spectroscopic properties of VCOP. S85A and S85T did not bind retinal. S85D bound retinal and had a wild-type dark state at room temperature and a red-shifted dark state at 45 K and formed an altered primary photointermediate. S85C absorbed maximally at 390 nm at neutral pH and at 365 nm at pH >7.5. The S85C dark state was red shifted by 20 nm at 45 K and formed an altered primary photointermediate. These data suggest that S85 is involved in a hydrogen bond with the protonated retinylidene Schiff base counterion in both the dark state and the primary photointermediate.

Amino Acid Sequence↗

Elevated levels of high-mobility-group chromosomal proteins, HMGA1, in murine skin carcinoma.

The high-mobility-group, HMGA1 (formerly HMGI(Y)) chromosomal proteins are known to be involved in gene regulation and their high expression is associated with neoplastic transformation of cells and metastatic tumor progression. Here, we present our results on the expression of HMGA1 in murine skin carcinoma as detected by acid-urea electrophoresis, reverse-phase high-performance liquid chromatography and Western blot. The enhanced expression of HMGA1 proteins directly correlates with the extent of cellular atypia and neoplastic changes noticed in the histopathology of tumor and suggest a potential use of these proteins as marker for determining the grade of skin tumor.

Acetic Acid↗

Repeat tuberculin testing in BCG-vaccinated subjects in the United Kingdom. The booster effect varies with the time of reading.

The booster effect varies between populations, but has not been studied in the UK. The aim of this study was to investigate the effect of repeat tuberculin tests at 1 wk in BCG-vaccinated healthy subjects (all hospital employees) in the UK; we have assessed whether a booster effect is present 48 and 72 h after injection. Twenty-six subjects received two tuberculin tests (both 10 units) administered by the Mantoux technique-Tests 1 and 2. At Test 2 there was a significant increase in induration at 48 h (mean, 7.8 mm; p < 0.001), no difference at 72 h (mean, 0.2 mm; p = 0.93), and a reduction at 96 h (mean, -4.2 mm; p = 0.02). There were more positive results (> 15 mm induration) at Test 2 compared with Test 1 at 48 h (19 vs. 9, respectively; p = 0.002), but similar numbers at 72 h (11 vs. 10, respectively). These results show that repeat tuberculin testing in this BCG-vaccinated population caused a booster effect that varied with the time of measurement and was maximal at 48 h.

Adolescent↗

Further observations on the nocturnal oviposition behaviour of blow flies (Diptera: Calliphoridae).

Calculating the age of immature stages of blow flies showing the longest period of association with a dead body often gives a fairly accurate estimate of the post-mortem interval (PMI). Determination of the exact time of oviposition by these flies had generally been made in the light of the conventional belief that blow flies are neither active nor do they lay eggs during night. This method of estimating the time of oviposition was modified when Greenberg [J. Med. Entomol. 27 (1990) 807] reported nocturnal oviposition by three calliphorid species that are occasionally used as forensic indicators. However, a technical problem with his experiment, having long term consequences, was placement of the bait on the ground among bushes. This could have made it possible for the flies already resting near the bait to climb over the piece of meat and lay eggs. Though Greenberg's experiment proves beyond any doubt that blow flies do lay eggs at night as well as by day, active attraction of these flies at night towards the oviposition medium had yet to be proved and the present experiment has been designed for this purpose.

Animals↗

The photobleaching sequence of a short-wavelength visual pigment.

