Search PubMed⌕ Search

Biomedical subjects

M Patel

Publications and source records attributed to M Patel.

At least 199 records · Page 11Linked to original sources
PubMed1998

Age and sex are important factors in determining normal retinol levels.

Cut-off levels for serum retinol levels of 20 micrograms/dl for marginal and 10 micrograms/dl for definite deficiency have been advocated and extensively used in population studies. However, the blood serum levels of retinol of the newborn are known to be very low and although the age dependency of the retinol binding protein has been described, the normal levels of serum retinol at different ages have not been reported from larger series. While studying poor populations of young infants in Lahore, Pakistan, we thought it necessary to try to achieve appropriate reference values by analysing the levels of serum retinol of expatriates from the Indian subcontinent who live in the affluent United Arab Emirates, where retinol deficiency is not seen either at the hospital or the community levels. We have studied material, cord blood, infantile and adult levels of retinol and found a highly significant age relationship of serum retinol levels. During very early infancy the 'normal' mean is below what has been considered deficiency. This is new information and important in the evaluation of retinol status of individuals as well as populations. In addition, we found lower levels in women, pregnant or non-pregnant, than those in adult men. This sex difference in adults was not seen in infants. We recommend a cut off level for deficiency of 10 micrograms/dl, but only for those above 1 month of postnatal age.

Adult↗
PubMed1998

Measles vaccine effectiveness in central Australian aboriginal children vaccinated at or after eight months of age.

An outbreak of measles in central Australia in 1994 provided the first opportunity to evaluate the effectiveness of the measles vaccine given to Aboriginal children at nine months of age since 1984. Children eligible for the study that was conducted in one community in the region were aged between nine months and 10 years. Eight of the 109 eligible children developed measles. The only unvaccinated child also developed measles. Vaccination failures occurred in 7.8% (6/77) of children vaccinated between eight and 11 months of age and in 3.2% (1/31) vaccinated after 11 months of age. Overall vaccine effectiveness was 93.5%. The level of vaccine uptake in central Australia is high and the last region-wide outbreak before 1994 occurred in 1981-82. If the age of vaccination against measles is to be determined by the average age of infection; the age of vaccination should now be raised to 12 months of age; this is the age at which Aboriginal children in all other states and all children in Australia are vaccinated.

Age Factors↗
PubMed1998

Comparative analysis of Haemophilus influenzae hifA (pilin) genes.

Adherence of Haemophilus influenzae to epithelial cells plays a central role in colonization and is the first step in infection with this organism. Pili, which are large polymorphic surface proteins, have been shown to mediate the binding of H. influenzae to cells of the human respiratory tract. Earlier experiments have demonstrated that the major epitopes of H. influenzae pili are highly conformational and immunologically heterogenous; their subunit pilins are, however, immunologically homogenous. To define the extent of structural variation in pilins, which polymerize to form pili, the pilin genes (hifA) of 26 type a to f and 16 nontypeable strains of H. influenzae were amplified by PCR and subjected to restriction fragment length polymorphism (RFLP) analysis with AluI and RsaI. Six different RFLP patterns were identified. Four further RFLP patterns were identified from published hifA sequences from five nontypeable H. influenzae strains. Two patterns contained only nontypeable isolates; one of these contained H. influenzae biotype aegyptius strains F3031 and F3037. Another pattern contained predominantly H. influenzae type f strains. All other patterns were displayed by a variety of capsular and noncapsular types. Sequence analysis of selected hifA genes confirmed the 10 RFLP patterns and showed strong identity among representatives displaying the same RFLP patterns. In addition, the immunologic reactivity of pili with antipilus antisera correlated with the groupings of strains based on hifA RFLP patterns. Those strains that show greater reactivity with antiserum directed against H. influenzae type b strain M43 pili tend to fall into one RFLP pattern (pattern 3); while those strains that show equal or greater reactivity with antiserum directed against H. influenzae type b strain Eagan pili tend to fall in a different RFLP pattern (pattern 1). Sequence analysis of representative HifA pilins from typeable and nontypeable H. influenzae identified several highly conserved regions that play a role in bacterial pilus assembly and other regions with considerable amino acid heterogeneity. These regions of HifA amino acid sequence heterogeneity may explain the immunologic diversity seen in intact pili.

