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Biomedical subjects

N Joshi

Publications and source records attributed to N Joshi.

At least 55 records · Page 3Linked to original sources
PubMed1997

Doxycycline revisited.

Although several new antibiotics have recently become available, in several clinical instances conventional antibiotics may be equally efficacious at a considerably lower cost. In today's era of cost containment, it is particularly relevant to revisit older, inexpensive antibiotics to reexplore their role in the face of the emergence of resistant microorganisms and competition from newer agents. Doxycycline is one such antibiotic. It is an inexpensive, broad-spectrum antimicrobial agent that remains the drug of first choice for several infections. In addition, it can be used for a variety of other indications. Adverse effects are infrequent and relatively minor. While interactions occur with several medications, none of these interactions has significant adverse consequences.

Animals↗
PubMed1997

Inhibition of allergic encephalomyelitis in marmosets by vaccination with recombinant vaccinia virus encoding for myelin basic protein.

A primary demyelinating form of experimental allergic encephalomyelitis (EAE) resembling human multiple sclerosis (MS) occurs in Callithrix jacchus marmosets following immunization with human white matter. Participation of a T-cell immune response against myelin basic protein (MBP) in this disease model is supported by observations of increased reactivity against MBP in PBMC and of adoptive transfer of an inflammatory form of EAE by MBP-reactive T-cells. To evaluate the effects of ectopic presentation of MBP on marmoset EAE, animals were vaccinated prior to induction of EAE by subcutaneous injection of attenuated strains of vaccinia virus genetically engineered to contain either the entire coding sequence for human MBP (vT15) or the equine herpes virus glycoprotein gH gene (vAbT249). Vaccination with vT15 was followed by transient cytoplasmic and surface membrane expression of MBP in circulating PBMC (15-45 days). The onset of clinical EAE after immunization (pi) was markedly delayed in vT15-vaccinated animals (37-97 days pi, n = 4) compared to vAbT249-vaccinated controls (14-18 days pi, n = 3). Proliferative responses against MBP but not against vaccinia antigens or phytohemagglutinin were suppressed in protected animals. Thus, development of attenuated live viruses carrying genes for myelin antigens could be useful for induction of immunologic tolerance and for modulation of autoimmune demyelination.

Animals↗
PubMed1997

Capsulorhexis phymosis following uncomplicated phacoemulsification surgery.

PURPOSE: The aim of the study was to assess and compare the degree of capsulorhexis phymosis following uncomplicated phacoemulsification cataract surgery in polymethylmethacrylate (PMMA) and silicone lens implants. METHOD: Sixty-four patients were evaluated 1 day, 6 weeks and 6 months following phacoemulsification cataract extraction. The anterior capsular diameters were measured with the illuminated beam of the slit lamp at 45 degrees and 135 degrees and the surface area of the opening calculated. We have measured and compared the change in the capsulorhexis size for both lens types and assessed its statistical significance with a paired Student's t-test. RESULTS: A statistically significant contraction of the capsulorhexis was noted in all patients within the first 6 weeks (p < 0.001). Capsular contraction continued between 6 weeks and 6 months post-operatively but to a lesser extent (p < 0.05). The difference in the degree of phymosis between the first period (1 day to 6 weeks) and the second (6 weeks to 6 months) was statistically highly significant for all patients (p < 0.001). The capsular areas for the silicone lens implants were significantly smaller than for the PMMA implants at 6 weeks and 6 months. None of our patients had a clinically significant capsular contracture requiring Nd:YAG laser capsulotomy. CONCLUSION: Anterior capsular contraction is commonly observed following capsulorhexis in phacoemulsification surgery. This study demonstrates that the maximum rate of contraction occurs in the first 6 weeks following surgery and is more pronounced with silicone lens implants.

Aged↗
PubMed1997

Variation in astigmatism following the single-step, self-sealing clear corneal section for phacoemulsification.

PURPOSE: A single-step, self-sealing, 3.2 mm clear corneal section is described and the incidence and variation of surgically induced astigmatism following phacoemulsification over a period of 3 months is determined. METHODS: Twenty-two patients who underwent uncomplicated 3.2 mm clear corneal phacoemulsification with foldable Allergan silicone intraocular lens implantation were autorefracted pre-operatively and on day 1, week 1, week 6 and at 3 months. The variation in induced astigmatism was analysed using the subtraction method and vector analysis. The change in direction of the cylindrical axis was examined. RESULTS: The induced astigmatism represented by the total vector on day 1 was 1.17 D and vector decomposition ratio, ATR:WTR (against-the-rule:with-the-rule), was 21.05:78.95. The total vector increased by 0.5 D in the first week and then stabilised. Vector decomposition showed an against-the-rule astigmatic drift so that by 3 months the ATR:WTR was 40.49:59.91. There was a tendency of the axis of the negative cylinder to swing towards the corneal section meridian on day 1 and to oscillate around that meridian at week 1 and week 6. By 3 months the direction reverted to that pre-operatively, in most cases. CONCLUSIONS: The single-step, self-sealing clear corneal section is mechanically stable and, though there is some variability in the measured astigmatism, there is an acceptable functional result throughout the post-operative period.

