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Biomedical subjects

N Hasan

Publications and source records attributed to N Hasan.

At least 19 recordsLinked to original sources
PubMed2006

Gross morphometry of human placenta in eclampsia.

The study was done to see the gross morphologic changes of placenta in human normal pregnancy and eclapmsia, with the aim that it would be able to increase the general body of knowledge regarding the gross morphology of normal placenta and the changes that occur in eclampsia in our population. Total of 45 (n=45) placenta, 25 (n=25) from eclampsia and 20 (n=20) from normal pregnant cases were collected from Gynaecology and Obstetric Department of Mymensingh Medical College & Hospital (MMCH). Study was done in Anatomy Department of Mymensingh Medical College (MMC). Macroscopic study of the formol saline fixed placentas revealed that, compared to the controls there was trends of lower weights and volumes of placentas in eclamptic group. Statistical significance of difference between two groups was calculated by using Students "t" test. A difference between the two groups was considered to be significant when p<0.005.

Adolescent↗
PubMed2006

Morphological study of recurrent laryngeal nerve in relation to thyroid gland.

The study was done to see the relationship of recurrent laryngeal nerves with corresponding inferior thyroid artery with the aim to increase the knowledge regarding variational anatomy in our population. Sixty samples were collected as block dissection of thyroid gland along with the surrounding structures containing the supplying vessels and adjacent nerves from 48 male and 12 female cadavers of different age groups and fixed in 10% formol-saline solution. Fine dissections were carried out to study the toporgaphic relationship of recurrent laryngeal nerves with corresponding inferior thyroid artery. The findings were compared between different age groups and also with the findings of western researchers. In this study, in majority of the cases the recurrent laryngeal nerves were found in their usual location that is posterior to the terminal branches of inferior thyroid artery on the left side and anterior to that artery on the right side. It was important to note that, on both sides recurrent laryngeal nerves were also frequently found to pass in between the terminal branches of inferior thyroid artery.

Adolescent↗
PubMed2001

Expression plasmid with a very tight two-step control: Int/att-mediated gene inversion with respect to the stationary promoter.

A very tightly controlled expression vector was constructed, which was originally designed as to be able to use any promoter, constitutive or regulated. Moreover, in vector pNH46T1, the repressible P(tac)/P(lac) promoters were used to transcribe genes cloned in the proximal multiple cloning site (MCS), which was flanked by convergent attB and attP sites. The gene of interest was cloned into MCS in the OFF orientation, i.e. facing the promoter(s). In such OFF orientation, the cloned gene could not be expressed, and only its anti-sense mRNA could be produced. Four strong rrnBT1 terminators, in a tandem arrangement and proximal to the N-terminal end of the cloned non-inverted gene, were protecting it from any inadvertent transcription originating in the vector. Moreover, the P(tac)/P(lac) promoters/operators are controlled by the LacI(q)ts and LacI(+) repressor(s) that further reduce the basal gene expression in the uninduced state. When induced, the total vector population is converted to the ON orientation by expression of the Int function that inverts the attB and attP-flanked MCS including the cloned gene. This places the gene under direct control of the P(tac)/P(lac) promoters, and thus results in very high expression. An additional feature is the anti-termination system that consists of the promoter-proximal nutL site and the inducible gene N, whose role in the ON state is to overcome the rrnBT1 terminators and any other adventitiously cloned terminators.

Attachment Sites, Microbiological↗
PubMed2000

Pigmented liver cell adenoma in two male patients.

We report two cases of hepatocyte neoplasia with extensive deposition of Dubin-Johnson-like pigment in men without Dubin-Johnson syndrome. This pigment has previously been described in hepatocellular carcinoma but not in liver cell adenoma. The tumors of both patients showed some atypical cytologic features, but no frank histologic evidence of malignancy. Long-term follow up for several years showed no evidence of recurrence after limited surgical excision. We conclude that tumors with this structure may be cured by limited surgical excision and should be considered as pigmented liver cell adenomas.

Adenoma, Liver Cell↗
PubMed2000

Outpatient pediatric surgery in a developing country.