Amino Acid Sequence↗
PubMed1998

Vasodilation elicited by liposomal VIP is unimpeded by anti-VIP antibody in hamster cheek pouch.

The purpose of this study was to determine whether a monoclonal anti-vasoactive intestinal peptide (VIP) antibody, which binds VIP with high affinity and specificity and catalyzes cleavage of the peptide in vitro, attenuates VIP vasorelaxation in vivo and, if so, whether insertion of VIP on the surface of sterically stabilized liposomes (SSL), which protects the peptide from trypsin- and plasma-catalyzed cleavage in vitro, curtails this response. Using intravital microscopy, we found that suffusion of monoclonal anti-VIP antibody (clone c23.5, IgG2ak), but not of nonimmune antibody (myeloma cell line UPC10, IgG2ak) or empty SSL, significantly attenuates VIP-induced vasodilation in the in situ hamster cheek pouch (P < 0.05). By contrast, anti-VIP antibody has no significant effects on vasodilation elicited by isoproterenol, nitroglycerin, and calcium ionophore A-23187, agonists that activate intracellular effector systems in blood vessels that mediate, in part, VIP vasoreactivity. Suffusion of VIP on SSL, but not of empty SSL, restores the vasorelaxant effects of VIP in the presence of anti-VIP antibody. Collectively, these data suggest that VIP catalysis by high affinity and specific VIP autoantibodies displaying protease-like activity constitutes a novel mechanism whereby VIP vasoreactivity is regulated in vivo.

Animals↗
PubMed1998

The process of rehabilitation and discharge planning in stroke: a controlled comparison between stroke units.

BACKGROUND AND PURPOSE: Stroke units improve outcome for stroke patients. Comparative controlled studies between stroke units are required to determine which components of stroke unit rehabilitation influence outcome and which may be investigated further in randomized controlled trials. This study compares 2 stroke units with regard to the effect differences in practice have on functional recovery (Barthel Index score) and discharge planning (length of stay). METHODS: Stroke unit patients with moderate disability (Barthel score of 4 to 10 at week 1) admitted over 18 months were studied. Barthel measurements were obtained weekly from week 1 to discharge. Details of stroke unit function were recorded. The core features of stroke units were in place in both units. Rehabilitation was impairment focused (theoretically driven) on one unit and disability oriented (pragmatic) on the other. RESULTS: Numbers of patients were comparable (85 versus 99). Median Barthel score at week 1 (6 versus 6), time to maximal Barthel score (14 versus 14 weeks), discharge Barthel score (14 versus 14), and institutionalization (32% versus 28%) were similar in both units. Median lengths of stay differed (68 versus 49 days; P<0.001). CONCLUSIONS: Comparisons with regard to the rehabilitation process can be made between stroke units. Differences in rehabilitation process between 2 units showed no effect on the rate of functional recovery. Length of stay was significantly different between units, an effect that cannot be attributed to functional recovery and therefore reflects differences in discharge planning, including postdischarge support.

Aged↗
PubMed1998

Neuroanatomic localization of magnetic resonance imaging signal hyperintensities in geriatric depression.

BACKGROUND AND PURPOSE: Increased frequency and severity of signal hyperintensities have been regularly reported in elderly depressed patients compared with normal subjects, however, greater neuroanatomic localization of lesions has been limited. METHODS: T2-weighted MRI scans in elderly depressed patients (n = 35) and normal comparison subjects (n = 31) were assessed for signal hyperintensities in lateralized discrete brain regions. RESULTS: Logistic regression revealed that left frontal deep white matter (P<.005) and left putaminal (P<.04) hyperintensities significantly predicted depressive group assignment. CONCLUSIONS: Findings suggest that greater neuroanatomic localization of hyperintensities than heretofore appreciated may relate to late-life depression.

