Biomedical subjects
J Rai
Publications and source records attributed to J Rai.
Polarized electromagnetic radiation from spatially correlated sources.
We consider the effect of spatial correlations in sources of polarized electromagnetic radiation. We evaluate the coherency matrix for a spatially extended three-dimensional source in order to obtain its dependence on the angular position of the observer in the far zone. We find a general condition on the source correlation matrix under which the polarization in the far zone shows no angular dependence. In general, however, we find that the polarization shows a rather striking dependence on the direction of observation. We illustrate this effect by considering some examples of monochromatic spatially correlated sources. The sources, assumed to be monochromatic, are constructed out of dipoles aligned along a line such that their orientation is correlated with their position. In one representative example, the dipole orientations are prescribed by a generalized form of the standard von Mises distribution for angular variables such that the azimuthal angle of dipoles is correlated with their position. In another example the tip of the dipole vector traces a helix around the symmetry axis of the source. Possible experimental observation of this effect, by considering an analog of the standard two-slit interference experiment, is also discussed. The effect may find useful applications in certain astrophysical sources.
Hepatitis C virus genotypes: distribution and clinical significance in patients with cirrhosis type C seen at tertiary referral centres in Europe.
The aim of this study was to evaluate the distribution and clinical significance of hepatitis C virus (HCV) genotypes in European patients with compensated cirrhosis due to hepatitis C (Child class A) seen at tertiary referral centres. HCV genotypes were determined by genotype-specific primer PCR in 255 stored serum samples obtained from cirrhotics followed for a median period of 7 years. Inclusion criteria were biopsy-proven cirrhosis, absence of complications of cirrhosis and exclusion of all other potential causes of chronic liver disease. The proportion of patients with types 1b, 2, 3a, 1a, 4 and 5 were 69%, 19%, 6%, 5%, 0.5% and 0.5%, respectively. Kaplan-Meier 5-year risk of hepatocellular carcinoma (HCC) was 6% and 4% for patients infected by type 1b and non-1b, respectively (P=0.8); the corresponding figures for decompensation were 18% and 7% (P=0.0009) and for event-free survival were 79% and 89% (P=0.09), respectively. After adjustment for baseline clinical and serological features, HCV type 1b did not increase the risk for HCC [adjusted relative risk=1.0 (95% confidence interval=0.47-2.34)], whereas it increased the risk for decompensation by a factor of 3 (1.2-7.4) and decreased event-free survival by a factor of 1.7 (0.9-3.10). In conclusion, type 1b and, to a lesser extent, type 2, are the most common HCV genotypes in European patients with cirrhosis. HCV type 1b is not associated with a greater risk for HCC, but increases the risk for decompensation by threefold in patients with cirrhosis.
Hepatocyte growth factor modulates the hepatic acute-phase response in thermally injured rats.
OBJECTIVE: Hepatocyte growth factor (HGF) has been shown to modulate the acute-phase response in vitro. The specific in vivo role of HGF in this multifactorial response, however, remains unknown. This study examines the effects of exogenous HGF on the acute-phase response in thermally injured rats. DESIGN: Prospective, randomized, laboratory study. SETTINGS: Shriners Hospital for Children and University of Texas Medical Branch laboratories. SUBJECTS: Fifty-six male Sprague-Dawley rats (weight range, 300-325 g). INTERVENTION: Animals received a 60% total body surface area third-degree scald burn and were randomly divided to receive either 400 microg/kg/day i.v. HGF or saline (control). MEASUREMENTS AND MAIN RESULTS: Serum acute-phase proteins, cytokines, and insulin-like growth factor (IGF)-I concentrations, as well as liver weight, protein and triglyceride content, IGF-I concentrations, and cytokine gene expression were measured 1, 2, 5, or 7 days after burn. Serum albumin was increased on days 2, 5, and 7 after burn, and transferrin was increased on day 7 after burn in HGF-treated rats compared with controls (p<.05). HGF increased alpha2-macroglobulin concentrations on postburn days 2, 5, and 7 compared with controls (p<.05). Serum interleukin-6 and tumor necrosis factor-alpha were significantly higher within 2 days of burn in rats treated with HGF (p<.05). HGF increased the hepatic gene expression of tumor necrosis factor-alpha compared with controls (p<.05). Serum IGF-I decreased in rats receiving HGF 1, 2, and 5 days after burn, whereas liver IGF-I concentrations were higher on days 1 and 7 after burn compared with controls (p<.05). Hepatic protein concentrations were higher in the HGF group compared with controls on postburn days 1, 2, and 7, with a concomitant increase in total liver weight (p<.05). HGF exerted a strong mitogenic effect on hepatocytes 1 and 2 days after thermal injury compared with controls (p<.05). CONCLUSIONS: These findings suggest that HGF modulates the acute-phase response in vivo after burn and causes changes in liver morphology.