OBJECTIVE: To access the prospects of daycare pediatric surgery in a developing country like Pakistan in view of economic advantages, parent's acceptability and utilization of hospital resources. METHODS: This prospective study was carried out in Karachi from 1st January 1994 to 31st December 1996 in three different private hospitals having optimum operating, anaesthetic and recovery facilities. Selection criteria included general fitness for surgical procedure, not requiring hospitalization, no associated congenital malformation and co-operative parents residing in Karachi. An evening before surgery, all patients were examined thoroughly and detailed instructions for pre-operative fasting and pre-medications were given to the family. Operations were carried out by same surgical team with different set of anesthetists. After surgery and recovery from anesthesia, the children were observed in a holding area adjacent to operating room till fully conscious and alert. Before leaving the hospital, the parents were briefed about post-operative care at home like feeding, ambulation and use of analgesics. A contact telephone number was also provided to the family for any difficulty or emergency. All patients were re-examined 36-48 hours post-operatively in clinic, for any problem at home and the parents were assessed for their attitude toward this modality. RESULTS: In 3-year period a total of 368 surgical procedures were carried out of whom 129 operations were done in children under 1-year of age and the youngest patient was one week old with a weight of 2.9 kg. The average age was 2.9 years and average weight was 13 kg. Male:female ratio was 3.6:1. The average operating time was 28 min, average anaesthesia time was 38 min and average recovery time was 17 min, which was not affected by the use of endotracheal tube. Majority of parents managed their children very well at home and only 17% of them called one of the surgeons to inquire about their apprehension at home and all were explained and satisfied. On an average 37% children required two doses of post-operative oral analgesia and 59% returned to normal activity after 24 hours. The overall incidence of complication was 3.6% and there were no deaths or major complications. Only one patient required post surgical hospitalization due to post-operative pneumonia. The mode of management was cost effective and also the parents appreciated the avoidance of hospitalization because of less disruption of their routine work at home and office. CONCLUSION: Based on the above experience, we recommended that a variety of common pediatric operations can be done safely as out patients in infants and children, with economic advantages, high parent's acceptability and better utilization of hospital resources without scarifying the quality of health services.

Ambulatory Surgical Procedures↗
PubMed1999

Recanalization of a portal-vein thrombosis and partial resolution of biliary cirrhosis following cholecystectomy for cholelithiasis in an infant.

Cholelithiasis in infants and children is unusual and is reputedly associated with underlying hemolytic disorders, total parenteral nutrition, ileal disease, and congenital anomalies of the biliary tree. We report a case of cholecystitis with pigmented stones in a 3-month-old infant associated with portal vein thrombosis (PVT) and biliary cirrhosis without the above-mentioned causes. Recanalization of the PV and partial resolution of the cirrhosis was observed following cholecystectomy. To our knowledge, cholelithiasis associated with PVT and cirrhosis in an infant has not been reported in the literature.

Biopsy, Needle↗
PubMed1999

The dishonest dean's letter: an analysis of 532 dean's letters from 99 U.S. medical schools.

PURPOSE: To quantify the censure of potentially negative information in dean's letters. METHOD: Concordance between 532 dean's letters and the corresponding transcripts was determined for six variables (failing grade in a preclinical course, marginal preclinical course grade, failing grade for a clinical rotation, marginal clinical rotation grade, leave of absence, and requirement to repeat an entire year of medical school). RESULTS: The evaluated variables were not found in the dean's letters 27% to 50% of the time that they were present on the transcripts. In three of nine instances (33%), a failing grade in a clinical rotation was not included. Four students had been required to repeat an entire year, but this was noted in only two cases. In toto, 35 of 104 (34%) of the variables identified on the transcripts were not reported. In addition, deans were significantly less likely to report a student's USMLE 1 score if the score was at or below the 20th percentile (p = .03). CONCLUSION: Some deans suppress negative information in their letters and potentially obfuscate the residency selection process.

Achievement↗
PubMed1998

Upper airway resistance syndrome.