Aged↗
PubMed1998

Osteosarcoma of the larynx.

About 11,600 cases of laryngeal cancer were reported in the United States in 1995, accounting for 1% of all reported cancers. Fewer than 1% of laryngeal cancers are sarcomas, osteosarcoma being the rarest type. Twelve cases of laryngeal osteosarcoma have been cited in the literature. A 47-year-old man presented with hoarseness following a benign vocal polypectomy. The entire larynx appeared swollen, although both vocal folds moved well. Biopsies did not reveal pathologic tissue. Computed tomographic imaging revealed a destructive, expansile lesion of the thyroid cartilage. A computed tomography-guided biopsy of this cartilage revealed a high-grade sarcoma. Laryngeal osteosarcoma was diagnosed following total laryngectomy. Laryngeal osteosarcoma is a highly malignant neoplasm with early hematogenous spread. Survival statistics for peripheral osteosarcoma are poor. Limited experience reveals that a combination of surgery and radiotherapy with adjuvant chemotherapy can offer some palliation. The literature and published cases of laryngeal osteosarcoma are reviewed.

Combined Modality Therapy↗
PubMed1998

Opl: a zinc finger protein that regulates neural determination and patterning in Xenopus.

In order to study the mechanism of neural patterning in Xenopus, we used subtractive cloning to isolate genes activated early during this process. One gene isolated was opl, (odd-paired-like) that resembles the Drosophila pair-rule gene odd-paired and encodes a zinc finger protein that is a member of the Zic gene family. At the onset of gastrulation, opl is expressed throughout the presumptive neural plate, indicating that neural determination has begun at this stage while, by neurula, opl expression is restricted to the dorsal neural tube and neural crest. opl encodes a transcriptional activator, with a carboxy terminal regulatory domain, which when removed increases opl activity. opl both sensitizes animal cap ectoderm to the neural inducer noggin and alters the spectrum of genes induced by noggin, allowing activation of the midbrain marker engrailed. Consistent with the later dorsal neural expression of opl, the activated form of opl is able to induce neural crest and dorsal neural tube markers both in animal caps and whole embryos. In ventral ectoderm, opl induces formation of loose cell aggregates that may indicate neural crest precursor cells. Aggregates do not express an epidermal marker, indicating that opl suppresses ventral fates. Together, these data suggest that opl may mediate neural competence and may be involved in activation of midbrain, dorsal neural and neural crest fates.

Amino Acid Sequence↗
PubMed1998

Determination of the zebrafish forebrain: induction and patterning.

We report an analysis of forebrain determination and patterning in the zebrafish Danio rerio. In order to study these events, we isolated zebrafish homologs of two neural markers, odd-paired-like (opl), which encodes a zinc finger protein, and fkh5, which encodes a forkhead domain protein. At mid-gastrula, expression of these genes defines a very early pattern in the presumptive neurectoderm, with opl later expressed in the telencephalon, and fkh5 in the diencephalon and more posterior neurectoderm. Using in vitro explant assays, we show that forebrain induction has occurred even earlier, by the onset of gastrulation (shield stage). Signaling from the early gastrula shield, previously shown to be an organizing center, is sufficient for activation of opl expression in vitro. In order to determine whether the organizer is required for opl regulation, we removed from late blastula stage embryos either the presumptive prechordal plate, marked by goosecoid (gsc) expression, or the entire organizer, marked by chordin (chd) expression. opl was correctly expressed after removal of the presumptive prechordal plate and consistently, opl was correctly expressed in one-eyed pinhead (oep) mutant embryos, where the prechordal plate fails to form. However, after removal of the entire organizer, no opl expression was observed, indicating that this region is crucial for forebrain induction. We further show that continued organizer function is required for forebrain induction, since beads of BMP4, which promotes ventral fates, also prevented opl expression when implanted during gastrulation. Our data show that forebrain specification begins early during gastrulation, and that a wide area of dorsal mesendoderm is required for its patterning.