The photobleaching pathway of a short-wavelength cone opsin purified in delipidated form (lambda(max) = 425 nm) is reported. The batho intermediate of the violet cone opsin generated at 45 K has an absorption maximum at 450 nm. The batho intermediate thermally decays to the lumi intermediate (lambda(max) = 435 nm) at 200 K. The lumi intermediate decays to the meta I (lambda(max) = 420 nm) and meta II (lambda(max) = 388 nm) intermediates at 258 and 263 K, respectively. The meta II intermediate decays to free retinal and opsin at >270 K. At 45, 75, and 140 K, the photochemical excitation of the violet cone opsin at 425 nm generates the batho intermediate at high concentrations under moderate illumination. The batho intermediate spectra, generated via decomposing the photostationary state spectra at 45 and 140 K, are identical and have properties typical of batho intermediates of other visual pigments. Extended illumination of the violet cone opsin at 75 K, however, generates a red-shifted photostationary state (relative to both the dark and the batho intermediates) that has as absorption maximum at approximately 470 nm, and thermally reverts to form the normal batho intermediate when warmed to 140 K. We conclude that this red-shifted photostationary state is a metastable state, characterized by a higher-energy protein conformation that allows relaxation of the all-trans chromophore into a more planar conformation. FTIR spectroscopy of violet cone opsin indicates conclusively that the chromophore is protonated. A similar transformation of the rhodopsin binding site generates a model for the VCOP binding site that predicts roughly 75% of the observed blue shift of the violet cone pigment relative to rhodopsin. MNDO-PSDCI calculations indicate that secondary interactions involving the binding site residues are as important as the first-order chromophore protein interactions in mediating the wavelength maximum.

Animals↗

Combined angiotensin II receptor antagonism and angiotensin-converting enzyme inhibition further attenuates postinfarction left ventricular remodeling.

BACKGROUND: ACE inhibition (ACEI) attenuates post-myocardial infarction (MI) LV remodeling, but the effects of angiotensin II type 1 receptor (AT(1)) antagonism alone or in combination with ACEI are unclear. Accordingly, we investigated the effects of AT(1) antagonism, ACEI, and their combination in a well-characterized ovine postinfarction model. METHODS AND RESULTS: Beginning 2 days after transmural anteroapical MI, 62 sheep were treated with 1 of 5 treatment regimens: no therapy (control, n=12), standard-dose ACEI (sACEI; ramipril 10 mg/d, n=14), high-dose ACEI (hACEI; ramipril 20 mg/d, n=8), AT(1) blockade (losartan 50 mg/d, n=13), and combination therapy with sACEI+AT(1) blockade (CT; ramipril 10 mg/d+losartan 50 mg/d, n=15). MRI was performed before and 8 weeks after MI to quantify changes in LV end-diastolic and end-systolic volume indices (DeltaEDVI, DeltaESVI) and ejection fraction (DeltaEF). Change in regional percent intramyocardial circumferential shortening in noninfarcted segments adjacent to the infarct (Adj Delta%S) was measured by tagged MRI. CT resulted in the most marked blunting of LV remodeling: DeltaESVI (+1.0+/-0.4, +0.7+/-0.4, +0.6+/-0.3, +0.9+/-0.5, and +0.4+/-0.2* mL/kg); DeltaEDVI (+0.9+/-0.4, +0.7+/-0.5, +0.6+/-0.5, +0.9+/-0.5, and +0.4+/-0.3 mL/kg); DeltaEF (-24+/-7, -18+/-6, -14+/-7, -18+/-10, and -11+/-9* %); and Adj Delta%S (-8+/-4, -7+/-3, -5+/-3, -5+/-3, and -2+/-3* %) for Control, sACEI, hACEI, AT(1) blockade, and CT, respectively (*P<0.04 versus sACEI, AT(1) blockade, and control; P<0.05 versus control; P<0.002 versus AT(1) blockade and control). EDVI and ESVI at 8 weeks after MI were smallest with CT (P<0.02 versus all). CONCLUSIONS: Combination therapy with sACEI+AT(1) blockade shows promise in attenuating postinfarction LV remodeling but was not clearly superior to hACEI in the present study.

Angiotensin Receptor Antagonists↗

Thermostable, alkalophilic and cellulase free xylanase production by Thermoactinomyces thalophilus subgroup C.