Laparoscopic removal of a rudimentary uterine horn during pregnancy. A case report.
BACKGROUND: A unicornuate uterus with a rudimentary horn is a müllerian anomaly associated with endometriosis and pregnancy complications, including miscarriage, ectopic pregnancy, uterine rupture, preterm labor and malpresentation. Therefore, the horn is removed if it is thought to contain functional endometrium. This is usually done by laparotomy in the nonpregnant state. CASE: A woman presented during pregnancy with symptoms, examination and ultrasonogram suspicious for an ectopic pregnancy. Intraoperative findings and final pathology, however, showed a rudimentary uterine horn, which was laparoscopically removed, and a concomitant intrauterine pregnancy. CONCLUSION: A rudimentary uterine horn may present during pregnancy and mimic an ectopic pregnancy. In this case, the horn was removed laparoscopically.
Recombinant human growth hormone alters acute phase reactant proteins, cytokine expression, and liver morphology in burned rats.
BACKGROUND: The effects of exogenous recombinant human growth hormone (rhGH) on hepatic acute phase reactant proteins, cytokine expression, and liver morphology were studied in thermally injured rats to define whether rhGH alters the acute phase response. MATERIALS AND METHODS: Sprague-Dawley rats (56 males) receiving a 60% TBSA third-degree scald burn were randomly divided into two groups to receive either 2.5 mg/kg/day sc rhGH or saline. Rats were sacrificed on Postburn Days 1, 2, 5, and 7. Serum acute phase reactant proteins and cytokines TNF-alpha, IL-1alpha, IL-1beta, and IL-6 were measured. Hepatocyte proliferation, hepatic cytokine gene expression, and liver protein concentrations were determined. RESULTS: Recombinant hGH increased serum albumin on Days 5 and 7 after burn (P < 0.05). Serum haptoglobin and alpha1-acid glycoprotein levels decreased at 2, 5, and 7 days after burn compared to saline (P < 0.05). In rats treated with rhGH, serum IL-1beta decreased 1 day postburn, while serum TNF-alpha increased 5 days after burn compared to saline (P < 0.05). Serum IL-6 and IL-1alpha did not change. Hepatic RNA levels for TNF-alpha were significantly elevated on Day 1 postburn compared to saline (P < 0. 05). Hepatic protein content increased on Days 2, 5, and 7 postburn compared to saline (P < 0.05). Hepatocyte proliferation in rhGH-treated rats increased on Day 5 after burn (P < 0.05). CONCLUSION: Data indicate that rhGH alters the hepatic acute phase response by decreasing type I acute phase proteins and modulating IL-1-like cytokine expression. These changes are associated with increased hepatocyte mitosis and serum and total liver protein concentrations.
Pronuclear orientation, polar body placement, and embryo quality after intracytoplasmic sperm injection and in-vitro fertilization: further evidence for polarity in human oocytes?
Three hypotheses were tested: (i) the distance between first and second polar bodies (PB) may relate to embryo morphology, (ii) that the orientation of pronuclei (PN) relative to PB may relate to embryo morphology, (iii) that the placement of a spermatozoon in a fixed plane relative to the first PB [intracytoplasmic sperm injection (ICSI)] may alter PN/PB orientation relative to in-vitro fertilization (IVF). A total of 251 two pronuclear (2PN) embryos (124 ICSI, 127 IVF) from 64 patients was studied. Angles were measured between the PN axis and the nearest PB (alpha), the furthest PB (beta), and between the two PB (gamma). On day 2, the morphological grades of embryos were recorded. gamma ranged from 0 to 150 degrees and was not significantly different for ICSI or IVF embryos of different grades; however, an unusual distribution of gamma suggested different populations of oocytes. The first hypothesis was rejected. alpha and beta ranged from 0 to 90 degrees : alpha did not relate significantly to embryo grade, but beta increased significantly with decreasing quality of ICSI embryos (P < 0.05) and the total group (P < 0.01), supporting hypothesis (ii). The difference in beta between ICSI and IVF embryos was not significant, so hypothesis (iii) was unproven. Significant differences between ICSI and IVF embryos in PN positions, irregular cleavage, and cleavage failure were noted.
Electrical injuries: a 30-year review.