Amino Acid Sequence↗
PubMed1998

The value of the intrinsic factor antibody test in diagnosing pernicious anaemia.

OBJECTIVE: Assessment of the usefulness of the intrinsic factor antibody (IF Ab) test in comparison to the Schilling test in diagnosing pernicious anaemia (PA) in patients with vitamin B12 deficiency. DESIGN: This study was designed to compare the If Ab test to the Schilling test using results obtained of patients presenting with megaloblastic anaemia and low serum vitamin B12 levels to a large referral hospital. SETTING: The Chris Hani Baragwanath Hospital, Soweto, Gauteng, South Africa. SUBJECTS: Results from 77 patients with megaloblastic anaemia, low serum vitamin B12 levels and with both Schilling and IF Ab test results available were included. MAIN OUTCOME MEASURES: The sensitivity and specificity of the IF Ab test was compared to the Schilling test with regard to making a diagnosis of PA in patients presenting with megaloblastic anaemia and low serum vitamin B12 levels. RESULTS: Relevant statistical analysis showed that in the correct clinical setting, a confident diagnosis of PA could be made without Schilling tests in patients with megaloblastic anaemia, vitamin B12 deficiency and positive IF Ab tests. In a small proportion of patients in whom the IF Ab is negative, Schilling tests still need to be performed. CONCLUSION: With the increased concern over rising medical costs and where limited facilities are available, the IF Ab, in the correct clinical setting, is a cost effective and reliable test for diagnosis of PA.

Anemia, Pernicious↗
PubMed1998

Marrow versus infection in the Charcot joint: indium-111 leukocyte and technetium-99m sulfur colloid scintigraphy.

UNLABELLED: This study evaluated the role of combined leukocyte/marrow scintigraphy in the assessment of the neuropathic or Charcot joint. METHODS: Seventeen patients with (111)In-labeled leukocyte accumulation in 20 radiographically confirmed Charcot joints underwent 99mTc-sulfur colloid marrow scintigraphy. Studies demonstrating labeled leukocyte accumulation without corresponding activity on marrow images were classified as positive for osteomyelitis. Six of the patients also underwent three-phase bone scintigraphy. Bone scans were interpreted as positive for osteomyelitis when focal hyperperfusion, focal hyperemia and focal bony uptake on delayed images were present. Bone images were also interpreted together with labeled leukocyte images using two different criteria for a positive study. One criterion was the presence of labeled leukocyte activity in a region demonstrating abnormal activity on the bone scan, which was more intense than adjacent marrow activity or marrow activity in the corresponding region of the contralateral foot. The second criterion was either a spatially incongruent distribution of the two tracers or hyperintense activity on the leukocyte study, as compared to the bone scan. RESULTS: Leukocyte/marrow studies were positive for osteomyelitis in 4 of the 20 neuropathic joints. Osteomyelitis was present in three of the four joints, whereas in the fourth, infection was confined to overlying soft tissues. None of the 16 neuropathic joints with negative leukocyte/marrow scans were infected. In one patient who underwent below-the-knee amputation, histological analysis confirmed the presence of hematopoietically active marrow corresponding to areas of congruent activity on the leukocyte and marrow images. Three-phase bone scintigraphy was positive in all six neuropathic joints studied; osteomyelitis was present in two of them. Using the first criterion, leukocyte/bone imaging was also positive in all six. Using the second criterion, leukocyte/bone imaging was positive in the two infected neuropathic joints, as well as in three uninfected ones. Leukocyte/marrow scintigraphy was positive in both infected joints and negative in the four without infection. CONCLUSION: Labeled leukocyte accumulation in the uninfected Charcot joint does occur and is related, at least in part, to hematopoietically active marrow. Leukocyte/marrow scintigraphy is a reliable way to differentiate between marrow and infection as the cause of labeled leukocyte accumulation in the neuropathic joint and, in this series, was superior to both three-phase bone scintigraphy and combined leukocyte/bone scintigraphy.