Aged↗
PubMed1997

Foot infections in patients with diabetes.

The combination of sensory neuropathy, ischemia and direct adverse effect on host defense mechanisms makes patients with diabetes vulnerable to foot infections. A high degree of clinical suspicion and vigilance is necessary for early diagnosis of soft tissue infections and their differentiation from noninfected ulcers. Diagnosis and assessment depend primarily on clinical history and physical examination, although radiographs, scans and laboratory tests may also provide useful clinical data. The ability to detect bone in the base of an ulcer with a blunt sterile probe may be particularly useful in assisting the recognition of osteomyelitis. Most non-limb-threatening infections are caused by Gram-positive cocci, but more serious infections are often polymicrobial. Effective treatment is based on a comprehensive strategy of wound care, avoidance of weight bearing, optimal metabolic control, appropriate antibiotic use and, possibly, surgical intervention.

Diabetic Foot↗
PubMed1996

Biased expression of T cell receptor genes characterizes activated T cells in multiple sclerosis cerebrospinal fluid.

To better characterize the inflammatory response that occurs in the nervous system in multiple sclerosis (MS), T-cell receptor (TCR) gene expression was quantified from cerebrospinal fluid (CSF) cells of 21 patients with active disease. Unstimulated CSF cells expressed each of 22 different TCR beta chain variable region (V beta) gene families in proportion to their expression in simultaneously sampled peripheral blood. When CSF cells from individuals with MS were expanded by in vitro culture in T-cell growth factor/interleukin 2 and 4-containing medium (TCGF/IL2/IL4), restricted numbers of V beta genes were expressed. In many subjects, expanded CSF cells expressed predominantly V beta 2. In contrast to CSF, expansion of corresponding peripheral blood mononuclear cells (PBMC) in TCGF/IL2/IL4 resulted in persistent expression of all V beta gene families. Within individuals, different V beta genes were overexpressed by PBMC compared with CSF cells. No effect of the HLA haplotype of the individual on CSF V beta gene expression was observed. Expanded CSF cells retained their capacity to respond to mitogen stimulation, but the proliferative response to myelin basic protein (MBP) was not enhanced. Finally, freshly obtained CSF cells stimulated directly with MBP also expressed a limited number of V beta genes, although these were generally different from patterns observed following stimulation with TCGF/IL2/IL4. Thus, restricted populations of T cells capable of responding to TCGF/IL2/IL4, presumably reflecting in vivo activated cells, are compartmentalized in the nervous system in MS.

Adult↗
PubMed1996

An assessment of intraocular pressure during fractionated peribulbar anaesthesia.

This study of 20 patients undergoing elective cataract surgery was performed to investigate the change in intraocular pressure that accompanies extraconal peribulbar anaesthesia. We have demonstrated that each injection during peribulbar anaesthesia causes a small rise in intraocular pressure. The routine use of conventional external ocular compression overcomes this pressure rise and safely provides a satisfactory and progressive reduction in intraocular pressure prior to surgery. Our findings suggest that the volumes of anaesthetic solutions used in fractional peribulbar anaesthesia, if used in conjunction with external compression devices, result in intraocular pressures acceptable for intraocular surgery.

Aged↗
PubMed1995

The use and misuse of new antibiotics. A perspective.

Many new antimicrobial agents have become available recently. Several of the new antibiotics may offer an extended spectrum of activity or an improved toxic effect profile. However, they pose such problems as excessive cost and the emergence of drug-resistant organisms as a result of "selection pressure." The majority of common infections can be treated with conventional agents, either singly or in combination. A careful, bedside clinical evaluation, in conjunction with simple laboratory tests, often narrows down microbiologic possibilities and allows simpler antibiotic choices. This results in a cost-conscious approach of using conventional, inexpensive antibiotics in most situations, with new agents being reserved for judiciously selected indications. Such an approach will not only contain health care costs but will also help to preserve the microbiologic ecosystem.

Anti-Infective Agents↗
PubMed1995

Contralateral median nerve autograft.

Interfascicular nerve autografting is a useful method to repair nerves with gaps, mainly if the removal of a nerve does not imply a defect to the donor area. Final results of peripheral nerve repair definitely depend on the size of the nerve gap, the level of the injury and the time elapsed from the time of injury until the nerve is repaired.

Electromyography↗
PubMed1994

Apparent absorption of copper and zinc from composite vegetarian diets in young Indian men.