Thermoactinomyces thalophilus produced cellulase free extracellular endo-1,4-beta-xylanase (EC 3.2.1.8) at 50 degrees C and pH 8.5. Maximum xylanase production was achieved in fermentation medium using birchwood xylan as substrate after 96 h of growth at 50 degrees C. Other agricultural substrates such as wheat bran, wheat straw, sugarcane bagasse and cornstover produced less xylanase. The crude enzyme preparation from mutant T. thalophilus P2 grown under optimised fermentation conditions showed no cellulase contamination and maximum xylanase activity of 42 U/ml at 65%deg;C and pH 8.5-9.0. This enzyme with initial xylanase activity of 42 U/ml was found thermostable up to 65 degrees C and retaining 50% of its activity after its incubation for 125 min at 65 degrees C.

Journal Article↗

Female body odour is a potential cue to ovulation.

Human body odours have been reported to influence female mate choice. Women prefer the odours of immunocompatible men and, during their fertile period, judge the body odours of men with symmetrical bodies--which is indicative of genetic quality--as sexy and pleasant. The reproductive success of men largely depends on mating with fertile women, but it is not known whether men can detect a woman's fertile period. We asked women who had regular menstrual cycles and who were not using hormonal contraceptives to wear a T-shirt for three consecutive nights during their late follicular (ovulatory) phase and another T-shirt during the luteal (non-ovulatory) phase of their menstrual cycle. Male raters judged the odours of T-shirts worn during the follicular phase as more pleasant and sexy than odours from T-shirts worn during the luteal phase. The odour differences between the follicular and luteal phases did not dissipate quickly over time as male raters were able to detect and judge follicular phase body odours as more pleasant and sexy than the odours from the luteal phase even after the T-shirts were kept at room temperature for one week. These findings suggest that ovulation may not be concealed and that men could use ovulation-linked odours in their mate selection.

Adult↗

Conformation and orientation of the retinyl chromophore in rhodopsin: a critical evaluation of recent NMR data on the basis of theoretical calculations results in a minimum energy structure consistent with all experimental data.

In the absence of a high-resolution diffraction structure, the orientation and conformation of the protonated Schiffs base retinylidinium chromophore of rhodopsin within the opsin matrix has been the subject of much speculation. There have been two recent reliable and precise NMR results that bear on this issue. One involves a determination of the C20-C10 and C20-C11 distances by Verdegem et al. [Biochemistry 38, 11316-11324 (1999)]. The other is the determination of the orientation of the methine C to methyl group vectors C5-C18, C9-C19, and C13-C20 relative to the membrane normal by Gröbner et al. [Nature 405 (6788), 810-813 (2000)]. Using molecular orbital methods that include extensive configuration interaction, we have determined what we propose to be the minimum energy conformation of this chromophore. The above NMR results permit us to check this structure in the C10-C11=C12-C13 region and then to check the global structure via the relative orientation of the three C18, C19, and C20 methyl groups. This method provides a detailed structure and also the orientation for the retinyl chromophore relative to the membrane normal and argues strongly that the protein does not appreciably alter the chromophore geometry from its minimum energy configuration that is nearly planar s-trans at the 6-7 bond. Finally, the chromophore structure and orientation presented in the recently published X-ray diffraction structure is compared with our proposed structure and with the deuterium NMR results.

Animals↗

Induction of preprotachykinin-I and neurokinin-1 by adrenocorticotropin and prolactin. Implication for neuroendocrine-immune-hematopoietic axis.

We studied the complex interactions within the neuroendocrine-immune-hematopoietic axis by determining a possible link among ACTH, PRL, PPT-I and the receptors for its peptides, NK-1 and NK-2. Indeed, ACTH and PRL induced the expression of PPT-I and NK-1 in human bone marrow stroma with no effect on NK-2. Consistent with a role for PPT-I in regulating the development of myeloid and erythroid progenitors, we found that ACTH and PRL, through NK-1 stimulated the proliferation of both types of progenitors. Induction of PPT-I was regulated at the transcriptional and post-transcriptional levels. The results showed that ACTH and PRL stimulated the proliferation of bone marrow progenitors, partly through PPT-I and NK-1 induction.

Adrenocorticotropic Hormone↗