Adult↗
PubMed1998

Fighting germs.

Explore the source record for details and available documents.

Anti-Bacterial Agents↗
PubMed1998

Placental binding and transfer of radiopharmaceuticals: technetium-99m d, 1-HMPAO.

UNLABELLED: Placental binding and transfer of 99mTc d, 1-hexamethyl propyleneamine oxime (HMPAO) was studied in vitro using human placenta and pregnant guinea pigs. MATERIALS AND METHODS: Five pieces of human placenta were incubated in 50 ml Earle's solution containing 1.85 MBq 99mTc d, 1-HMPAO. The percent binding of the tracer to the placenta per 1 ml standard solution was calculated. Pregnant guinea pigs representing first, second and third trimesters were each injected with 74 MBq 99mTc d, 1-HMPAO through the jugular or femoral vein after sedation was induced with pentabarbital sodium. Static images were obtained, the guinea pigs were killed, and the fetuses were removed, weighed and imaged separately. The placentas, maternal and fetal brains, lungs, livers and kidneys also were removed, and the radioactivity was assayed in a dose calibrator for each organ. The percent radioactivity in each organ was calculated. RESULTS: The binding of 99mTc d, 1-HMPAO to human placenta ranged from 2.95% +/- 1.5% to 5.82% +/- 0.3% per 1 ml standard solution. Both the binding of 99mTc d, 1-HMPAO to guinea pig placenta and its transfer to the fetus increased with gestational age. The percent binding ranged from 0.09% +/- 0.06% to 0.43% +/- 0.05%, whereas that of transfer to the fetus ranged from 0.05% +/- 0.03% to 2.19% +/- 0.64%. Of the amount transfered to the fetus, the order of accumulation in the fetal organs was liver > blood >> brain > lungs > kidneys > heart. CONCLUSION: Technetium-99m d, 1-HMPAO binds to the placenta, and a minimal amount crosses the placental barrier and is transfered into the fetal circulation, mostly in the liver but a measurable amount is found in brain tissue.

Animals↗
PubMed1998

Modified preparation and rapid quality control test for technetium-99m-tetrofosmin.

OBJECTIVE: The objectives of this study were to: modify the preparation of 99mTc-tetrofosmin by using twice the amount of 99mTcO4- recommended by the manufacturer; evaluate the use of miniaturized rapid paper chromatography (MRPC) for quality control (QC) testing; and determine the in vitro stability of the modified preparation using MRPC. METHODS: Two preparations of 99mTc-tetrofosmin were made: one with 4.4-8.8 GBq (120-240 mCi) and the other with 13.9-17.6 GBq (380-480 mCi) 99mTcO4-, referred to as regular and modified preparations, respectively. Routine QC tests were performed using MRPC and instant thin-layer chromatography/silica-gel (ITLC/SG) systems. The preparations were injected into 58 patients. Planar and SPECT images of stress and rest studies were obtained. The technical quality of the SPECT images was graded visually by four observers. Heart-to-lung and heart-to-background ratios were calculated from the planar images. RESULTS: The QC testing procedure took 4.18 +/- 0.15 min with MRPC and 54 +/- 5.3 min with ITLC/SG systems. The percent labeling efficiency, as determined by both techniques, ranged from 95.6 +/- 1.6 to 97.2% +/- 0.8%. Both preparations were stable up to 6 hr after reconstitution. There was no difference between the cardiac-to-lung and cardiac-to-background ratios of the two preparations. CONCLUSION: The results indicate that MRPC is a faster and effective chromatographic technique for routine QC testing of 99mTc-tetrofosmin. Doubling the amount of 99mTcO4- used in preparing 99mTc-tetrofosmin did not affect its in vitro stability, its efficacious use in patients or the technical quality of the images.

Chromatography, Paper↗