In order to identify the factors affecting apparent absorption of copper and zinc in vegetarian subjects, percent absorption of copper and zinc was estimated during 6 metabolic experiments, each of 2 weeks duration, carried out on 6 healthy young men. They were observed at 3 levels of energy, i.e. 9.2, 10.5 and 12.1 MJ/day. Intakes of zinc were in the range of 20.6-27.1 mg/day and the observed values of apparent absorption (intake-fecal output) were 11.2-20.3%. In case of copper, intakes were 2.7-5.2 mg/day while the apparent absorption was to the tune of 10.6-21.7%. These values of absorption were lower than those of the non-vegetarian diets. Multiple regression analysis of 17 dietary factors suggested that hemicellulose, milk protein, niacin and cereal protein act as significant enhancers in zinc absorption while thiamine, phytate, oxalates, ascorbic acid and phosphorus acted as inhibitors. Copper absorption was enhanced by the dietary levels of riboflavine, cellulose, milk proteins, oxalates and zinc, while phosphorus, niacin, calcium and pulse protein inhibited the absorption of copper.

Adult↗
PubMed1994

In healthy primates, circulating autoreactive T cells mediate autoimmune disease.

A T cell response against myelin basic protein (MBP) is thought to contribute to the central nervous system (CNS) inflammation that occurs in the human demyelinating disease multiple sclerosis. To test whether MBP-reactive T cells that are normally retrieved from the circulation are capable of inducing CNS disease, MBP-reactive T cell clones were isolated from the peripheral blood of healthy, unimmunized Callithrix jacchus (C. jacchus) marmosets. This primate species is characterized by a natural chimerism of bone marrow elements between siblings that should make possible adoptive transfer of MBP-reactive T cells. We report that MBP-reactive T cell clones efficiently and reproducibly transfer CNS inflammatory disease between members of C. jacchus chimeric sets. The demyelination that is characteristic of experimental allergic encephalomyelitis induced in C. jacchus by immunization against human white matter did not occur after adoptive transfer of the MBP-reactive clones. It was noteworthy that encephalitogenic T cell clones were diverse in terms of their recognition of different epitopes of MBP, distinguishing the response in C. jacchus from that in some inbred rodents in which restricted recognition of MBP occurs. These findings are the first direct evidence that natural populations of circulating T cells directed against a CNS antigen can mediate an inflammatory autoimmune disease.

Animals↗
PubMed1994

Achilles tendon ossification.

The authors describe the case of a patient who had an ossified Achilles tendon without fracture. Such ossification is uncommon, occurring most often after trauma or surgery.

Achilles Tendon↗
PubMed1993

Colinear laser-induced fluorescence detector for capillary electrophoresis. Analysis of glutamic acid in brain dialysates.

Experiments with capillary electrophoresis using a laser-induced fluorescence detector with a colinear optical arrangement demonstrated several important points. First, increasing the numerical aperture of the microscope objective that is used simultaneously for focusing the excitation laser light as well as collection of emitted fluorescence enhances the signal used for the measurement of the emitted fluorescence and at the same time decreases the noise of interfering light. Second, detection of fluorescein-labelled amphetamine was performed at high-picomolar (10(-10) M) levels. Third, the signal-to-noise ratio of 280 found at the above-mentioned picomolar concentrations indicates that the measurement of low-picomolar concentrations (10(-12) M) of this compound in biological samples should be possible. Fourth, narrow-bore capillaries (5-10 microm internal diameter) were used to detect the neurotransmitters glutamic acid and aspartic acid as their naphthalene-2,3-dicarboxaldehyde derivatives in brain dialysates obtained from a freely moving rat. A mathematical model was developed to explain the relationship between numerical aperture, working distance, magnification of the lens, noise due to laser scattering and signal due to fluorescence. The model correctly predicted the observed values of photomultiplier tube current due to both laser scattering and fluorescence. The potential of the application of capillary electrophoresis with laser-induced fluorescence detection in the neurosciences is discussed.

Animals↗
PubMed1993

The T-cell response to myelin basic protein in familial multiple sclerosis: diversity of fine specificity, restricting elements, and T-cell receptor usage.

Indirect evidence suggests that an autoimmune response to myelin basic protein (MBP) may be involved in the pathogenesis of multiple sclerosis (MS). In MS, several reports have suggested that restricted T-cell populations respond to MPB, as in inbred rodents with the MS disease model experimental allergic encephalomyelitis. In experimental allergic encephalomyelitis, the T-cell repertoire to MBP varies between strains, and in MS it is likely that the response to MBP is also best defined under conditions where genetic differences between subjects are controlled. In this report, the fine specificity of the T-cell response to MBP was assessed in three families, each with multiple individuals affected with MS. We found that (1) comparable frequencies of MBP-reactive T-cell lines were obtained from peripheral blood of MS patients and their healthy siblings. Human leukocyte antigen (HLA) identical sibling pairs discordant for MS had similar frequencies of MBP-reactive T-cell lines. (2) A broad spectrum of MBP epitopes was recognized by T-cell lines from all individuals studied. Within a family, the fine specificity of MBP recognition showed little or no overlap between individuals, even between HLA identical siblings. (3) Recognition of MBP epitopes occurred in the context of different HLA class II alleles. At least four DR alleles each served as restricting elements for recognition of P82-101 or the carboxy terminal region of MBP, two regions thought to be important in the human T-cell response to the molecule. No relationship between the use of a particular DR allele and a response to a particular region of MBP could be established.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