Many clinicians are familiar with the clinical symptoms and signs of obstructive sleep apnea (OSA). In its most blatant form, OSA is complete airway obstruction with repetitive, prolonged pauses in breathing, arterial oxyhemoglobin desaturation; followed by arousal with resumption of breathing. Daytime symptoms of this disorder include excessive daytime somnolence, intellectual dysfunction, and cardiovascular effects such as systemic hypertension, angina, myocardial infarction, and stroke. It has been recently recognized that increased pharyngeal resistance with incomplete obstruction can lead to a constellation of symptoms identical to OSA called "upper airway resistance syndrome" (UARS). The typical findings of UARS on sleep study are: (1) repetitive arousals from EEG sleep coinciding with a (2) waxing and waning of the respiratory airflow pattern and (3) increased respiratory effort as measured by esophageal pressure monitoring. There may be few, if any, obvious apneas or hypopneas with desaturation, but snoring may be a very prominent finding. Treatment with nasal positive airway pressure (NCPAP) eliminates the symptoms and confirms the diagnosis. Herein we describe two typical cases of UARS.

Adult↗
PubMed1997

Vitamin A deficiency among adolescent female garment factory workers in Bangladesh.

OBJECTIVE: To investigate the prevalence of vitamin A deficiency among adolescent female factory workers in Bangladesh, and examine the association between various factors and vitamin A status. DESIGN: A cross-sectional study. SETTING: Garment factories in Dhaka city, Bangladesh. SUBJECTS: Three hundred and eighty eight adolescent girls aged 12-19 y from ten garment factories were selected randomly for the present study. Information on socio-economic conditions and usual pattern of dietary intake were obtained by interview. Anthropometric data and blood samples were collected following the interview. RESULTS: By NCHS reference standard, 15.5% of the participants were thin (< 90% Wt/Ht) and about 7% overweight (> 120% Wt/Ht). In about 56%, serum vitamin A level was below the adequate level of 1.05 mumol/l, with 14% having vitamin A deficiency (< 0.70 mumol/l). Forty four per cent of the participants were found to be anaemic (haemoglobin < 120 g/l). Food frequency data on vitamin A rich foods revealed that a large percentage of the participants do not take eggs (41%), milk (64%), liver (85%) and sweet pumpkin (85%); while about 40% of the girls take dark green leafy vegetables (DGLV) and 17% take small fish at least four servings a week. The girls who consumed four or more servings per week of DGLV had significantly higher serum vitamin A level than the girls who took three servings or less. There was a significant positive association between the level of serum vitamin A and frequency of intake of DGLV (r = 0.12; P = 0.023). When age, level of education, percapita income, haemoglobin concentration, serum protein concentration, menstruation at the time of blood collection, prevalence of current morbidity, frequency of intake of egg, milk, small fish, DGLV, liver and sweet pumpkin were accounted for by multiple regression analysis, a strong relationship was found for serum vitamin A concentration with age, menstruation, haemoglobin level and frequency of intake of DGLV. For every unit change in the frequency of consumption of DGLV, there was 0.013 mumol/l change in serum vitamin A level whilst taking other factors into account. CONCLUSION: The data show that there is a high prevalence of subclinical vitamin A deficiency among the adolescent female garment factory workers in Bangladesh, although the anthropometric indices suggest that they do not suffer from acute under nutrition. Consumption of DGLV appears to have an important relation with the vitamin A status of these girls.

Adolescent↗
PubMed1997

Lithium treatment of conduct disorders in adolescents.

OBJECTIVE: The authors examined the efficacy of lithium carbonate for treating conduct disorder in adolescents. METHOD: The subjects were 33 inpatients aged 12-17 years. Lithium or placebo was administered in a double-blind fashion for 2 weeks. RESULTS: On several measures of clinical change the groups showed no significant differences. Of the patients who completed the study, 8.3% of those receiving placebo (one of 12) versus 21.4% (three of 14) of those receiving lithium were considered responders. CONCLUSIONS: Lithium does not appear beneficial for this indication.

Adolescent↗
PubMed1995

Construction of lacIts and lacIqts expression plasmids and evaluation of the thermosensitive lac repressor.