INTRODUCTION: Electrical injuries currently remain a world-wide problem. This study determines whether electrical injuries at our institution have changed in the past 30 years, and identifies electrical burn complications and any high-risk groups. METHODS: From 1967 to 1997, 185 children admitted to our institute were identified with electrical burns. Fifty-five percent of these electrical burns occurred from 1987 to 1997. RESULTS: During the last 10 years of this study, 43% of the electrical injuries (n = 44) were from low voltage (120-240 V) and 57% (n = 58) from high voltage (>1,000 V). In 17 children, serious low-voltage burns were identified as oral commissure burns. These were treated conservatively with one to two reconstructive procedures within 2 years. High-voltage injuries were mainly identified in male children (age 11 to 18 years). Thirty-three percent of high-voltage burns required amputation, 29% had deep muscle involvement, and 24% required either escharotomy or fasciotomy. No mortalities were reported. CONCLUSION: Although the incidence of low-voltage burns is currently on a steady decline, high-voltage injuries remain a problem, particularly in adolescent males.
Small bowel necrosis in association with jejunostomy tube feedings.
Nutritional support is thought to be an important adjunct for minimizing perioperative morbidity. For a variety of reasons, it is now felt that nutrition delivered by the enteral route is preferred over that given parenterally. Although delivery of nutrients into the small intestine, either via a nasoduodenal tube or a surgically placed jejunostomy, is effectively tolerated by most patients, morbid complications are being described with increased frequency. Herein, we describe two patients who underwent major intra-abdominal surgery, one for a malignancy, the other for trauma management. Immediate postoperative feedings were instituted through a surgically placed jejunostomy tube. Several days later, each patient underwent emergency reoperation for clinical findings of an intra-abdominal catastrophe. In both patients, small intestinal infarction in juxtaposition to the site of the tube feedings was found. This experience suggests that the enteral feedings were causally related to this morbid complication, which proved fatal in one patient.
Uncertainties of Schwinger angular-momentum operators for squeezed radiation in interferometers.
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Cooperative bistability in dense, excited atomic systems.
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The role of Streptococcus viridans in human infections in Mauritius.
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Comminuted intra-articular fractures of the distal humerus.
Seventy-five intra-articular fractures of the distal humerus were treated from 1980 to 1991 in our hospital by open reduction and internal fixation with AO small and mini-fragment instrumentation. Müller's classification into C1, C2 and C3 types was used and the results graded by Burri and Lob's criteria after a minimum follow up of 1.6 years to a maximum of 12 years. Results were satisfactory in 77%, fair in 16% and poor in 7%. The correct indications are important together with anatomical reduction and postoperative physiotherapy. These results are encouraging compared with others previously reported.
Study of microflora in well-nourished and mal-nourished children in relation to dental caries.
Forty-five children in the age group of 2-12 years comprising 20 well-nourished (W.N.), 20 malnourished (M.N.) (both groups having DMFS of > or = 5) and 5 caries free well nourished children (control group) were studied to find out the oral microflora in these groups S. mutans was present in 55%, 20% and 0% in W.N., M.N., and control groups while S. Salivarius was isolated in 45%, 80% and 40% in the three groups respectively. There was no significant difference in the prevalence of Lactobacillus and C. albicans in the three groups. The correlation between means DMFS and the prevalence of S. mutans in W.N. and M.N. groups was highly significant (P < 0.001). Nutritional status including different grades of malnutrition had no significant bearing on the prevalence of micro-organisms isolated. The caries prevalence was higher in the W.N. group (P) while the gingival index was higher in M.N. group.
Effect of streptozotocin-induced diabetes on magnesium inhibition of contractions of the rat uterus and G.I. tract.
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Source-correlation effects in the time domain.
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Magnesium inhibition of carbachol-induced contractions of the rat uterus and gastrointestinal tract: ex vivo effect of long term streptozotocin-induced diabetes.
Rats were rendered diabetic by a single administration of streptozotocin (STZ). They were maintained in the diabetic state for six weeks before being killed, and diabetic state was confirmed by routine urine and blood glucose estimations. The contractile sensitivity of jejunum, colon, stomach fundus and uterus to carbachol was reduced in control animals by increasing buffer magnesium concentration from 1.9 mmol/litre to 23.8 mmol/litre. This magnesium effect was reversed in the colon, stomach fundus and uterus of streptozotocin-diabetic animals, with contractile sensitivity being enhanced in the presence of increased magnesium concentration. In the jejunum, however, the magnesium effect was not reversed by STZ-induced diabetes. In diabetic animals, magnesium generally had the opposite effect on gastrointestinal and uterine tissues when compared with control animals. This suggests that, in the diabetic condition, any altered gastrointestinal function may be due to an underlying difference in the sensitivity to changes in magnesium.
Quantum-statistical analysis of superfluorescence and amplified spontaneous emission in dense media.
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