To characterize a thermosensitive lacIts mutant isolated by Bukrinsky et al. [Gene 70 (1989) 415-417] and to adapt it as a convenient control element, we have (i) mapped the mutation to the inducer-binding domain of the LacIts repressor, (ii) determined that the mutation resulted in the loss of a HaeIII site in lacIts due to a G-->A transition, leading to a Gly187-->Ser substitution, (iii) removed extraneous lacZop DNA downstream of lacI, and (iv) cloned lacIts (in plasmids based on ori of either ColE1 or P15A) under control of the wild-type or lacIq promoters. The LacIts repressor is insensitive to IPTG. The repression of lacZop by LacIts is very efficient at 30 degrees C and total induction was achieved at 42 degrees C, providing that the LacIts concentrations are not excessive and that repressor-to-operator ratios are not too high.

Amino Acid Sequence↗
PubMed1995

Chronic copper intoxication due to ingestion of coins: a report of an unusual case.

We report an unusual case of acute copper intoxication in a patient who died after swallowing more than 700 coins mainly of 1p and 2p denomination. At autopsy the liver showed fibrosis and extensive copper deposition was demonstrated in the histological sections. Electron probe microanalysis also confirmed the presence of copper in the hepatic tissue.

Copper↗
PubMed1994

Escherichia coli genome targeting, I. Cre-lox-mediated in vitro generation of ori- plasmids and their in vivo chromosomal integration and retrieval.

We have constructed a plasmid system designed for the insertion of cloned DNA (e.g., genes, gene fusions, regulatory elements, etc.) into the Escherichia coli genome. Its principal feature is the presence of two tandem lox sites on the plasmids, which upon Cre-mediated in vitro recombination resolve the plasmids into ori- and ori+ DNA circles. The non-replicating ori- circles contain the lambda attP site, several unique restriction sites for cloning, a NotI site and KmR, a kanamycin-resistance-encoding gene. The ori+ circles carry the origin of DNA replication (ori) together with several cleavage sites not present in the ori- circles, including the rare site for the very efficient I-SceI enzyme, that are used to inactivate the ori+ circles and any unresolved plasmid DNA. We have used this system to insert cloned DNA into the host genome at (i) the attB site, by Int-mediated integration and (ii) at any predetermined sequence, as mediated by the Rec system(s) of the host. The genomes of the resulting transformants were analyzed by NotI digestion of the chromosomal DNA, embedded in agarose microbeads, followed by pulsed-field gel electrophoresis. A system for the retrieval of DNA fragments inserted at the attB site was also developed.

Base Sequence↗
PubMed1994

In vivo excision and amplification of large segments of the Escherichia coli genome.

In vivo excision and amplification of large segments of a genome offer an alternative to heterologous DNA cloning. By obtaining predetermined fragments of the chromosome directly from the original organism, the problems of clone stability and clone identification are alleviated. This approach involves the insertion of two recognition sequences for a site-specific recombinase into the genome at predetermined sites, 50-100 kb apart. The integration of these sequences, together with a conditional replication origin (ori), is targeted by homologous recombination. The strain carrying the insertions is stably maintained until, upon induction of specifically engineered genes, the host cell expresses the site-specific recombinase and an ori-specific replication protein. The recombinase then excises and circularizes the genomic segment flanked by the two insertions. This excised DNA, which contains ori, is amplified with the aid of the replication protein and can be isolated as a large plasmid. The feasibility of such an approach is demonstrated here for E. coli. Using the yeast FLP/FRT site-specific recombination system and the pi/gamma-ori replication initiation of plasmid R6K, we have devised a procedure that should allow the isolation of virtually any segment of the E. coli genome. This was shown by excising, amplifying and isolating the 51-kb lacZ--phoB and the 110-kb dapX--dsdC region of the E. coli MG1655 genome.

Antiporters↗
PubMed1994

Respiratory obstruction caused by lipoma of the esophagus.

A four-year-old boy presented with wheezing of 5 months' duration after a cold. During examination, an opacity was noted in the superior mediastinum, causing displacement of the trachea to the right. A barium swallow showed a mass in the wall of the esophagus, occupying the lumen, without causing any obstruction. Through further examination by computed tomography and magnetic resonance imaging, the mass was confirmed to be a lipoma in the wall of esophagus, causing displacement of trachea. The mass was removed via the transcervical approach, and the postoperative course was uneventful. Respiratory obstruction caused by a lipoma of esophagus in childhood had not been reported in the English language literature.

Child, Preschool↗